Papers - Koike, Yasuhiro

Graded-index plastic optical fiber for needle-sized lens and rigid endoscope

Yamashita H., Koike I., Nakamura M., Koike Y.

Proceedings of SPIE - The International Society for Optical Engineering 13389 2025

ISSN  0277786X

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We have been developing a graded-index plastic optical fiber (GI-POF) for a needle-sized lens and a rigid endoscope. With highly accurate control of refractive index within a plastic lens, we can utilize it for an ultra-fine lens as a replacement for a relay lens or fiber-bundled lens in conventional rigid endoscopes. The 0.5-mm diameter lens performs high resolution with about 200-line pairs/mm. For endoscope imaging, we used optical and digital correction of chromatic aberration caused by material properties of GI-POF lens. The rigid endoscope with the GI-POF lens has a possibility to allow doctors to directly observe a patient's inner affected area before and after surgery in a minimally invasive procedure, enabling rapid and accurate assessment of the patient's condition and efficient post-operative followup.

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Randomizing polarization of displays for fundamental improvement of color mura caused by birefringence

Sasaki S., Koike Y.

Optics Letters 49 ( 22 ) 6501 - 6504 2024.11

ISSN  01469592

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Most existing displays utilize polarization technologies to produce images and improve image quality. However, polarized light from displays causes color mura because of the birefringence of the polymer films used. Thus, eliminating color degradation remains a challenge despite the incorporation of complex polarization technologies such as retardation films. Our proposed random depolarization film (RDF) addresses this issue by randomizing the polarization of light from displays. Chromaticity measurements demonstrate that the RDF effectively compensates for color mura due to low-cost polymer films. Notably, the RDF compensation mechanism is independent of the RDF position and light source spectrum. Therefore, the RDF could be an innovative solution for color degradation in existing displays.

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Random depolarization film design based on modulation transfer function measurements of displays with different pixel pitches

Sasaki S., Masaoka K., Koike Y.

Applied Optics 63 ( 11 ) 2900 - 2905 2024.04

ISSN  1559128X

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Polarized light emitted frommost displays causes blackout and color change problems when viewed through polarized sunglasses. These problems are addressed by random depolarization films (RDFs) doped with birefringent particles. These dopant particles, however, scatter light and degrade the sharpness of the displayed images.To maintain the image sharpness, we designed an RDF based on modulation transfer function measurements of displays with different pixel pitches. RDFs doped with larger particles achieved higher modulations; however, particles larger than a specific size caused undesirable sparkles on the displayed image. A display with a larger pixel pitch achieved higher modulations, suggesting that the RDF is particularly suitable for large-screen displays.

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Stabilized Plastic Optical Fiber Link Even Without a Physical-Contact Fiber Connection

Muramoto K., Minami H., Koike Y.

Journal of Lightwave Technology 42 ( 2 ) 875 - 881 2024.01

ISSN  07338724

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We propose a novel graded-index plastic optical fiber (GI POF) link that enables stable high-speed data transmission without the requirement for conventional coupling techniques to reduce reflection at fiber connection, as typified by physical-contact (PC) fiber connection, for short-reach multimode fiber (MMF) applications with vertical-cavity surface-emitting lasers (VCSELs). In the novel GI POF link, noise caused by light reflected at the fiber connection back into a VCSEL cavity can be suppressed through strong mode coupling in the fiber. It thereby improves the bit error rate of the data transmission compared with conventional silica and polymer MMFs. The capability of the novel GI POF link will be advantageous for optical interconnects in household and automotive applications, in which PC connection is not ideal to apply. The novel GI POF link will also be invaluable for multi-fiber interconnects based on multi-fiber connectors for data center applications, in which complete PC connections are difficult to obtain.

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Proposal of Novel Random Depolarization Film for Real-Color Displays with Sharp Images

Sasaki S., Koike Y.

Digest of Technical Papers - SID International Symposium 55 ( 1 ) 425 - 428 2024

ISSN  0097966X

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The random depolarization film (RDF), a polymer film doped with birefringent particles, converts linearly polarized light to randomly polarized light. This paper shows that a novel RDF with controlled birefringence resolves polarization problems of the display such as blackout, color change, and color mura problems. Furthermore, the novel RDF achieved a higher contrast ratio and a sharper image than a conventional RDF doped with calcite particles.

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Proposal of Error-Free GI POF for beyond 5G Society

Koike Y., Muramoto K.

16th Pacific Rim Conference on Lasers and Electro-Optics, CLEO-PR 2024  2024

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We propose Error-free plastic optical fiber for 53.125 Gb/s PAM4 transmission without the need for forward error correction, contributing to energy saving and lower latency in high-speed interconnects, especially for data centers and high-performance computing.

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Design of Random Depolarization Films Based on Modulation Transfer Function Measurements

Sasaki S., Masaoka K., Koike Y.

Digest of Technical Papers - SID International Symposium 54 ( 1 ) 547 - 550 2023

ISSN  0097966X

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The random depolarization film (RDF), a polymer film doped with birefringent microparticles, solves polarization problems of displays. To design the RDF that realizes sharper images, the optimal dopant particle size and suitable display’s pixel size were investigated based on modulation transfer function (MTF) measurements. The MTFs indicated that the dopant particle size of the RDF and the pixel size of the display should be larger to prevent the sharpness degradation.

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Random depolarization film design for real-color displays

Sasaki S., Udono M., Koike Y.

Applied Optics (Applied Optics)  61 ( 3 ) 669 - 675 2022.01

ISSN  1559128X

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Liquid crystal displays and organic light-emitting diode displays emit polarized light through polarizers and quarter-wave plates, which cause blackout and color change problems when the displays are viewed through polarizers, such as polarized sunglasses. Random depolarization films (RDFs) are polymer films doped with calcite particles, which randomize the polarization of light emitted from displays to resolve polarization problems. To realize displays without any color change, we investigate the retardation values and fabrication conditions required for RDFs. Analysis of the transmittance spectra and interference colors of different RDFs suggested that retardation values of approximately 600–1200 nm are sufficient to realize real-color displays. In addition, the color change measurements of displays with the RDFs revealed that an optimal dopant particle size exists and that the RDFs doped with 3.6 and 7.3 µm calcite particles achieved chromaticity changes of less than 0.02 for all 24 colors in the Macbeth chart.

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Improvement of Color Mura by Using a Triple-Zero-Birefringence Polymer Film

Sasaki S., Koike Y.

Proceedings of the International Display Workshops 29   332 - 335 2022

ISSN  18832490

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This study proposes triple-zero-birefringence polymer (TZBP) to prevent color mura due to birefringence of polymer films used in displays. Chromaticity measurements of the display clarified the advantage of the TZBP film to prevent the color mura and reproduce an actual color of the displays.

Error-free PAM-4 transmission by a high-speed plastic optical fiber without forward error correction

Koike Y., Muramoto K.

Optics Letters (Optics Letters)  46 ( 15 ) 3709 - 3712 2021.08

ISSN  01469592

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This Letter reports, to the best of our knowledge, the first study in which error-free four-level pulse-amplitude modulation (PAM-4) transmission has been achieved using a graded-index plastic optical fiber (GI POF) without the use of forward error correction (FEC) techniques, at a high data rate (>50 Gb/s), for short-reach applications (10 m). The GI POF that is developed has the characteristic microscopic heterogeneities in the fiber core material, which provide distinct mode coupling and significantly stabilize PAM-4 data transmission. The results of the study in this Letter indicate that the GI POF achieves highly stable PAM-4 transmission without the need for the current FEC techniques, which seriously increase the communication delay and power consumption of the transmission systems. Our GI POF material is paving the way for “material changes the system” approaches for achieving unprecedented optical interconnects in real time at a high speed and with low power consumption.

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Real-color displays realized by randomized polarization

Sasaki S., Udono M., Koike Y.

Applied Optics (Applied Optics)  60 ( 11 ) 3108 - 3113 2021.04

ISSN  1559128X

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This study achieves real-color displays using a randomizing effect based on the concept of "natural light."At present, most displays emit linearly polarized light, which causes essential blackout and color degradation problems when the displays are viewed through polarizers such as sunglasses. To address this, complex polarization-control technologies are added to existing displays, but the problems remain unresolved. In contrast, this study randomizes the polarization using a polymer film called a random depolarization film (RDF) that is doped with specific birefringent crystal particles. The RDF placed on a display reproduces colors that are very close to the natural colors seen in reality without the need for complex polarization technologies.We believe that it has the potential to change the approach to color-reproducing technology for displays.

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Proposal of novel temperature-independent Zero–Zero-birefringence polymer with high heat-resistance

Watanabe K., Kobayashi Y., Koike Y.

IEICE Transactions on Electronics (IEICE Transactions on Electronics)  E104C ( 2 ) 59 - 63 2021.02

ISSN  09168524

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Copyright © 2021 The Institute of Electronics, Information and Communication Engineers. Temperature-independent zero–zero-birefringence polymer (TIZZBP), which exhibits very small birefringence over the wide temperature range, is required to realize real-color images for displays, particularly vehicle-mounted displays. Previously, a TIZZBP was synthesized, but they did not put into practical use because of their too complex composition and low mechanical strength. In this paper, we propose a practical TIZZBP that has high heat resistance, high transparency and sufficient mechanical strength, using a simple binary copolymerization system. Our proposed novel polymer exhibits very low photoelastic birefringence and very low orientational birefringence. Both types of birefringence of this TIZZBP satisfy the negligible levels for displays, which are defined as follows: the absolute values of photoelastic coefficient and intrinsic birefringence are less than 1 ×10−12 Pa−1 and 1 ×10−3, respectively. In addition, temperature dependency of orientational birefringence was very low. Orientational birefringence satisfies the negligible level all over the temperature range from around −40◦C to 85◦C. This temperature range is important because it is the operational temperature range for vehicle-mounted display. Furthermore, our proposed novel TIZZBP showed high heat resistance, high transparency and sufficient mechanical strength. The glass transition temperature was 194◦C. The total light transmittance and the haze value is more than 91% and less than 1%, respectively. The tensile strength of non-oriented films was 35 ∼ 50 MPa. These results suggest our proposed novel TIZZBP has high practicality in addition to very low birefringence. Therefore, this TIZZBP film will be very useful for various displays including vehicle-mounted displays and flexible displays.

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Design of random depolarization film with random retardation for real-color displays

Sasaki S., Udono M., Koike Y.

Digest of Technical Papers - SID International Symposium (Digest of Technical Papers - SID International Symposium)  52 ( 1 ) 1283 - 1286 2021

ISSN  0097966X

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Our proposal, the random depolarization film (RDF) is highly efficient in preventing color change problem of LCD and OLED displays. We designed the RDF that realizes real-color displays by considering the retardation. The RDF with random retardation above 600 nm achieved much lower color change that human eyes cannot recognize.

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Random Depolarization Film Doped with Calcite Microparticles for Clear Real-Color Displays

Sasaki S., Udono M., Koike Y.

26th Microoptics Conference, MOC 2021 (26th Microoptics Conference, MOC 2021)   2021

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Random depolarization film, a polymer film doped with birefringent particles, can resolve blackout and color change problems of existing displays. This study optimized the dopant particle size with respect to image sharpness and color change of the display. Calcite microparticles improved the sharpness and color change, and realized real-color displays.

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Low-Noise Graded-Index Plastic Optical Fiber Achieved by Specific Copolymerization Process

Akashi T., Inoue A., Koike Y.

Journal of Lightwave Technology (Journal of Lightwave Technology)  39 ( 11 ) 3553 - 3559 2021

ISSN  07338724

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Ultra-high-definition (UHD) technologies have recently received attention on account of their practical applications in consumer electronics. UHD devices require uncompressed video transmission at a data rate exceeding 100 Gb/s; thus, an optical fiber connection is essential. In consumer applications, optical fibers are very short. Moreover, their connections must permit variations in the fiber alignment, which accommodates rough handling by consumers. Under this condition, the transmitted signal quality is significantly degraded owing to noise and instabilities that strongly depend on the fiber alignment conditions in optical modules and connectors. Therefore, graded-index plastic optical fibers (GI POFs) are promising optical cables for consumer applications because of their flexibility, safety, and high bandwidth. Recently, the authors experimentally demonstrated that GI POFs can reduce interferometric noise, such as modal noise and multipath interference noise, in a multimode fiber link based on a vertical-cavity surface-emitting laser (VCSEL). This noise reduction effect results from strong mode coupling of GI POFs, which is closely related to microscopic heterogeneous structures of a core polymer matrix. In this paper, a control method of mode coupling using the copolymerization process for fiber core materials is proposed. The formation of composition fluctuations by copolymerization increases the mode coupling in the GI POF core. It thereby enables highly stable and robust data transmission with a large fiber misalignment tolerance in a VCSEL-based multimode fiber link. The proposed method for mode coupling control is expected to contribute to household optical communication systems in the upcoming UHD era.

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Noise and Distortion Reduction in OFDM Radio-Over-Fiber Link by Graded-Index Plastic Optical Fiber

Muramoto K., Inoue A., Koike Y.

IEEE Photonics Technology Letters (IEEE Photonics Technology Letters)  32 ( 13 ) 835 - 838 2020.07

ISSN  10411135

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© 1989-2012 IEEE. We demonstrate that a graded-index plastic optical fiber (GI POF) enables higher-quality radio-over-fiber (RoF) transmission of an orthogonal frequency-division multiplexing (OFDM) signal, compared with a conventional multimode fiber, for short-distance household applications (< 100 m). It is shown that the improvement in OFDM signal transmission, using the GI POF, can be attributed to the reduction in noise and intermodulation distortion, owing to the external optical feedback from the transmission fibers. The low noise and low distortion in the signal transmission are mainly due to the strong mode coupling in the GI POF, which is closely related to the microscopic heterogeneous structures in core polymer materials. The developed GI POF will be invaluable for RoF networks in households as a solution for indoor broadband wireless communications in the upcoming 5G era.

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Low-noise radio over graded-index plastic optical fiber

Inoue A., Koike Y.

Optics Letters (Optics Letters)  45 ( 12 ) 3192 - 3195 2020.06

ISSN  01469592

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© 2020 Optical Society of America We developed a graded-index plastic optical fiber (GI POF) that enables lower-noise radio frequency (RF) transmission than conventional multimode fibers for short-distance household applications (<100 m). It is shown that reflection noise degrades RF transmission, regardless of the carrier frequency, through the spurious generation that accompanies the RF modulation of a vertical-cavity surface-emitting laser. The GI POF with distinctive mode coupling, which is closely related to its microscopic polymer structure, suppresses noise and spurious generation to improve transmission quality. Our low-noise radio-over-GI-POF technology will offer significant advantages for optical wiring systems for broadcast and communication in small- and medium-scale buildings.

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Reflowable optical connector with glass-ceramic ferrule for advanced pluggable transceiver packaging

Shikama K., Koike Y.

Optical Fiber Technology (Optical Fiber Technology)  54 2020.01

ISSN  10685200

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© 2019 Elsevier Inc. We describe a new physical-contact optical fiber connector/receptacle that can withstand a solder-reflow process with a maximum temperature of 260 °C for advanced pluggable transceiver packaging such as the co-packaging of photonic and electronic chips using the reflow process. We experimentally clarify the problems that occur in the conventional simplex optical connector through the reflow process while discussing the glass-transition behavior of the adhesive used in the connector. We then present an improved receptacle structure with glass-based ferrules whose coefficients of thermal expansion are closer to that of the fiber compared to the conventional zirconia ferrule. We demonstrate through testing that our proposed receptacle results in a dramatic decrease of permanent fiber withdrawals after the reflow process. The proposed connector, which is composed of a glass-ceramic ferrule, a polyimide tube, and a mechanical clip, achieved physical-contact connection and maintained satisfactory connection and return losses of below 0.3 dB and over 45 dB, respectively, even after six reflow processes. We examined the withdrawal behaviors for both the zirconia and the glass-ceramic ferrules during reflow based on the online measurement of connection and return losses, and observed the multiple reflections caused by the change in the air-gap width between the mated connectors. We also confirmed that the developed simplex optical connectors based on the glass-ceramic ferrule yielded sufficient environmental durability even after multiple reflow processes.

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Proposal of novel polymer materials with no birefringence over wide temperature range

Watanabe K., Yuma K., Koike Y.

Digest of Technical Papers - SID International Symposium (Digest of Technical Papers - SID International Symposium)  51 ( 1 ) 1600 - 1602 2020

ISSN  0097966X

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© 2020 SID. We propose two types of temperature-independent zero–zero-birefringence polymers (TIZZBPs), which have different Tgs of 194°C and 156°C. These TIZZBPs also exhibit sufficient mechanical strength and high transparency. These TIZZBPs will achieve real-color images not only for vehicle-mounted displays but also for flexible displays.

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Analysis of random depolarization films with birefringent micro particles for liquid-crystal and oled displays

Sasaki S., Udono M., Koike Y.

Digest of Technical Papers - SID International Symposium (Digest of Technical Papers - SID International Symposium)  51 ( 1 ) 1596 - 1599 2020

ISSN  0097966X

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© 2020 SID. Our proposal, the random depolarization film (RDF), prevents blackout and color change of the display image viewed through polarized sunglasses. We demonstrated that the RDF doped with micro-sized particles realized the real-color display without the blackout and the color change, and the clear display.

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A wide color gamut lcd with a polarized laser backlight

Komura S., Okuda K., Onoda K., Kijima H., Tagaya A., Kikutani T., Koike Y.

Digest of Technical Papers - SID International Symposium (Digest of Technical Papers - SID International Symposium)  51 ( 1 ) 5 - 8 2020

ISSN  0097966X

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© 2020 SID. We have developed a 17.3-inch 8K wide color gamut in-plane switching LCD (IPS-LCD) with a polarized laser backlight. By applying a zero–zero-birefringence polymer, the polarized laser backlight emits polarized light with 88% polarization. The IPS-LCD with the developed polarized laser backlight achieves a wide color gamut with high efficiency.

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Analysis of nano-creep deformation of epoxy adhesive in optical fiber connector for long-term reliability prediction

Shikama K., Aratake A., Koike Y.

Optical Fiber Technology (Optical Fiber Technology)  52 2019.11

ISSN  10685200

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© 2019 Elsevier Inc. We describe a comprehensive analysis of the nano-creep deformation of an epoxy adhesive used in physical-contact optical fiber connectors. To design a highly reliable multicore fiber connector and predict the long-term reliability of commercially installed optical connectors, we focus on the change in fiber withdrawal, which is a key parameter for achieving physical-contact connection. We also propose an adhesive creep model that includes long-term time dependence by detailing through a finite element analysis the parameters that influence the fiber withdrawal, such as shear stress with connection, thermal stress, residual stress, swelling, and cure shrinkage. The measurement results for fiber withdrawal under several environmental conditions provided in this paper support the behaviors considered in our proposed model. From our obtained short-term results and rheological approach, we predict the nano-creep deformation observed in the connector over the long term by applying the time-temperature superposition principle, and discuss the correspondence with exposure test results. Our verified mechanism and estimated values of creep deformation prove the high reliability of the optical connectors and also provide guidelines for determining the need to update installed connectors and for designing future connection devices such as physical-contact multicore fiber connectors.

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Nonlinear Distortion Reduction Effect of Graded-Index Plastic Optical Fiber

Muramoto K., Inoue A., Koike Y.

IEEE Photonics Technology Letters (IEEE Photonics Technology Letters)  31 ( 10 ) 791 - 794 2019.05

ISSN  10411135

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© 2019 IEEE. We experimentally demonstrate that a graded-index plastic optical fiber (GI POF) can significantly reduce transmitted signal distortion caused by the nonlinear response of a multimode fiber (MMF) link based on a vertical-cavity surface-emitting laser (VCSEL). The low distortion of the signal transmission is attributed to the strong mode coupling in the GI POF, which suppresses the increment in signal distortion due to the external optical feedback, by reducing the self-coupling of problematic back-reflected light into the VCSEL cavity. The strong mode coupling is closely associated with polymer-specific microscopic heterogeneous structures in the fiber core materials, suggesting that the signal distortion can be further reduced by controlling the microscopic properties. The nonlinear distortion reduction effect of our developed GI POF will be invaluable for next-generation MMF links based on multilevel modulation in the ultrahigh-definition era.

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Unconventional plastic optical fiber design for very short multimode fiber link

Inoue A., Koike Y.

Optics Express (Optics Express)  27 ( 9 ) 12061 - 12069 2019.04

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© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement We introduce a graded-index plastic optical fiber (GI POF) design for very short-distance household applications, in which the transmission quality is predominantly determined by system noise rather than the loss and bandwidth. The developed GI POF has strong mode coupling with low accompanying scattering loss, which is closely related to the specific microscopic heterogeneities in the core material. Such characteristic mode coupling significantly decreases reflection noise, improving the transmission quality compared with silica GI multimode fiber (MMF) for lengths below 30 m. Moreover, in the GI POF link, the transmission quality tends to improve with increasing fiber length, despite the increased loss and decreased bandwidth. This feature suggests that the system noise can be controlled by the microscopic heterogeneous properties of the GI POF for a very short MMF link, where the fiber loss and bandwidth are sufficiently low and high, respectively. This unconventional concept for optical-fiber design can advance fiber-optic communication in emerging applications in households located near optical network terminals.

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Low-Noise Radio over Plastic Optical Fiber for TV Broadcasting in Ultrahigh-Definition Era

Inoue A., Koike Y.

2019 Optical Fiber Communications Conference and Exhibition, OFC 2019 - Proceedings (2019 Optical Fiber Communications Conference and Exhibition, OFC 2019 - Proceedings)  Part F160-OFC 2019 2019.04

ISSN  9781943580538

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© 2019 OSA. We develop plastic optical fibers that significantly improve TV transmission qualities compared with conventional multimode fibers despite their higher attenuation. This improvement is attributed to mode coupling that is closely related to microscopic core-material properties.

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Intrinsically Stabilized Plastic Optical Fiber Link Subject to External Optical Feedback

Inoue A., Koike Y.

IEEE Photonics Journal (IEEE Photonics Journal)  11 ( 1 )  2019.02

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© 2009-2012 IEEE. We develop a graded-index plastic optical fiber (GI POF) that can significantly stabilize a multimode fiber (MMF) link with a vertical-cavity surface-emitting laser (VCSEL) subject to external optical feedback. It is demonstrated that the dominant mechanism for this stabilization effect is the strong mode coupling of the GI POF, which is closely related to the polymer-specific microscopic heterogeneities in the GI POF core material. Such mode coupling decreases correlation between the problematic reflected light field and VCSEL cavity field, increasing tolerance of the MMF link for external optical feedback. Our developed GI POF with specific microscopic heterogeneities prevents the external-optical-feedback-induced critical destabilization observed for silica GI MMFs. These results suggest that the stabilization effect can be controlled by microscopic properties regardless of the fiber attenuations and core refractive indices.

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Low-noise graded-index plastic optical fiber for significantly stable and robust data transmission

Inoue A., Koike Y.

Journal of Lightwave Technology (Journal of Lightwave Technology)  36 ( 24 ) 5887 - 5892 2018.12

ISSN  07338724

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© 1983-2012 IEEE. Internet traffic continues to grow with the increase of network-connected smartphones, tablets, televisions, and monitoring devices in the Internet-of-Things (IoT) era. This trend will be significantly accelerated by the introduction of ultrahigh-definition (UHD) imaging technologies in various applications, and existing optical networks including datacenter networks are under urgent development to accommodate this traffic. However, optical fibers have not been introduced into households located in optical network terminal areas, even though UHD device connections require decompressed high-volume data transmission at more than 100 Gb/s, where a multilevel modulation scheme is vital. In UHD applications, very short optical cables (typically less than several meters) are connected and disconnected by consumers in a manner similar to metal interface cables. Under such conditions, a data transmission quality is predominantly limited by noise and instability rather than bandwidth and loss. Here, we propose low-noise graded-index plastic optical fibers (GI POFs) that enable significantly stable and robust data transmission through strong mode coupling, whose mechanism is fundamentally different from that of silica optical fibers. The low-noise GI POF link eliminates the need for the precise fiber alignment, angled fiber facets, and optical isolators typically used in conventional links. Our proposed GI POF material paves the way for quick optical fiber connections for multilevel UHD video transmission, becoming the first 'capillaries of light' from optical network terminals in the IoT era.

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Development of Graded-Index Plastic Optical Fiber for Significantly Low-Noise Data Transmission

Inoue A., Koike Y.

European Conference on Optical Communication, ECOC (European Conference on Optical Communication, ECOC)  2018-September 2018.11

ISSN  9781538648629

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© 2018 IEEE. We develop plastic optical fibers (POFs) with microscopic material properties designed for stable data transmissions for ultrahigh-definition applications in households (<30m). In the POF link, transmission quality tends to be improved with increase in link length despite loss increase.

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Pump-Polarization Effects in Dye-Doped Polymer Optical Fibers

Asuncion Illarramendi M., Zubia J., Bikandi I., Ayesta I., Parola I., Aramburu I., Arrue J., Tagaya A., Koike Y.

Journal of Lightwave Technology (Journal of Lightwave Technology)  36 ( 18 ) 4090 - 4098 2018.09

ISSN  07338724

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© 1983-2012 IEEE. This paper presents a study on the influence of the polarization of the pump beam on the emission properties of dye-doped polymer optical fibers. The fiber samples, which are pumped transversely with linearly polarized light, are graded-index polymer optical fibers doped with rhodamine 6G. The variation of the intensity and angular distribution of the output emission are theoretically and experimentally analyzed as the polarization direction of the pump is changed. The analysis is carried out both in the regime of fluorescence and in the regime of amplified spontaneous emission. It is shown that a pump polarization perpendicular to the fiber symmetry axis yields not only higher emission efficiency but also narrower axial angular width. The effect of the polarization of the pump beam on the properties of the amplified spontaneous emission is also measured, including its threshold-like energy, relative efficiency, and optical gain. The results indicate that the pump polarization determines the light-emitting performance of dye-doped polymer optical fibers.

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Significantly robust data transmission by ballpoint-pen interconnect for graded-index plastic optical fiber

Kaseda Y., Inoue A., Koike Y.

Journal of Lightwave Technology (Journal of Lightwave Technology)  36 ( 18 ) 4167 - 4173 2018.09

ISSN  07338724

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© 1983-2012 IEEE. We have developed a novel optical interconnect for graded-index plastic optical fibers based on the use of ballpoint-pen connectors, where ball lenses are precisely mounted on fiber end faces by a simple and low-cost ballpoint-pen production technology. This report demonstrates that the ballpoint-pen interconnect allows us for significantly robust data transmission with sufficient misalignment tolerance and mating durability for consumer applications, where very short optical fibers are frequently connected and disconnected to the consumer electronics in a manner similar to metal cables. In the ballpoint-pen interconnect, power penalties are barely affected even by misalignments with a lateral offset of 50 μm or a connector separation of 1.0 mm, allowing for optical fiber connections without the requirements of precise alignment or high manufacturing accuracy. Moreover, it is suggested that modal noises due to dusts and scratches on fiber end-faces are generated for conventional butt-coupling based on physical contact in applications that require frequent connection and disconnection of optical fibers. This modal noise generation can be prevented using nonphysical contacts with the ballpoint-pen connectors. We achieve high-speed data transmission that is barely influenced by 2500 mating cycles. These results suggest that the ballpoint-pen interconnect allows us for consumer-friendly optical fiber connections without the requirement of any cleanings in a manner similar to electrical interconnect.

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Depolarization effect of graded-index plastic optical fiber with strong mode mixing

Suzuki H., Inoue A., Koike Y.

Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)  Part F98-BGPPM 2018 2018

ISSN  9781557528209

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© 2018 The Author(s). We demonstrate that propagating light through graded-index plastic optical fibers is significantly depolarized by intrinsic mode mixing because of microscopic core heterogeneities. This depolarization effect allows for stable optical link through reduction of interference-induced noises.

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Reflection noise characteristics in graded-index plastic optical fiber link based on ballpoint-pen interconnect

Yagi T., Inoue A., Koike Y.

Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)  Part F98-BGPPM 2018 2018

ISSN  9781557528209

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© 2018 The Author(s). We investigate the influence of reflection noises in graded-index plastic optical fiber link based on ballpoint-pen interconnect. The results suggest that the link quality tend to improve through reflection noises reduction despite system loss increase.

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Significant reduction of nonlinear signal distortion by graded-index plastic optical fiber with intrinsic strong mode mixing

Muramoto K., Inoue A., Koike Y.

Optics InfoBase Conference Papers (Optics InfoBase Conference Papers)  Part F111-SOF 2018 2018

ISSN  9781557528209

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© 2018 The Author(s). We demonstrate that novel graded-index plastic optical fibers significantly reduce nonlinear distortion of transmitted signals in optical links because of strong mode mixings caused by microscopic heterogeneities in polymers, enabling high-quality multilevel 4K/8K video transmission.

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Proposal of novel random polarization film with birefringent crystal for real-color displays

Udono M., Koike Y.

Proceedings of the International Display Workshops (Proceedings of the International Display Workshops)  2   467 - 469 2018

ISSN  9781510883918

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© 2018 International Display Workshops. All rights reserved. We proposed the novel film, random depolarization film, which is the polymer film doped with the birefringent crystal particles. With using this film, we succeeded to solve the "blackout problem " of displays and to achieve much lower chromaticity change with polarized sunglasses.

Optical Characterization of Doped Thermoplastic and Thermosetting Polymer-Optical-Fibers

I. Ayesta, M. A. Illarramendi, J. Arrue, I. Parola, F. Jiménez, J. Zubia, A. Tagaya and Y. Koike

Polymers Vo. 9 ( No. 3 ) Article No. 90 2017

Research paper (scientific journal), Joint Work, Accepted

High-Speed Graded-Index Plastic Optical Fibers and their Simple Interconnects for 4K/8K Video Transmission

A. Inoue and Y. Koike

Journal of Lightwave Technology Vol. 34 ( No. 6 ) 1551 - 1555 2016

Research paper (scientific journal), Joint Work, Accepted

Temperature-independent zero-birefringence polymer for liquid crystal displays

M. Shikanai, A. Tagaya, and Y. Koike

Applied Physics Letters Vol. 108 ( Issue 13 ) 131902-1 - 131902-4 2016

Research paper (scientific journal), Joint Work, Accepted

Gas Separation Membranes Prepared with Copolymers of Perfluoro(2-Methylene-4,5-Dimethyl-1,3-Dioxlane) and Chlorotrifluoroethylene

M. Fang, Y. Okamoto, Y. Koike. Z. He, and T. C. Merkel

Journal of Fluorine Chemistry Vol. 188   18 - 22 2016

Research paper (scientific journal), Joint Work, Accepted

Characterization of the Optical Gain in Doped Polymer Optical Fibres

I. Parola, M. A. Illarramendi, J. Arrue, I. Ayesta, F. Jiménez, J. Zubia, A. Tagaya, and Y. Koike

Journal of Luminescence Vol. 177   1 - 8 2016

Research paper (scientific journal), Joint Work, Accepted

Dependence of Brillouin Frequency Shift on Water Absorption Ratio in Polymer Optical Fibers

K. Minakawa, K. Koike, N. Hayashi, Y. Koike, Y. Mizuno and K. Nakamura

J. Appl. Phys. Vol. 119   223102 2016

Research paper (scientific journal), Joint Work, Accepted

Misalignment Tolerance of Pluggable Ballpoint-Pen Interconnect of Graded-Index Plastic Optical Fiber for 4K/8K UHD Display

A. Inoue and Y. Koike

IEICE TRANS. Electron. Vol. E99-C ( No. 11 ) 1271 - 1276 2016

Research paper (scientific journal), Joint Work, Accepted

Effects of Para-Fluorine Substituent of Polystyrene on Gradient-Index Fiber-Optic Properties

K. Koike, A. Suzuki, K. Makino, and Y. Koike

Optical Materials Vol. 39   143 - 147 2015

Research paper (scientific journal), Joint Work, Accepted

Structural Behavior Thin Glass Ionomer Laminates with Optimized Specific Strength and Stiffness

Y. Shitanoki, S. J. Bennison, and Y. Koike

Composite Structures Vol. 125   615 - 620 2015

Research paper (scientific journal), Joint Work, Accepted

Mechanisms of Orientational and Photoelastic Birefringence Generation of Methacrylates for the Design of Zero–Zero-Birefringence Polymers

H. Shafiee, S. Beppu, S. Iwasaki, A. Tagaya, and Y. Koike

Polymer Engineering & Science Vol. 55 ( Issue 6 ) 1330 - 1338 2015

Research paper (scientific journal), Joint Work, Accepted

Temperature Dependence of Brillouin Frequency Shift in Polymers Controlled by Plasticization Effect

K. Minakawa, K. Koike, Q. Du, N. Hayashi, Y. Koike, Y. Mizuno, and K. Nakamura

Journal of Applied Physics Vol. 117 ( Issue 14 ) 144505-1 - 144505-5 2015

Research paper (scientific journal), Joint Work, Accepted

ボールペン技術による家庭用高精細映像光伝送システム開発　―　安価で簡易な光接続を可能とするボールペン型光インターコネクトの提案　―

当麻 哲哉、瀧塚 博志、鳥飼 俊敬、鈴木 等、小木 哲朗、小池 康博

Synthesiology（シンセシオロジー） Vol. 7 ( No. 2 ) 118 - 128 2014.11

Research paper (scientific journal), Joint Work, Accepted

Evaluation of Modal Noise in Graded-Index Silica and Plastic Optical fiber links for Radio-Over-Multimode Fiber Systems

M. Matsuura, R. Furukawa, Y. Matsumoto, A. Inoue, and Y. Koike

Optics Express Vol. 22 ( No.6 ) 6562 - 6568 2014.03

Research paper (scientific journal), Joint Work, Accepted

Light Scattering of Ideal Random Copolymers in Bulk

K. Koike, Q. Du, S. Nishino, and Y. Koike

Polymer Vol. 55 ( No. 3 ) 878 - 885 2014.02

Research paper (scientific journal), Joint Work, Accepted

Design and Synthesis of Zero–Zero-Birefringence Polymers Using N-Methylmaleimide

S. Beppu, S. Iwasaki, F. Shafiee, A. Tagaya, and Y. Koike

Journal of Applied Polymer Science Vol. 131 ( No. 12 ) 40423-1 - 9 2014.01

Research paper (scientific journal), Joint Work, Accepted

New Perfluoro-Dioxolane-Based Membranes for Gas Separations

Y. Okamoto, H. Zhang, F. Mikes, Y. Koike, Z. He, and T. C. Merkel

Journal of Membrane Science Vol. 471   412 - 419 2014

Research paper (scientific journal), Joint Work, Accepted

Effect of Dopant Structure on the Refractive Index and Glass Transition Temperature of Polymeric Fiber-Optic Materials

K. Koike, H. Teng, Y. Koike, and Y. Okamoto

Polymers for Advanced Technologies Vol. 25 ( No. 2 ) 204 - 210 2014

Research paper (scientific journal), Joint Work, Accepted

New Insights into Dopant Design for Graded-Index Plastic Optical Fibers for Transmission at 850 nm

A. Sengupta, K. Koike, Y. Koike, and Y. Okamoto

Optical Materials Vol. 36 ( No.4 ) 782 - 786 2014

Research paper (scientific journal), Joint Work, Accepted

A Practical, Nondestructive Method to Determine the Shear Relaxation Modulus Behavior of Polymeric Interlayers for Laminated Glass

Y. Shitanoki, S. J. Bennison, and Y. Koike

Polymer Testing Vol. 37   59 - 67 2014

Research paper (scientific journal), Joint Work, Accepted

A Rational Strength Prediction Approach to the Design of Double-glass Photovoltaic Modules

Y. Shitanoki, S. J. Bennison, and Y. Koike

IEEE Journal of Photovoltaics Vol. 4 ( No. 4 ) 1071 - 1078 2014

Research paper (scientific journal), Joint Work, Accepted

Analytic Models of a Thin Glass-Polymer Laminate and Development of a Rational Engineering Design Methodology

Y. Shitanoki, S. J. Bennison, and Y. Koike

International Journal of Applied Mechanics Vol. 81 ( Issue 12 ) 121009-1 - 7 2014

Research paper (scientific journal), Joint Work, Accepted

Effect of Cladding-Layer Glass Transition Temperature on Thermal Resistance of Graded-Index Plastic Optical Fibers

H. Yoshida, R. Nakao, Y. Masabe, K. Koike, and Y. Koike

Polymer Journal Vol. 46   823 - 826 2014

Research paper (scientific journal), Joint Work, Accepted

A Highly Transparent and Thermally Stable Copolymer of 1-Adamantyl Methacrylate and Styrene

K. Koike, T. Araki, and Y. Koike

Polymer International Vol. 64 ( Issue 2 ) 188 - 195 2014

Research paper (scientific journal), Joint Work, Accepted

Investigation of optical and thermal properties of N-(alkyl-substituted) maleimides for designing of zero–zero-birefringence polymer

S. Beppu, H. Hotta, H. Shafiee, A. Tagaya, and Y. Koike

Polymer Vol. 54 ( Issue 4 ) 779 - 788 2014

Research paper (scientific journal), Joint Work, Accepted

Influence of Dielectric Fluctuation on Light-Scattering Properties of Random Copolymers in Bulk

K. Koike, T. Araki, and Y. Koike

Polymer Vol. 55 ( No. 11 ) 2697 - 2703 2014

Research paper (scientific journal), Joint Work, Accepted

Dependece of Brillouin Frequency Shift on Temperature in Poly(pentafluorostyrene)-Based Polymer Optical Fibers Estimated by Acoustic Velocity

K. Minakawa, K. Koike, N. Hayashi, Y. Koike, Y. Mizuno, and K. Nakamura

IEICE Electron. Express Vol. 11 ( No. 10 ) 1 - 7 2014

Research paper (scientific journal), Joint Work, Accepted

Reflection Noise Reduction Effect of Graded-Index Plastic Optical Fiber in Multimode Fiber Link

A. Inoue, R. Furukawa, M. Matsuura, and Y. Koike

Optics Letters Vol. 39 ( No. 12 ) 3662 - 3665 2014

Research paper (scientific journal), Joint Work, Accepted

High-Speed Optical Home Network Using Graded Index Plastic Optical Fibers for a Smart House

T. Toma, H. Asada, T. Ogi, and Y. Koike

Advances in Computer Science : an International Journal Vol. 2 ( Issue 5, No. 6 ) 141 - 149 2013.11

Joint Work, Accepted

Core stress Distribution of Phase Shifting Multimode Polymer Optical Fiber

R. Furukawa, M. Nagata, K. Mishima, M. Matsuura, A. Inoue, A. Tagaya, and Y. Koike

Applied Physics Letters Vol. 103 ( No. 21 ) 213301-1 - 4 2013.11

Research paper (scientific journal), Joint Work, Accepted

Synthesis and Characterization of Copolymers of Perfluoro(2-methylene-4,5-dimethyl-1,3-dioxolane) and Perfluoro(2-methylene-1,3-dioxolane)

K. Koike, F. Mikes, H. Zhang, Y. Koike, and Y. Okamoto

Journal of Fluorine Chemistry Vol. 156   198 - 202 2013.11

Joint Work, Accepted

Amplified Spontaneous Emission in Graded-Index Polymer Optical Fibers: Theory and Experiment

M. A. Illarramendi, J. Arrue, I. Ayesta, F. Jiménez, J. Zubia, I. Bikandi, A. Tagaya, and Y. Koike

Optics Express Vol. 21 ( No. 20 ) 24254 - 24266 2013.10

Joint Work, Accepted

遠隔診療における4K超高精細映像の有効性評価 －皮膚科診療への適用の可能性－

当麻哲哉、鈴木創史、戸倉一、稲葉義方、小木哲朗、小池康博

日本遠隔医療学会雑誌 Vol.9 ( 2 ) 66 - 73 2013.10

Joint Work, Accepted

Investigation of the physical properties of poly(ortho- and para-trifluoromethoxy styrenes)

A. Sengupta, Y. Koike, and Y. Okamoto

Macromolecular Chemistry and Physics Vol. 214 ( No. 15 ) 1734 - 1737 2013.07

Joint Work, Accepted

Efficient Group Delay Averaging in Graded-Index Plastic Optical Fiber with Microscopic Heterogeneous Core

A. Inoue, T. Sassa, R. Furukawa, K. Makino, A. Kondo, and Y. Koike

Optics Express Vol. 21 ( No. 14 ) 17379 - 17385 2013.06

Joint Work, Accepted

4 x 10 Gbit/s full-duplex optical link with compact optical sub-assemblies and thin GI 50/125 plastic optical fibre ribbon

N. Schlepple, M. Nishigaki, H. Uemura, H. Furuyama, Y. Sugizaki, H. Shibata, and Y. Koike

Electronics Letters Vol. 49 ( No. 13 ) 835 - 836 2013.06

Joint Work, Accepted

Thermal and Optical Properties of Highly Fluorinated Copolymers of Methacrylates

H. Teng, Z. Wan, Y. Koike, and Y. Okamoto

Polymers for Advanced Technologies Vol. 24 ( No. 5 ) 520 - 523 2013.05

Joint Work, Accepted

Fluorination Effects on Attenuation Spectra of Plastic Optical Fiber Core Materials

A. Takahashi, A. Inoue, T. Sassa, and Y. Koike

Optical Materials Express Vol. 3 ( Issue 5 ) 658 - 663 2013.04

Joint Work, Accepted

Low Loss and High Bandwidth Polystyrene-based Graded Index Polymer Optical Fiber

K. Makino, Y. Akimoto, K. Koike, A. Kondo, A. Inoue, and Y. Koike

Journal of Lightwave Technology Vol. 31 ( No. 14 ) 2407 - 2412 2013.03

Joint Work, Accepted

Multidimensional NMR Characterization of Perfluorinated Monomer and its Precursors

B. Zhang, L. Li, F. Mikes, Y. Koike, Y. Okamoto, and P. L. Rinaldi

Journal of Fluorine Chemistry 147   40 - 48 2013

Joint Work, Accepted

Design of Zero-Zero-Birefringence Polymers in Methacrylate Copolymer Systems Containing Trichloroethyl Methacrylate

'S. Iwasaki, Z. Sato, H. Shafiee, A. Tagaya, and Y. Koike'

Journal of Applied Polymer Science Vol. 130 ( No. 1 ) 138 - 144 2013

Research paper (scientific journal), Joint Work, Accepted

Improvement of the Physical Properties of Poly(Methyl Methacrylate) by Copolymerization with N-Pentafluorophenyl Maleimide; Zero-Orientational and Photoelastic Birefringence Polymers with High Glass Transition Temperatures

'A. Tagaya, L. Lou, Y. Ide, Y. Koike and Y. Okamoto'

Science China Chemistry 55 ( 5 ) 850-853 2012

Research paper (scientific journal), Joint Work, Accepted

Fabrication of High Glass Transition Temperature Graded-Index Plastic Optical Fiber: Part 1 - Material Preparation and Characterizations

'R. Nakao, A. Kondo, and Y. Koike'

Journal of Lightwave Technology 30 ( 2 ) 247-251 2012

Research paper (scientific journal), Joint Work, Accepted

Mechanism of Generation of Birefringence in Poly(Methyl Methacrylate/Styrene)

'T. Kojo, A. Tagaya, and Y. Koike'

Polymer Journal 44 ( 2 ) 167-173 2012

Research paper (scientific journal), Joint Work, Accepted

Compensation and Control of the Birefringence of Polymers for Photonics

'A. Tagaya, and Y. Koike'

Polymer Journal 44   306-314 2012

Research paper (scientific journal), Joint Work, Accepted

Copolymers of Methyl Methacrylate with N-Trifluorophenyl Maleimides:High Glass Transition Temperature and Low Birefringence Polymers

'L. Lou, A. Tagaya, Y. Ide, Y. Koike, and Y. Okamoto'

Journal of Polymer Science Part A: Polymer Chemistry Vol. 50 ( No. 17 ) 3530?3536 2012

Research paper (scientific journal), Joint Work, Accepted

Zero-Birefringence Pressure-Sensitive Adhesives

'H. Ito, S. Yanai, S. Oda, A. Tagaya, and Y. Koike'

AIP Advances Vol. 2 ( No. 2 ) 022142-1/5 2012

Research paper (scientific journal), Joint Work, Accepted

Intrinsic Transmission Bandwidths of Graded-Index Plastic Optical Fibers

'A. Inoue, T. Sassa, K. Makino, A. Kondo, and Y. Koike'

Optics Letters Vol. 37 ( No. 13 ) 2583-2585 2012

Research paper (scientific journal), Joint Work, Accepted

Low Loss Graded Index Polymer Optical Fiber with High Stability under Damp Heat Conditions

'K. Makino, T. Kado, A. Inoue, and Y. Koike'

Optics Express Vol. 20 ( No. 12 ) 12893-12898 2012

Research paper (scientific journal), Joint Work, Accepted

Design and synthesis of zero-zero-birefringence polymers in a quaternary copolymerization system

'S. Iwasaki, Z. Sato, H. Shafiee, A. Tagaya, and Y. Koike'

Polymer Vol. 53   3287-3296 2012

Research paper (scientific journal), Joint Work, Accepted

A Polarized Laser Backlight Using a Zero-Zero-Birefringence Polymer for Liquid Crystal Displays

'T. Kurashima, K. Sakuma, T. Arai, A. Tagaya, and Y. Koike'

Optical Review Vol. 19 ( No. 6 ) 415-418 2012

Research paper (scientific journal), Joint Work, Accepted

4 x 10 Gb/s High-Speed Link Over Thin GI 50/125 Plastic Optical Fibers and Compact Optical Sub-Assembly

'N. Schlepple, M. Nishigaki, H. Uemura, K. Obara, H. Furuyama, Y. Sugizaki, H. Shibata, and Y. Koike'

IEEE Photonics Technology Letters Vol. 24 ( No.19 ) 1670-1672 2012

Research paper (scientific journal), Joint Work, Accepted

Optoelectronic High-Speed HDMI Cable with Compact Optical Sub-Assembly and 4 x 3.4 Gbit/s Plastic Optical Fibre Link

'N. Schlepple, M. Nishigaki, H. Uemura, H. Furuyama, K. Obara, H. Furuyama, Y. Sugizaki, H. Shibata, and Y. Koike'

Electronics Letters Vol.48 ( No.25 ) 1611-1613 2012

Research paper (scientific journal), Joint Work, Accepted

Alternating Copolymers of Hexafluoroisobutylene with Vinyl Trifluoroacetate and Vinyl Pentafluorobenzoate

'F. Mikes, H. Teng, Y. Koike, and Y. Okamoto'

Journal of Polymer Science Part A: Polymer Chemistry Vol. 50 ( No.22 ) 4717-4720 2012

Research paper (scientific journal), Joint Work, Accepted

Fabrication of High Glass Transition Temperature Graded-Index Plastic Optical Fiber: Part 2 - Fiber Fabrication and Characterizations

'R. Nakao, A. Kondo, and Y. Koike'

Journal of Lightwave Technology 30 ( 7 ) 969-973 2012

Research paper (scientific journal), Joint Work, Accepted

Poly(styrene)-Based Graded-Index Plastic Optical Fiber for Home Networks

'Y. Akimoto, M. Asai, K. Koike, K. Makino, and Y. Koike'

Optics Letters 37 ( 11 ) 1853-1855 2012

Research paper (scientific journal), Joint Work, Accepted

Optimization of the Refractive-Index Distribution of Graded-Index Polymer Optical Fiber by the Diffusion-Assisted Fabrication Process

'Y. Mukawa, A. Kondo, and Y. Koike'

Applied Physics Express 5 ( 4 ) 042501-1/3 2012

Research paper (scientific journal), Joint Work, Accepted

プラスチック光ファイバによる高速ネットワーク

小池 康博、牧野建志

応用物理 (応用物理学会)  80 ( 12 ) 1029-1033 2011.12

Research paper (scientific journal), Joint Work

「ゼロ・ゼロ複屈折ポリマー」を用いた偏光レーザー・バックライト

倉島 高広、荒井 孝之、多加谷 明広、小池 康博

ディスプレイ技術年鑑2012 (日経BP社)     50-54 2011.10

Research paper (scientific journal), Joint Work

プラスチック光ファイバー

小池 康博、近藤　篤志

日本接着学会誌 (The Adhesion Society of Japan)  47 ( 7 ) 290-293 2011.07

Research paper (scientific journal), Joint Work

フォトニクスポリマー概論

KOIKE YASUHIRO,TAGAYA AKIHIRO,KOIKE KOTARO

機能材料/特集　次世代フォトニクスポリマーへの期待 (（株）シーエムシー出版)  31 ( 4 ) 6-13 2011.04

Research paper (scientific journal), Single Work

特集にあたって

KOIKE YASUHIRO

「機能材料」特集　次世代フォトニクスポリマーへの期待 (（株）シーエムシー出版)  31 ( 4 ) 5 2011.04

Single Work

Synthesis and characterization of trifluoromethyl substituted styrene polymers and copolymers with methacrylates: Effects of trifluoromethyl substituent on styrene

H. Teng, L. Lou, K. Koike, Y. Koike, Y. Okamoto

polymer 52 ( 4 ) 949-953 2011.01

Research paper (scientific journal), Joint Work, Accepted

A Wide-Viewing-Angle Liquid-Crystal Display Using Front-Scattering Film and Directional Backlight

T. Saruta, A. Tagaya, and Y. Koike

Emerging Liquid Crystal Technologies VI 7955 2011

Research paper (international conference proceedings), Joint Work, Accepted

A High-Retardation Polymer Film for Viewing Liquid Crystal Displays through Polarized Sunglasses without Chromaticity Change in the Image

D. Kobayashi, A. Tagaya, and Y. Koike

Japanese Journal of Applied Physics 50 ( 4 ) 042602-1/6 2011

Research paper (scientific journal), Joint Work, Accepted

Effects of Rotation of Benzene Rings on Diffusion of Solvents in Polymer Melts

M. Asai, M. Awata, and Y. Koike

American Chemical Society Industrial & Engineering Chemistry Research 50 ( 6 ) 3280-3286 2011

Research paper (scientific journal), Joint Work, Accepted

Methodological Approach to Control Refractive Index Profile of Graded-Index Polymer Optical Fiber

M. Asai, Y. Mukawa, S. Takahashi, and Y. Koike

Industrial & Engineering Chemistry Research 50 ( 7 ) 3895-3899 2011

Research paper (scientific journal), Joint Work, Accepted

Novel Dopant for Graded-Index Polymer Optical Fiber with High-Thermal Stability

Y.Yamaki, M.Asai, S.Takahashi, and Y.Koike

Applied Physics Express 3 ( 7 ) 071601-1/3 2011

Research paper (scientific journal), Joint Work, Accepted

Control of the Birefringence Dispersion of an Optical Polymer by Doping with an Inorganic Crystal

H. Shafiee, K. Shikama, A. Tagaya, F. Hardinghaus, T. Miyaji, K. Köhler, and Y. Koike

Japanese Journal of Applied Physics 50 ( 3 ) 032602-1/6 2011

Research paper (scientific journal), Joint Work, Accepted

Design and Synthesis of a Zero-Photoelastic Birefringence Polymer with a High Glass-Transition Temperature by a Random Copolymerization Method

H. Shafiee, A. Tagaya, and Y. Koike

Polymer Journal 43   306-312 2011

Research paper (scientific journal), Joint Work, Accepted

High-bandwidth Graded-Index Plastic Optical Fiber with Low-Attenuation, High-Bending Ability, and High-Thermal Stability for Home-Networks

M. Asai, Y. Inuzuka, K. Koike, S. Takahashi, and Y. Koike

Jounal of Lightwave Technology 29 ( 11 ) 1620-1626 2011

Research paper (scientific journal), Joint Work, Accepted

Alternating Copolymerization of Bis(hexafluoroisopropyl) Fumarate with Styrene and Vinyl Pentafluorobenzoate:　Transparent and Low Refractive Index Polymers

H. Teng, W. Liu, Y. Koike, and Y. Okamoto

Journal of Polymer Science Part A: Polymer Chemistry 49 ( 13 ) 2834-2838 2011

Research paper (scientific journal), Joint Work, Accepted

A Novel Copolymer of Methyl Methacrylate with N-Pentafluorophenyl Maleimide:High Glass Transition Temperature and Highly Transparent Polymer

'ML. Lou, Y. Koike, and Y. Okamoto'

Polymer 52 ( 16 ) 3560-3564 2011

Research paper (scientific journal), Joint Work, Accepted

High-Thermally Stable and High-Bandwidth Graded Index Plastic Optical Fiber for Vehicle Networks

'M. Asai, Y. Yamaki, S. Takahashi, and Y.Koike'

Journal of Polymer Science Part B: Polymer Physics 49 ( 20 ) 1464-1469 2011

Research paper (scientific journal), Joint Work, Accepted

Common Origin of Dynamics Heterogeneity and Cooperatively Rearranging Region in Polymer Melts

'M. Asai, M. Shibayama, and Y. Koike'

Macromolecules 44 ( 16 ) 6615-6624 2011

Research paper (scientific journal), Joint Work, Accepted

Characterization and Properties of Semicrystalline and Amorphous Perfluoropolymer: poly(perfluoro-2-methylene-1,3-dioxolane)

'F. Mikes, J. Baldrian, H. Teng, Y. Koike, and Y. Okamoto'

Polymers for Advanced Technologies 22 ( 8 ) 1272-1277 2011

Research paper (scientific journal), Joint Work, Accepted

フォトニクスポリマーが拓くFace-to-Face コミュニケーション

KOIKE YASUHIRO

O Plus E「特集：フォトニクスポリマー」 (アドコム・メディア(株))  通 ( 373 ) 1437-1439 2010.12

Single Work

総論

KOIKE YASUHIRO

O Plus E「特集：フォトニクスポリマー」 (アドコム・メディア(株))  通 ( 第373 ) 1412-1415 2010.12

Single Work

Progress in Low-Loss and High-Bandwidth Plastic Optical Fibers

Y. Koike and K. Koike

Journal of Polymer Science Part B: Polymer Physics 49 ( 1 ) 2-17 2010.11

Research paper (scientific journal), Joint Work, Accepted

私にとってのファンダメンタルズ

KOIKE YASUHIRO

清陵サイエンスフォーラム２１～未来をひらく知の誘い～ (諏訪清陵高等学校)   2010.10

Single Work

高速・低損失プラスチック光ファイバーが開発されるまで/私の自慢

KOIKE YASUHIRO

化学と工業 63 ( 8 ) 648- 650 2010.08

Single Work

Mechanism of Generation of Photoelastic Birefringence in Methacrylate Polymers for Optical Devices

H. Shafiee, A. Tagaya, and Y. Koike

Journal of Polymer Science Part B; Polymer Physics 48 ( 19 ) 2029-2037 2010.06

Research paper (scientific journal), Joint Work, Accepted

プラスチック光ファイバー

KOIKE YASUHIRO

(社）ニューガラスフォーラム機関誌「NEW GLASS」  ( 93 )  2010.03

Single Work

フォトニクスポリマーの新展開

KOIKE YASUHIRO

高分子同友会勉強会 (高分子学会)   2010.01

Single Work

The Effect of Trans-Stilbene Unit in the Compensation of Birefringence of Poly(Methylmethacrylate) in the Random Copolymerization Method and Anisotropic Molecule Dopant Method

H. Shafiee, A. Tagaya, and Y. Koike

Organic Photonic Materials and Devices XII 7599 2010

Research paper (international conference proceedings), Joint Work, Accepted

Synthesis and Properties of Copolymers of Methyl Methacrylate with 2,3,4,5,6-Pentafluoro and 4-Trifluoromethyl 2,3,5,6-Tetrafluoro Styrenes: An Intrachain Interaction between Methyl Ester and Fluoro Aromatic Moieties

L. Lou, Y. Koike, Y. Okamoto

Journal of Polymer Science Part A: Polymer Chemistry 48 ( 22 ) 4938–4942 2010

Research paper (scientific journal), Joint Work, Accepted

Optical and thermal properties of methyl methacrylate and pentafluorophenyl methacrylate copolymer: Design of copolymers for low-loss optical fibers for gigabit in-home communications

K. Koike, T. Kado, Z. Satoh, Y. Okamoto, and Y, Koike

Polymer 51 ( 3 ) iss.6 , pp. 1377-1385 2010

Research paper (scientific journal), Joint Work, Accepted

Bandwidth Enhancement of Graded Index Plastic Optical Fiber by Control of Differential Mode Attenuation

T. Noda and Y. Koike

Optics Express 18 ( 3 ) 3128-3136 2010

Research paper (scientific journal), Joint Work, Accepted

Design of Zero-Birefringence Cross-Linked Polymers

S. Yamazaki, A. Tagaya, and Y. Koike

Applied Physics Express 3   022602-1 – 3 2010

Research paper (scientific journal), Joint Work, Accepted

最先端フォトニクスポリマー技術～人にもどるFace-to-Faceコミュニケーション～

KOIKE YASUHIRO

第3回　機能性分科会　講演会 (財）化学技術戦略推進機構（JCII）)   2009.12

Single Work

フォトニクス・イノベーションへの思い

KOIKE YASUHIRO

日本光学会機関誌「光学」 38 ( 12 ) 特集「有機光デバイス―導波素子から受発光素子まで」巻頭言 2009.12

Single Work

光学材料とファンダメンタルズ

KOIKE YASUHIRO

若手社員のための高分子基礎講座 (高分子学会)   2009.10

Single Work

高齢化社会を支えるFiber-To-The-Display ～近未来の遠隔地医療をめざして～

KOIKE YASUHIRO

中野区杉並区泌尿器科特別講演会　第1回「これからの泌尿器科を考える」  2009.05

Single Work

フォトニクスポリマー研究会　未来のコミュニケーションを目指して

KOIKE YASUHIRO

高分子（特集高分子学会研究会） 58 ( 5月 ) 317-318 2009.05

Single Work

High Retardation Polymer Films for Liquid Crystal Displays

KOIKE YASUHIRO、TAGAYA AKIHIRO

高分子学会　「高分子」  ( 4月 )  2009.04

Joint Work

Synthesis and Characterization of Perfluoro-3-methylene-2,4-dioxabicyclo[3,3,0] octane: Homo- and Copolymerization with Fluorovinyl Monomers

F. Mikes, H. Teng, G. Kostov, B. Ameduri, Y. Koike, and Y. Okamoto

Journal of Polymer Science Part A-Polymer Chemistry 47 ( 23 ) 6571 - 6578 2009

Research paper (scientific journal), Joint Work, Accepted

Design of Low-Loss Graded-Index Plastic Optical Fiber Based on Partially Fluorinated Methacrylate Polymer

K. Koike and Y. Koike

Journal of Lightwave Technology 27 ( 1 ) 41-46 2009

Research paper (scientific journal), Joint Work, Accepted

Compensation of Birefringence of Polymers for Photonics

A. Tagaya and Y. Koike

International Journal of Polymers and Technologies January-April 2009    23-33 2009

Research paper (scientific journal), Joint Work, Accepted

Differential Mode Analysis of a Polarization-Maintaining Graded-Index Plastic Optical Fiber Using Macrobending

R. Furukawa, A. Tagaya, and Y. Koike

Japanese Journal of Applied Physics 48 ( 2009 ) 022503-1/7 2009

Research paper (scientific journal), Single Work

Design, Synthesis, and Characterization of a Partially-Chlorinated Acrylic Copolymer for Low-Loss and Thermally-Stable Graded Index Plastic Optical Fibers

K. Koike, F. Mikes, Y. Okamoto, and Y. Koike

Journal of Polymer Science: Part A: Polymer Chemistry 47 ( 13 ) 3352-3361 2009

Research paper (scientific journal), Joint Work, Accepted

Application of Graded-Index for Astigmatism Reduction in Progressive Addition Lens

Y. Shitanoki, A. Tagaya, and Y. Koike

Appllied Physics Express 2 ( 3 ) 032401-1 – 032401-3 2009

Research paper (scientific journal), Joint Work, Accepted

Pressure measurement based on a multimode phase retarder plastic optical fiber

R. Furukawa, A. Tagaya, and Y. Koike

ACS Applied Materials & Interfaces 1 ( 3 ) 720-725 2009

Research paper (scientific journal), Joint Work, Accepted

Copolymer-Based progressive addition lens with graded index designed for astigmatism and distortion correction

Y. Shitanoki, A. Tagaya, and Y. Koike

ACS Applied Materials & Interfaces 1 ( 4 ) 907-912 2009

Research paper (scientific journal), Joint Work, Accepted

Design of Zero Zero-birefringence Polymers for Injection Molded Products with Low Birefringence

A. Tagaya, T. Harada, and Y. Koike

Seikei-Kakou 21 ( 7 ) 426-435 2009

Research paper (scientific journal), Joint Work, Accepted

The future of Plastic Optical Fiber

Y. Koike, and M. Asai

NPG Asia Materials １ ( 1 ) 22－28 2009

Research paper (scientific journal), Joint Work

Analysis of Scattering in Photonics Polymer Doped with Optically Anisotropic Cylinder Particles

Y. Kato, A. Tagaya, and Y. Koike

2009 IEEE/LEOS Winter Topicals Meeting Series (WTM 2009)    104 2009

Research paper (international conference proceedings), Joint Work, Accepted

Application of Polymer Graded-Index Materials for Aberration Correction of Progressive Addition Lenses

Y. Shitanoki, A. Tagaya, and Y. Koike

Organic Photonic Materials and Devices XI 7213 2009

Research paper (international conference proceedings), Joint Work, Accepted

Birefringence Analysis of a Photonics Polymer Doped with a Birefringent Crystal

Y. Yamada, A. Tagaya, and Y. Koike

Organic Photonic Materials and Devices XI 7213 2009

Research paper (international conference proceedings), Joint Work, Accepted

Dopant Designing for Thermally Stable Graded Index Plastic Optical Fiber

Y. Yamaki, A. Kondo, and Y. Koike

Organic Photonic Materials and Devices XI 7213 2009

Research paper (international conference proceedings), Joint Work, Accepted

Reduction of Orientational Birefringence of Polymer Using Nanoparticles

T. Otani, A. Tagaya, and Y. Koike

Organic Photonic Materials and Devices XI 7213 2009

Research paper (international conference proceedings), Joint Work, Accepted

Power Flow Equation Analysis of Graded-Index Polymer Optical Fibers

K. Nehashi and Y. Koike

Organic Photonic Materials and Devices XI 7213 2009

Research paper (international conference proceedings), Joint Work, Accepted

フォトニクスポリマーへの思い

KOIKE YASUHIRO

アドコム・メディアO Plus E 2009年 ( 1月号 ) 43-45 2008.12

Single Work

Graded Index Plastic Optical Fiber Prepared by the Co-extrusion Process

KONDO ATSUSHI、TAKAHASHI SATOSHI、KOIKE YASUHIRO

高分子  ( 12月 ) 962 2008.12

Joint Work

耐熱性GI型プラスチック光ファイバの実現を目指して　～家庭や自動車にギガの光を～

KOIKE KOTARO, KOIKE YASUHIRO

日本化学会　化学と工業 61 ( 12 ) 1154-1155 2008.12

Joint Work

ERATOとイノベーション

KOIKE YASUHIRO

文部科学省　「文部科学時報」 1595   24 2008.12

Single Work

最新 フォトニクスポリマー －特性を生かしてIT社会を支援-

TAGAYA AKIHIRO, KOIKE YASUHIRO

工業材料(日刊工業新聞社) 56 ( 4 ) 17-23 2008.04

Joint Work

高分子と光の相互作用

TAGAYA AKIHIRO,KOIKE YASUHIRO

プラスチック成形加工学会誌 20 ( 3 ) 74-79 2008.03

Joint Work

フォトニクスポリマー

KOIKE YASUHIRO、TAGAYA AKIHIRO

工業材料 56 ( 1 ) 70-71 2008.01

Joint Work

Synthesis of poly[1,1,1,3,3,3-hexafluoro-2-(pentafluorophenyl)propan-2-yl methacrylate]: Thermal and optical properties of the copolymers with methyl methacrylate

D. Zhou, Y. Koike, and Y. Okamoto

Journal of Fluorine Chemistry 129 ( 4 ) 248 - 252 2008

Joint Work, Accepted

Design and Synthesis of Graded Index Plastic Optical Fibers by Copolymeric System

KOIKE YASUHIRO

Polymers for Advanced Technologies 19   516-520 2008

Research paper (scientific journal), Single Work

Control of Refractive Index Distribution for High-Bandwidth Graded Index Plastic Optical Fiber

KOIKE YASUHIRO

Journal of Lightwave Technology 26 ( 16 ) 2909-2918 2008

Research paper (scientific journal), Single Work

Graded-Index Plastic Optical Fiber Prepared by the Coextrusion Process

KOIKE YASUHIRO

Applied Optics 47 ( 22 ) 4177–4185 2008

Research paper (scientific journal), Single Work

Polarization-Maintaining Mechanism of a Birefringence-Reduced Plastic Optical Fiber Fabricated Using Poly(methyl methacrylate/benzyl methacrylate) Copolymer

KOIKE YASUHIRO

The Journal of Physical Chemistry C 112 ( 21 ) 7946-7952 2008

Research paper (scientific journal), Single Work

Copolymers of Methyl Methacrylate and Fluoroalkyl Methacrylates: Effects of Fluoroalkyl Groups on the Thermal and Optical Properties of the Copolymers

KOIKE YASUHIRO

Journal of Polymer Science: Part A : Polymer Chemistry 46 ( 14 ) 4748-4755 2008

Research paper (scientific journal), Single Work

Modal Analysis of a Multimode Polarization-Maintaining Plastic Optical Fiber Fabricated Using Poly(methyl methacrylate/benzyl methacrylate) Copolymer

KOIKE YASUHIRO

Applied Physics Letters 93 ( 103303 )  2008

Research paper (scientific journal), Single Work

Microoptics and Photonics Polymer

KOIKE YASUHIRO

Japanese Journal of Applied Physics 47 ( 8 ) 6629-6634 2008

Research paper (scientific journal), Single Work, Accepted

High Glass Transition Temperatures of Poly(methyl methacrylate) Prepared by Free Radical Initiators

H. Teng, K. Koike, D. Zhou, Z. Satoh, Y. Koike, and Y. Okamoto

Journal of Polymer Science: Part A: Polymer Chemistry 47   315-317 2008

Research paper (scientific journal), Joint Work, Accepted

Noise Reduction for Fiber Optic NTSC Signal Transmission

R. Furukawa, K. Uehara, S. Takahashi, N. Ohtsu, and Y. Koike

Integrated Optics: Devices, Materials, and Technologies XII 6896   T8960 2008

Research paper (international conference proceedings), Joint Work, Accepted

フォトニクスポリマーの基礎と新展開

KOIKE YASUHIRO

日本学術会議　学術の動向 12 ( 22 ) 66-67 2007.12

Single Work

私にとってのファンダメンタルズ

KOIKE YASUHIRO

高分子学会若手社員のための基礎講座  2007.10

Single Work

フォトニクスポリマーの基礎と新展開

KOIKE YASUHIRO

東京大学物性研究所談話会  2007.10

Single Work

High-performance Polymer Optical Fiber

TKAHASHI SATOSHI、KOIKE YASUHIRO

New Breeze 19 ( 3 ) 18-19 2007.07

Joint Work

Zero Zero Birefringence Polymer

KOIKE YASUHIRO

高分子  ( 7月 ) 485 2007.07

Single Work

プラスチック光ファイバの最新動向

KOIKE YASUHIRO

光技術コンタクト 45 ( 4月 ) 29-32 2007.04

Single Work

液晶ディスプレイのためのフォトニクスポリマー

KOIKE YASUHIRO

第16回光反応・電子用材料研究会講座  2007.01

Joint Work

ディスプレイのためのフォトニクスポリマー

KOIKE YASUHIRO

KAST教育講座  2007.01

Joint Work

ゼロ・ゼロ複屈折性ポリマー

KOIKE YASUHIRO、TAGAYA AKIHIRO

日本液晶学会誌「液晶」 11 ( 1 ) 6-15 2007.01

Joint Work

Preparation of Nanocomposite for Optical Application Using ZnTe Nanoparticles and a Zero-Birefringence Polymer

C. Inui, H. Kura, T. Sato, Y. Tsuge, S. Shiratori, H. Ohkita, A. Tagaya, and Y. Koike

Journal of Materials Science 42 ( 19 ) 8144-8149 2007

Research paper (scientific journal), Joint Work, Accepted

High-Bandwidth PVDF-Clad GI POF With Ultra-Low Bending Loss

KOIKE YASUHIRO

Journal of Lightwave Technology 25 ( 1 ) 335-345 2007

Research paper (scientific journal), Single Work

The effect of fluorine substituents on the polymerization mechanism of 2-methylene-1,3-dioxolane and properties of the polymer products

KOIKE YASUHIRO

Journal of Fluorine Chemistry 128 ( 3 ) 202-206 2007

Research paper (scientific journal), Single Work

Improvement of physical properties of poly (methyl methacrylate) by the copolymerization with pentafluorophenyl methacrylate

KOIKE YASUHIRO

Journal of Applied Polymer Science 106   4219-4224 2007

Research paper (scientific journal), Single Work

Property modification of poly(methyl methacrylate) through copolymerization with fluorinated aryl methacrylate monomers

KOIKE YASUHIRO

Polymers for Advanced Technologies 18   453-457 2007

Research paper (scientific journal), Single Work

High-Bandwidth Graded-Index Plastic Optical Fiber by the Dopant Diffusion Coextrusion process

KOIKE YASUHIRO

Journal of Lightwave Technology 25 ( 10 ) 3062-3067 2007

Research paper (scientific journal), Single Work

Waveguiding property of a plastic optical fiber fabricated using low-birefringence copolymer

KOIKE YASUHIRO

Japanese Journal of Applied Physics 46 ( 47 ) L1182-L1184 2007

Research paper (scientific journal), Single Work

Preparation of Graded-Index Plastic Optical Fiber by Co-extrusion Process

R. Hirose, M. Asai, A. Kondo, T. Ishigure, and Y. Koike

Organic Photonic Materials and Devices IX 6470   K4700 2007

Research paper (international conference proceedings), Joint Work, Accepted

Fiber Optic Transmission of Analog Signals

R. Furukawa, K. Uehara, S. Takahashi, N. Ohtsu, and Y. Koike

Linear and Nonlinear Optics of Organic Materials VII 6653   G6530 2007

Research paper (international conference proceedings), Joint Work, Accepted

Bandwidth Performance of W-Shaped Plastic Optical Fiber and Its Stability under Static Microbending

K. Aoyagi, Y. Ishikawa, T. Ishigure, and Y. Koike

2007 Conference on Lasers & Electro-Optics/Quantum electronics and Laser Science Conference (CLEO/Qels 2007), Vols 1-5 7599 2007

Research paper (international conference proceedings), Joint Work, Accepted

Investigation of homopolymerization rate of perfluoro-4,5-substituted-2-methylene-1,3-dioxolane derivatives and properties of the polymers

KOIKE YASUHIRO

Journal of Fluorine Chemistry 127   227-281 2006.12

Research paper (scientific journal), Single Work

私にとってのファンダメンタルズ

KOIKE YASUHIRO

2006年度高分子学会若手社員のための高分子基礎講座  2006.10

Single Work

フォトニクスポリマーの複屈折制御と液晶ディスプレイへの応用

KOIKE YASUHIRO

第14回SPE　Japan　RETEC講演発表会  2006.10

Joint Work

フォトニクスポリマーの基礎と新展開

KOIKE YASUHIRO

第22回高分子同友会総合講演会  2006.10

Single Work

私にとってのファンダメンタルズ

KOIKE YASUHIRO

清陵サイエンスフォーラム２１～未来をひらく知の誘い～  2006.10

Single Work

Zero-Birefringence Optical Polymers By Nano-Birefringent Crystals for Liquid Crystal Displays

KOIKE YASUHIRO

Materials Science and Engineering B, Materials Science & Engineering C-Biomimetic and Supramolecular Systems Vol.26 ( No.5-7 ) 966-970 2006.07

Research paper (scientific journal), Single Work

Zero-birefringence optical polymers

KOIKE YASUHIRO

Macromolecules Vol.39   3019-3023 2006.05

Research paper (scientific journal), Single Work

Waveguide Parameter Design of Graded-Index Plastic Optical Fibers for Bending-Loss Reduction

KOIKE YASUHIRO

Journal of Lightwave Technology Vol.24 ( No.5 ) 2108-2114 2006.05

Research paper (scientific journal), Single Work

Novel Amorphous Perfluorocopolymeric System: Copolymers of Perfluoro-2-methylene-1, 3-dioxolane Derivatives

KOIKE YASUHIRO

Journal of Polymer Science: Part A :Polymer Chemistry 44   1613-1618 2006.03

Research paper (scientific journal), Single Work

プラスチック光ファイバー・POFコンソーシアム

KOIKE YASUHIRO

（社）高分子学会「高分子」 55 ( 2 ) 30 2006.02

Single Work

プラスチック光ファイバー・POFコンソーシアム

KOIKE YASUHIRO

高分子55巻1月号(2006年） ((社）高分子学会)  55 ( 1月 )  2006.02

Research paper (scientific journal), Single Work

　View Summary

プラスチック光ファイバーの1０ギガビットの超高速伝送実証、マンション、病院への導入など、POFの現状の説明とPOFコンソーシアム設立の背景、活動内容の紹介が述べられている。

Zero-Birefringence Optical Polymer by Birefringent Crystal and Analysis of the Compensation Mechanism

Y. Koike, K. Yamazaki, H. Ohkita, and A. Tagaya

Macromolecular Symposia 235   64 - 70 2006

Research paper (international conference proceedings), Joint Work, Accepted

Index Profile Design for High-Bandwidth W-Shaped Plastic Optical Fiber

KOIKE YASUHIRO

Journal of Lightwave Technology 24 ( 7 ) 2867-2876 2006

Research paper (scientific journal), Single Work

High-Bandwidth Plastic Optical Fiber for Fiber to the Display

KOIKE YASUHIRO

Journal of Lightwave Technology 24 ( 12 ) 4541-4553 2006

Research paper (scientific journal), Single Work

Modal Bandwidth Enhancement of Plastic Optical Fibers by W-Shaped Refractive Index Profile

T. Ishigure and Y. Koike

2006 IEEE LEOS Annual Meeting Conference Proceedings, Vols 1 and 2    635 2006

Research paper (international conference proceedings), Joint Work, Accepted

Mode-Coupling Control and New Index Profile of GI POF for Restricted-Launch Condition in Very Short-Reach Networks

KOIKE YASUHIRO

IEEE Journal of Lightwave Technology Vol. 23 ( No.12 ) 4155-4168, 2005.12

Research paper (scientific journal), Single Work

GI-POF Prepared by The Dopant Diffusion Co-extrusion Process

KONDO ATSUSHI, ASAI MAKOTO, HIROSE RYOMA, ISHIGURE TAKAAKI, KOIKE YASUHIRO

Nonlinear Optics, Quantum Optics, Concepts in Modern Optics Vol. 34 ( No. 1-4 ) 71-75 2005.12

Research paper (scientific journal), Joint Work,  ISSN  1543-0537

　View Summary

We have proposed the dopant-diffusion co-extrusion process for fabricating a graded-index polymer optical fiber (GI-POF), where small-size dopants can be diffused during the fabrication process. It was confirmed that the refractive index profiles were controlled to the optimized index profile by changing the temperature of the diffusion zone and screw rotation speed.

フォトニクスポリマーが拓く高速光伝送・高画質ディスプレイ

KOIKE YASUHIRO

鉱山 (Bulletion of Japan Mining Industry Association)  第58 ( 第10（11月） ) 29-33 2005.11

Research paper (scientific journal), Single Work,  ISSN  0287-9840

　View Summary

不均一構造のディメンジョン毎の相互作用および導出される光機能によって実現するフォトニクスポリマーについてその現状および将来展望について紹介した。

フォトニクスポリマーが拓く高速光伝送・高画質ディスプレイ

KOIKE YASUHIRO

（財）金属鉱山会・日本鉱業協会機関誌「鉱山 58 ( 10 ) 29-33 2005.11

Single Work

Synthesis and Radical Polymerization of Perfluoro-2-methylene-1,3-dioxolanes

KOIKE YASUHIRO

Macromolecules Vol.38   9466-9473 2005.11

Research paper (scientific journal), Single Work

私にとってのファンダメンタルズ

KOIKE YASUHIRO

若手社員のための高分子基礎講座 (社団法人高分子学会関東支部)   2005.10

Single Work

　View Summary

これまで行ってきた研究成果を光の偏波（またはフォトン）と高分子物質との係わりという視点で原子系のディメンジョンからマクロな不均質構造にわたって順に述べた。

Proposal of zero-birefringence optical polymers and its potential to practical application

TAGAYA AKIHIRO, KOIKE YASUHIRO

Polyfile (株式会社　大成社)  Vol.42 ( No. 499 ) 21-25 2005.09

Research paper (scientific journal), Single Work

　View Summary

現在のIT社会における光学ポリマーデバイスの重要性、光学ポリマーにおける複屈折の発現機構について述べ、さらにゼロ複屈折性光学ポリマーとその実用化への可能性および波及効果について解説する。

ゼロ複屈折性光学ポリマーの提案とその可能性

TAGAYA AKIHIRO,KOIKE YASUHIRO

Polyfile 42 ( 499 ) 21-25 2005.09

Joint Work

フォトニクスポリマーが拓く高速光伝送・高画質ディスプレイ

KOIKE YASUHIRO

日本鉱業協会講演会 (日本鉱業協会)   2005.08

Single Work

　View Summary

これまで当研究室にて研究開発してきたフォトニクスポリマーについて解説し、これらの現状と今後の展開について述べた。

Compensation of The Photoelastic Birefringence of A Polymers by Anisotropic Molecules and Analysis of Compensation Mechanism

OHKITA HISANORI, ISHIBASI KAYOKO, TSURYMOTO DAISAKU, TAGAYA AKIHIRO, KOIKE YASUHIRO

Applied Physics A: Materials Science & Processing Vol. 81 ( No. 3 ) 617-620 2005.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0947-8396

　View Summary

We report on a method to compensate the photoelastic birefringence of a polymer. In this method, a rod-like molecule that has a polarizability anisotropy was chosen and doped in a polymer. We demonstrated this method by compensating the negative photoelastic birefringence of poly(methylmethacrylate) at a wavelength of 633 nm. Homogeneous doping with 2.2 wt.&#8201;% of trans-stilbene almost eliminated the photoelastic birefringence of the polymer. The photoelastic coefficient of the synthesized zero-photoelastic birefringence polymer was 0.057×10-12 Pa-1. We found that the photoelastic birefringence of poly(methylmethacrylate) was compensated by the motion of trans-stilbene in the polymer by the analysis of the infrared absorption spectrum.

Fabrication Process and Optical Properties of Perdeuterated Graded-Index Polymer Optical Fiber

KONDO ATSUSHI, ISHIGURE TAKAAKI, KOIKE YASUHIRO

IEEE Journal of Lightwave Technology (IEEE)  Vol. 23 ( No. 8 ) pp.2443-2448 2005.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We proposed low-loss perdeuterated PMMA (PMMA-d8) based GI-POFs enabling a gigabit data transmission over 300-m prepared by a modified interfacial-gel polymerization process. With using this process, the PMMA-d8 material could be used only in its core region and the index exponent g value of the GI-POF was closed to optimized value (g=2.3). It was verified that the hydrogen bonding in the PMMA that composed the cladding had a small effect on the total attenuation. Furthermore, the -3 dB bandwidth of the GI-POF when all the modes were uniformly launched was 1.02 GHz through 300-m.

Compensation of Photoelastic Birefringence of Polymers by Anisotropic Molecules and Analysis of Compensation Mechanism

OHKITA HISANORI, ISHIBASHI KAYOKO, TANAKA RYO, TAGAYA AKIHIRO, KOIKE YASUHIRO

Japanese Journal of Applied Physics (The Japan Society of Applied Physics)  Vol. 44 ( No. 6A ) 3975-3982 2005.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We report the anisotropic molecular dopant method for compensating the photoelastic birefringence of polymers. In this method, a rodlike molecule that has a polarizability anisotropy was chosen and doped in a polymer. We demonstrate this method by compensating the negative photoelastic birefringence of PMMA and poly (2,2,2-trifluoroethyl methacrylate) at a wavelength of 633nm. Trans-Stilbene and fluorine were selected as the anisotropic molecules. Homogeneous doping with the molecule almost eliminated the photoelastic birefringence of the polymers. We found that the photoelastic birefringence of PMMA was compensated by the elastic motion of trans-stilbene in the polymer as determined by the analysis of the infrared absorption spectrum. Furthermore, the orientation distribution function of trans-stilbene in a uniaxcially strained PMMA film in a solid glass state was estimated by the investigation of the infrared dichotic ratios.

Analysis of Graded-Index Polymer Optical Fiber Link Performance Under Fiber Bending

MAKINO KENJI, NAKAMURA TAKUHIRO, ISHIGURE TAKAAKI, KOIKE YASUHIRO

IEEE Journal of Lightwave Technology Vol. 23 ( No.6 ) pp. 2062-2072 2005.06

Research paper (scientific journal), Joint Work

　View Summary

Bending effects on bandwidth and loss of a graded index polymer optical fiber (GI POF) were investigated, and those influences on the optical link performance were discussed simultaneously for the first time.

Synthesis and Characterization of an Amorphous Perfluoropolymer: Poly(perfluoro-2-methylene-4-methyl-1,3-dioxolane)

FRANTIS&#711;EK MIKES&#711;, YU YANG, TERAOKA IWAO, ISHIGURE TAKAAKI, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Macromolecules Vol. 38 ( No. 10 ) 4237 &#8211; 4245 2005.05

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A perfluorinated monomer, perfluoro-2-methylene-4-methyl-1,3-dioxolane (PFMMD), was synthesized by various methods. The monomer was polymerized in bulk and/or in the solution by a free radical mechanism using perfluorodibenzoyl peroxide and/or perfluorodi-tert-butyl peroxide as an initiators. The polymers obtained (poly(PFMMD)) were colorless and transparent. However, a polymer rod exposed to the atmosphere turned hazy. When the polymers were purified by precipitating the polymer solution into chloroform, they did not turn hazy when exposed to air for a long period of time and remained clear with a high UV-vis light transmittance. The glass transition temperature of the purified polymer was 130-134 °C. NMR measurements indicate that the purified polymers have mostly vinyl addition polymer structure. Nevertheless, we suppose that the pristine polymers contain structural units formed by ringopening polymerization. The molecular weight of poly(PFMMD) samples can be regulated using carbon tetrachloride, carbon tetrabromide, and sulfuryl chloride as chain transfer agents. Polymerization in the presence of these regulators is characterized by nondegradative chain transfer. The intrinsic viscosity of poly(PFMMD) samples was determined in hexafluorobenzene. Hexafluorobenzene is a thermodynamically good solvent for poly(PFMMD). The molecular weights of poly(PFMMD)s were characterized by the intrinsic viscosity and dynamic light scattering (DLS). The refractive index of poly(PFMMD) between 400 and 1550 nm was between 1.3360 and 1.3270. The material dispersion of poly(PFMMD) is superior to that of a commercial poly(1,1,2,4,4,5,5,6,7,7-decafluoro-3-oxa-1,6-heptadiene) (Cytop).

ナノ粒子添加ゼロ複屈折性ポリマー

TAAGAYA AKIHIRO, KOIKE YASUHIRO

月刊ディスプレイ 11 ( 4 ) 19-24 2005.05

Joint Work

ゼロ複屈折光学フィルムと高輝度光散乱ポリマー導光体の研究動向

KOIKE YASUHIRO

社団法人高分子学会高分子同友会勉強会 (社団法人高分子学会高分子同友会)   2005.04

Single Work

　View Summary

これまで行ってきた研究成果を光の偏波（またはフォトン）と高分子物質との係わりという視点で原子系のディメンジョンからマクロな不均質構造にわたって順に述べ、特にゼロ複屈折光学フィルムと高輝度光散乱ポリマー導光体の最新の研究動向について詳しく報告した。

Nano Particle-Doped Zero-Birefringence Photonics Polymer

TAGAYA AKIHIRO, KOIKE YASUHIRO

Monthly Display ((株）テクノタイムズ社)  第１１ ( 第４ ) 19-24 2005.04

Research paper (scientific journal), Joint Work

　View Summary

これまでに実証したゼロ複屈折性光学ポリマーを紹介した。特に最も新しいナノ粒子を添加したゼロ複屈折性光学ポリマーについて、詳細なデータとともにその可能性を詳しく解説した。複屈折制御という観点から、LCDへの応用が期待できる。

Modal Bandwidth Enhancement in a Plastic Optical Fiber by W-Refractive Index Profile

ISHIGURE TAKAAKI, ENDO HIDEKI, OHDOKO KUNIHIRO, TAKAHASHI KEITA, KOIKE YASUHIRO

Journal of Lightwave Technology Vol. 23 ( No. 4 ) pp. 1754-1762 2005.04

Research paper (scientific journal), Single Work, Accepted

　View Summary

A plastic optical fiber (POF) having a W-shaped refractive index profile (W-shaped POF) was prepared for the first time that had a possibility to realize a higher bit rate transmission than those of the conventional silica-based multimode fiber and graded index (GI) POF links. Since the W-shaped POF has a valley of the refractive index at the boundary of the core and cladding of the conventional graded-index (GI) POF, the group delay of higher order modes is strongly influenced, and the modal dispersion in the GI POF is compensated. By comparing the propagating mode properties of the W-shaped POF with those of the GI POF, we clarified theoretically and experimentally that the index valley has a remarkable modal dispersion compensation effect.

Zero-Birefringence Optical Polymer Films

KOIKE YASUHIRO

社団法人高分子学会2004年度印刷・情報記録・表示研究講座 (社団法人高分子学会)   2005.02

Single Work

　View Summary

ゼロ複屈折性光学ポリマーの液晶ディスプレイへの応用とその波及効果について解説する。LCDのコストの内、ポリマー関連部材のコストは約６割を占めるといわれ、それらの高性能化とコスト低減ができれば、LCDにさらなる普及に貢献できる可能性が高い。

Low-loss High-bandwidth PMMA-d8 based GI-POF

KONDO ATSUSHI, ISHIGURE TAKAAKI, KOIKE YASUHIRO

40th International Union of Pure and Applied Chemistry (IUPAC) International Symposium on Macromolecules, World Polymer Congress, MACRO 2004 (E-Polymers, the Scientific E-Only Polymer Journal, Conference Papers (Proceedings)/The French National Center for Scientific Research (CNRS))   2005.01

Research paper (conference, symposium, etc.), Joint Work

　View Summary

We proposed low-loss perdeuterated PMMA (PMMA-d8) based GI-POFs enabling a gigabit data transmission over 200-m prepared by a modified interfacial-gel polymerization process. With using this process, the PMMA-d8 material could be used only in its core region and the index exponent g value of the GI-POF was closed to optimized value (g=2.3). It was verified that the hydrogen bonding in the PMMA that composed the cladding had a small effect on the total attenuation. Furthermore, the -3 dB bandwidth of the GI-POF when all the modes were uniformly launched was 1.42 GHz through 200-m.

Novel Photonics Polymer for Broadband Society

KOIKE YASUHIRO

40th International Union of Pure and Applied Chemistry (IUPAC) International Symposium on Macromolecules, World Polymer Congress, MACRO 2004 (E-Polymers, the Scientific E-Only Polymer Journal, Conference Papers (Proceedings)/The French National Center for Scientific Research (CNRS))   2005.01

Research paper (conference, symposium, etc.), Single Work

　View Summary

Novel photonics polymers for the real time face to face communication in broadband society are proposed. The Graded-Index Optical Fiber (GI-POF) has been proposed for the first time from the Keio University. Very recentry, the data transmission of 10GHz bandwidth for 500m was achieved by the Perfluorinated GI-POF, which was higher than that of silica based multimode fiber. The highly scattering optical transmission (HSOT) polymer backlight of LCD has been proposed, where the brightness is two times of that of conventional transparent backlight. And also, the zero-birefringence polymers, which are doped with needle-like crystals, for novel LCD films have been proposed.

Zero-Birefringence Optical Polymer in Elastic Deformation

ISHIBASHI KAYOKO, OHKITA HISANORI, TSURUMOTO DAISAKU, TAGAYA AKIHIRO, KOIKE YASUHIRO

40th International Union of Pure and Applied Chemistry (IUPAC) International Symposium on Macromolecules, World Polymer Congress, MACRO 2004 (E-Polymers, the Scientific E-Only Polymer Journal, Conference Papers (Proceedings)/The French National Center for Scientific Research (CNRS))   2005.01

Research paper (conference, symposium, etc.), Joint Work

　View Summary

ポリマー中に分極率異方性を持つ低分子を添加することにより、ポリマーの光弾性複屈折を消去する方法を提案した。実際にtrans-stilbene添加によりPMMAの光弾性複屈折消去にはじめて成功した。

Propagating Mode Analysis and Design of Waveguide Parameters of GI POF for Very Short-Reach Network Use

OHDOKO KUNIHIRO, ISHIGURE TAKAAKI, KOIKE YASUHIRO

IEEE Photonics Technology Letters Vol. 17 ( No. 1 ) 79-81 2005.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We investigated the way to reduce the mode-coupling in a GI POF, and it was found that the mode-coupling strength in the GI POF depended on the numerical aperture of the fiber. Moreover, we proposed a new optimum waveguiding design of GI POFs under the UFL condition and demonstrated its superiority.

A novel Copolymeric System of Perfluoro-1,3-Dioxolane Compounds

Y. Okamoto, Y. Yang, W. Liu, F. Mikeš, and Y. Koike

Abstracts of Papers of the American Chemical Society 230   U4309 2005

Research paper (international conference proceedings), Joint Work, Accepted

高画質ディスプレイのためのフォトニクスポリマー

KOIKE YASUHIRO

電気学会東京支部山梨支所講演会 (電気学会東京支部山梨支所)   2004.11

Single Work

　View Summary

これまでディスプレイの主役であったCRTディスプレイは、急速にフラットパネルディスプレイに置き換わりつつある。本講演では、これからの液晶ディスプレイ支えていくと期待される「ゼロ複屈折性光学ポリマー」と「光散乱ポリマー導光体」について紹介する。

Preparation of A Zero-Birefringence Polymer Doped with A Birefringent Crystal and Analysis of Its Characteristics

OHKITA HISANORI, TAGAYA AKIHIRO, KOIKE YASUHIRO

Macromolecules Vol. 37 ( No. 22 ) pp. 8342-8348 2004.11

Research paper (scientific journal), Joint Work

　View Summary

We proposed the “birefringent crystal dopant method” in order to compensate the birefringence of polymers. In this method, the birefringence was compensated by homogeneous doping with a needlelike crystal which has the opposite birefringence to that of the polymers. Strontium carbonate (SrCO3) was selected for this purpose because it has a large birefringence and a needlelike shape. SrCO3 was synthesized, with a length of about 200 nm and a width of about 20 nm, and doped into a poly-(MMA/BzMA)78/22(w/w)) film. The film was drawn at 130 °C and 4 mm/min. The orientational birefringence of the drawn polymer film at a wavelength of 633 nm was compensated by doping with 0.3 wt % SrCO3 without losing its transparency and thermostability. The analysis of infrared dichroism of the films showed that the birefringence of the films was compensated at a low concentration of SrCO3 because of its orientation-inhibition effect and its high orientation degree as compared with that of the polymer main chains.

Synthesis and Properties of Partially Fluorinated Amorphous Ring Containing Polymers: Poly[bis(2,2-difluorovinyl) formal], Poly[bis(2,2-difluorovinyl) difluoroformal], and Poly[bis(1-deutorio-2,2- difluorovinyl)difluoroformal]

YANG YU, MIKES FRANTISEK, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Macromolecules Vol. 37 ( No. 21 ) 7918-7923 2004.10

Research paper (scientific journal), Single Work, Accepted

　View Summary

Three novel partially fluorinated monomers, bis(2,2-difluorovinyl)formal (I), bis(2,2-difluorovinyl)difluoroformal (II), and bis(1-deutrio-2,2-difluorovinyl)difluoroformal (III) , were prepared. These monomers were polymerized in bulk via free radical mechanism. Monomer I produced a cross-linked polymer, but monomers II and III yielded amorphous polymers (II-P and III-P) having five &#8211; and six- membered rings along the backbone. Polymers II-P and III-P were soluble not only in fluorinated solvents but also in nonfluorinated solvents such as THF, 1, 4-dioxane, DMF, and DMSO. They have good thermal stability, high glass transmission temperature, and low dielectric constant. Furthermore, these polymers are completely amorphous and possess outstanding optical clarity extending from visible to near-IR region. The refractive indices of both polymers were measured at various wavelengths to evaluate material dispersion. The material dispersion of II-P and III-P were similar and had low values, which are comparable to perfluorinated polymers and much lower than perdeuterioPMMA. The unique optical properties of these polymers make them attractive for use optical materials.

私にとってのファンダメンタルズ

KOIKE YASUHIRO

若手社員のための高分子基礎講座 (社団法人高分子学会関東支部)   2004.10

Single Work

　View Summary

これまで行ってきた研究成果を光の偏波（またはフォトン）と高分子物質との係わりという視点で原子系のディメンジョンからマクロな不均質構造にわたって順に述べた。

Free-Radical Polymerization of Dioxolane and Dioxane Derivatives: Effect of Fluorine Substituents on the Ring Opening Polymerization

LIU WEIHONG, MIKES FRANTISEK, GUO YINZHONG, KOIKE YASUHIRO, YOSHIYUKI OKAMOTO

Journal of Polymer Science: Part A: Polymer Chemistry Vol. 42 ( Issue 20 ) 5180-5188 2004.09

Research paper (scientific journal), Single Work, Accepted

　View Summary

Partially fluorinated and perfluorinated dioxolane and dioxane derivatives have been prepared to investigate the effect of fluorine substituents on their free-radical polymerization products. The partially fluorinated monomer 2-difluoromethylene-1,3-dioxolane (I) was readily polymerized with free-radical initiators azobisisobutyronitrile or tri (n-butyl) borane-air and yielded a vinyl addition product. However, the hydrocarbon analogue, 2-methylene-1,3-dioxolane (II), produced as much as 50% ring opening product at 60 °C by free-radical polymerization. 2-Difluoromethylene-4-methyl-1,3-dioxolane (III) was synthesized and its free-radical polymerization yielded ring opening products: 28% at 60 °C, decreasing to 7 and 4% at 0 °C and -78 °C, respectively. All the fluorine-substituted, perfluoro-2-methylene-4-methyl-1,3-dioxolane (IV) produced only a vinyl addition product with perfluorobenzoylperoxide as an initiator. The six-membered ring monomer, 2-methylene-1,3-dioxane (V), caused more than 50% ring opening during free-radical polymerization. However, the partially fluorinated analogue, 2-difluoromethylene-1,3-dioxane (VI), produced only 22% ring opening product with free-radical polymerization and the perfluorinated compound, perfluoro-2-methylene-1,3-dioxane (VII), yielded only the vinyl addition polymer. The ring opening reaction and the vinyl addition steps during the free-radical polymerization of these monomers are competitive reactions. We discuss the reaction mechanism of the ring opening and vinyl addition polymerizations of these partially fluorinated and perfluorinated dioxolane and dioxane derivatives.

High-Bandwidth Plastic Optical Fiber with W-Refractive Index Profile

ISHIGURE TAKAAKI, ENDO HIDEKI, OHDOKO KUNIHIRO, KOIKE YASUHIRO

IEEE Photonics Technology Letters Vol. 16 ( No. 9 ) pp. 2081-2083, 2004.09

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A plastic optical fiber having a W-shaped refractive index profile [W-shaped plastic optical fiber (POF)] was prepared for the first time to realize a higher bit rate transmission than those of the conventional silica-based multimode fiber and graded-index (GI) POF links. Since the W-shaped POF has a valley of the refractive index at the boundary of the core and cladding of the conventional GI POF, the group delay of higher order modes is strongly influenced, thus compensating the modal dispersion that exists in the GI POF. The modal dispersion compensation effect by the W-shaped index profile was theoretically and experimentally confirmed.

Plastic Optical Fiber

KOIKE YASUHIRO, KONDOU ATSUSHI

Chemical Engineering of Japan (The Society of Chmical Engineers, Japan)  Vol. 68 ( No. 8 ) 442-444 2004.08

Research paper (scientific journal), Joint Work

　View Summary

通信媒体となりうるプラスチック光ファイバーのうち、高速通信が可能な屈折率分布型プラスチックファイバー(GI型POF)について解説する。

Stereochemistry of The Radical Polymerization of Vinyl Pentafluorobenzoate

WRIHONG LIU, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Polymer Vol. 45 ( Issue 16 ) pp. 5491-5495 2004.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The free-radical polymerization of vinyl pentafluorobenzoate (VPBz) was carried out under various conditions in order to compare its stereochemistry to that of the vinyl benzoate (VBz) polymerization using similar conditions. Contrary to the stereochemistry of the radical polymerization of VBz, VPBz favors syndiotactic propagation. The poly(VPBz) obtained in hexafluoroisopropanol (HFIP) with nBu3B&#8211;air at &#8722;30 °C has a triad syndiotacticity (rr) of 52% which achieved the highest syndiotacticity reported for the radical polymerization of vinyl esters. The stereochemistry difference for the VPBz polymerization was ascribed to the electron-withdrawing effect of the fluorine on the aromatic ring. The solvent effect of enhancing the rr specificity in HFIP may be related to the hydrogen-bonding between HFIP and VPBz or the growing species. It was also found that the glass transition temperatures (Tg) of the VPBz polymers apparently increased with an increase in their diad syndiotacticities (r): the Tg of poly(VPBz) with r=72% was 79 °C, which was 25 °C higher than that of poly(VPBz) with r=56% obtained in toluene.

Zero-birefringence photonics polymer films

TAGAYA AKIHIRO, KOIKE YASUHIRO

Chemistry and Chemical Industry (The Chemical Society of Japan)  57 ( 7 ) 749-751 2004.07

Research paper (scientific journal), Joint Work

　View Summary

複屈折性結晶により、世界で初めて光学ポリマーの複屈折を相殺したことについて、その原理，学術的意義および工業的意義について平易に紹介する。

Birefringence Reduction Method for Optical Polymers by The Orientation-Inhibition Effect of Silica Particles

OHKITA HISANORI, ABE YASUYUKI, KOJIMA HIROSHI, TAGAYA AKIHIRO, KOIKE YASUHIRO

Applied Physics Letters Vol. 84 ( No. 18 ) 3534-3536 2004.05

Research paper (scientific journal), Joint Work

　View Summary

A method for reducing the orientational birefringence of polymers by doping with optically isotropic silica particles is reported. Particles with a diameter of 16 nm were selected and their surface was treated with dimethyldichlorosilane. Doping with 1 wt% of the particles reduced about 15% of the orientational birefringence of polycarbonate and poly(methylmethacrylate) films regardless of the sign and the magnitude of their birefringence. The analysis of the infrared dichroic ratio confirmed an effect in which the particles reduced the orientation of polycarbonate main chains. The effect that caused the reduction of birefringence was named "the orientation-inhibition effect."

ITを支えるフォトニクスポリマーとその展開

KOIKE YASUHIRO

先端通信技術　新技術説明会 (Japan Science and Technology Agency (JST))   2004.02

Single Work

　View Summary

近年、従来の金属線と同様な取扱い性を有しながらギガビット以上の伝送を可能とする高速プラスチック光ファイバー（POF）に新たな注目が寄せられている。ビデオをレンタルしないで家庭にいながらのダウンロード、臨場感あるリアルタイム動画伝送など、ギガビット光ファイバー網が可能とする膨大な新しい光通信技術を展望する

Face-to-Faceコミュニケーションの実現へ ブロードバンド社会を拓くフォトニクスポリマー

KOIKE YASUHIRO

化学経済  ( 2月 )  2004.02

Research paper (scientific journal), Single Work

　View Summary

ブロードバンド社会を拓くフォトニクスポリマーについて「伝送とディスプレイ」という切り口で解説した

A Novel Thermally and Chemically Stable Polymer: Poly (2-difluoromethylene-1,3-dioxolane)

W. LIU, Y. GUO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Macromolecules (American Chemical Society)  Vol. 37 ( 2 ) 254-255 2004.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Fluorinated polymers have become of increasing interest in the development of advanced materials having superior thermal and chemical stability, excellent electrical insulating ability, and unique optical properties. Perfluoropolymers such as Teflon AF and Cytop have been commercialized by DuPont and Asahi Glass, respectively.2,3 These polymers have high chemical and thermal stability and are soluble in selected fluorinated solvents. However, the polymers are quite expensive due to the high manufacturing costs for their monomers.3 Here, we report that a partially fluorinated polymer, poly(2-difluoromethylene-1,3-dioxolane) (P1), is thermally and chemically stable and is soluble in fluorinated alcohols.

大量な情報を伝達するソフトマテリアル

KOIKE YASUHIRO

学術月報 Vol.57 ( No, 2 ) 125-129 2004.02

Research paper (other academic), Single Work

　View Summary

ハードのブロードバンド化を達成しうる通信メディアとして近年注目されているPOFについて解説した。

ゼロ複屈折光学ポリマー －複屈折性結晶による光学ポリマーの複屈折相殺－

TAGAYA AKIHIRO, OOKITA HISANORI, KOIKE YASUHIRO

O Pluse E (新技術コミュニケーションズ)  Vo. 26 ( No. 2 ) 113-114 2004.02

Research paper (scientific journal), Joint Work

　View Summary

ポリマー鎖が配向しても複屈折性が生じない「ゼロ複屈折性光学ポリマー」という概念とその有用性について述べ、ゼロ複屈折性光学ポリマーを実現するために新たに提案した「複屈折性結晶ドープ法」について紹介した。

Synthesis of A Zero-Birefringence Optical Polymer by The Birefringent Crystal Dopant Method and Analysis of Its Characteristics

OHKITA HISANORI, TAGAYA AKIHIRO, KOIKE YASUHIRO

Transactions of The Materials Research Society of Japan (Transactions of The Materials Research Society of Japan)  Vol. 29 ( No. 1 ) 259-262 2004.02

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Birefringence induced by the orientation of polymer mainchains during an injection- molding or extrusion processing restricts the application of optical polymer to optical devices that require maintaining the polarization state of incident light. We propose the "birefringent crystal dopant method" to compensate the birefringence of polymers by homgeneous doping with an opposite birefringent needle-like crystal. SrCO3 was selected for this method and synthesised, with a length of about 200nm and a width of about 20nm. SrCO3 was doped into PMMA/BzMA film. The film was uniaxcially drawn at 130℃ and 4mm/min. For the first time, the positive birefringence of the drawn coplymer film at a wavelength of 633nm was compensated by doing with 0.3we.% of SrCO3 without losing transparency and thermostability. The orientational birefringence of the zero-birefringence film was lower than that of blank copolymer film at any angle of incidence of light.

複屈折ゼロの光学ポリマーを開発 液晶テレビの大幅コストダウンに道拓く

KOIKE YASUHIRO

JST基礎研究最前線  ( No. 4 ) 2-3 2004.01

Research paper (other academic), Single Work

　View Summary

当研究室では、複屈折ゼロの光学ポリマーを開発した。この光学ポリマーで最も重要視されるのが複屈折の低減である。複屈折ゼロの光学ポリマーは世界でも初めてである。このポリマーの研究開発のを狙いとその背景、特徴、今後の展望を含めて紹介した。

Graded-Index Plastic Optical Fiber with High Mechanical Properties Enabling Easy Network Installations. I

ISHIGURE TAKAAKI, HIRAI MIKI, SATO MASATAKA, KOIKE YASUHIRO

Journal of Applied Polymer Science Vol. 91 ( No.1 ) 404-409 2004.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A doped poly(methyl methacrylate) (PMMA)-based graded-index plastic optical fiber (GI POF) with high mechanical strength is reported for the first time. Although the POF is generally believed to have a good mechanical flexibility even if it has a large-core diameter, such a high mechanical strength has been provided by making the polymer chains in the POF highly oriented in its axial direction. If such an orientation of polymer chains is eliminated, the POF becomes brittle, which is similar to silica-based fibers. On the other hand, too high an orientation of the polymer chains induces fiber deformation in a high-temperature atmosphere resulting from orientation relaxation. This study reports how high mechanical strengths such as the tensile strength and the large elongation are provided to the GI POF. By selecting the optimum heat-drawing conditions, the GI POF has a mechanical strength comparable to that of the commercially available step index (SI) POF.

Graded-Index Plastic Optical Fiber with High Mechanical Properties Enabling Easy Network Installations. II

ISHIGURE TAKAAKI, HIRAI MIKI, SATO MASATAKA, KOIKE YASUHIRO

Journal of Applied Polymer Science Vol. 91 ( No.1 ) 410-416 2004.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

It was shown how high mechanical strength should be provided in the high numerical aperture (NA) graded-index plastic optical fiber (GI POF). In this newly developed GI POF, a copolymer of methyl methacrylate (MMA) and 2,2,2-trifluoroethyl methacrylate (3FMA) was used to increase the NA. The GI POF we proposed previously was composed of a PMMA homopolymer cladding and a doped PMMA core. It was previously shown that substituting the copolymer P(MMA-3FMA) for the PMMA as the cladding material made little change in the fiber's light-transmission characteristics. This study focused on mechanical flexibility, which is one of the most important advantages of the POF. It was found that the P(MMA-3FMA)-clad GI POF had almost the same or superior mechanical strength in addition to the excellent light-propagation characteristics. It was also found that such excellent mechanical properties were achieved using a small dopant concentration and optimum heat-drawing conditions.

Train Communication System Using Graded-Index Leaky Plastic Optical Fiber

A. Shimura, Y. Sugawara, S. Haruyama, M. Nakagawa, H. Suzuki, A. Kondo, T. Ishigure, and Y. Koike

2004 IEEE International Conference on Industrial Conference on Industrial Technology (ICIT), Vols. 1-3    78 2004

Research paper (international conference proceedings), Joint Work, Accepted

High-Definition Projection Screen Based on Multiple Light Scattering Technique

T. Okumura, H. Suzuki, A. Tagaya, Y. Koike, and E. Higuchi

Liquid Crystal Materials, Devices, and applications X and Projection Displays X 5289   294 2004

Research paper (international conference proceedings), Joint Work, Accepted

Synthesis of a Zero-Birefringence Optical Polymer Doped with an Inorganic Birefringent Crystal

H. Ohkita, A. Tagaya, and Y. Koike

Functional Nanomaterials for Optoelectromics and Other Applications 99-100   143 2004

Research paper (international conference proceedings), Joint Work, Accepted

Molecular Characterization of a Amorphous Perfluoropolymer: Poly (perfluoro-2-methylene-4-methyl-1,3-dioxolane)

F. Mikes, I. Teraoka, Y. Koike, and Y. Okamoto

Abstracts of Papers of the American Chemical Society 228   U646 2004

Research paper (international conference proceedings), Joint Work, Accepted

Synthesis and Characterization of Poly (perfluoro-2-methylene-1,3-dioxolanes)

W. Liu, Y. Koike, and Y. Okamoto

Abstracts of Papers of the American Chemical Society 228   U337 2004

Research paper (international conference proceedings), Joint Work, Accepted

Novel Photonics Polymer for Broadband IT

T. Ishigure and Y. Koike

2004 IEEE International Conference on Industrial Technology (ICIT), Vols. 1-3    87 2004

Research paper (international conference proceedings), Joint Work, Accepted

プラスチック光ファイバーとブロードバンド社会

KOIKE YASUHIRO

慶應義塾大学　公開講座 明日の社会と科学技術 (慶應義塾大学、川崎市教育委員会)   2003.12

Single Work

　View Summary

低コストで光情報化が可能な高速プラスチック光ファイバーとそのネットワークについて紹介した。更にそれがもたらす現在のインターネットの延長でないリアルタイムのフェイストゥフェイスコミュニケーションの生活と社会のあり方について説明した。

A Novel Perfluoromonomer: Perfluoro-2,3-dihydro-1,4-benzodioxin

WEIHONG LIU, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Journal of Fluorine Chemistry Vol. 124 ( Issue 2 ) 183-188 2003.12

Research paper (scientific journal), Joint Work

　View Summary

A novel perfluoromonomer, perfluoro-2,3-dihydro-1,4-benzodioxin (FDB), was synthesized. The homopolymerization and copolymerizations of FDB were investigated. The structure and physical properties of those polymers were characterized.

超高速伝送・高画質ディスプレイを実現するフォトニクスポリマー

KOIKE YASUHIRO

第27回先端繊維素材研究委員会(AFMc)講演会  2003.11

Single Work

　View Summary

これまで行ってきた研究成果を光の偏波（またはフォトン）と高分子物質との係わりという視点で原子系のディメンジョンからマクロな不均質構造にわたって順に述べた。

High-Bandwidth Graded-Index Plastic Optical Fiber Enabling Power Penalty-Free Gigabit Data Transmission

ISHIGURE TAKAAKI, MAKINO KENJI, TANAKA SHO, KOIKE YASUHIRO

Journal of Lightwave Technology Vol. 21 ( No. 11 ) 2923-2930 2003.11

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A relation between the -3 dB bandwidths of graded-index plastic optical fibers (GI POFs) and the total power penalty of 50-m GI POF links is investigated in detail. The bandwidth of the GI POF is deliberately varied by controlling the index profile. It is theoretically and experimentally confirmed that sufficiently high bandwidth on the order of gigahertz is necessary for the GI POF, even for several hundreds of megabit per second (Mb/s) data rate, in order to achieve the power penalty free in the bit error rate performance of the link. In the case of silica-based multimode fiber links, it has been reported that the launch condition strongly affects the bit error rate performances; hence, a special launching technology for the silica-based multimode fiber is developed to achieve a 1-Gb/s transmission in the gigabit Ethernet protocol. In this paper, it is also found that the power penalty-free state is realized in the GI POF link, which is independent of the launch condition, when a GI POF with a nearly ideal index profile is used. The GI POF is a promising physical layer for realizing stable, high-speed and low-cost data-com networks.

高速光通信・高画質ディスプレイのためのフォトニクスポリマー

KOIKE YASUHIRO

平成15年(2003年)度若手社員のための高分子基礎講座 (社団法人　高分子学会　関東支部)   2003.10

Single Work

　View Summary

これまで行ってきた研究成果を光の偏波（またはフォトン）と高分子物質との係わりという視点で原子系のディメンジョンからマクロな不均質構造にわたって順に述べた。

Highly-Efficient Backlight for Liquid Crystal Display Having No Optical Films

OKUMURA TAKAMITSU, TAGAYA AKIHIRO, KOIKE YASUHIRO, HORIGUCHI MASAHIRO, SUZUKI HIROMASA

Applied Physics Letters Vol. 83 ( No. 13 ) 2515-2517 2003.09

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We propose a highly-efficient backlight that requires no optical films with a polymer containing spherical particles of micron size. The developed backlight is provided with microprisms at the bottom surface, which can reflect directly the incident light into the front direction. The modeling simulation program, employing a Monte Carlo method based on Mie scattering theory, has optimized both the prismatic condition and the multiple scattering characteristics. We confirm that a uniformity of brightness can be achieved without using any optical films, resulting in a high optical efficiency of 62%.

Tacticity Control in The Radical Polymerization of 2,2,2-Trifluoroethyl Methacrylate with Fluoroalcohol

WEIHONG LIU, KAI TANG, YINZHONG GUO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Journal of Fluorine Chemistry Vol. 123 ( Issue 1 ) 147-151 2003.09

Research paper (scientific journal), Joint Work

　View Summary

The free-radical polymerization of 2,2,2-trifluoroethyl methacrylate (TEMA) was carried out in fluoroalcohols to achieve stereoregulation. The polymerization reactivity at low temperature and syndiotactic specificity were enhanced by the use of fluoroalcohol as a solvent. The polymer having triad syndiotacticity (rr) of 70% was obtained in perfluoro-t-butyl alcohol. It was noted that the stereochemistry was nearly independent of reaction temperature. The stereoeffect of fluoroalcohols seemed to be due to the hydrogen-bonding interaction between the alcohol and the monomer or growing species. The hydrogen-bonding formation was determined by FTIR. The copolymerization of TEMA with methyl methacrylate (MMA) in hexafluoroisopropanol afforded a copolymer with syndiotactic specificity. By this method, a cladding material for an optical fiber based on poly(methyl methacrylate) (PMMA) with high mechanical strength and low refractive index could be obtained.

高画質ディスプレイを支えるフォトニクスポリマー

KOIKE YASUHIRO, TAGAYA AKIHIRO

学術月報 Vol. 56 ( No. 9 ) 61(941)-64(944) 2003.09

Research paper (other academic), Joint Work

Optical Design for The Liquid Crystal Display Backlighting with The Highly Scattering Optical Transmission Polymer

OKUMURA TAKAMITSU, ISHIKAWA TAKESHI, TAGAYA AKIHIRO, KOIKE YASUHIRO

Journal of Optics A: Pure and Applied Optics Vol. 5 ( No. 5 ) S269-S275 2003.09

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We have developed a highly scattering optical transmission (HSOT) polymer, and have succeeded in applying it to a highly efficient backlight light guide in liquid crystal displays (LCDs). In the present work, a multiple scattering modeling simulation has been developed. Also the effects of adjacent particles inside the HSOT polymer are demonstrated. The numerical calculation, improved by taking account of the adjacent particles, has precisely reproduced the multiple scattering phenomena inside the HSOT polymer. Based upon the results of the multiple scattering analyses, an optimal design has been developed and applied to an LCD backlighting system. By altering the internal particle conditions, uniformity of color and brightness on the top face of the backlight has been achieved.

Compensation of The Birefringence of A Polymer by A Birefringent Crystal

TAGAYA AKIHIRO, OHKITA HISANORI, MUKOH MASAKI, SAKAGUCHI RYUICHI, KOIKE YASUHIRO

Science Vol. 301 ( Issue 5634 ) 812-814 2003.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We report a method for compensating the birefringence of optical polymers by doping them with inorganic birefringent crystals. In this method, an inorganic birefringent material is chosen that has the opposite birefringence to that of the polymer and has rod-shaped crystals that are oriented when the polymer chains are oriented. The birefringence of the polymer is thus compensated by the opposing birefringence of the crystal. Birefringence is minimized in various polymer optical devices by adjusting process conditions, because it degrades the performance of devices. This method minimizes it, independent of process conditions, which potentially improves the productivity of devices.

The Christiansen Effect of Brightly Colored Colloidal Dispersion with An Amphiphilic Polymer

OKOSHI KENTO, NAOKO SANO, OKUMURA TAKAMITSU, TAGAYA AKIHIRO, MAGOSHI JUN, KOIKE YASUHIRO, FUJIKI MICHIYA, WATANABE JUNJI

Journal of Colloid and Interface Science Vol. 263 ( Issue 2 ) 473-477 2003.07

Research paper (scientific journal), Joint Work

　View Summary

A novel coloration phenomenon in a colloidal dispersion with an amphiphilic polymer was found. The dispersion consists of tetrahydrofuran (THF), an aqueous solution of sodium thiosulfate (Na2S2O3&middot;5H2O), and hydroxypropylcellulose (HPC). The dispersion was emulsified by HPC as an amphiphilic polymer, so that the aqueous phase was confined in droplets in the THF matrix. It typically appeared bluish violet at room temperature and turned into blue with increasing temperature. In this system, the refractive indices of the inside and outside of the droplet coincided at a certain wavelength at which the light passes through without scattering, which is called the Christiansen effect. The color observed was successfully simulated by Mie's scattering theory in combination with the Christiansen effect.

Data transmission over polymer optical fibers

I. T. MONROY, H. P. A. VD BOOM, A. M. J. KOONEN, G. D. KHOE, WATAMABE YUUJI, KOIKE YASUHIRO, ISHIGURE TAKAAKI

Optical Fiber Technology Vol. 9 ( Issue 3 ) 159-171 2003.07

Research paper (scientific journal), Joint Work

　View Summary

Polymer optical fiber (POF) is a promising transmission medium for providing broadband telecommunication services within the customer's premises. POF offers several attractive features for data transmission such as broad bandwidth and low cost for in-house, access, and LAN applications. This article presents a review on optical transmission systems using POF and their enabling technologies. A summary is given of experimental data links with record capacity over record transmission distances. Standardization activities in POF technology and transmission are reported. To conclude, we discuss trends for further development and research.

Observation of Fluorescence in An Optically Pumped Erbium-Containing Perfluorinated Medium at 1.5 &micro;m

KURIKI KEN, NISHIHARA SUSUMU, NISHIZAWA YUKIHISA, YOSHINAGA TADAHIKO, TAGAYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Optics Letters (Optical Society of America)  Vol. 28 ( No.7 ) 570-572 2003.04

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We report what is to our knowledge the first observation of erbium fluorescence at the optical communication wavelength of 1.5&micro;m in a perfluorinated medium. Using a Nd:YAG (355nm) source, we observed fluorescence of the 4I13/2-4I15/2 transition with a peak wavelength of 1.535&micro;m and with a full width at half-maximum of 28nm. These results can lead to new active devices that use all fluorinated polymers.

Synthesis of A Zero-Birefringence Optical Polymer by the Birefringent Crystal Dopant Method

OHKITA HISANORI, MUKOH MASAKI, TAGAYA AKIHIRO, KOIKE YASUHIRO

Procedings of Material Research Society Symposium / Materials Research Society Spring Meeting, (MRS 2003), (Material Research Society)  Vol. 771   207-211 2003.04

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

Birefringence induced by orientation of polymer main chains during an injection-molding or extrusion processing restricts the application of optical polymers to optical devices that require maintaining the polarization state of incident light. We propose the "birefringence crystal dopant method" to compensate the birefringence of polymers by homogeneous doping with an opposite birefringent needle-like crystal. Strontium carbonate was selected for this method and synthesized, with particle length of 50-200nm and aspect ratios of 2-5. Strontium carbonate was doped into poly (PMMA/BzMA=78/72(wt. /wt9) film. The film was uniaxcially drawn at 130℃ and 4mm/min. For the first time, the positive birefringence of the drawn copolymer film at a wavelength of 633nm was compensated by doping with 0.3 wt% of Strontium carbonate without losing transparency and thermostability.

Zero-Birefringence Optical Polimer

TAGAYA AKIHIRO, KOIKE YASUHIRO

成形加工/プラスチック成形加工学会誌 (社団法人　プラスチック成形加工学会)  第15 ( 第3 ) 194-198 2003.03

Research paper (other academic), Joint Work

　View Summary

ポリマー鎖が配向しても複屈折性が生じない「ゼロ複屈折性光学ポリマー」という概念とその有用性について述べ、ゼロ複屈折性光学ポリマーを実現するために新たに提案した「ランダム共重合法」と「異方性低分子ドープ法」について、詳細に紹介する。

高速プラスティック光ファイバーが拓くブロードバンド ―安心とやすらぎの街づくりをめざして―

KOIKE YASUHIRO

Ｋ２タウンキャンパスオープンセミナー (学校法人　慶應義塾大学、川崎市)   2003.02

Single Work

　View Summary

現在ＩＴ不況と言われているが、それはソフトに対する期待と、最後の数百メートルのブロードバンド化が進まないハードとのギャップがその一因と考えられている。本セミナーでは、この最後の数百メートルを低コストで光情報化が可能な、高速プラスチック光ファイバーとそのネットワークについて紹介する。更に、それがもたらす現在のインターネットの延長でないリアルタイムの Face to Face Communication の生活と社会の在り方について述べる。

Scattering Polanzer with Anisortropic Crystals in Polyolefin Polymer

OKUMURA TAKAMITSU, ISHIKAWA TAKESHI, TAGAYA AKIHIRO, KOIKE YSUHIRO

Applied Physics Letters Vol.82 ( No.4 ) 496-498 2003.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A scattering polarizer containing carbonate whiskers (aragonite) in a polyolefin polymer has been developed. A selective multiple scattering technique, generating transmitted linearly polarized light and backward scattered light, has been demonstrated. A refractive index match and mismatch arise from the uniaxial orientation of the host polymer and the alignment of aragonite in the drawing direction. The dependence of the transmittance on the polarization direction of the incident light has been observed. The polarization efficiency has been measured to be 60% with a 150&micro;m thickness.

Fundamentals for Me

KOIKE YASUHIRO

Fuji 21c Forum (Teijin Group)   2003.01

Single Work

　View Summary

光散乱研究の支えとなった、Einstein や Debye の論文を通し、最先端の研究を進めるのには必ずしも最先端の論文が役に立つわけではなく、いかにファンダメンタルズが大切であったかをこれまでの研究成果を通してわかりやすく解説した。

ITのためのナノファイバー(GI系光ファイバーと表示デバイス)

KOIKE YASUHIRO

ナノファイバー勉強会  2003.01

Single Work

Nano-Fiber for IT High Speed Data Transmission and High Quality Display -

KOIKE YASUHIRO, ISHIGURE TAKAAKI, TAGAYA AKIHIRO

Fiber (The Society of Fiber Science and Technology, Japan)  Vol.59 ( No.1 ) 12-17, 2003, 2003.01

Research paper (other academic), Joint Work

　View Summary

GI型POFによる高速・長距離の通信を実現するために必要な、高分子鎖中でのドーパント化合物のナノメートルオーダー分布制御技術と高速POF、高画質ディスプレイが可能にする「人にかえるギガアイランド構想」について述べる。

Novel Photonics Polymer for IT-High Speed Data Transmission and High Quality Display-

KOIKE YASUHIRO

Special Seminar on POF MIT, (Boston, USA)  2002.11

Research paper (other academic), Single Work

　View Summary

情報技術の進歩により生み出されたフォトニクスポリマーによる新規デバイスを本プロジェクトにて研究中のＧＩ－ＰＯＦ、ＨＳＯＴを中心に解説する。

Optical Network Evolution in Asia-Plastic Optical Fiber (POF) and Keio University

石槫 崇明、小池 康博

Optical Networks World Asia 2002 (Raffles City, Singapore)  2002.09

Joint Work

　View Summary

近年、期待が高まってきている情報家電機器間の高速ネットワーク、並びに高速オフィス、キャンパスＬＡＮなどの通信メディアとして期待が寄せられているＧＩ－ＰＯＦの伝送損失特性、信頼性、伝送帯域特性および、応用展開に関する近年の動向について述べた。

私の心に残る論文 Scattering by an Inhomogeneous Solid

KOIKE YASUHIRO

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  51 ( 9月 ) 737 2002.09

Research paper (other academic), Single Work

　View Summary

1949年のDebyeらによって書かれた論文につき、解説。

ブロードバンド光ネットワークと新しいライフスタイル

KOIKE YASUHIRO

慶應工学会設立40周年記念会 (財団法人　慶応工学会)   2002.09

Single Work

　View Summary

GI-POFの高速ホームネットワーク、LANへの応用展開について実例を用いた簡易に解説した。

Graded-Index Polymer Optical Fiber with High Temperature and High Humidity Stability.

ISHIGURE TAKAAKI, SATO MASATAKA, KONDO ATSUSHI, TUKIMORI YASUYUKI, KOIKE YASUHIRO

IEEE Journal of Lightwave Technology Vol.20 ( No.10 ) 1818-1825 2002.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

It was clarified for the first time that the slight attenuation increment observed in the previous PMMA dopant system GI POF we reported originated in the excess scattering loss induced by the aggregation of absorbed water into toe POF. Although, the PMMA material generally absorbed two weight% of water at maximum, the low attenuation of the conventional SI POF whose core material is PMMA can be maintained at 70℃, 80% relative humidity (RH) atmosphere because the absorption water might be homogeneously dispersed without any aggregation in the core of POF. On the other hand, addition of dopant material having higher refractive index than that of PMMA is required to form the refractive index distribution in the GI POF, which decreases the amount of water absorption into polymer, because the dopant material is more hydrophobic than PMMA. Therefore, in spite of the small amount of absorbed water such as 0.5wt%, the absorbed water molecules can not be uniformly dispersed but must be aggregated to form heterogeneities in the refractive index of the polymer matrix. It was clarified that a dopant materials that is as hydrophilic as PMMA-dopant system GI POF under high temperature and high humidity atmosphere, and such a suitable dopant system GI POF was proposed.

Spectroscopic Properties of Lanthanide Chelates in Perfluorinated Plastics for Optical Applications

KURIKI KEN, NISHIHARA SUSUMU, NISHIZAWA YUKIHISA, TAGAYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Journal of The Optical Society of America B (Optical Society of America)  Vol.19 ( No.8 ) 1844-1848 2002.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The absorption spectra of neodymium (Nd), praseodymium (Pr), erbium (Er), and thulium (Tm) ions in perfluorinated (PF) plastic solutions were measured, and the Judd-Ofelt parameters of the Er and Nd ions have been calculated. The radiative properties of the Nd and Er ions in PF plastic solutions were determined from the absorption measurements and the Judd-Ofelt theory. The fluorescence spectrum of Nd^3+ in a PF plastic solution from 900 nm to 1350 nm was measured for the first time, to our knowledge. Furthermore, the PF plastic films containing lanthanide chelates were fabricated by spin coating, and the refractive indices of the films were measured.

High-Bandwitch Graded-Index Polymer Optical Fiber with High Temperature Stability

ISHIGURE TAKAAKI, SATO MASATAKA, KONDO ATSUSHI, KOIKE YASUHIRO

IEEE Journal of Lightwave Technology Vol.20 ( No.8 ) 1443-1448 2002.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A new developed GI POF with high-temperature and high-humidity stability was proposed. As it was found that the high numerical aperture and high glass transition temperature (Tg) at the core center of the GI OPF were key issue to achieve both high-temperature and humidity stability, a partially fluorinated polymer material was adopted to obtain both characteristics in the GI POF. The newly developed GI POF had low-loss, high-bandwidth, high-temperature and humidity stability at 70℃, 80% relative humidity (R.H.) and low bending loss.

Accurate Refractive Index Profiling in A Graded-Index Plastic Optical Fiber Gigabit Transmission Rates.

ISHIGURE TAKAAKI, TANAKA SHO, KOBAYASHI EIJI, KOIKE YASUHIRO

IEEE Journal of Lightwave Technology Vol.20 ( No.8 ) 1449-1456 2002.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

An optimum index profile offering the highest bit rate communication was formed in a PMMA based GI-POF by modifying the polymerization process. The interfacial gel polymerization process we have proposed to fabricate the PMMA-based GI-POF is capable of forming a nearly optimum refractive index profile. However, the theoretically calculated bandwidth from the measured index profile was reduced compared with the GI POF having optimum index profile. In this paper, we report how to obtain a PMMA-based GI POF having exactly the optimum index profile. The bandwidth of this ideal GI POF was experimentally measured and the very high bandwidth of 2.88GHz even for a 150m fiber length was confirmed. The calculated bandwidth agreed well with experimentally measured one. These results indicate that very low modal dispersion can be expected in a GI POF fabricated by the modified interfacial-gel polymerization process.

高速ネットワークアイランド構想とライフスタイル

KOIKE YASUHIRO

多摩美術大学特別講演 (多摩美術大学)   2002.06

Single Work

　View Summary

ギガビットの情報を各家庭、オフィスまで導入するアイランド構想とそれにより実現される現状のブロードバンド技術とは一線を画するリアルタイムコミュニケーション社会を展望する。

Broadband Network Realized with Polymer Optical Fiber

ISHIGURE TAKAAKI, KOIKE YASUHIRO

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  51 ( 6月 ) 451 2002.06

Research paper (other academic), Joint Work

　View Summary

GI-POFの特性の解説、大学、マンション、小学校などの内部にGI-POFを張り巡らし、双方向のギガビット通信等に付き、最新の研究結果および現在実施されている実証実験等の話を交え解説した。

Plastic Optical Fiber Lasers and Amplifiers Containing Lanthanide Complexes

KURIKI KEN, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Chemical Reviews Vol.102 ( No.6 ) 2347-2356 2002.05

Research paper (scientific journal), Joint Work, Accepted

　View Summary

This review describes recent progress of plastic optical fiber lasers and amplifiers with lanthanides. We focus especially on the design and selection of plastic optical fiber and chelate materials.

High Efficiency Optical Coupler for A Small Photo Acceptance Area Photodiode Used in The High Speed Plastic Optical Fiber Communication

MATSUMOTO YOSHIHNORI, NAKAZONO AKIMICHI, KITAHARA TAISUKE, KOIKE YASUHIRO

Sensors And Actuators A: Physical Vol. 97-98   318-322 2002.04

Research paper (other academic), Joint Work

　View Summary

A high efficiency optical coupler has been developed for high speed plastic optical fiber communication. The coupler was designed for a small photo acceptance area photodiode based on the shape of compound parabolic concentrator. The theoretical efficiency of the coupler for graded index plastic optical fiber (GI-POF) was simulated with ray trace simulation, and the coupling loss was calculated less than 0.4 dB. The coupler was batch fabricated in a glass substrate using sand blast technique. The reflection layer of reflectance 90% was formed by Gold/Nickel mirror plating method. The coupler was bonded with a custom designed high speed PIN photodiode. The photocurrent was 20% higher than the current of a ball lens type PIN photodiode. The cut-off frequency was over 1 Gbps at reverse bias of 1.5 V.

The Advanced Highly Scattering Optical Transmission Polymer Backlight for Liquid Crystal Displays

TAGAYA AKIHIRO, ISHII SUGURU, YOKOYAMA KAZUAKI, HIGUCHI EIZABURO, KOIKE YASUHIRO

Japanese Joumal of Applied Physics Vol.41, Part 1 ( No.4A ) 2241-2248 2002.04

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We have demonstrated that the advanced highly scattering optical transmission (HSOT) polymer backlight that was designed by the HSOT designing simulation program. This backlight exhibited approximately three times higher luminance and 20% higher efficiency than the conventional flat type HSOT backlight of 14.1inch diagonal because of the microscopic prism structures at the bottom of the advanced HSOT light guide plate. The HSOT polymer containing the optimized heterogeneous structures produced homogeneous scattered light with forward directivity and sufficient color uniformity. Optimization of the heterogeneous structure is important in order to utilize the taper effect and the microscopic prism structure.

高速POFによるブロードバンドネットワーク

KOIKE YASUHIRO, ISHIGURE TAKAAKI

JEITA Review/電子情報技術産業協会機関紙 (社団法人　電子情報技術産業協会)   ( 1月 ) 7-15 2002.01

Research paper (other academic), Single Work

　View Summary

近年のPOFを取り巻く技術的同行について述べた。

Plastic Optical Fibers Containing Lanthanide Chelates and Organic Dyes for Laser and Amplifier Applications

KURIKI KEN, NISHIHARA SUSUMU, TAGYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Proceedings of The International Society of OpticalEngineering, (SPIE) / Organic Photonic Materials and Devices IV (SPIE The International Society for Engineering)  Vol. 4642   62-70 2002.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

Absorption spectra of lanthanide ions in perfluorinated (PF) plastic solution were measured, and the radiative properties were determined by the absorption measurements and the Judd-Ofelt theory. Fluorescence spectrum of Nd3+ in PF plastic solution from 900nm-1350nm, pumped at 580 nm, were measured for the first time. Lasting properties of a Rhodamine 6G-doped graded-index plastic optical fiber laser (GI POFL) and rod laser were investigated. All measurements demonstrated the superior performance of the GI POFL. This paper also discusses the lasing properties on the basis of near-field pattern measurements.

Thin Liquid-Crystal Display Backlight System with Highly Scattering Optical Transmission Polymers

TAGAYA AKIHIRO, NAGAI MICHIO, KOIKE YASUHIRO, YOKOYAMA KAZUAKI

Applied Optics Vol. 40 ( No. 34 ) 6274-6280 2001.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We described an advanced highly scattering optical transmission (HSOT) polymer backlight system that has shown twice the brightness of a conventional transparent system in spite of its having a thinner backlight. The HSOT polymer that contains optimized heterogeneous structures produced homogeneous scattered light with forward directivity and sufficient color uniformity. Although it was thought that polymers for light-guide plates (LPGs) must be transparent to minimize scattering, we have come to the conclusion that HSOT polymer, which is not an absorbing medium but a scattering medium, is a more suitable medium for LPGs.

Zero-Birefringence Polymers for Optical Devices

TAGAYA AKIHIRO, KOIKE YASUHIRO

Proceedings of SPIE / 2nd International Symposium on Photonics and Applications (ISPA 2001), Conference on Design,Fabrication,and Characterization of Photonic Devicesll (The International Society for Optical Engineering, (SPIE) Nanyang Technological UniversityO)  Vol. 4594   348-358 2001.11

Research paper (scientific journal), Joint Work

　View Summary

Optical polymers which exhibit no birefringence with any orientation of polymer chains are desirable to realize high performance optical devices that handle light. We defined such polymers as "zero-birefringence polymer" and demonstrated two methods for synthesizing the polymers: the random copolymerization method and the anisotropic molecular dopant method. Orientational birefringence is compensated by random copolymerization using positive and negative birefringence monomers at special ratio in the random copolymerization method. Poly (MMA-co-BzMA) (82/18 (wt/wt)) synthesized by this method showed no orientational birefringence with any orientation degree. In the anisotropic molecular dopant method, orientational birefringence of polymers is compensated by doping anisotropic molecules having opposite anisotropy of polarization compared to host polymers. Orientational birefringence of PMMA was completely compensated by doping with 3% of trans-stilbene as the anisotropic molecule. Furthermore, we demonstrated the isotropic particle dopant method to reduce orientational birefringence of polymers. Orientational birefringence for PMMA film was decreased by approximately 20% by doping with 2% of silica particles with average diameter 7nm as the isotropic particle dopant.

ITを支えるフォトニクスポリマー

KOIKE YASUHIRO

綜研化学講演会 (綜研化学株式会社)   2001.11

Single Work

　View Summary

ITにおけるこれらの骨格技術と相関する、フォトニクスポリマーとして、屈折率分布型ポリマー光ファイバ（GI型POF）、光散乱ポリマー導光体、それに０複屈折性ポリマー（偏波保存ポリマー）を提案し、それらの問題の解決法と今後の展開について述べる。

ITを支えるフォトニクスポリマー　〜伝送とディスプレイ〜

KOIKE YASUHIRO

第22会高分子学会湘南地区講演会・見学会 (社団法人　高分子学会　関東支部　湘南幹事会)   2001.11

Single Work

　View Summary

近年、従来の金属線と同様な取扱い性を有しながらギガビット以上の伝送を可能とする高速プラスチック光ファイバーに新たな注目が寄せられている。ビデオをレンタルしないで家庭にいながらのダウンロード、臨場感あるリアルタイム動画伝送など、ギガビット光ファイバー網が可能とする膨大な新しい光通信市場を展望する

フォトニクスポリマーの基礎とITへの展開

KOIKE YASUHIRO

高分子学会千葉地域講演会 (社団法人　高分子学会)   2001.11

Single Work

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情報技術の骨格をなしている、情報ネットワーク技術、情報表示技術及び情報蓄積技術と関連させて本プロジェクトで研究を概略的に紹介している。

High-Bandwidth Plastic Optical Fiber

KOIKE YASUHIRO, SATO MASATAKA, ISHIGURE TAKAAKI

応用物理/応用物理学会誌 (The Japan Society of Applied Physics)  第70 ( 第11 ) 1287-1293 2001.11

Research paper (other academic), Joint Work

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近年、期待が高まっている情報家電機器間の高速ネットワーク、ならびに高速オフィス、キャンパスLANなどの通信メディアとして期待が寄せられているGI型POFの伝送損失特性、信頼性、伝送帯域特性および、応用展開に関する近年の動向について述べる。

高速光通信がもたらす新しい生活とは

小池康博

三田評論　2001年11月号（講演録）  ( No.1040 ) 40-51 2001.11

Single Work

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平成13年6月28日に行われた三田演説会での講演録。「高速光通信が今後どんな生活をもたらすか」ということに焦点を当て,光ファイバーで可能になる生活につき、わかり易く解説した。

Anisotropic Molecule Dopant Method for Synthesizing A Zero-Birefringence Polymer

TAGAYA AKIHIRO, IWATA SHUICHI, KAWANAMI ERIKO, TSUKAHARA HISASI, KOIKE YASUHIRO

Japanese Joumal of Applied Physics Vol. 40, ( Part 1, No. 10, ) 6117-6123 2001.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We have demonstrated the anisotropic molecular dopant method for synthesizing a zero-birefringence polymer that showed no orientational birefringence at any orientation degree of polymer chains. In this method, rod-like molecules such as trans-stilbene having opposite Polarizability anisotropy to that of a host polymer were chosen to compensate orientational birefringence. Orientational birefringence of PMMA was completely compensated by doping with some type of anisotropic molecules. Compensation of orientational birefringence for drawn films of the zero-birefringence polymers was analyzed by the rotating parallel nicols method, and orientation functions for polymer main chains and anisotropic molecules were determined by IR Dichroism, which showed that both the polymer chains and the anisotropic molecules were oriented almost equivalently in the drawing process resulting in complete compensation at any draw ratio. Furthermore, the high transparency of the zero-birefringence polymer was confirmed by light scattering measurement.

Zero-Birefringence Polymer by The Anisotropic Molecule Dope Method

TAGAYA AKIHIRO, IWATA SYUICHI, KAWANAMI ERIKO, TSUKAHARA HISASI, KOIKE YASUHIRO

Applied Optics Vol. 40 ( No. 22 ) 3677-3683 2001.08

Research paper (scientific journal), Joint Work, Accepted

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We propose to use the anisotropic molecular dope method for synthesizing a zero-birefringence polymer that showed no orientational birefringence at any orientation degree of polymer chains. In this method, a rodlike molecular with Polarizability anisotropy was chosen to compensate orientational birefringence. The zero-birefringence polymer was synthesized by doping of 3-wt% trans-stilbene as an anisotropic molecular into PMMA. The zero-birefringence at the 590nm wavelength in the drawn film and the injection-molded plate made from zero-birefringence polymer was confirmed by the rotating parallel nicols method. Furthermore, transparency of at the zero-birefringence polymer at the 633nm wavelength was confirmed by the light-scattering measurement.

Graded-Index Plastic Optical Fiber (POF) Realizing HIgh Speed Data

KOIKE YASUHIRO

マテリアルインテグレ-ション (（株）ティー・アイ・シー)  Vol.14 ( No.8 ) 27-30 2001.08

Research paper (scientific journal), Single Work

　View Summary

GI-POFにつき、その開発史、構造、性能につき簡潔に解説した。

GI Polymer Optical Fiber Enabling HIghest Data Transmission Worldwide

KOIKE YASUHIRO, ISHIGURE TAKAAKI, OHTSU NOBUHIRO

The Review of Laser Engineering (The Laser Society of Japan)  Vol. 29 ( No. 8 ) 496-500 2001.08

Research paper (other academic), Joint Work

　View Summary

This paper describes the potential bandwodth achieved by the graded-index polymer optical fiber (GI POF). Modal dispersion should be minimized to realize the high-speed data transmission in multimode type GI POF. On the other hand, when the refractive index profile is optimized to reduce the modal dispersion, mode coupling, and differential mode attenuation come affect the bandwidth characteristic. In this paper, the maximum bandwidth of the GI POF is clarified by considering all important factors mentioned above, and ideal design of fiber material and structure is also described. And, it is described that this highspeed GI POF will be used in the future how.

高速光通信がもたらす社会変革

KOIKE YASUHIRO

財団法人あさひ中小企業新高事業団技術懇親会 (財団法人あさひ中小企業新高事業団)   2001.07

Single Work

　View Summary

次世代のLAN、情報家電ネットワークへの応用展開を目的とした屈折率傾斜型POFの現状と、今後の展望について述べる

光ファイバーが拓く新しい生活とビジネス

KOIKE YASUHIRO

丸の内シティキャンパス定例講演会「夕学５０講」 (Keio Academic Enterprise Co. LTD.)   2001.07

Single Work

　View Summary

近年、従来の金属線と同様な取扱い性を有しながらギガビット以上の伝送を可能とする高速プラスチック光ファイバーに新たな注目が寄せられている。ビデオをレンタルしないで家庭にいながらのダウンロード、臨場感あるリアルタイム動画伝送など、ギガビット光ファイバー網が可能とする膨大な新しい光通信市場を展望する。

Fabrication and Properties of Optical Fiber Containing Nd-Chelate for Optical Amplification

KURIKI KEN, KOBAYASHI TAKEYUKI, IMAI NANA, TAMURA TOSHIHIKO, NISIHARA SUSUMU, TAGAYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

OSA, Optical Amplifiers and Their Applications, TOPS, Proceedings Vol. 44   67-71 2001.07

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Ndキレートを添加したポリマー光ファイバーの近赤外波長蛍光スペクトルを観測した。またJudd-Ofelt法を用いてNdの輻射遷移確率、誘導放出断面積などを求めた。

Development of High-Speed Polymer Optical Fiber

ISHIGURE TAKAAKI, KOIKE YASUHIRO

電子情報通信学会誌 (The Institute of Electronics, Information, and Communication Engineers)  Vol. 84 ( No.4 ) 238-243 2001.04

Research paper (other academic), Joint Work

　View Summary

インターネット加入者の爆発的増加とともに、オフィス・家庭内においても数百Mbit/s以上の高速データ通信の要求が高まってきており、このような、中・短距離通信網に対しても高速光ネットワークインライフを構築する事が望まれている。この高速ネットワークメディアとして世界規模で検討が進められている石英系光ファイバは、コア径が数&micro;m程度であるためにシステム構築に関してのコスト面が大きな問題となっている。これに対して、本稿では、近年注目を集めている大口径、低損失、広帯域ポリマー光ファイバ(POF)の現状と今後の展開についてまとめた。

Fabrication and Optical Properties of Neodymium-,Praseodymium- and Erbium-Chelates-Doped Plastic Optical Fibers

KOIKE YASUHIRO, NISHIHARA SUSUMU, NISHIZAWA YUKIHISA, TAGAYA AKIHIRO, KOIKE YASUHIRO

Electronics Letters Vol. 37 ( No. 7 ) 415-417 2001.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Neodymium, praseodymium and erbium ions are successfully incorporated into the core of deuterated polymer-based optical fibers. The spectra of three fibers have several strong absorption bands in the visible and infrared regions. The fluorescence lifetime at 1060nm of Nd-chelate doped POF with an uncooled photodiode is obtained.

Photosensitivity in Low-Loss Perfluoropolymer (CYTOP) Fiber Material

H.Y. Liu, G.D. Peng, P.L. Chu, 小池康博、Y. Watanabe

Electronics Letters Vol .37 ( No. 6 ) 347-348 2001.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Photosensitivity in a perfluoropolymer (CYTOP) optical fiber is investigated. Significant diffraction has been observed from transmission gratings made from the fiber. A maximum diffraction efficiency of 1.6% has been achieved corresponding to an index change &#8783;3/10000. This study demonstrates for the first time the existence of significant photosensitivity and the feasibility of writing Bragg grating in CYTOP fiber.

Recent Status of High-Speed Plastic Optical Fiber and Its Future Prospect

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Technical Report of IEICE / Lasers and Quantum Electronics (The Institute of Electronics, Information and Communication Engineers)   2001.02

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Plastic optical fiber (POF) which has distinguished features such as high bandwidth, low loss like silica optical fiber and easy handling similar to copper cable, is expected to be a high speed network medium. It has been reported that the GI POF enabled gigabit data transmission. Furthermore, it was also confirmed that higher bandwidth than silica base multimode fiber can be achieved by the perfluorinated polymer base GI POF because of the small material dispersion. In this paper, the recent development of the GI POF is described in detail.

Recent Status of High-Speed Plastic Optical Fiber and Its Future Prospect

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Technical Report of IEICE / Lasers and Quantum Electronics (The Institute of Electronics, Information and Communication Engineers)  Vol. 100 ( No. 626 ) 43-49 2001.02

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Plastic optical fiber (POF) which has distinguished features such as high bandwidth, low loss like silica optical fiber and easy handling similar to copper cable, is expected to be a high speed network medium. It has been reported that the GI POF enabled gigabit data transmission. Furthermore, it was also confirmed that higher bandwidth than silica base multimode fiber can be achieved by the perfluorinated polymer base GI POF because of the small material dispersion. In this paper, the recent development of the GI POF is described in detail.

プラスチック光ファイバーを展望する

KOIKE YASUHIRO

O plus E (新技術コミュニケーションズ)  vol.23 ( No.1 ) 72-75 2001.01

Research paper (scientific journal), Single Work

　View Summary

GI型POFの現状として、石英系に匹敵する伝送損失の可能性が明らかにされ、また全フッ素化ポリマーにより低材料分散化され高速化が実現していることを紹介。今後として、基礎的な研究を深めることで、さらなる低損失化の実現を見込めることについて述べた。

Novel Photonics Polymers in High-Speed Telecommunication

ISHIGURE TAKAAKI, KOIKE YASUHIRO

Molecular Crystals and Liquid Crystals (MCLC) Vol.353,   451-469 2000.12

Research paper (other academic), Joint Work

　View Summary

Recent status of the POF for high-speed data communication and telecommunication is reviewed. The GI POF was proposed for the first time at Keio University, and currently, several methodologies to fabricate GI POF have been proposed. In this paper, we clarified the great advantage of perfluorinated (PF) polymer as the polymer matrix of low-loss and high bandwidth GI POF. It is generally known that the PF polymer can decrease the intrinsic absorption loss compared with PMMA, which is the conventional material for POF. Furthermore, it was found that low material dispersion of the PF polymer is another advantage to obtain the high bandwidth GI POF. It was clarified for the first time that power distribution of the modes formed by the mode dependent attenuation was the dominant factors of the higher bandwidth of the GI POF than theoretically predicted bandwidth, while the effect of the mode coupling was small.

High Temperature Resistant Graded-Index Polymer Optical Fiber

SATO MASATAKA, HIRAI MIKI, ISHIGURE TAKAAKI, KOIKE YASUHIRO

Journal of Lightwave Technology, Vol.18 ( No.12, ) 2139-2145 2000.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The dopant system GI POF for high temperature stability both in bandwidth and in attenuation is reported for the first time. We confirmed that the Numerical Aperture (NA) of the GI POF strongly influences the temperature stability of the GI POF in the attenuation. It was confirmed in this paper that the attenuation increment was mainly induced by the bending loss, since the GI POF drawn by high tension tended to show its length shrinkage, resulting in irregular bending due to the orientation relaxation of polymer chain. We clarified optimum drawing tension which maintains high mechanical properties and minimize the length shrinkage of the GI POF at high temperature, and the optimum fabrication conditions of the GI POF for high temperature stability both in bandwidth and in attenuation.

Organic Dye-Doped Polymer Optical Fiber Lasers

KURIKI KEN, KOBAYASHI TAKEYUKI, IMAI NANA, TAMURA TOSHIHIKO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Polymers for Advanced Technologies, Vol.11, ( Issue, 8-12 ) 612-616 2000.11

Research paper (scientific journal), Joint Work

　View Summary

We report on the lasing action of the graded-index polymer optical fibers containing dyes, such as Rhodamine B, Rhodamine 6G, Perylene orange and Pyrromethene 567. These dyes have been incorporated into poly(methyl methacrylate-co-2-hydroxyethyl methacrylate). These fibers were transversely pumped at 532 nm with a frequency-doubled Q-switched Nd-YAG laser. Slope efficiency of 24% and output of 1.2 mJ were obtained with a Rhodamine 6G-doped fiber. Lifetime of 200,000 pulses at 10 Hz was achieved with a Rhodamine B-doped fiber.

Fundamentals and Creative Research and Development of Photonics Polymer

KOIKE YASUHIRO

繊維と工業/繊維学会誌 (社団法人　繊維学会)  Vol. 56 ( No. 10 ) 277-281 2000.10

Research paper (other academic), Single Work

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光と高分子物質の相互作用という視点の下に原子レベルからマクロな不均一構造に至るまで光学ポリマーにおける光作用の基礎原理とその応用につき紹介する。

プラスチック光ファイバ最近の話題

ISHIGURE TAKAAKI, KOIKE YASUHIRO

Optp News (Optical Industry and Technology Development Association)  通 ( 119 ) 38-42 2000.09

Research paper (scientific journal), Joint Work

　View Summary

GI型POFを用いた情報家電インターフェースの国際標準化動向や、PFポリマー系GI型POFのLAN導入実施例など最近のPOFによる高速通信関連技術に関してを紹介した。

Fabrication and Properties of Polymer Optical Fibers Containing Nd-Chelate

KURIKI KEN, KOBAYASHI TAKEYUKI, IMAI NANA, TAMURA TOSHIHIKO, NISHIHARA SUSUMU, TAGAYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

IEEE Photonics Technology Letters, Vol.12 ( No.8, ) 989-991 2000.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

PMMA based GI POF containing a ND-chelate have been fabricated. The absorption spectrum of the fiber exhibited several strong bands in the visible and infrared regions. We have observed infrared fluorescence of the ND3+ ion of the fiber at room temperature when it was pumped with an Ar+ -pumped dye laser at 480nm.

High-Efficiency Organic Dye-Doped Polymer Optical Fiber Lasers

KURIKI KEN, KOBAYASHI TAKEYUKI, IMAI NANA, TAMURA TOSHIHIKO, NISHIHARA SUSUMU, NISIZAWA YUKIHISA, TAGAYA AKIHIRO, KOIKE YASHUIRO, OKAMOTO YOSHIYUKI

Applied Physics Letters, Vol.77 ( No.3 ) 331-333 2000.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A GI POF containing Rhodamine 6G in poly (MMA-co-2-hydroxyl methacrylate) has been fabricated. Lasing behavior of the fiber was observed by pumping with a frequency-doubled Q-switched Nd: yttrium-aluminum-garnet laser. A slope efficiency of 43% and a lifetime of 110000 shots at a repetition rate of 10 Hz have been observed. With 1.5mJ pump energy, output energy of 640&micro;J was produced.

Which is A More Serious Factor to The Bandwidth of GI POF: Differential Mode Attenuation or Mode Coupling?

ISHIGURE TAKAAKI, KANO MARIKO, KOIKE YASUHIRO

Journal of Lightwave Technology, (IEEE)  Vol.18 ( No.7 ) 959-965 2000.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

It is clarified for the first time that the effect of the mode coupling on the bandwidth characteristics is very small in the GI POF compared with in the SI POF. Although there have been several trials regarding the theoretical prediction of bandwidth characteristics of GI POF, a disagreement between measured and estimated properties was observed. The origin of disagreement has bees generally explained as the mode coupling effect. However, it is clarified in this paper that the effect of differential mode attenuation is the dominant factor of disagreement between measured and predicted bandwidth characteristics, while the effect of the mode coupling is small. In order to clarify the reason why the calculated bandwidth characteristics of the GI POF shows a disagreement with that measured, differential mode delay and differential mode attenuation were investigated. It was found that the highest order mode in the PMMA based GI POF attenuated 17dB compared with the lowest order mode through 100m transmission. By taking into account this differential mode attenuation, an excellent agreement is observed between calculated and measured result of both the bandwidth characteristics and group delay, in which no mode coupling was considered.

POF: Friendly and the Highest Bandwidth

KOIKE YASUHIRO, ISHIGURE TAKAAKI

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  49 ( 7月 ) 431-434 2000.07

Research paper (other academic), Joint Work

　View Summary

分子内に全く水素原子を含まない全フッ素化ポリマーは、屈折率の波長依存性が極めて小さい低材料分散性を有していることから、石英系光ファイバが伝送することの出来ない世界最高速の伝送を可能にするのはポリマー光ファイバであることを紹介した。

High-Speed Plastic Optical Fibers

SATO MASATAKA, ISHIGURE TAKAAKI, KOIKE YASUHIRO

Science and Technology in Japan,  ( No.74 ) 15-27 2000.07

Research paper (other academic), Joint Work

　View Summary

これまで、慶應大学で研究を続けてきたPMMA系GI型POFの低伝送損失特性、広伝送帯域特性（伝搬モード特性）に加えて、高温、高湿下での伝送特性の経時変化が全くないという優れた信頼性について解説した。

Thermally Stable High-Bandwidth　Graded-Index Polymer Optical Fiber

SATO MASATAKA, ISHIGURE TAKAAKI, KOIKE YASUHIRO

Journal of Lightwave Technology, (IEEE)  Vol.18 ( No.7 ) 952-958 2000.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

High bandwidth PMMA based GI POF with high thermal stability is proposed. No distortion of bandwidth was observed even after more than 10000 hours aging at 85℃ by selecting the large size aromatic dopant which has the stable secondary interaction with PMMA matrix and maintains the high glass transition temperature (Tg) of the core of GI POF. The relationship between the heat-drawing condition from the GI preform to the fiber and the thermal stability in the attenuation was investigated. It was clarified that the length shrinkage of the fiber during the aging at high temperature caused large attenuation increase. On the other hand, the degree of shrinkage could be tightly controlled by changing the heat-drawing tension. It was confirmed that the GI POF drawn with optimized heat-drawing tension had no shrinkage of the fiber during aging at 70℃ and no attenuation increase was observed.

ポリマー光ファイバー増幅器・レーザー

A. Tagaya, K. Kuriki, Y. Koike

光学/日本光学会誌 (Optical Society of Japan, (An Affiliate of the Japan Society of Applied Physics))  29 ( 4 ) 237(39)-242(44) 2000.04

Research paper (other academic), Joint Work

　View Summary

ポリマー光ファイバー増幅器とポリマー光ファイバーレーザーの構成、作製方法、増幅・発信特性について解説した。

Recent Status of High-Speed Polymer Optical Fiber and Its Future Prospect

ISHIGURE TAKAAKI, KOIKE YASUHIRO

Laser and Quantum Electronics (社団法人　電子情報通信学会)  Vol. 99 ( No. 652 ) 31-36 2000.02

Research paper (conference, symposium, etc.), Joint Work

　View Summary

A lot of research interests are focused on the introduction of optical fiber even in the access network because of the growing demand for accessing Internet with high bit rate. Since inexpensive total system cost is strong]y required for LAN or access network, we have proposed a large-core, low-loss and high-bandwidth graded-index polymer optical fiber (GI POF) as a promising candidate of physical media. In this paper, we describe the recent development of the GI POF in its attenuation and bandwidth achieved by investigating a new polymer material and by theoretical analysis.

Optimum Index Profile of The Perfluorinated Polymer-Based GI Polymer Optical Fiber and Its Dispersion Properties

ISHIGURE TAKAAKI, KOIKE YASUHIRO, JAMES W. FLEMING

Journal of Lightwave Technology Vol. 18 ( No. 2 ) 178-184 2000.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The significant advantages in bandwidth and low material dispersion of perfluorinated (PF) polymer-based GI POF are theoretically and experimentally reported for the first time. It is confirmed that the low attenuation and low material dispersion of the PF polymer enables 1 Gb/s km and 10Gb/s km transmission at 0.85&micro;m and 1.3&micro;m wavelength, respectively. The PF polymer-based GI POF has very low material dispersion, compared with those of the conventional PMMA-based POF and of multimode silica fiber. Since the PF polymer-based GI POF has low attenuation from the visible to near infrared region, not only the 0.65&micro;m wavelength which is in the low attenuation window of the PMMA-based POF, but other wavelength such as 0.85&micro;m or 1.3&micro;m etc. can be adopted for the transmission wavelength. It is clarified in this paper that wavelength dependence of the optimum index profile shape of the PF polymer-based GI POF is very small, compared to that of silica-based multimode fiber. As a result, the PF polymer based GI POF has greater tolerance in index profile variation for higher speed transmission than multimode silica fiber. The impulse response function of the PF polymer-base GI POF was accurately analyzed from the measured refractive index profile using a Wentzel, Kramers, Brillouin (WKB) numerical computation method. By considering all dispersion factors involving the profile dispersion, predicted bandwidth characteristics of the PF polymer-based GI POF agreed well with that experimentally measured.

High-Performance Polymer Optical Fiber Lasers and Amplifiers

KURIKI KEN, KOBAYASHI TAKEYUKI, TAMURA TOSHIHIKO, TAGYA AKIHIRO, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Proceedings of SPIE The Society for Optical Engineering / Photonics West, Optelectronics 2000, Technical Conference on Organic Photonics Materials and Devices II (The International Society for Optical engineering (SPIE))  Vol. 3939   28-38 2000.01

Research paper (conference, symposium, etc.), Single Work, Accepted

　View Summary

We report on the lasing action of the GI POF containing dyes, such as Rhodamine B, Rhodamine 6G, Perylene Orange, and Pyrromethene 567. These dyes have been incorporate into poly (methyl methacrylate-co-2-hydroxyethyl methacrylate). These fibers were transversely pumped at 532 nm with a frequency-doubled Q-switching ND: YAG laser. Slope efficiency of 24% and output of 1, 3 mJ was obtained with a Rhodamine 6G-doped fiber. A Lifetime of 200,000 pluses at 10 Hz was achieved with a Rhodamine B-doped fiber.
GI POF containing a Nd-chelate has also been fabricated. The absorption spectrum of the fiber exhibited several strong bands in the visible and infrared region. We have observed infrared fluorescence (0.90, 1.60, and 1.3&micro;m) of the Nd3+ ion of the fiber at room temperature when it was pumped with an Ar+ -pumped dye laser at 580 nm. The Judd-Often theory was applied to the absorption spectrum of Nd+ in polymer to determine the Judd-Ofelt parameters. From the theory, various radiative properties, such as transition probability, branching ratio, and emission cross section for various emission levels, have been determined and reported.

Rare Earth-Doped Graded Index Polymer Optical Fibers for Optical Amplification

TAKEYUKI KOBAYASHI, KURIKI KEN, NISHIHARA SUSUMU, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Proceedings of SPIE, The Society for Optical Engineering / Photonics West, Technical Conference, Rare-Earth-Doped Materials and Devices IV (The International Society for Optical Engimeering (SPIE))  Vol. 3942   158-165 2000.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

We encapsulated rare earth ions such as europium and neodymium with organic ligands to in corporate them into polymer materials. Their spectroscopic properties in polymer hosts and organic solutions were studied. Infrared emission has been observed from a neodymium-doped perdeuterated core GI POF.

光通信と情報家電の動向

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Promoting Machine Industry in Japan (Japan Society for The Promoting of Machine Industry)   ( 通巻380号、 ) 65-71 2000.01

Research paper (other academic), Joint Work

　View Summary

高速GI型POFの低損失性、耐熱性の向上とともに、情報家電機器間ネットワークインターフェースとして注目を集めるようになってきた。GI型POFの特性の現状を紹介するとともに、特にIEEE1394をベースとした伝送方式にGI型POFを導入し、国際標準化規格としようとする情報家電メーカーの動きなどを紹介した。

What is The Most Transparent Polymer?

TANIO NORIHISA, KOIKE YASUHIRO

Polymer Journal (The Society of Polymer Science, Japan)  Vol.32 ( No.1, ) 43-50 2000.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The development of POF leads to the fundamental question about the transmission loss limit of amorphous polymer glasses. The two intrinsic loss factors of amorphous POFs are molecular visible absorption and scattering due to fluctuation. In this paper, we have investigated the lower limit of the inherent light transmission loss of amorphous polymer glass from its molecular structure by using the Morse potential theory for absorption and the fluctuation theory for scattering. The theoretical lower limit of the attenuation of the amorphous perfluoropolymer is 0.3&micro;m, and is comparable with that of silica fiber. Amorphous perfluoropolymer seems to be a most transparent polymer.

New Highly Scattering Optical Transmission Polymers for LCD Backlight

TAGAYA AKIHIRO, KOIKE YASUHIRO

Optical and Electro-Optical Engineering Contact (Japan Optoelectron-Mechanics Association (JOEM))  Vol. 38 ( No. 1 ) 47-55 2000.01

Research paper (other academic), Joint Work

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光散乱ポリマー導光体の提案からその液晶バックライトへの応用、多重散乱解析、次世代型光散乱ポリマー導光体バックライトまで、詳しく解説している。

Slab Waveguide-Type Optical Modulators Using Optically Active and Nonlinear Polymers

MUTO SHINZO, TATSUZAWA YUKIYASU, ISHIYAMA KIYOSHI, KOIKE YASUHIRO

Nonlinear Optics Vol. 22   449-452 1999.11

Research paper (other academic), Joint Work

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A new waveguide-type simple optical modulator, which consists of PMtMA core with an optical activity and electrically poled PVDF-PMMA polymer alloy cladding layer, has been studied. This device is based on toe TE-TM mode conversion controlled by the cladding nonlinearity. When a high voltage signal was applied to the device, a low-loss optical modulation was obtained at a wavelength of 441.6nm.

Highly Scattering Optical Transmission Polymers for Liquid Crystal Display

TAGAYA AKIHIRO, KOIKE YASUHIRO

Proceedings of SPIE The Society for Optical Engineering / International Symposium on Photonics and Applications (ISPA’99), COnference on Design,Fabrication,and Characterization of Photonic Devices Vol. 3896   214-222 1999.11

Research paper (conference, symposium, etc.), Joint Work, Accepted

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We proposed highly scattering optical transmission (HSOT) polymers and applied it to a light pipe of a backlighting system for liquid crystal displays (LCDs). The HSOT polymer backlighting system having not only approximately twice the brightness but also twice the efficiency of the conventional one was realized based on analysis of multiple scattering in the HSOT polymers. The problem of color dispersion which had been believed to be the nature of scattering phenomenon was solved by optimizing the heterogeneous structures in the HSOT polymers. As a result, the HSOT polymer backlighting system with sufficient color uniformity was achieved. In addition, the HSOT polymer backlighting system is suitable for recent thin LCDs because of these advantages.

Design Characterization of Functionally Graded Photonics Polymer Materials

小池康博、石榑崇明、二瓶栄輔

Physics and Chemistry of Functionally Graded Materials Research Report 1998,    125-128 1999.10

Joint Work

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GI-PDFのモード分散の最新結果と分析の結果を基にしてデザインした屈折率分布について述べた。

Theory and Practice of Rapid Flow-Through Analysis Based on Ion-Selective Optode Detection and Its Application to Sodium Ion Determination

HISAMOTO HIDEAKI, SATOH SAYAKA, SATOH KAZUNARI, TSUBUKU MICHIHIKO, DWI SISWANTA, SHICHI YUSHI, KOIKE YASUHIRO, SUZUKI KOUZI

Analytica Chimica Acta Vol.396, ( Issues2-3, ) 131-141 1999.09

Research paper (scientific journal), Joint Work

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One simple example of a rapid flow-through analysis (RFA) system based on ion-selective optode detection was demonstrated, and its performance was discussed. The RFA is a flow analytical method based on a reagentless analyte flow injection system combined with an analyte selective monitor/sensor such as an optical chemical sensor (optode) involving mathematical response simulation using a semi-empirical theoretical response equation. The response of RFA with optode detection can basically be expressed by the equation derived from Fick’s law of diffusion and Kubelka&#8211;Munk’s law, and two other variable parameters in relation to the experimental response. Mathematically simulated results using the proposed equation indicated that the equation can be useful for the prediction of the flow analytical response. In the present demonstration of RFA, highly selective ionophores based on 16-crown-5 derivatives were used for the ion-sensing component of the optode for sodium ion determination. A sodium ion-selective optode based on C14-DD16C5 and KD-A3 exhibited high selectivity for sodium ion over potassium ion, with a selectivity coefficient (log Ki,jopt) of &#8722;2.6. This optode responded to sodium ion in the concentration range from 10&#8722;5 to 10&#8722;1 M at pH 8.0 by measuring the absorbance change at 510 nm in the sensing phase of the optode. The RFA system equipped with a sodium ion-selective optode offers a reagent-less advanced ion-determination methodology for conventional flow injection analysis.

Graded Refractive Index Polymer Optical Fiber

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Materiasl Integration (株式会社　ティー・アイ・シー)  第12巻 ( 第10号 ) 33-38 1999.09

Research paper (other academic), Joint Work

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高速G1型POFとして現在、PMMA系、PFポリマー系と、構成材料をベースに2種類に分類され、それぞれの光学特性、それらについて考えられる応用展開に関して解説した。

マルチメディアのためのフォトニクスポリマー

KOIKE YASUHIRO, TAGAYA AKIHIRO, ISHIGURE TAKAAKI

journal of JSPP (プラスチック成形加工学会)  11 ( 8 ) 680-684 1999.08

Research paper (other academic), Joint Work

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マルチメディアを支えるフォトニクスポリマーとして、伝送を司る高速G1型POF、表示を司る液晶ディスプレイの高輝度光錯乱ポリマー導光体バックライトの作製方法及びその光学特性について紹介した。

Polymer Optical FIber Amplifiers and Lasers

KURIKI KEN, TAGAYA AKIHIRO, KOIKE YASUHIRO

OPTRONICS (株式会社　オプトロニクス社)  18 ( No. 8 ) 131-136 1999.08

Research paper (other academic), Joint Work

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Recent development of efficient polymer optical fiber amplifier and lasers are reviewed. The gains of a highly efficient organic dye-doped graded index polymer optical fiber amplifiers (POFAs) were measured pumped at 532 nm wavelength. Moreover than 20dB of gain was obtained in the Rohdamine B-doped POFA in wide wavelength range from 560nm to 600nm. The maximum gain of the dye-doped POFA for signal at 580nm was measured to be 36dB.
High-power polymer optical fiber was also proposed by utilizing the dye-doped polymer optical fiber, and remarkable lasing properties were obtained. With a 2.5mJ pump power, output energy of 0.6mJ was observed for a Rohdamine 6G-doped polymer optical fiber laser.
The simple and innovative functions of dye-doped polymer optical fiber were clarified in this paper.

Bandwidth and Transmission Distance Achieved by POF*

KOIKE YASUHIRO, ISHIGURE TAKAAKI

IEICE Transactions on Communications, Vol.E82-B ( No.8 ) 1287-1295 1999.08

Research paper (conference, symposium, etc.), Joint Work

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Recent status of POF for high speed data communication and telecommunication is reviewed. The GI POF was proposed for the first time 20 years ago at Keio University and several methodologies to fabricate GI POF have been currently proposed worldwide. In this paper, both theoretically and experimentally verify that the most transparent GI POF can be obtained by the polymer dopant system. The relation between the refractive index profile and the dispersion characteristics of GI POF was quantitatively clarified. The refractive index profile of the GI POF obtained by the interfacial gel polymerization process was controlled to enable to transmit the order of gigabit per second bit rate. Furthermore, the accurate approximation of the refractive index profile and consideration of mode dependent attenuation enabled precisely predict the dispersion characteristics of the GI POF.

プラスチックファイバー増幅器

TAGAYA AKIHIRO, KOBAYASHI TAKEYUKI, KOIKE YASUHIRO

O plus E (株式会社　新技術コミュニケーションズ)  Vol. 21 ( No. 8 ) 998-1005 1999.08

Research paper (other academic), Joint Work

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色素添加型と希土類キレート添加型ポリマー光ファイバー増幅器について、作製法から、光増幅特性まで、全般に渡り詳しく解説している。

Recent Status of Polymer Optical Fiber for High-Speed Date Communication

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Proceedings for SPIE Annual Meeting 1999, Conference on Organic Materials for Photonics Linear Optical Properties of Waveguides and fibers (SPIE)  Vol. 3799   290-300 1999.07

Research paper (conference, symposium, etc.), Joint Work, Accepted

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Recent status of the polymer optical fiber (POF) for high speed communication and telecommunication is reviewed. The GI POF was proposed for the first time at Keio University, and several methodologies to fabricate GI POF have been currently proposed. In this paper, we clarify the great advantage of perfluorinated (PF) polymer which can decrease the intrinsic absorption loss compared with poly methyl methacrylate (PMMA), which is the conventional material of POF. Furthermore, it was found that low material dispersion of the PF polymer is another advantage to obtain the high bandwidth GI POF. It was clarifoed for the first time that the power distribution of modes formed by the mode dependent attenuation was the dominant factor of the higher bandwidth of the GI POF than theoretically predicted bandwidth, while the effect of the mode coupling was small.

プラスチック光ファイバの研究開発

小池康博、石榑崇明、多加谷明広

平成11年度　研究発表予稿集 (通信・放送機構)     21-26 1999.06

Research paper (conference, symposium, etc.), Joint Work

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プラスチック光ファイバの低損失、広帯域化を目的とし、その製造方法、評価方法および測定結果に付き、報告した。

GI型POFの最新動向

KOIKE YASUHIRO

O plus E (株式会社　新技術コミュニケーションズ)  Vol. 21 ( No. 6 ) 641-648 1999.06

Research paper (scientific journal), Single Work

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低損失・広帯域GI型POFの現状と将来展望につき解説した。

High-Power Polymer Optical Fiber Lasers and Amplifiers

KOBAYASHI TAKEYUKI, KURIKI KEN, IMAI NANA, TAMURA TOSHIHIKO, SASAKI KEISKUKE, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Proceedings of The Society for Optical Engineering, (SPIE) / Photonics West, Optoelectronics ’99, Symposium on Organic Photonic Device (The Society for Optical Engineering, (SPIE))  Vol. 3623   206-214 1999.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

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We demonstrate efficient and photostable laser action in graded index polymer fiber lasers with organic dyes such as Rhodamine, Perylene and Pyrromethene. Slope efficiency of 47% and output of 2.6 mJ have been obtained with a Rhodamine 6G-doped fiber laser. Moreover, we encapsulated rare ions to incorporate them into polymer matrix and studies spectroscopic properties of europium chelates in polymer hosts. Superfluorescent polymer fiber source based on Eu chelate-doped polymer optical fiber was demonstrated.

情報通信へのロマン

KOIKE YASUHIRO

化学と工業/日本化学会誌 (社団法人　日本化学会)  第52 ( 第1 ) 20-22 1999.01

Research paper (scientific journal), Single Work

High-Speed Photonics Polymer-Transmission and Display

ISHIGURE TAKAAKI, HORIBE AKIHIRO, KOIKE YASUHIRO

Science and Technology of Polymers and Advanced Materils    309-327 1998.12

Research paper (other academic), Joint Work

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This paper focuses on the transmission and display technologies for the broadband network systems by newly developed photonics polymers as high bandwidth POF and HSOT polymer.

Potential of Plastic Optical Fiber

KOIKE YASUHIRO, ISHIGURE TAKAAKI

The Journal of Institution of Electronics, Information, and Communication Engineers (The Institute of Electronics, Information and Communication Engineers)  Vol.81 ( No.2 ) 1261-1263 1998.12

Research paper (other academic), Joint Work

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高速通信用途として注目を集め始めたGI型POFについて解説した。

High-Efficiency and High-Quality LCD Backlight Using Highly Scattering Optical Transmission Polymer

HORIBE AKIHIRO, BABA MASAHIRO, NIHEI EISUKE, KOIKE YASUHIRO

IEICE Transactions on Elictronics, Vol.E81-C, ( No.11, ) 1697-1702 1998.11

Research paper (scientific journal), Joint Work

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We have proposed a highly scattering optical transmission (HSOT) polymer for use as a high efficiency light source medium. This polymer contains specified internal microscopic heterogeneous structures for controlling light transmission properties. A LCD backlighting system having a new light pipe made of this polymer has twice the brightness of the conventional one. A light scattering phenomenon inside the HSOT polymer was quantitatively analyzed by a ray tracing simulation based on the Mie scattering theory and the Monte Carlo method. The illumination of the backlight which is optimized by using the simulation program has enough uniformity of intensity and colors because of specified multiple light scattering phenomena inside the HSOT polymer. We propose the new backlighting system having fewer components and twice efficiency of the conventional one.

Design and Charecterization of Functionally Graded Photonics Polymer Materials

Y. Koike, E. Nihei, T. ishigure

Physics and Chemistry of Functionally Graded Materials Research Report 1998,  ( No. 274 ) 125-128 1998.11

Research paper (other academic), Joint Work

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GI型のPOFの最新モード分析の結果及び屈折率分布デザインの検討結果に付き報告した。

A LCD Backlight System Using The Highly Scattering Optical Transmission Polymer.

KOIKE YAUSHIRO, HORIBE AKIHIRO, BABA MASAHIRO, TAGAYA AKIHIRO

Microoptics News (Group of Microoptics The Optical Society of Japan (The Japan Society of Applied Physics))  Vol. 16 ( No. 3 )  1998.09

Research paper (conference, symposium, etc.), Joint Work

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A new new concept LCD backlighting system using the highly sacattering optical transmission (HSOT) polymer has the twice the brightness of the conventional backlight and uniform illumination. Light scattering phenomenon of a spheircal perticle inside the HSOT polymer is caluculated in detail by the Mie scattering theory. It was confirmed theoretically that, the color illuminated from the HSOT backlight could be controlled by the sphesified scatter leading to a high efficiency and high-visual quarity LCD backlighting system.

Plastic Optical Fiber

KOIKE YASUHIRO, ISHIGURE TAKAAKI

Technical Report of IEICE (The Institute of Electronics, Information asn Communication Engineers)  Vol. 98 ( No. 265, 266 ) 1-8 1998.09

Research paper (conference, symposium, etc.), Joint Work

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アクセス系やLAN等、システムの低価格性が期待されるネットワークにおいて実用化が期待される、大口径、低損失、広帯域屈折率分布型(GI)型ポリマー光ファイバー(POF)に関して、近年得られてきた、材料検討による実験的なアプローチ、及び理論的な解析を通した低損失化・広帯域化技術について述べる。

Graded Index Polymer Optical Fiber Amplifier

KOBAYASHI TAKEYUKI, SASAKI KEISUKE, KOIKE YASUHIRO

Molecular Crystal and Liquid Crystals (MCLC) Vol.315   123-128 1998.08

Research paper (other academic), Joint Work

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Gain dynamics such as signal wavelength dependence and pump wavelength dependence for organic dye-doped GI POFA are characterized. A Rhodamine B-doped POFA, 1m in length and 0.3mm in core diameter, has exhibited more than 20 dB gain at signal wavelengths from 560nm to 600nm when optically pumped at 532nm. The maximum gain of 37dB was achieved with a Rhodamine B-doped POFA pumped at 550nm, which was optimum pump wavelength. For an Oxazine 4-doped POFA, signal gain of 20dB was obtained when pumped at 605nm. It is shown that pumping at absorption maximum wavelengths optimizes amplifier performance.

Preliminary Experiment for Polymer Waveguide-Type Optical Isolator:A Pulsed Optical Isolator Operation in Poly(l-Methylmethacrylate/Benzylmethacrylate) Copolymer Slab Waveguide

MUTO SHINZO, ISHIYAMA KIYOSHI, NIHEI EISUKE, KOIKE YASUHIRO

Japanese Journal of Applied Physics, Vol.37 ( Part1,No.8, ) 4405-4408 1998.08

Research paper (scientific journal), Joint Work, Accepted

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A copolymer of MtMA and BzMA, Poly (MtMA/BzMA) was synthesized to construct a polymer slab waveguide-type optical isolator operating in the blue wavelength region. This isolator is based on the simultaneously occurring reciprocal and nonreciprocal TE-TM mode conversions in a three-layered slab waveguide which consist of the poly (MtMA/BzMA) copolymer core on a fused quartz substrate. When a high magnetic field of about 18kOe was applied to a device with a core thickness of 4.5&micro;m and a 5cm propagation length, a pulsed optical isolator operation with an isolation ratio of approximately 15dB was obtained at a wavelength o 441.6nm, for the first time.

High-Speed Polymer Optical Fiber Network

KOIKE YASUHIRO

Molecular Crystals and Liquid Crystals (MCLC) Vol.316   1-6 1998.08

Research paper (other academic), Single Work

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The status of the POF for high-speed data communication is reviewed. Recently, low-loss, and high-bandwidth perfluorinated GI POF which has no serious absorption loss from visible to near infrared region was successfully prepared at Keio university. Since the core diameter of GI POF is much larger than that of the multimode silica fiber, the serious modal noise in the conventional multimode silica fiber was virtually eliminated, resulting in stable giga bit order data transmission with inexpensive couplers and connectors.

Recent Progress in High-Speed Polymer Optical Fiber

KOIKE YASUHIRO

Molecular Crystal and Liquid Crystals (MCLC) Vol.315   247-256 1998.08

Research paper (other academic), Single Work

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Recent progress of the GI POF is reviewed. The low-loss perfluorinated (PF) polymer based GI POF experimentally achieved gigabit transmission for more than 200m in the range of visible to infrared region. In addition, improvement of the thermal and long term stability of the bandwidth of the GI POF with using a new dopant material is described.

Graded-Index Polymer Optial Fiber with High Thermal Stability of Bandwidth

ISHIGURE TAKAAKI, SATO MASATAKA, NIHEI EISUKE, KOIKE YASUHRIO

Japanese Journal of Applied Physics Vol.37 ( Part1,No.7 ) 3986-3991 1998.07

Research paper (scientific journal), Joint Work, Accepted

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The development of the perfluorinated (PF) polymer based GI POF for high-speed data communication is described. It was experimentally confirmed that gigabit data transmission for 500-1000m at 1.3&micro;m wavelength was achieved by the low loss PF polymer based GI POF. The thermal stability of PMMA based GI POF is discussed. We selected several kinds of dopants that can maintain a high glass transition temperature (Tg) of the GI POF core. By using the newly selected dopants, we succeeded in maintaining the parabolic refractive index profile of GI POF with no degradation even at 85 to 90℃ for more than 5000h.

高速通信のためのプラスチック光ファイバー（POF）とマルチメディアネットワーク

KOIKE YASUHIRO

KAST REPORT Vol.9 ( No.2 ) 10-17 1998.03

Research paper (other academic), Single Work

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高速ポリマー光ファイバーの特性評価と実際のマルチメディアネットワークへの応用検討

High-Speed Photonics Polymer and Its Application

ISHIGURE TAKAAKI, SATOH MASATAKA, NIHEI EISUKE, KOIKE YASUHIRO

Pure and Applied Optics, Journal of The European Optical Society Part A Vol.7 ( No.2 ) 201-210 1998.03

Research paper (scientific journal), Joint Work

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Recent progress in the GI POF is reviewed. The low-loss perfluorinated (PF) polymer-based GI POF achieved gigabit transmission experimentally over more than 100m in the visible to near-infrared region. In addition, improvement of thermal and ling-term stability of the bandwidth of the GI POF by using a new dopant material is described.

光散乱ポリマーの液晶バックライトへの応用

HORIBE AKIHIRO, KOIKE YASUHIRO

光学/日本光学会誌 (Optical Society of Japan, (An Affiliate of The Japan Society of Applied Physics))  27 ( 2 )  1998.02

Research paper (other academic), Joint Work

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　時々刻々と進歩する科学技術の中で近年の液晶ディスプレイの発展は非常に目覚しいものであり、今だ留まるところを知らず、さらなる性能向上を遂げている。その中で液晶パネルを背面から照射するための平面光源(バックライト)の性能は、消費電力に始まり、薄型軽量、輝度の角度特性、色の均一性等にいたるまで、液晶ディスプレイの性能を広範囲にわたって支配するものである。
　この液晶バックライトシステムにも目的に応じて様々な構成が考えられるが、ここでは特に、低消費電力化を課題とする液晶ディスプレイを対象とした、光散乱ポリマー導光体を用いた高効率バックライトシステムについて詳細に紹介する。

Polymer Optical Fiber Amplifiers for Communication and Sensor Applications

KOBAYASHI TAKEYUKI, SASAKI KEISUKE, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Proceedings of The International Society for Optical Engineerng, (SPIE) / Optoelectronics'98, Photonics West, Conference on Polymer Photonics Devices (The International Society for Optical Engineerng, (SPIE))  Vol. 3281   84-91 1998.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

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Organic dyes and rare earth chelates have been chosen and incorporated into the core regions of graded index (GI) polymer optical fiber (POF) as gain media. Since the synthetic polymer shows much better compatibility with organic fluorescent materials and is amenable to high active dopant concentrations, the doped POFs produce high gains in short length of fiber. We demonstrated that organic dye-doped polymer optical amplifier (POFA) cover a wide spectral range in the visible with a best observed gain of 37 dB in a Rhodamine B-doped POFA pumped at 550 nm. Also, with a GI POF doped with europium chelate of hexafluoroacetylacetone in tris form, we observed organic dyes and rare earth chelates offers optical amplifiers and superfluorescence source for a variety of communication and sensor applications.

High-Bandwidth and High-Thermal Stability Graded-Index Polymer Optical Fiber

ISHIGURE TAKAAKI, SATO MASATAKA, NIHEI EISUKE, KOIKE YASUHIRO

Proceedings of The International Society for Optical Engineerng, (SPIC) / Optoelectronics'98, Photonics West, Conference on Polymer Photonics Devices Vol. 3281 1998.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

Recent progress of the graded-index polymer optical fiber (GI POF) is reviewed. Because the low attenuation of light transmission in the perfluorinated (PF) polymer based GI POF enables 500 to 1000m transmission, more accurate analysis is required in the refractive index profile to realize the order of giga bit transmission. Furthermore, recent improvement of the thermal stability of the GI POF is introduced. We clarify that the stability of the refractive index profile and the attenuation under high temperature and high humidity atmosphere can be improved by selecting the suitable dopant materials.

High-Performance LCD Backlight Using Highly Scatteting Optical Transmission Polymer

HORIBE AKIHIRO, NIHEI EISUKE, KOIKE YASUHIRO

Proceedings of The International Society for Optical Engineerng, (SPIE) / Optoelectronics'98, Photonics West, Conference on Polymer Photonics Devices (The International Society for Optical Engineerng, (SPIE))  Vol. 3281   47-54 1998.01

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

We have proposed a highly scattering transmission (HSOT) polymer for use as a high luminance light source medium. This polymer contains specified microscopic heterogeneous structure for controlling light scattering properties. A LCD backlight using the HSOT polymer has twice the brightness of the conventional transparent PMMA-based backlight because of multiple scattering phenomenons inside the HSOT polymer. In this paper, such a light scattering phenomenon was quantitatively analyzed by a ray tracing based on Mie scattering and Monte Carlo simulations. Subsequently, we propose the new HSOT backlight system having higher luminance and uniformity of white color illumination.

マルチメディア社会の実現へ、期待のインフラ　　　 プラスチック光ファイバ

KOIKE YASUHIRO

KDD Technical Journal  ( No.31冬号, ) 8-11 1998.01

Research paper (other academic), Single Work

　View Summary

LAN等のシステムの低価格性が期待されるネットワークにおいて実用化が期待される、大口径、低損失、広帯域GI－POFに関し、近年得られてきた材料検討による実験的なアプローチ、及び理論的な解析を通した低損失・広帯域化技術について紹介している。

Physical Aging and Light Scattering of Low-Loss Poly(Methyl Methacrylate) Glass

TANIO NORIHISA, KATO HISAO, KOIKE YASUHIRO, HARVEY E. BAIR, MATSUOKA SHIRO, LEE L. BLYLER

Polymer Journal (The Society of Polymer Science, Japan)  Vol.30 ( No.1 ) 56-59 1998.01

Research paper (scientific journal), Joint Work

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Isothermal aging has been carried out on low-loss PMMA glass at 18℃ below the glass transition temperature (Tg). The effect of enthalpy relaxation on light scattering loss of PMMA glass which had no excess scattering was investigated by the use of differential scattering calorimeter (DSC) and light scattering measurement. The light scattering intensity of PMMA glass did not increase with increasing aging time. It is seen that the light scattering loss of glassy PMMA is not affected inherently by physical aging as a result of its approach to thermodynamic equilibrium at a temperature 18℃ below its Tg.

Graded Index Polymer Optical Fiber Amplifiers

KOBAYASHI TAKEYUKI, SASAKI KEISUKE, KOIKE YASUHIRO

Function & Materials (The Japan Society of Plastic Technology)  Vol.18 ( No.1 ) 76-82 1998.01

Research paper (other academic), Joint Work

　View Summary

有機色素添加ポリマー光ファイバーの光増幅特性を明らかにした。さらに、希土類イオンを有機物の配位子で取り囲むことで、ポリマー中に高濃度に添加することを可能にした。希土類添加ポリマー光ファイバーを用いて初めて光り増幅現象を確認した。

Giga Bit Transmission in High-Bandwidth Low-Loss Perdeuterated Polymer Base Graded-Index Polymer Optical Fiber Link

ISHIGURE TAKAAKI, NIHEI EISUKE, KOIKE YASUHIRO

Journal of Fiber Science and Technology,Japan, (The Society of Fiber Science and Technology, Japan)  Vol.53 ( No.12 ) 520-525 1997.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

This paper describes the high speed transmission characteristics of the Perdeuterated PMMA (PMMA-d8) based GI POF. The PMMA-d8 base GI POF was obtained by the interfacial-gel polymerization technique. We succeeded in 1Gb/s 160m transmission at 650-nm wavelength in the 160m GI POF link. In general, the possible transmission distance of the PMMA POF link is limited to approximately 100m because of high attenuation. However, substitution of hydrogen atoms in the polymer for deuterium atoms decreases the intrinsic absorption loss. The total attenuation of the PMMA-d8 base GI POF at 650nm wavelength was about 60dB/km which is approximately half of the attenuation of PMMA base GI POF. Therefore, the low-loss PMMA-d8 base GI POF enables longer distance communication. We also analyzed the dispersion property of the PMMA-d8 base GI POF by utilizing WKB method in which both modal and material dispersion were taken into consideration. It was clarified that approximately 2Gb/s transmission can be achieved by PMMA-d8 base GI POF with 200m length when 650nm wavelength is adopted as the signal wavelength. The PMMA-d8 base fiber has two optical windows of light transmission which are located around 650-680nm and 780nm wavelength. As the material dispersion decrease with increasing the signal wavelength, the use of the light source operating at 780nm is effective for higher bit rate transmission. It was also confirmed that the PMMA-d8 base GI POF can transmit about 3Gb/s for 200m when the signal wavelength is 780nm. These experimental and theoretical results indicate that the PMMA-d8 base GI POF could be one of the promising candidates of the physical layers in the high speed multimedia network.

Formation of The Refractive Index Profile in The Graded Index Polymer Optical Fiver for Gigabit Data Transmission

ISHIGURE TAKAAKI, SATOH MASATAKA, TAKAHASI OSAMU, NIHEI EISUKE, NYU TAKAYUKI, YAMAZAKI SYUNNTAROU, KOIKE YASUHIRO

Journal of Lightwave Technology Vol.15 ( No.11 ) 2095-2100 1997.11

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Bandwidth characteristics of the large core GI POFs are theoretically and experimentally clarified in this paper. The refractive index profile of the GI POF was controlled by the interfacial-gel polymerization to investigate the relation between the index profile and the bandwidth characteristics. It was experimentally confirmed that the maximum bandwidth of the PMMA base GI POF is at most 3GHz for 100m transmission with using the typical laser diode emitting at 650-nm wavelength (3nm source spectral width) when its refractive index profile is optimized. The maximum bandwidth theoretically estimated by considering both modal and material dispersion is approximately 3GHz which is exactly the same as the measured value, while higher than 10GHz for 100m was expected if only modal dispersion was taken into account. The optimum refractive index profile of the PMMA base GI POF is theoretically and experimentally clarified by further considering the profile dispersion.

Fabrication and Superfluorescence of Rare Earth Chelate-Doped Graded Index Polymer Optical Fibers

KOBAYASHI TAKEYUKI, NAKATSUKA SHIRO, IWAFUJI TAKAMI, KURIKI KEN, IMAI NANA, NAKAMOTO TAKASHI, CHARLED D. CLAUDE, SASAKI KEISUKE, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Applied Physics Letters, Vol.71 ( No.17 ) 2421-2423 1997.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Rear-earth chelate-doped GI POFs are proposed and fabricated. The attenuation loss was measured to be 0.4dB/m at 650nm for a GI POF doped with 1wt% of Eu chelate. Lifetime shortening and spectral narrowing verified the occurrence of Superfluorescence at 614nm in the Eu chelate-doped GI POF pumped with xenon flashlamps. The demonstration of Superfluorescence shows that rare-earth chelate-doped GI POFs are appealing as optical amplifiers and superfluorescent sources in a variety of communication and sensor applications.

Transparent Zero-Birefringence Copolymer and Its Optical Properties

IWATA SHUICHI, TSUKAHARA HISASI, NIHEI EISUKE, KOIKE YASUHIRO

Applied Optics Vol.36 ( No.19 ) 4549-4555 1997.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Birefringence is caused by both orientation of polymer chain and photoelasticity. These birefringence were compensated by random copolymerization of negative birefringent MMA and positive birefringence BzMA, but orientational and photoelastic zero birefringence were achieved by quite different compositions of the copolymer. Note that the birefringence of the copolymer that occurred in the process of injection molding was almost completely eliminated with a composition for orientational zero birefringence. The orientational and photoelastic zero-birefringence copolymer processed enough transparency as optical materials that the total scattering losses were 30.4 and 19.5 dB/km, respectively, competing with the transparency of homopolymers.

Highly Scattering Optical Transmission Polymer

小池康博

Miyazaki International Symposium The 11^th^Symposium on Optical and Electorical Properties of Organic Materials  1997.06

Single Work

　View Summary

低分子ドーパント系GI型POFにおいて懸念された耐熱性について、ドーパントによるマトリックスポリマーのガラス転移温度の低下について検討し、屈折率分布、伝送損失が85oC以下でも安定に維持されるGI型POFの作製に成功したことを報告した。

Highly Scattering Optical Transmission Polymer

小池康博

Miyazaki International Symposium The 11th Symposium on Optical and Electrical Properties of Organic Materials  1997.06

Single Work, Accepted

　View Summary

低分子ドーパント系GI型POFにおいて懸念された耐熱性について、ドーパントによるマトリックスポリマーのガラス転移温度の低下について検討し、屈折率分布、伝送損失が85oC下でも安定に維持されるGI型POFの作製に成功したことことこ報告した。

光ファイバーの新しい展開

KOIKE YASUHIRO

Polyfile Vol.34 ( No.400 ) 33-37 1997.06

Research paper (other academic), Single Work

　View Summary

最近のポリマー光ファイバーの応用とその原理

High Gain and High Power Organic Dye-Doped Polymer Optical Fiber Amplifiers:Absorption and Emission Cross Sections and Gain Characteristics

TAGAYA AKIHIRO, KOBAYASHI TAKEYUKI, NAKATSUKA SHIRO, NIHEI EISUKE, SASAKI KEISUKE, KOIKE YASUHIRO

Japanese Journal of Applied Physics, Vol.36, Part 1 ( No.5A ) 2705-2708 1997.05

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Amplification of high signal gain and high output power was achieved in a Rhodamine B (RB)-doped GI POFA based on a prediction in which absorption and emission cross section data were used. The absorption and emission cross section spectra of RB, R6G, and DCM in PMMA bulk were determined. The cross section data enable us to predict gain characteristics of RB, R6G, and DCM-doped GIPOFA. The wide spectral coverage in the visible is achievable with GI POFAs doped with several selected dyes.

Application of Highly Scattering Optical Transmission Polymer to LCDs

HORIBE AKIHIRO. KOIKE YAUSHIRO

The Journal of The institute of Electronics,Information and Communication Engineers  ( 3月 ) 17-22 1997.03

Research paper (scientific journal), Joint Work

　View Summary

We have proposed a new brighter backlight using highly scattering optical-transmission (HSOT) polymer. This polymer material consists of specified microscopic heterogeneous structures inside the polymer. The high order scattering phenomenon in the HSOT polymer was exactly investigated by Monte Carlo simulation based on Mie scattering theory. We obtained a good agreement between the calculated and the experimental results. The scattering property inside the HSOT polymer can be optimized for the LCD backlight by using this simulation program. As the result, our back-light system consisting of the HSOT polymer plate has simpler system, brighter luminance, and better luminance profile. The property of our backlight system which was actually applied to the LCD is shown.

Perfluorinated Polymer GI-POF

KOIKE YASUHIRO, YOSIHARA NORIYUKI, SUGIYAMAHIDENORI, TAKANOYASUNOBU, KOGANEZAWA KOJI, NARITOMI MASAKI

Technical Reporta of IEICE (The Institute of Electronics, Information and Communication Enigineerings)  Vol. 96 ( No. 516 ) 75-80 1997.02

Research paper (other academic), Joint Work

　View Summary

パーフルオロ非晶質樹脂CYTOPを用いたGI-POFを開発中であり、試作したGI-POFの伝送特性を測定した結果、650-1.300nmの広い波長域で使用でき、長波長では100m以上の伝送が可能であること、および300MHZ・KM以上の高帯域を有していることを実証した。

Estimate of Light Scattering Loss of Amorphous Polymer Glass from Its Molecular Structure

TANIO NORIHISA, KOIKE YASUHIRO

Japanese Journal of Applied Physics Vol.36, part 1 ( No.2 ) 743-748 1997.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The fluctuation theory indicates that the isotropic scattering loss of amorphous polymer glass, which is used as a material for POF, decreased with the decrease in isothermal compressibility β and refractive index. In order to prepare low light-scattering-loss polymer glass, it is necessary to know the isothermal compressibility of polymers. However, the β for most polymers has not yet been measured precisely using a mechanical procedure. In this work, we estimate the isothermal compressibility of amorphous polymer glass from its molecular structure and calculate its isotropic light scattering loss.

High-Power Polymer Optical Fiber Amplifier

KOBAYASHI TAKEYUKI, SASAKI KEISUKE, KOIKE YASUHIRO

The Review of Laser Engineering (The Laser Society of Japan)  Vol.25 ( No.2 ) 153-157 1997.02

Research paper (scientific journal), Joint Work

　View Summary

In quest of high-power optical amplifier in the visible, we incorporated organic dyes into POFs. Organic dyes were chosen as gain media based on the following features: a large emission cross section, which allows the achievement of high gains in a short length and a broadband fluorescence spectrum that provides wide tunability. A Rhodamine B-doped POFA, 1m in length and 0.3mm in core diameter, has exhibited more than 20dB gain at signal wavelength from 560nm to 600nm when optically pumped at a wavelength of 532 nm. Furthermore, we have obtained the optical amplification covering most of the spectral range from 560 to 650nm. The spectral range in the visible can be continuously covered with the POFAs doped with several selected dyes. The broad spectral coverage demonstrates the versatility of the organic dye-doped POFA.

High-Power and High-Gain Organic Dye-Doped Polymer Optical Fiber Amplifiers:Novel Techniques for Preparation and Spectral Investigation

TAGAYA AKIHIRO, TERAMOTO SHIGEHIRO, NIHEI EISUKE, SASAKI KEISUKE, KOIKE YASUHIRO

Applied Optics Vol.36 ( No.3 ) 572-578 1997.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Rhodamine B (RB), Rhodamine 6G (R6G), Oxazine 4 perchlorate (O4PC), and 4-Dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl-4H-pyran)-doped GI POFAs were successfully prepared by novel technique to prevent degradation of organic dyes and to enhance solubility of the dyes in MMA and in PMMA. High-power and high-gain amplification was achieved for RB-doped GI POFA’s based on the spectral investigation of dyes in PMMA bulk. It should be noted that amplification in the low-loss region of POF was achieved in the R6G- and O4PC-doped GI POFA.

The Plastics

堀部晃啓・小池康博

合成樹脂 (The Japan Society of Plastic Technology)  Vol. 43 ( No. 1 ) 11-12 1997.01

Research paper (other academic), Joint Work

　View Summary

ポリマー固体内部に不均一構造を有し、光の導波と拡散出射の二つの機能を有する光散乱ポリマー導光体を提案した。またMonte Carlo 法によってその内部の多重散乱現象を理論的に解析し、液晶用バックライトに応用するために最適化を行った。その結果、輝度の均斉度が低下することなく市販品よりも高輝度なバックライトを作製した。（解説）

Present Prospect of Graded-Index Plastic Optical Fiber in Telecommunication

NIHEI EISUKE, ISHIGURE TAKAAKI, TANIO NORIHISA, KOIKE YASUHIRO

IEICE Transactions on Electronics, Vol.E-80-C ( No.1 ) 117-122 1997.01

Research paper (scientific journal), Joint Work

　View Summary

The status of the POF for high-speed data communication is described. Very recently, the low-loss and high-bandwidth perfluorinated GI POF which has no serious absorption loss from visible to 1.3&micro;m wavelength was successfully prepared at Keio University. Since the core diameter of GI POF is Much larger than that of the multimode silica fiber was virtually eliminates, resulting in stable giga bit order data transmission with inexpensive couplers and connectors.

High Bandwidth Graded-Index Polymer Optical Fiber for Near Infrared Use

E. Nihei, T. Ishigure, and Y. Koike

Applied Optics Vol.35 ( No.36 ) 7085-7090 1996.12

Joint Work, Accepted

　View Summary

屈折率分布型ポリマー材料に、含フッ素材料を用いることにより、通常の炭素-水素結合からなるポリマーでは伝送損失の値が数100dB/km以上となる、688nmや773nmの近赤外領域の波長において、それぞれ約56dB/kmと約773dB/kmの低損失を実現した。また伝送帯域についても100mで５.12GHzを達成し、これまでのポリマー材料での値よりも約２倍程度優れた値であることを実験的にも確認した。

High Speed POF

KOIKE YASUHIRO, ISHIGURE TAKAAKI, NIHEI EISUKE

Transaction of the Materials Research Society(MRS)of Japan,Transactions (the Materials Research Society(MRS)of Japan)  Vol.22   32-35 1996.12

Research paper (conference, symposium, etc.), Joint Work

　View Summary

The status of the POF for high-speed data communication is reviewed. Very recently, the low-loss and high-bandwidth perfluorinated GI POF which has no serious absorption loss from visible to 1.3&micro;m wavelength was successfully prepared at Keio University. Since the core diameter of GI POF is much larger than that of the multimode silica fiber, the serious modal noise in the conventional multimode silica fiber was virtually eliminated in stable giga bit order data transmission with inexpensive couplers and connectors.

Amplified Spontaneous Emission in Dye-Doped Polymer Optical Fiber

YAMAMOTO TSUYOSHI, NIHEI EISUKE, SASAKI KEISUKE, KOIKE YASUHIRO

The Joumal of The Institute of Electronics,Information and Communication Engineers,平成8年12月号  ( 12月 ) 13-18 1996.12

Research paper (scientific journal), Joint Work

　View Summary

ASE in laser dye doped DPOF is investigated experimentally and theoretically. Rate equations on laser intensity with the fluorescence intensity considered is developed to discuss the basic performance of the ASE in the DPOF. The model was useful to explain the experimentally obtained results. In addition, ASE-power on DPOF length dependence, pumping power dependence, pumping wavelength, output spectra, output waveform is evaluated. The maximum energy conversion efficiency obtained form the Rhodamine 6G 5-ppm doped DPOF was about 40%.

プラスチック光ファイバ

KOIKE YASUHIRO

OPTORONICS 15 ( 10 ) 126-132 1996.10

Research paper (other academic), Single Work

　View Summary

Recently, information service which can be represented by the Internet service have become available to the general households, and a broadband network has been demanded to deliver video services with low cost and easy handling.
Under such circumstances, plastic optical fiber (POF) has been widely studied as the transmission medium of the high-speed information communication network system. The POF can be prepred with a large core diameter because of the high flexibility, which would enable easy connection and branching in the network system. Moreover, the realization of high bandwidth can be achieved by making a graded-nidex type.
In this paper, we report on the process of the studies and development of POF and the present situation of POF.

High-Speed Polymer Optical Fiber -Polymers for high-Speed Information Communication-

KOIKE YASUHIRO

化学と工業/日本化学会誌 (社団法人　日本化学会)  49 ( 10 ) 1379-1381 1996.10

Research paper (other academic), Single Work

　View Summary

マルチメディア社会で必要な伝送容量をすべてカバーしうる、高速、低損失のポリマー光ファイバーが近年開発され、POFが高速ネットワークやLANの媒体として大きな注目を浴びている。本稿では、POFの特性とその背景について解説する。

Light Scattering Loss and Glass Transition Temperature of Optical Polymer Glass

TANIO NORIHISA, KOIKE YASUHIRO

Kobunshi Ronbunshu,Japanese Journal of Polymer Science and Technology, Vol.53 ( No.10 ) 682-688 1996.10

Research paper (scientific journal), Joint Work

　View Summary

The glass transition temperature (Tg) was the critical temperature for determining the excess light scattering of PMMA glasses. When PMMA glass is polymerized or heat-treated above the Tg, the excess scattering intensity disappears and the isotropic light scattering loss is reduced to the value calculated from the refractive index and the isothermal compressibility using the thermally induced fluctuation theory. The isotropic light scattering loss of the amorphous polymer can be estimated from its molecular structure by assuming a frozen model around Tg.

New Cladding Polymer for Optical Oxygen Sensor Using Fluorescent Plastic Fiber

MORISAWA MASAYUKI, UCHIYAMA KOJI, HOSAKA TOSHIKI, INOUE HIDEKI, MUTO SHINZO, NAMAZUE AKIRA, NIHEI EISUKE, KOIKE YASUHIRO

SPIE- The International Society for Optical Engineering, Photopolymer Device Physics, Chemistry, and Applications III, Proceedings (SPIE- The International Society for Optical Engineering)  Vol. 2836   336-340 1996.08

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Improvement of the optical fiber sensor based on the fluorescence quenching by oxygen gas was studied. Using the newly synthesized PMtMA and its blend of the PMtMA/PMP as the cladding layer, in which sensing dye was doped, the POF O2 sensor with high sensitivity and a fast response time could be realized. In addition, this sensor didn’t receive any affect by humidity.

Phase-Matched Operation of Polymer TE-TM Mode Converter

MUTO SHINZO, SAKAGAMI TOMOYASU, YOSHIHIKO SAKANE, NAMAZUE AKIRA, NIHEI EISUKE, KOIKE YASUHIRO

SPIE- The International Society for Optical Engineering, Photopolymer Device Physics, Chemistry, and Applications III, Proceedings (SPIE- The International Society for Optical Engineering)  Vol. 2851   105-109 1996.08

Research paper (conference, symposium, etc.), Joint Work

　View Summary

A novel TE-TM mode converter using optical active polymers (OAPs), which can be fabricated much more easily than the conventional ones, was proposed. To achieve its phase-matched operation, two methods for controlling birefringence in the OAP waveguides were studied and hence TE0-TM0 mode convention with a high efficiency of about 70% was obtained for the first time.

New Cladding Polymer for Optical Oxyzen Sensor Using Fluorescent Plastic Fiber

M. Morisawa, K. Uchiyama, T. Hosokawa, H. Inoue, S. Muto, A. Namazue, E. Nihei, and Y. Koike

Proceedings of SPIE-The International Society for Optical Engineering / Chemical,Biochemical,and Environmental Fiber SensorsVlll Vol.2836   336-340 1996.08

Research paper (conference, symposium, etc.), Joint Work

　View Summary

ポリメンチルメタクリレートをクラッド層にコーティングすることにより,これまで作製されていた蛍光ポリマー光ファイバー型酸素センサーの感度を大幅に向上させることに成功した。

Phase-Matched Operation of Polymer TE-TM Mode Converter

S. Muto, T. Sakagami, Y. Sakane, A. Namazue, E. Nihei, and Y. Koike

Proceedings of SPIE-The INternational Society for Optical Engineering / Photopolymer Device Physics, Chemistry, and ApplicationsⅢ Vol.2851   105-109 1996.08

Research paper (conference, symposium, etc.), Joint Work

　View Summary

ポリマーTE-TMモード変換器の位相整合動作について述べた。

Compensation for Birefringence of Oriented Polymers by Random Copolymerization Method

IWATA SHUICHI, TSUKAHARA HISASI, NIHEI EISUKE, KOIKE YASUHIRO

Japanese Joumal of Applied Physics Vol.35,Part1, ( No.7 ) 3896-3901 1996.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Birefringence is caused by orientation of polymer during injection molding or extrusion, and is a large obstacle to optical applications. Transparent Zero-birefringence copolymers were successfully synthesized by randomly copolymerizing two monomers having positive and negative birefringence, respectively. Since the anisotropic polymerization of the negative birefringence monomer units is compensated by the positive birefringent monomer units on the same polymer chain, the birefringence is compensated on the length scale of only several monomer units and becomes zero for any degree of orientation. MMA was used as the negative birefringent monomer, and 3FMA as the positive birefringent monomer. Poly (MMA-co-3FMA) copolymer synthesized with a composition of MMA/3FMA=45/55 (wt/wt) shows no birefringence for any draw ratio when a sample film was 65.9dB/km, which is comparable to those of homopolymers.

マルチメディアのための高速プラスチック光ファイバー

KOIKE YASUHIRO

三田評論 (慶應義塾)   ( 980 ) 34-40 1996.05

Research paper (other academic), Single Work

　View Summary

広伝送帯域を実現する屈折率分布型ポリマー光ファイバーの解説。

Optimum Refractive-Index Profile of The Graded-Index Polymer Optical Fiber, Toward Gigabit Data Links

ISHIGURE TAKAAKI, NIHEI EISUKE, KOIKE YASUHIRO

Applied Optics Vol.35 ( No.12 ) 2048-2053 1996.04

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The Optimum refractive index distribution of the high-bandwidth GI POF was clarified for the first time by consideration of both modal and material dispersion. The ultimate bandwidth achieved by the POF is investigated by a quantitative estimation of the material dispersion as well as the modal dispersion. The results indicate that even if the refractive index is tightly controlled, the bandwidth of the GI POF is dominated by the material dispersion when the required bit rate becomes larger than a few gigabits per second. It is also confirmed that the material dispersion strongly depends on the matrix polymer and that the use of PMMA allows for a 10Bb/s signal transmission.

ＰＯＦ

NIHEI EISUKE, KOIKEYASUHIRO

工業材料 Vol. 44 ( No. 4 ) 29-34 1996.04

Research paper (other academic), Joint Work

　View Summary

現在、マルチメディア社会を実現する上で最も大きな問題となっているドロップラインなどの近距離高速情報伝送の媒体として、屈折率分布型ポリマー光ファイバーの利用を提案し、その作製方法から光学特性までを明らかにしている。

ポリマー光ファイバー

NIHEI EISUKE, KOIKE YASUHIRO

O plus E (株式会社　新技術コミュニケーションズ)   ( No.197 ) 80-86 1996.04

Research paper (other academic), Joint Work

　View Summary

ポリマー光ファイバーの特徴を他のファイバーと比較検討し、屈折率分布型ポリマー光ファイバーが、将来のマルチメディア社会の情報伝送媒体として十分な特性を有していることを明らかにし、その作製方法や伝送損失特性などを明らかにしている。

旋光性ポリマーによるモード制御型光導波デバイスの開発

MUTOH SHINZOU, KOIKE YASUHIRO

Polyfile Vol.33, ( No.385, ) 40-42 1996.04

Research paper (other academic), Joint Work

　View Summary

素子作製が非常に簡単かる安価であり、加えて光アイソレータや光変調器などへの新たな展開が期待できる旋光性ポリマーの動作原理と基礎的実験結果について紹介する。

TE-TM Mode Converter Using Optically Active Polymer

MUTO SHINZO, SAKAGAMI TOMOYASU, SAKANE YOSHIHIKO, NAMAZUE AKIRA, NIHEI EISUKE, KOIKE YASUHIRO

Optical Review Vol.3 ( No.2 ) 120-123 1996.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A novel TE-TM mode converter using optically active polymer: poly-l-menthylmethacrylate (PMtMA) was studied theoretically and experimentally. In a three-layered slab waveguide consisting of the PMtMA core layer on a fused quartz substrate, a low-loss TE0-TM0 mode conversion with an efficiency of 60 to 70% was easily obtained for the first time at a wavelength of 441.6 nm. The method to achieve a phase-matched operation of this polymer TE-TM mode converter was also discussed.

Optimization of The Refractive-Index Distribution of High-Bandwidth GI Polymer Optical Fiber Based on Both Modal and Material Dispersions

ISHIGURE TAKAAKI, NIHEI EISUKE, KOIKE YASUHIRO

Polymer Journal (The Society of Polymer Science, Japan)  Vol.28 ( No.3 ) 272-275 1996.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The optimum refractive-index distribution of the high bandwidth GI POF in which material dispersion is taken into account was clarified for the first time. Since modal dispersion remarkably decreased by GI POF, this paper focuses on the ultimate bandwidth achieved by POF, quantitatively estimating the material dispersion as well as modal dispersion. The results indicated that the bandwidth of the PMMA based GI POF was dominated by material dispersion when the required data rate becomes larger than a few GB/s. It was also confirmed that material dispersion strongly depends on the matrix polymer and that use of fluorinated polymer whose material dispersion is lower than that of PMMA allows for 10Gb/s signal transmission.

Preparation of Plastic GRIN Materials

NIHEI EISUKE, KOIKE YASUHIRO

光学/日本光学会誌 (Optical Society of Japan (An affiliate of the Japan Society of Applied Physics))  25 ( 2 ) 104-105 1996.02

Research paper (other academic), Joint Work

　View Summary

プラスチック材料を用いて屈折率分布型光学素子を作製する方法には幾つかあるが、この総説中では特に拡散現象を利用して屈折率分布を形成させる界面ゲル重合法とカーブドモールド法について示した。界面ゲル重合法はプラスチック光ファイバーに応用されており、高伝送帯域を有するファイバーが作製され、またカーブドモールド法では、大口径なレンズの作製に応用されている。

Large Radial Graded-Index Polymer

SHANG PIN WU, NIHEI EISUKE, KOIKE YASUHIRO

Applied Optics Vol.35 ( No.1 ) 28-32 1996.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A very large GRIN polymer successfully prepared for the first time, to the best of our knowledge, by two methods: the curved mold method and the diffusion copolymerization method. Both methods gave a radial GRIN polymer with a diameter of 70mm and a Δn value greater than 0.02. Ray tracing through these radial GRIN polymers was used to predict that such a GRIN polymer could be a promising candidate for thinner ophthalmic lenses with no spherical aberration of multifocusing characteristics.

Photochemical Property of Photosensitizer using Dye-Doped Plastic Optical Fibe

MINAMITANI HARUYUKI, YAMAMOTO TUYOSI, IINO TOORU, SASAKI KEISUKE, KOIKE YASUHIRO

応用物理/応用物理学会誌 (The Japan Society of Applied Physics)  第65 ( 第1 ) 36-40 1996.01

Research paper (scientific journal), Single Work

　View Summary

本稿では、癌のphotodynamic診断やphotodynamic治療光源として色素ドーププラスチック光ファイバー（DPOF)を用いる上での動作特性と光感受性物質に対する光化学作用の基礎特性を示す。波長560nm付近で出力が得られるRhodamine 6GドープPOFを光源とし、光感受性物質の亜鉛ポルフィリン化合物の光化学反応により、活性酸素の一種であるスーパーオキシドの発生をルミノール反応を用いて検出する。さらに医用デバイスDPOFの今後の可能性について論じている。

High-Power Optical Source Using Dye-Doped Polymer Optical Fiber

YAMAMOTO TSUYOSHI, FUJII KAZUHITO, TAGAYA AKIHIRO, KOIKE YASUHIRO, SASAKI KEISUKE

Journal of Nonlinear Optical Physics and Materials Vol.5 ( No.1 ) 73-88 1996.01

Research paper (scientific journal), Joint Work

　View Summary

Basic characteristics of organic-dye doped polymer optical fibers (DPOFs) are demonstrated. The devices contain laser dye, such as Rhodamine 6G (R6G) and Rhodamine B (RB) in the core region. Firstly, amplification characteristics of DPOF amplifiers (POFAs) excited by a pulse-operated, doubled Nd:YAG laser are demonstrated, e.g., a 250mm-length of RB-POFA gives 1kW (30dB) of amplified signal at 591nm. Next, an all solid state system of RB DPOF laser (POFL) is discussed by numerical simulation and the experimental result of high-power amplified spontaneous emission (ASE) by strong excitation of DPOF is shown.

Plastic Optical Fiber Amplifier and Its Application

YAMAMOTO TSUYOSHI, TAGAYA AKIHIRO, MINAMITANI HARUYUKI, NIHEI EISUKE, KOIKE YASUHIRO, SASAKI KEISUKE

回路実装学会誌 (社団法人　プリント回路学会)  Vol.11 ( No.1 ) 36-40 1996.01

Research paper (other academic), Joint Work

　View Summary

　Laser-dye doped plastic optical fiber amplifier (POFA) is fabricated and its basic perfprmances are demonstrated. As doped dye, Rhodamine B (RB) is prepared. Output power os 1kW with a gain of 30dB can be obtained by using RB doped POFA at a concentration of 1ppm. The energy conversion efficiency, which is defined as output signal power normalized by lounched pump power, is 25%. Possibility of plastic optical fiber laser (POFL) is discussed by analyzing a rate equation of laser. It is proved that a RB doped POFL (core diameter ; 100&micro;m, lengtth : 30mm) has high performance around 580nm. As one of the applications of POFA, photodynamic diagnosis (PDD) for medicine is proposed. Fluorecence from Zinc-Porphyrin is confirmed by a Rhodamine 6G doped POFA.

Theoretical and Experimental Investigation of Rhodamine B-Doped Polymer Optical Fiber Amplifiers

TAGAYA AKIHIRO, TERAMOTO SHIGEHIRO, YAMAMOTO TSUYOSHI, FUJII KAZUHITO, NIHEI EISUKE, KOIKE YASUHIRO, SASAKI KEISKUKE

IEEE Journal of Quantum Electronics Vol.31 ( No.12 ) 2215-2222 1995.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

High power (620W) and high gain (28dB) amplification was achieved by a Rhodamine B (RB)-doped GI POFA with a 1-m length. A theoretical analysis of the amplification in the RB-doped GI POFA was carried out using the rate equation for the fast three-level system. The calculated gain behavior reasonably fit the experimentally data. The possibility of higher power (more than 620W) and higher gain (more than 28dB) amplification covering a wide range in the visible region is shown from the calculation. Absorption and emission cross section of RB in PMMA bulk were determined and used in the calculation. The values of the cross sections were approximately 10,000 times larger than those of ER3+ in GeO2-SiO2 glass.

Brighter Backlights Using Highly Scattered Optical-Transmission Polymer

HORIBE AKIHIRO, IZUHARA MEGUMI, KOIKE YASUHIRO

Journal of The Society for Information Display / 1995 SID International Symposium (The Society for Information Display)  Vol.3 ( No.4 ) 169-171 1995.12

Research paper (scientific journal), Joint Work

　View Summary

We propose a new concept, highly scattered optical transmission (HSOT) polymer, which consists of specific microscopic heterogeneous structure, as a new light source medium. Therefore, the incident beam is efficiently converted to the homogeneous illumination from the surface of the HSOT polymer by effective scattering due to such heterogeneous structures. This HSOT polymer was applied to the LCD backlight that was simpler in system and more than 50% brighter than in a conventional transparent PMMA-based backlight system.

High-Power Polymer Optical Fiber Amplifier

YAMAMOTO TSUYOSHI, HUJII KAZUHITO, TAGAYA AKIHIRO, NIHEI EISUKE, KOIKE YASUHIRO, SASAKI KEISUKE

The Joumal of The Institute of Electronics,Information and Communication Engineers,(Electronics and Communications in Japan, English Edition) Vol.78 ( No.11 ) 36-44 1995.11

Research paper (scientific journal), Joint Work

　View Summary

Organic dye-doped POFA are fabricated and their amplification characteristics are fabricated and their amplification characteristics are investigated. Rhodamine 6G, Rhodamine B, and Perylene Red are used as organic dyes for optical amplification. The amplification of optical signals at 571 nm, 591nm, and 621nm wavelength is confirmed through pumping by the second harmonic of a pulse-operated Nd: YAG laser. It is shown that very high output powers can be achieved by increasing the caliber of Rhodamine B doped POFA. One kW optical signal output (30 dB gain) is obtainable at dye doping of 1 ppm, 500-&micro;m core radius, and POFA length of 250mm. The conversion efficiency of such a high output amplifier is 27%. The POFAs are advantageous over liquid-dye laser because they are easily handled. Multistage POFAs ins the form of joint POFAs are proposed as new light source and their oscillation characteristics are discussed.

High-Speed Polymer Optical Fiber and polymer Optical Fiber Amplifier

KOIKE YASUHIRO

OPTORONICS  ( No.11, ) 142-146 1995.11

Research paper (other academic), Single Work

　View Summary

通信のための広帯域POFを中心に近年開発された光ファイバー増幅器についても解説した。

可視光源レーザ用色素添加プラスチック光ファイバ

山本剛、飯野徹、小池康博、佐々木敬介、南谷晴之

日本レーザー医学会 大会論文集    155-160 1995.11

Joint Work

　View Summary

医療分野で利用できるような、高強度のパルス光を、ポリマー光ファイバー増幅器を用いて発生させることに成功した。ここではその応用例を示した。

ポリマー光ファイバー増幅器の利得特性

小林毅之、中塚史朗、多加谷明広、二瓶栄輔、小池康博、佐々木敬介

信学技報 (電子情報通信学会)   ( No.10, ) 31-36 1995.10

Research paper (other academic), Joint Work

　View Summary

有機色素をドープした屈折率分布型ポリマー光ファイバー増幅器を作製した。有機色素であるローダミンＢを用いて作製された長さ０.９ｍのポリマー光ファイバー増幅器において、0.3Ｗの信号光を約1200Ｗまで増幅すること（36dBの利得）に成功した。（解説）

Plastic Optical Fiber

KOIKE YASUHIRO

NEW GLASS (社団法人ニューガラスフォーラム)  Vol.10 ( No.3 ) 14-21 1995.09

Research paper (other academic), Single Work

　View Summary

様々なプラスチック光ファイバーの応用例（センサーやディスプレイ-、光通信など）を、その原理とともに示した。

Gradient-Index Contact Lens

KOIKE YASUHIRO, ASAKAWA AKIHIKO, SHANG PIN WU, NIHEI EISUKE

Applied Optics Vol.34 ( No.22 ) 4669-4673 1995.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A GRIN CL is proposed to decrease spherical aberration and to increase the Diopter. A plastic radial GRIN rod was successfully obtained by using the vapor-phase diffusion copolymerization technique. The resulting index distribution of the GRIN rod was almost parabolic against the distance from the center axis, and Δn value was -0.030. The GRIN CL was prepared by grinding and polishing the rod. It is theoretically and experimentally concluded that using the radial GRIN can significantly improve the optical properties of CL’s.

Possibility of Polymer for Light Guide Materials

NIHEI EISUKE, KOIKE YASUHIRO

回路実装学会誌 (社団法人　プリント回路学会)  Vol.10 ( No.5 ) 355-360 1995.08

Research paper (other academic), Joint Work

　View Summary

ポリマーを光導波材料として用いる場合の特性について示し、特に光ファイバーとして応用した場合の接続特性、伝送帯域特性について明らかにしている。また、マルチメディア社会でのポリマー光ファイバーの活用についても論じている。

High-Bandwidth, High-Numerical Aperture Graded-Index Polymer Optical Fiber

ISHIGURE TAKAAKI, HORIBE AKIHIRO NIHEI EISUKE, KOIKE YASUHIRO

Journal of Lightwave Technology Vol.13 ( No.8 ) 1686-1691 1995.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A new large core (0.5-1.0mm) GI POF was proposed to solve the connection problem of the single mode silica fiber indoor use for high speed multimedia network. The bending loss for 10-mm bending diameter was dramatically decreased from 20dB to less than 1dB by preparing the high numerical aperture GI POF. The band-width was 585.2 MHz km which was one hundred times larger than that of any existent SI POF, and the attenuation was 150dB/km at 650nm wavelength.

High-Bandwidth Graded-Index Polymer Optical Fiber

ISHIGURE TAKAAKI, NIHEI EISUKE, KOIKE YASUHIRO

Journal of Lightwave Technology, Vol.13 ( No.7 ) 1475-1489 1995.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

High-bandwidth (2GHz km) GI POF was successfully obtained by the new interfacial-gel polymerization technique in which the unreactive component was used in order to obtain the quadratic refractive index distribution. This high-bandwidth GI POF makes it possible to transmit high-speed optical signals in the short range network which was not covered by SI type POF commercially available. The high-bandwidth GIPOF will open the way for great advantage in the high-speed multimedia network.

High Bandwidth Polymer Optical Fiber

KOIKE YASUHIRO

Electronics and Communications in Japan (The Institute os Electronics. Information and Communication Engineers)  Vol.78 ( No.6 ) 560-564 1995.06

Research paper (other academic), Single Work

　View Summary

広帯域な特性を有するポリマー光ファイバーについて、その構造と伝送特性について明らかにした。（解説）

Most Transparent Polymer

KOIKE YASUHIRO

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  44 ( 6月 ) 388-389 1995.06

Research paper (other academic), Single Work

　View Summary

POFの開発研究をもとに、最も光をよく通す高分子について平易に解説した。

High-Power Polymer Optical Fiber Amplifier

YAMAMOTO TSUYOSHI, FUJII KAZUHITO, TAGAYA AKIHIRO, TERAMOTO SHIGEHIRO, NIHEI EISUKE, KOIKEYASUHIRO, SASAKI KEISUKE

The Journal of The Institute of Electronics,Information and Communication Engineers,(Electronics and Communications in Japan,) (電子情報通信学会)  Vol.J78-C-I ( No.6 ) 282-288 1995.06

Research paper (scientific journal), Joint Work

　View Summary

屈折率分布型ポリマー光ファイバーアンプに用いる有機色素を変えることにより、可視光領域における任意の波長の信号光の増幅の可能性を明らかにした。実験では用いる有機色素をローダミン6G、ローダミンB、ペリレンレッドと変えることにより、３つの信号光波長（571、591、621nm)での増幅現象を確認した。

ポリマー光ファイバー

KOIKE YASUHIRO

Japanese Journal of Optics (Optical Society of Japan, (An Affiliate of The Japan Society of Applied physics))  第24 ( 第5 ) 286-287 1995.05

Research paper (scientific journal), Single Work

　View Summary

近年シングルモード(SM)型のガラスファイバーが長距離幹線系に広く用いられ、Gbpsオーダーの高速通信が現実に行われるようになってきた。更に各家庭にまで高速情報を送り込むfiber to the home(FTTH)、LANを中心とした高速情報化社会に向けての研究が行われている。本稿では高速通信のためのポリマー光ファイバー（POF)について解説した。

Large-Core,High-Bandwidth Polymer Optical Fiber for Near Infrared Use

ISHIGURE TAKAAKI,NIHEI EISUKE, KOIKE YASUHIRO, CHARLES E. FORBES, LESLIE LALIEVE, RICH STRAFF, HELLMUTH A. DECKERS

IEEE Photonics Technology Letters Vol.7, ( NO.4, ) 403-405 1995.04

Research paper (scientific journal), Joint Work, Accepted

　View Summary

High bandwidth (more than 500 MHz km) GI POF for near infra-red use was successfully fabricated by using partially fluorinated acrylate monomer. Since only three carbon-hydrogen bonds exist in a monomer unit, an absorption loss due to the stretching vibration of the carbon-hydrogen bonds was remarkably reduced compared with the conventional POF’s. The attenuation of the GI POF at 780 nm wavelength was 135dB/km, which is much lower than that of the PMMA core POF (800dB/km). The fluorinated polymer-based GI POF is satisfying a significant segment of high-speed multimedia network applications.

2.5Gbit/s 100m Data Transmission Using Graded-Index Polymer Oprical Fibre and High-Speed Laser Diode at 650nm Wavelength

ISHIGURE TAKAAKI, NIHEI EISUKE, YAMAZAKI SHUNTAROU, KOBAYASHI KENICHI, KOIKE YASUHIRO

Electronics Letters Vol.31 ( No.6 ) 467-468 1995.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

High-bandwidth GI POF has been successfully obtained which realizes 2.5 Gbit/s signal transmission over 100m spans for the first time by using a 650nm high-speed laser diode. In the letter the advantage of the GI POF for high-speed short-range optical communication is described.

Basic Performance of An Organic Dye-Doped Polymer Oprical Fiber Amplifier

TAGAYA AKIHIRO, KOIKE YASUHIRO, NIHEI EISUKE, TERAMOTO SHIGEHIRO, FUJII KAZUHITO, YAMAMOTO TSUYOSHI, SASAKI KEISUKE

Applied Optics Vol.34 ( No.6 ) 988-992 1995.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A POFA of the GI type, with gain in the visible region, was successfully prepared for the first time, to our knowledge, with the interfacial-gel polymerization technique. An input signal of 0.85 W at 591 nm was amplified to 420 W (27dB gain) by injection of 690 W of pump power at523 nm in to a GI POFA with a 0.5m length. The efficiency of conversion of pump energy to signal amplification was more than 60%.

Polymer Optical Fiber Amplifier

TAGAYA AKIHIRO, KOIKEYASUHIRO, SASAKI KEISUKE

応用物理/応用物理学会誌 (The Japan Society of Applied Physics)  第64 ( 第1 ) 32-35 1995.01

Research paper (scientific journal), Joint Work

　View Summary

著者らにより初めて提案された、プラスチック光ファイバー光増幅器という新規なデバイスを紹介した論文である。プラスチック光ファイバー光増幅器の作製方法、光増幅特性、理論解析などについて詳細に紹介している。

プラスチック光ファイバーと情報社会

KOIKE YASUHIRO

三田評論  1995.01

Research paper (other academic), Single Work

　View Summary

広伝送帯域を実現する屈折率分布型ポリマー光ファイバーが、情報化社会でどのように利用されていくかを平易に解説。（解説）

The Large Dimensional Radial GRIN Polymer

SHAN PIN WO, NIHEI EISUKE, KOIKE YASUHIRO

Polymer Journal Vol.27 ( No.1 ) 21-25 1995.01

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A new method for preparing very large radial GRIN polymer plates is proposed . The resulting radial-GRIN plate has a diameter of 70mm of the GRIN region and Δn of 0.02. The optical characteristics of the large radial-GRIN lens were estimated by calculating the trajectory of a ray through GRIN lens which was based on Maxwell’s ray equation. It was confirmed that such large GRIN polymers are promising for eye glasses with no spherical aberration or multifocus properties.

Plastic Optical Fiber

KOIKE YUASHIRO, NIHEI EISUKE

繊維と工業/繊維学会誌 (The Society of Fiber Science and Technology, Japan)  第50 ( 12 ) 623-627 1994.12

Research paper (scientific journal), Joint Work

　View Summary

これまでに開発されてきたプラスチック光ファイバーの経緯を示し、その種類、光学特性等を明らかにし、近未来の情報伝送媒体としての利用の可能性を明らかにしている。

マルチメディアへ向けてのＰＯＦ

KOIKE YASUHIRO

OPTORONICS (株式会社　オプトロニクス)   ( No.10 ) 101-106 1994.10

Research paper (scientific journal), Single Work

　View Summary

マルチメディアにおけるＰＯＦの可能性を具体的に述べる。

High Bandwidth and High Numerical Aperture Graded-Index Polymer Optical Fiber

ISHIGURE TAKAAKI, HORIBE AKIHIRO, NIHEI EISUKE, KOIKE YASUHIRO

Electronics Letters Vol.30 ( No.14 ) 1169-1170 1994.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A large core (0.5-1.0mm), high-bandwidth (586MHz km), and low-loss (150dB/km at 650nm of wavelength) GI POF was successfully realized. The high index gradient Δn (0.028) resulted in a significant improvement in the bending loss for less than 50mm bending diameter compared with previous GI POFs.

Graded-Index Polymer Optial Fiber for High-Speed Data Communication

ISHIGURE TAKAAKI, NIHEI EISUKE, KOIKE YASUHIRO

Applied Optics Vol.33 ( No.19 ) 4261-4266 1994.07

Research paper (scientific journal), Joint Work, Accepted

　View Summary

We successfully obtained a high-bandwidth (1GHz km) and low-loss (90dB/km at 0.572&micro;m of wavelength) GI POF by using the interfacial-gel polymerization technique, in which we used an unreactive component to obtain the quadratic refractive-index distribution. This high-bandwidth GI POF makes it possible to transmit a high-speed optical signal in a short-rage network, which is not possible when we use the SI type of POF commercially available.

Spherical Gradient-Index Polymer Lens with Low Spherical Aberration

KOIKE YASUHIRO, KANEMITSU AKIYOSHI, NIHEI EISUKE, OHTSUKA YASUJI

Applied Optics Vol.33 ( No.16 ) 3394-3400 1994.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A sphere lens with a spherical GRIN was prepared by the modified suspension polymerization technique. GRIN spheres with quadratic- and linear-index distributions were obtained by two different methods to confirm the effect of the GRIN profile on the focusing property of the sphere lens. It was confirmed in both theory and experiment that the spherical aberration of such GRIN sphere was remarkably decreased compared with that of a homogenous sphere.

Highly Scattered Optical Transmission polymer

KOIKE YASUHIRO

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  43 ( 4月 ) 291 1994.04

Research paper (scientific journal), Single Work

　View Summary

ポリマー中に理論的にある条件を満足させるように不均一構造を形成させることで優れた光散乱特性を実現する方法を示した。

Polarization-Maintaining Optical lsolator Using Transparent Plastics with Optical Activity and Magnetooptical Property

TSUKAMOTO TOHRU, MUTO SHINZO, NIHEI EISUKE, KOIKE YASUHIRO

Kogaku(Japanese Joumal of Optics) Vol.23 ( No.3 ) 212-215 1994.03

Research paper (scientific journal), Joint Work

　View Summary

In the copolymer of MMA and BzMA doped with TPED, a rotatory angle increased with increasing the TPED concentration and the Verdet constant increased with increasing the BzMA composition. A new plastic optical isolator which keeps the light beam polarization, was tested using this TPED-doped poly (MMA-BzMA) rod. The isolation of about 20dB was obtained though the insertion loss was high due to the light scattering caused by the dopant molecules.

Graded-Index Optical Polymer Materials and Its Applications

KOIKE YASUHIRO, NISHIZAWA YUKIE

CERAMICS JAPAN (日本セラミックス協会)  Vol.29 ( No.3 ) 194-196 1994.03

Research paper (other academic), Joint Work

　View Summary

屈折率傾斜型ポリマー材料について、その作製方法や光学特性および光学材料への応用について解説する。

Measurement Method of Optical Properties

KOIKE YASUHIRO, NIHEI EISUKE

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  43 ( 2月 ) 82-85 1994.02

Research paper (scientific journal), Joint Work

　View Summary

高分子の光学特性の測定方法として、屈折率分布及び不均一構造について解説している。屈折率分布については、Maxwellの光線方程式をルンゲ?クッタ法を用いて直接数値積分して得られる結果と、実測して得られる結果とを一致させて求める方法を、ポリマー内部の不均一構造については、そのポリマーからの散乱光の角度依存性を測定し、これをデバイの式へ代入して求める方法を示している。（解説）

Highly Scattered Optical-Transmission Polymer and Its Application

KOIKE YASUHIRO, NIHEI EISUKE

Transactions of Material Research Society(MRS)Japan / IUMRS-ICAM-93, The 3rd IUMRS International Conference on Advanced Materials Vol. 15A   175-180 1993.09

Research paper (conference, symposium, etc.), Joint Work

　View Summary

We propose a new concept, Highly Scattered Optical Transmission Polymer (HSOT Polymer) as a new light source medium in which the light is effectively scattered and illuminated from the surface during light transmission. Since the light scattering is caused inside the HSOT Polymer due to specific heterogeneous structure, surrounding device such as diffuser film asnd dot printing etc. which is indispensable in conventional ones are not necessary in our proposal. The intensity of illumination is about 50% stronger than that of conventional PMMA plate systems.

Low-Loss High-Bandwidth GI Polymer Optical Fiber

ISHIGURE TAKAAKI, HORIBE AKIHIRO, NIHEI EISUKE, KOIKE YASUHIRO

Transactions of Material Research Society(MRS)Japan / IUMRS-ICAM-93, The 3rd IUMRS International Conference on Advanced Materials Vol. 15A,   181-184 1993.09

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Low Loss, high bandwidth GI polymer optical fiber was successfully obtained by the interfacial-gel polymerization technique using PMMA and other dopant as the core material. The GI POF could cover whole bandwidth which is required for the B-ISDN and Optical Interconnection concept.

Polymer Optical Fiber Amplifier

TAGAYA AKIHIRO, KOIKEYSUHIRO, KINOSHITA TAKESI, NIHEI EISUKE, YAMAMOTO TSUYOSHI, SASAKI KEISUKE

Applied Physics Letters, Vol.63 ( No.7 ) 883-884 1993.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

Polymer optical fiber amplifiers (POFA) of GI type, which have a gain in visible region, were successfully prepared by the interfacial-gel polymerization technique. The gain of 27 dB was observed at 591nm signal wavelength with 690W launched pomp power at 532 nm in a GI POFA with 0.5m length.

High-Bandwidth Organic Dye-Doped Polymar Optical Fiber Amplifier

YAMAMOTO TSUYOSHI, FUJII KAZUHITO, TERAMOTO SHIGEHIRO, TAGAYA AKIHIRO, NIHEI EISUKE, KINOSHITA TAKESHI, KOIKE YASUHIRO, SASAKI KEISUKE

Mulitigigabit Fiber Communcation Systems / SPIE-The international Society for Optical Engineering Proceedings (SPIE-The international Society for Optical Engineering)  Vol. 2024   42-51 1993.07

Research paper (conference, symposium, etc.), Joint Work

　View Summary

organic dye (Rhodamine B) doped polymer optical fiber amplifier (POFA) of GI type was successfully prepared for the first time. The GI POFA of only 500nm in length gave 27dB in gain at 591nm of signal wavelength. Additionally, absorption cross section and emmision cross section of Rhodamine B in PMMA matrix were estimated, which were required to analyze amplification mechanism in the POFA.

High-Power Polymer Optical Fiber Amplifier and Their Applications

YAMAMOTO TSUYOSHI, FUJII KAZUHITO, TERAMOTO SHIGEHIRO, TAGAYA AKIHIRO, NIHEI EISUKE, KINOSHITA TAKESHI, KOIKE YASUHIRO, SASAKI KEISUKE

SPIE- The International Society for Optical Engineering, Doped Fiber Devices and Systems (SPIE- The International Society for Optical Engineering)  Vol. 2042   42-51 1993.07

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Amplification characteristics of GI type organic dye doped POFA are discussed. As an organic dye for optical amplification, Rhodamine 6G, Rhodamine B, Perylene Red are doped in the core region of POFs. These POFA can obtain optical gain in the visible region of wavelength from 570nm to 620nm. POFA is promising for extraordinary high power optical amplification in comparison with rare-earth ions doped silica fiber amplifier. For example, output power of 1kW with a gain of 30dB can be obtained by using a Rhodamine B doped POFA at a low dye concentration of 1ppm. Additionally, a novel solid-state POFA amplifier system is demonstrated.

有機色素ドープポリマー光ファイバー増幅器

山本剛、寺本茂弘、多加谷明弘、二瓶栄輔、木下岳司、小池康博、佐々木敬介、藤井和人

電子情報通信学会技術研究報告書／電子デバイス；光・量子エレクトロニクス (社団法人電子情報通信学会)  Vol. 93 ( No, 168, 169 ) 51-57 1993.07

Research paper (other academic), Joint Work

　View Summary

Rhodamine B、Rhodamine 6G、Perylene Redを添加したポリマー光ファイバー増幅器をそれぞれ作製し、光増幅特性を実験的に確認し、報告している。信号光利得のファイバー長依存性について述べている。

High-Bandwidth Organic Dye-Doped Polymer Optical Fiber Amplifier

YAMAMOTO TSUYOSHI, FUJII KAZUHITO, TERAMOTO SHIGEHIRO, TAGAYA AKIHIRO, NIHEI EISUKE, KINOSHITA TAKESHI, KOIKE YASUHIRO, SASAKI KEISUKE

SPIE- The International Society for Optical Engineering, Multigigabit Fiber Communication Systems (SPIE- The International Society for Optical Engineering)  Vol. 2042   42-51 1993.07

Research paper (conference, symposium, etc.), Joint Work

　View Summary

Organic dye (Rhodamine B) doped POFA of GI type was successfully prepared for the first time. The GI-POF of only 500mm in length gave 27dB in gain at 591nm of signal wavelength. Additionally, absorption cross section and emission cross section of Rhodamine B in PMMA matrix were estimated, which were required to analyze amplification mechanism in the POFA.

High-Speed Opticalfiber and Contactlens by GRIN Polymer Materials

KOIKE YASUHIRO, NISIZAWA YUKIE

Chemical Education (社団法人　日本化学会)  41 ( 11 ) 749-753 1993.01

Research paper (other academic), Joint Work

　View Summary

光は、伝わる媒質が均一ならばまっすぐに進む。しかし、その道筋において媒質の形状や屈折率が変化すると、光は入射角に応じて反射や屈折率の現象を示してその進行方向を変える。私達のまわりでは、こういった光の現象を利用した、眼鏡やコンタクトレンズ、光ファイバー等の光学材料がいろいろ使われている。
従来の光学材料では、ほとんどのものが材料の形状を変化させることによって光線を制御しているが、近年、材料の形状に依存せず、材料中で光線を曲げることによってその進行方向を制御する材料が開発され、注目されている。
本稿ではその「光を曲げる材料」についてその作製方法および応用例について解説する。

GI型ポリマー光ファイバー

KOIKE YASUHIRO

Kao Chemical Forum  ( No.27 ) 15 1993

Research paper (other academic), Single Work

　View Summary

GI POFにつき簡潔に解説。

有機色素ドープポリマー光ファイバー増幅器

藤井和人、山本剛、寺本茂弘、多加谷明弘、二瓶栄輔、木下岳司、小池康博、佐々木敬介

電子情報通信学会技術研究報告 (社団法人 電子情報通信学会)  Vol. 92 ( No. 322-325 ) 63-68 1992.11

Research paper (conference, symposium, etc.), Joint Work

　View Summary

A Rhodamine B doped graded index polymer optical fiber was successfully prepared and the gain of 27dB was observed for the signal pules(591nm)by the excitation with SHG of Nd:YAG laser

Origin of Excess Light Scattering in Poly(Methyl Methacrylate) Glasses

KOIKE YASUHIRO, MATSUOKA SIROU, HARVEY E. BAIR

Macromolecules Vol.25 ( NO.18 ) 4807-4815 1992.09

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The Origin of the excess light scattering invariably observed in purified PMMA glasses was investigated. The isotropic heterogeneous structure with a dimension of about 1000Å, which increases the scattering loss by at least 1 order of magnitude (to several hundred dB/km) is generated during polymerization below Tg at high conversion and is not due to high molecular weight, specific tacticities, formation of cross-links, or aging. It is clearly shown that the remaining monomer in concentrations of several wt% does not aggregate spontaneously at high conversion to cause excess scattering unless polymerization takes place. The excess scattering is, we believe, mainly due to voids caused by the volume shrinkage accompanying polymerization of remaining monomer trapped inside the polymer glass. The excess scattering model proposed in this paper shows that if a slight amount of monomer in the PMMA glass is polymerized in situ at high conversion, generating slightly localized voids due to the aggregation of the unreacted initiator, a rise of only 1 wt% in the conversion increases the scattering loss by several hundred dB/km, which can reasonably explain the experimental result in this paper.

情報伝送量が従来の100倍以上のポリマー光ファイバー

KOIKE YASUHIRO

Chemistry and Chemical Industry (社団法人　日本化学会)  第45 ( 第7 ) 1261-1264 1992.07

Research paper (scientific journal), Single Work

　View Summary

高速伝送POFについての最近の結果を中心に述べる。

Gradient-Index Optical Polymer Materials

KOIKE YASUHIRO, NIHEI EISUKE

繊維と工業/繊維学会誌 (The Society of Fiber Science and Technology, Japan)  第.48 ( .5 ) 248-252 1992.05

Research paper (scientific journal), Joint Work

　View Summary

屈折率分布型光学機能材料の中でも、特に老視に用いることのできる２重焦点コンタクトレンズと、高帯域屈折率分布型光ファイバーのコネクタ部品として用いることが期待される低収差な屈折率分布型球レンズの作製方法、光学特性について解説している。（解説）

Gradient-Index Optical Polymer Materials

KOIKE YASUHIRO, NIHEI EISUKE

FGM　ニュース/傾斜機能材料研究会会報/ 傾斜機能材料研究会第14回ワークショップ (科学技術庁　傾斜機能材料研究会)   ( No. 16 ) 11-23 1992.04

Research paper (other academic), Joint Work

　View Summary

A Gradient-indax (GRIN) materials display unique and useful optical properties which are not achieved by conventional optical devices with a constant refractive indax. In this paaer, GRIN polymer materials for bifocal GRIN contact lens and GRIN polymer Optical Fibers are described.
In the GRIN fiber, the bandwidth is about 1 GHz・km which is two hundred times larger than that of conventional step-index (SI) polymer optical fiber. The total attenuation of transmission is 90-100dB/km at 572-nm wavelength.
The contact lens was obtained by polishing the GRIN sontactlens exactly satisfied the bifocal condition.

Waveguide Devices from Nonlinear Organic Materials

SASAKI KEISUKE, NONAKA YASUSHI, NIHEI EISUKE, KOIKE YASUHIRO

Molecular Crystal and Liquid Crystals (MCLC) Science Technology -Section B: Nonlinear Optics Vol.3,   61-68 1992.03

Research paper (other academic), Joint Work

　View Summary

Organic materials have bees applied to second and third order nonlinear optical thin film wave guide devices. In second-order devices, the basic material was a side-chained disperse red 1 (DR1)-MMA co-polymer system which was used for frequency doubling in the shorter wavelength region. The co-polymer was spin-coated on a Pyrex substrate and poled under a high DC-electric field over the glass transition temperature. Phase matching at double wavelengths, 532 and 406nm were realized by Cherenkov type in-phasing between fundamental and doubled waves avoiding strong absorption. In the third-order device, the basic was vacuum evavporated PDA film which was applied to all optical bistable waveguide devices together with a DFB structure.

Graded-Index and Single-Mode Polymer Optical Fibers

KOIKE YASUHIRO

Material Research Society(MRS) Symposium Proceedings (Material Research Society(MRS))  Vol. 247   817-828 1992

Research paper (conference, symposium, etc.), Single Work, Accepted

　View Summary

High-Bandwidth GI POF and single-mode POF with good mechanical properties were successfully obtained by our interfacial gel polymerization technique. The bandwidth of the GI POF is about 1GHz・km which is two hundred times larger than that of the conventional SI POF. The minimum attenuation of transmission is 56dB/km at 688nm wavelength and 94 dB/km at 780nm wavelength. The single-mode POF in which the core diameter was 3-15&micro;m and the attenuation of transmission was 200dB/km at 652nm wavelength was successfully obtained for the first time.

Second-Harmonic Generation by Cherenkov-Type Phase Matching in A Poled Polymer Waveguide

SUGIHARA OKIHIRO, KUNIOKA S, NONAKA YASUSHI, AIZIAWA RIKA, KOIKE YASUHIRO, KINOSITA TAKESI, SASAKI KEISUKE

Journal of Applied Physics Vol. 70 ( No.12 ) 7249-7252 1991.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A copolymer of MMA and azo-dye-substituted methacrylate is corona-poled. Cerenkov-type second harmonic generation (SHG) of Nd:YAG laser is observed in the poled polymer waveguide even though there is strong absorption of the SHG wavelength. The total SHG conversion efficiency is 1.72×10-3 %, and the next SHG conversion efficiency in the waveguide is 0.12%.

単分散、低収差ＧＲＩＮ球レンズ

KOIKE YASUHIRO

Koubunshi, High Polymers Japan (The Society of Polymer Science, Japan)  40 ( 10月 ) 690 1991.10

Research paper (scientific journal), Single Work

　View Summary

新たに提案した懸濁重合を用いることにより,非常に単分散で特性のそろった屈折率分布型球レンズを作製する方法を示した。

Grade-Index Polymer Optical Fiber by New Random Copolymerization Technique

KOIKE YASUHIRO, HONDOU YUKIE, NIHEI EISUKE

Proceedings of SPIE's International Symposium on Plastic Optical Fiber (SPIE (The Internatinal Society for Optical Engineering))  Vol. 1592   62-72 1991.09

Research paper (conference, symposium, etc.), Joint Work

　View Summary

A high-bandwidth Graded-Index (GI) polymer optical fiber (POF) was successfully obtained by our new random interfacial-gel copolymerization technique. The bandwidth of the GI POF is about 1GHz.km which is two hundred times higher than that of the conventional Step-Index (SI) POF. The total attenuation of the light transmission through these GI POFs is 150-200db/km at 625nm wavelength and the tensile strength is 1600 kg/cm2

High-Bandwidth Grade-Index Polymer Optical Fibre

KOIKE YASUHIRO

Polymer Vol.32 ( No.10 ) 1737-1745 1991.06

Research paper (scientific journal), Single Work, Accepted

　View Summary

A low-loss and high-bandwidth GI POF in which the attenuation of transmission was less than 150dB/km at 650nm wavelength and the bandwidth was several hundreds MHz km has been successfully obtained by a copolymerization process utilizing the difference of the monomer reactivities. The control of the refractive index profile and the light scattering of such GI materials are the theoretically and experimentally investigated.

非複屈折性光学ポリマー固体

KOIKE YASUHIRO

Japanese Journal of Optics (Optical Society of Japan, (An Affiliate of The Japan Society of Applied Physics))  第20 ( 第2 ) 80-81 1991.02

Research paper (scientific journal), Single Work

　View Summary

複屈折の値が正負異なるポリマーを与えるモノマーをランダムに共重合することにより、均一性、透明性に優れる非複屈折性光学ポリマー固体を提案し、そのようなポリマーの合成を行ってきた。その原理と光学特性について解説する。

Contact Lens Prepared from Gradient Refractive Index Plastic Rod.PartⅢ;Application for Bifocal Contact Lens

KURIAKI MASAMITSU, NAKAMURA KANICHI, MIZUTANI YUTAKA, SAISIN MOTOTSUGU, UOZATO HIROSI, HARA YOSIAKI, OHTSUKA YASUJI, KOIKE YASUHIRO

Japanese Journal of Visual Science (日本眼光学会)  Vol.11 ( No.1 ) 57-61 1990.10

Research paper (scientific journal), Joint Work

　View Summary

We have continued some works of the application of a GRIN plastic rod for a CL, the index is gradually increasing (a type of LDR, an application for (-) lens) and decreasing (a type of LFR, an application for (+) lens) to periphery of rod from principal optic axis. The report related to the application of GRIN-complexed LDR and LFR for bifocal CL. GRIN-complexed LFR in certain part and LDR in peripheral part was available to the bifocal of simultaneous type, arranging near zone in central part and distance zone in peripheral part. Also, GRIN-complexed LDR in central part and LFR in peripheral part was available to the bifocal CL of translating type, arranging distance zone in central part and near zone in peripheral part.

Graded-Index Optical Fibers of Methyl Methacrylate-Vinyl Benzoate Copolymer with Low Loss and High Bandwidth

OHTSUKA YASUJI, NIHEI EISUKE, KOIKE YASUHIRO

Applied Physics Letter Vol.57 ( No.2 ) 120-122 1990.08

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The interfacial-gel copolymerization of 3/1, or 4/1 (wt/wt) MMA-VB monomer mixture followed by heat drawing result in GI POFs with attenuation loss of 212 and 134dB/km at 652nm, respectively, and with bandwidth of 170 and 260 MHz km, respectively, in comparison with 6 MHz km of the current SI POF. Now, it has been confirmed experimentally that GI fibers are tremendously superior to SI fibers for data-carrying capacity, while attenuation losses of both fibers are comparable.

Low-Loss GI Plastic Optical Fiber and Novel Optical Polymers

小池康博、二瓶栄輔、大塚保次

Specialty Polymer'90, Plenaly talk (Baltimore,USA)  1990.08

Joint Work

　View Summary

米国ボルチモアで開かれた国際会議で低損失,屈折率分布型ポリマー光ファイバーの作製法およびその特性について講演した。

AT & T ベル研究所滞在レポートとプラスチック光ファイバの現状

KOIKE YASUHIRO

Optoelectronics Magazine New Era (日本鉱業株式会社)   ( 7月 ) 36-39 1990.07

Research paper (scientific journal), Single Work

　View Summary

米国ベル研究所の概要、組織、研究内容、研究環境等につき、簡潔に紹介しプラスチック光ファイバの研究の現状につき解説した。

Graded-Index Plastic Optical Fiber Composed of Methyl Methacrylate and Vinyl Phenylacetate Copolymers

KOIKE YASUHIRO, NIHEI EISUKE, TANIO NORIHISA, OHTSUKA YASUJI

Applied Optics Vol.29 ( No.18 ) 2686-2691 1990.06

Research paper (scientific journal), Joint Work, Accepted

　View Summary

GI-POF whose transmission attenuation is 143dB/km at 651nm wavelength was fabricated by heat drawing the corresponding GI Preform rod. This rod is prepared by the interfacial-gel copolymerization technique of MMA and VPAc. The total scattering loss of the GI preform rod is 〜60dB/km at 633nm. The GI profiles of the optical fibers are almost the same as those of the corresponding preforms with cladding sheaths. The index distributions of their core regions are quadratic against the distance from the center axis. The numerical aperture estimated from the index is 〜0.20.

AT & T Bell Laboratories

KOIKE YASUHIRO

繊維と工業/繊維学会誌 (The Socety of Fiber Science and Technology)  第46 ( 1 ) 33-37 1990.01

Research paper (other academic), Single Work

　View Summary

米国ベル研究所の概要、組織、研究内容、研究環境等につき、簡潔に紹介した。

Low-Loss GI Plastic Optical Fiber and Novel Optical Polymers

KOIKE YASUHIRO, OHTSUKA YASUJI

MRS Symposium Proceedings (Material Research Society (MRS))  Vol. 172   247-252 1990

Research paper (conference, symposium, etc.), Joint Work

　View Summary

A low-loss GI Plastic optical fiber in which the attenuation of transmission was 130 dB/km at 650 nm wavelength was successfully obtained by a new interfacial-gel copolymerization technique. Novel optical functional polymer and optically active amorphous polymer which act as polarization modulators were synthesized and characterized.

Gradient-Index Polymer Materials and Their Optical Devices

KOIKE YASUHIRO, TANIO NORIHISA, NIHEI EISUKE, OHTSUKA YASUJI

Polymer Engineering and Science Vol.29 ( No.17 ) 1200-1204 1989.09

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A GRIN plastic optical fiber was prepared by a heat drawing process of the GRIN preform rod obtained by a new interfacial-gel copolymerization technique. The attenuation loss of the GRIN fiber was 179kB/km at 650nm wave-length and its numerical aperture was 0.20-0.25. To attain low loss and highly dense integrated circuits, steric radial-GRIN optical waveguide components such as GRIN branching, star coupler, multi-coupler, and a 2-D GRIN lens array, were monolithically fabricated by this technique. A novel spherical GRIN sphere lens, whose index function is symmetrical about the center of the sphere, with a low spherical aberration, was prepared by a modified suspension polymerization technique. A W-shaped GRIN sphere has been newly proposed to further reduce the spherical aberration, compared with the parabolic GRIN sphere previously proposed.

Contact Lens Prepared from Gradient Refractive Index Rod. Part II; Application to (-) Lens of Light Diffusing Plastic Rod.

M. Kuriaki, J. Mizutani, Y. Mizutani, M. Saishin, H. Uozato, Y. Hara, Y. Ohtsuka, and Y. Koike

Japanese Journal of Visual Science (日本眼光学会)  Vol.10 ( No.1 ) 40-45 1989.03

Research paper (scientific journal), Joint Work

　View Summary

近視用コンタクトレンズへの屈折率分布材料の応用を提案、実証した。

Light Scattering and Heterogeneities in Low-Loss Poly(Methyl Methacrylate) Glasses

KOIKE YASUHIRO, TANIO NORIHISA, OHTSUKA YASUJI

Macromolecules, VOl.22 ( No. 3 ) 1367-1373 1989.03

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A PMMA glass was prepared for the first time, in which the light-scattering loss was much smaller than any reported data and no large size of heterogeneities existed. The total scattering loss was much 13dB/km which represents an intrinsic limiting loss of the PMMA glasses attainable in the atmosphere. The isotropic scattering loss widely varied between ca. 9 and 400 dB/km according to the conditions of polymerization or heat treatment, while the anisotropic scattering loss was almost unchanged in the range 4-6 db/km. The origins of the large heterogeneities with the diameter of ca. 1000Å, which have been invariably observed in PMMA glasses reported so far, were investigated by the angular dependence of the light scattering. The large excess scattering is caused mainly by the isotropic strain inhomogeneities caused during polymerization and not by a small amount of remaining monomers or additives, the molecular weight of polymers, the stereoregularity due to the specific tacticity of PMMA, or cross-linking as a result of the gel effect.

Inherent Light Scattering Losses by Amorphous Optical Polymer Glasses

TANIO NORIHISA, KOIKE YASUHIRO, OHTSUKA YASUJI

Polymer Journal (The Society of Polymer Science, Japan)  Vol.21 ( No.3 ) 259-266 1989.03

Research paper (scientific journal), Joint Work

　View Summary

Inherent light scattering losses by several methacrylic ester polymers were investigated. The intensities of polymerization scattering Vv from PMMA reported so far were in the order of 10-5 cm-1 even in a sample polymerized with rigorous purification, and had angular dependence in its Vv intensity, which implied the existence of large size heterogeneities of several hundred Å. In this paper, alkyl (ethyl and isobutyl) and fluoroalkyl (trifluoroethyl and trihydroperfluoropropyl) methacrylate glasses as well as PMMA, in which the Vv intensities were in the order of 10-6 cm-1 and no large size of heterogeneities were recognized, were prepared for the first time. Considering that our data are quite near the value predicted by the thermally induced fluctuation theory, and on the basis of our previous study, it is suggested that the thermally induced fluctuation theory, and on the basis of our previous study, it is suggested that the scattering data presented in this paper show an inherent limited loss for these methacrylic ester polymer glass in the atmosphere.

Gradient Refractive Index Plastic Rod(GRIN)as Contact Lens Diffusing Plastic Rod(LDR)as(-)Lens Material

KURIAKI MASAMITSU, NAKAMURA KANICHI, MIZUTANI YUTAKA, SAISIN MOTOTSUGU, UOZATO HIROSI, HARA YOSHIAKI, OHTUSKA YASUJI, KOIKE YASUHIRO

Jourmal of Japan Contact Lens Society Vol.31 ( No.2 ) 163-170 1989.03

Research paper (scientific journal), Joint Work

　View Summary

We reported the application of a GRIN plastic rod, a type of light focusing rod (LFR), a material of comparatively high central refractive index, the index gradually decreasing from principal optic axis (POA) to periphery. The LFR-GRIN possesses excellent properties for use as material for positive power contact leness (CL). This paper concerns negative power CL material application of GRIN type of light diffusing rod (LDR), whose POA index is lowest, the index gradually increasing from POA to periphery. As well LFR-GRIN and GRIN complexed LFR-LDR were used in negative power CLs. The result was that the center thickness of a CL made from LDR-GRIN is thinner than PMMA. From a theoretical focusing viewpoint, because the power differential between the center part of the CL and the periphery ranges from 1.00D to 3.00D.

Optical Waveguide

KOIKE YASUHIRO

繊維と工業/繊維学会誌 (The Society of Fiber Science and Technology, Japan)  第45 ( 2 ) 62-67 1989.02

Research paper (scientific journal), Single Work

　View Summary

オプトエレクトロニクスの中で、光の伝達部分を担当するプラスチック光ファイバー、光導波路について、最近の研究成果と今後の可能性について概説する。

Temparature Dependence of Light Scattering by Low-Loss Poly(Methyl Methacrylate) Glasses

TANIO NORIHISA, KOIKE YASUHIRO, OHTSUKA YASUJI

Polymer Journal (The Society of Polymer Science, Japan)  Vol.21 ( No.2 ) 119-125 1989.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A PMMA glass with the lowest light scattering loss among data reported so far and with no angular dependence in its scattering intensity was prepared by radical polymerization above Tg (Sample A). The temperature dependence of the light scattering intensity for this PMMA glass was investigated, in comparison with the PMMA glass polymerized below Tg and having excess scattering loss due to large-size heterogeneous structures (Sample B). In the sample A, the polarized scattering intensity (Vv) slightly changed below Tg and increased smoothly with increasing temperature above Tg in accordance with the fluctuation theory for structureless liquids. On the other hand, in the sample B, an abrupt decrease in Vv scattering around Tg was observed with increasing temperature. On the basis also of our previous study, it is suggested that the different trend of temperature dependence of light scattering and of excess scattering even in highly purified PMMA glasses depends on whether the strain inhomogeneities generated during the polymerization process are already relaxed above Tg or retained below Tg, and that the scattering behavior is not directly affected by first order structures such as molecular weight, tacticity, and remaining monomers.

Refractive Index, Refractive Index Distribution, Birefringence

KOIKE YASUHIRO

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  37 ( 10月 ) 768-771 1988.10

Research paper (other academic), Single Work

　View Summary

光学特性の測定法の中で、測定精度が高く実際的である方法に絞って解説する。

High-Bandwidth, Low-Loss Graded-index Polymer Optical Fiber

石榑崇明、二瓶栄輔、小池康博

24^th^ European Conference on Optical Communication (ECOC'98), (Madrid,Spain),1988  1988.09

Joint Work

　View Summary

全フッ素化ポリマーを母材として作製したGI型POFの伝送帯域が石英系の伝送帯域を凌駕することが明らかになった結果を示した招待講演。

A Contact Lans Prepared from Gradient Index Material

YUUKI HIROTO, MIZUTANI JUN, MIZUTANI YUTAKA, OHTSUKA YASUJI KOIKE YASUHIRO

Japanese Joumal of Visual Science (日本眼光学会)  Vol.9 ( No.1 ) 24-29 1988.05

Research paper (scientific journal), Joint Work

　View Summary

In this paper we report that plastic with GRIN was applied to material of contact lens. The plastic GRIN was successfully prepared by a special 2 step co-polymerization technique. The index profile of the plastic GRIN was measured by shearing interferometry. It was confirmed that the index profile was almost quadratic and the index difference between at the center and at the periphery was 0.03. We confirmed that the plastic GRIN corrects a spherical aberration of contact lens.

Gradient-Index Polymer Materials and Their Optical Devices

KOIKE YASUHIRO, OHTSUKA YAUJI

SPE-Society of Plastic Engineers 46^th^ Annual Technical Conference & Exhibits International Symposium of ANTIC'88 (SPE-Society of Plastic Engineers)     424-428 1988.04

Research paper (conference, symposium, etc.), Joint Work, Accepted

　View Summary

We have proposed four techniques to prepare axial-, radial-, spherical-, and other novelGRIN materials. The technologies of obtaining GRIN polymer and the resulting products, proposed in our laboratory until now are summerized. Since the two-step copolymerization and photocoplymerization techniques have been frequently reported so far, we focus, in this paper, on the GRIN optical fiber and optical waveguide by the interfacial-gel copolymerization technique, and the spherical GRIN spher lens with a low spherical aberration by the suspension polymerization technique.

New Interfacial-Gel Copolymerization Technique for Steric GRIN Polymer Optical Waveguides and Lens Arrays

KOIKE YASUHIRO, TAKEZAWA YOSHITAKA, OHTSUKA YASUJI

Applied Optics Vol.27 ( No.3 ) 486-491 1988.02

Research paper (scientific journal), Joint Work, Accepted

　View Summary

A new interfacial-gel copolymerization technique is proposed to prepare steric GRIN optical waveguides and lens arrays. Since the GRIN profile is obtained from the thin-gel phase formed on the wall of a polymer substrate, many geometrical GRIN materials, such as axial-, radical-GRIN, can be monolithically fabricated. In this paper, the principle of GRIN formation is clarified, and a few steric radial-GRIN circuit components are demonstrated.

Gradient-Index Polymer Lens and Optical Waveguide

KOIKE YASUHIRO, OHTSUKA YASUJI

応用物理/応用物理学会誌 (The Japan Society of Applied Phisics)  第56 ( 第11 ) 1447-1452 1987.11

Research paper (scientific journal), Joint Work

　View Summary

有機ポリマーは、無機ガラスに比べ、いろいろな分布屈折率パターンを形成しうることから、今まで得られなかった新しいGRIN光デバイスが試作されはじめており、興味深い。軸ずれ収差が原理的に存在しない低収差GRIN球レンズ、立体GRIN光導波路素子、レンズアレーなどである。これらの光デバイスならびに、広伝送帯域GRIN光ファイバーの開発について述べる。（解説）

GRIN '87会議に参加して

KOIKE YASUHIRO

光学/日本光学会誌 (Optical Society of Japan (An Affiliate of the Japan Society of Applied Optics))  第16 ( 第5 ) 220（40）-221（41） 1987.05

Research paper (scientific journal), Single Work

　View Summary

国際会議GRIN’87への参加報告。

屈折率分布型球レンズ

KOIKE YASUHIRO, OHTSUKA YASUJI

高分子/高分子学会誌 (The Society of Polymer Science, Japan)  35 ( 12月 ) 1102 1986.12

Research paper (scientific journal), Joint Work

　View Summary

従来の球に比べ、内部に球対称に屈折率分布を付与とすると集光スポットが小さくなることを立証.。

Spherical Gradient-Index Sphere Lens

KOIKE YASUHIRO, SUMI YUJI, OHTSUKA YASUJI

Applied Optics Vol.25 ( No.19 ) 3356-3363 1986.10

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The sphere lens with a spherical GRIN was prepared for the first time by two modified suspension polymerization techniques. The index change of the 0.05-3.0 mm diam GRIN sphere was 0.02-0.04, and the index profile was almost quadratic. The optimum condition minimizing the spherical aberration of the GRIN sphere embedded in a certain substrate was confirmed. Furthermore, 1-D GRIN sphere lens arrays were fabricated.

Plastic Gradient-Index Optical Fiber and Optical Devices

KOIKE YASUHIRO

繊維と工業/繊維学会誌 (The Society of Fiber Science and Technology, Japan)  第42 ( 4 ) 122-129 1986.04

Research paper (scientific journal), Single Work

　View Summary

本題について、現状と展望を中心に解説。

光学プラスチック

KOIKE YASUHIRO

第12回　冬期講習会テキスト「結像光学用の材料と加工」 (応用物理学会、光学懇話会)     1-39 1986.01

Research paper (other academic), Single Work

　View Summary

プラスチック工学材料について解説。

Plastic Axial Gradient-Index Lens

KOIKE YASUHIRO, HIDAKA HIROSHI, OHTSUKA YASUJI

Applied Optics Vol.24 ( No.24 ) 4321-4325 1985.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

An axial GRIN lens, where the refractive index varies along the optical axis of a convex lens, can reduce the spherical aberration compared with the conventional homogeneous lens. The transparent plastic axial GRIN material was successfully fabricated by chemical copolymerization and diffusion technique. The depth of the gradient index was 〜20 mm with the refractive-index change Δn=0.07. By carrying out the ray tracing of the axial gradient index, the optimum refractive-index distribution reducing the spherical aberration was determined. If we assume that the axial GRIN lens was constructed from the sample experimentally obtained, it was theoretically confirmed that the spherical aberration of this lens would be remarkably improved.

Studies on The Light-Focusing Plastic Rod.18: Control of Refractive-Index Distribution of Plastic Radial Gradient-Index Rod by Photocopolymerization

OHTSUKA YASUJI, KOIKE YASUHIRO

Applied Optics Vol.24 ( No.24 ) 4316-4320 1985.12

Research paper (scientific journal), Joint Work, Accepted

　View Summary

The refractive-index distribution patterns obtainable by the photocopolymerization of ternary monomer systems were predicted with the help of the mechanism for forming a radial gradient index reported by Ohtsuka and Koike. On the basis of this prediction, we successfully fabricated a convex lens, a concave lens, and a fiber with the W-shaped index distribution expected of an optical fiber with low modal dispersion. It was theoretically and experimentally confirmed that the index distribution of the rod by the photocopolymerization of a ternary monomer system could be widely controlled.

Light Scattering and Local Structure in Low-Loss Poly(Methyl Methacrylate)Glasses

大塚 保治、小池 康博、淡路 治子、谷尾 宣久

Kobunshi Ronbunshu,Japanese Joumal of Polymer Science and Technology Vol.42 ( No.4 ) 265-271 1985.04

Research paper (scientific journal), Joint Work

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The attenuation of light transmittance through a POF in the range of visible light is governed by light scattering loss. In this paper, the possibility of decreasing scattering loss in PMMA, which is one of the core materials of POF, is discussed. The light scattering loss of the PMMA glass prepared from a contaminant-free monomer depended on the conditions of polymerization and heat-treatment. We succeeded in preparing the PMMA glass with a light scattering loss lower than the value, 14 dB/km, which was reported as the theoretical limitation at 633 (nm)-wavelength in the fluctuation theory for structureless liquids. The angular dependence of light-scattering intensity suggested the existence of heterogeneous regions (several hundreds Å) with the order of 10-5 of refractive-index differences. This fluctuation would be caused by the stress-strain due to volume-contraction during tacticity nor by the small amount of remaining monomer.

Studies on The Light-Focusing Plastic Rod.17: Plastic GRIN Rod Lenz Prepared by Photocopolymerization of A Ternary Monomer System

KOIKE YASUHIRO, HATANAKA HIDEYUKI, OHTSUKA YASUJI

Applied Optics Vol.23 ( No.11 ) 1779-1783 1984.06

Research paper (scientific journal), Joint Work, Accepted

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Plastic GRIN rod lenses have been fabricated by photocopolymerization of ternary monomer system. To select the monomer appropriate to photocopolymerization, we developed a computer program to predict the physical constants of homopolymer from the chemical structure. Furthermore, according to the model of the gradient-index formation, MMA-VB monomer system and MMA-benzyl acrylate-VB monomer system were chosen as suitable systems. In both monomer system, plastic GRIN rods with good lens functions up to the periphery were successfully obtained.

Studies on The Light-Focusing Plastic Rod.16: Mechanism of Gradient-Index Formation in Photocopolymerization of Multiple Monomer Systems

OHTSUKA YASUJI, KOIKE YASUHIRO

Applied Optics Vol.23 ( No.11 ) 1774-1778 1984.06

Research paper (scientific journal), Joint Work, Accepted

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In this paper, we propose a general mechanism for forming a radial GRIN rod by photocopolymerization in multiple monomer systems and a method of selecting new monomer systems applicable to GRIN. By using the simulation with various monomer systems, it is shown that the index distribution of a plastic GRIN rod can be tightly controlled by the selection of ternary monomer system and the photocopolymerization condition.

The Plastic GRIN Rod Prepared by The Photocopolymerization Process-Control of The Refractive-Index Distribution

OHTSUKA YASUJI, KOIKE YASUHIRO

日本光学会誌「光学」/　日本光学会第８回光学シンポジウム (Optical Society of Japan, An Affiliate of the Japan Society of Applied Phisics)  第12 ( 第6 ) 470(58)-475(63) 1983.12

Research paper (scientific journal), Joint Work

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Plastic GRIN Rods with various profiles of refractive-index distributions were successfully obtained by the photocopolymerization process. We propose a mechanism to form radial GRIN by photocopolymerization in multimonomer systems. By developing the computer program which calculates the physical conditions of polymer from the chemical structure, and which predicts the index profile of the GRIN rods on the basis of the above mechanism, the index profile of the GRIN rods fabricated were tightly controlled.

Studies on The Light-Focusing Plastic Rod.15: GRIN Rod Prepared by Photocopolymerization of A Ternary Monomer System

KOIKE YASUHIRO, OHTSUKA YASUJI

Applied Optics Vol.22 ( No.3 ) 418-423 1983.02

Research paper (scientific journal), Joint Work, Accepted

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Plastic GRIN rod and fiber lenses have been fabricated by photocopolymerization of a ternary monomer system, methyl methacrylate-N-vinyl carbazole vinyl acetate. We now propose the general mechanism for forming radial GRIN in the ternary monomer system using computer simulation. The relationship between the preparation condition and the optical characteristics was clarified. The region having quadratic-index distribution and the numerical aperture were remarkably improved by the ternary monomer system.

Studies on The Light-Focusing Plastic Rod.XIII: Photocopolymerization of Methyl Methacrylate-Vinyl Esters of Aromatic Carboxylic Acid

KOIKE YASUHIRO, KIMOTO YOSHIHIKO, OHTSUKA YASUJI

Journal of Applied Polymer Science Vol.27 ( No.9 ) 3253-3264 1982.09

Research paper (scientific journal), Joint Work, Accepted

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The light-focusing rod (LFR) was prepared by the photocopolymerization of MMA with VPAC and VB, using BPO, BN, and BME as an initiator. The LFR with high transparency and steep refractive-index distribution was obtained using MMA-VPAc pair and BME. The difference in the index distributions under BPO, BN, and BME initiations was clarified in terms of the photoinitiation rate and the accompanying thermal polymerization during the photocopolymerization process. The light scattering intensity from the LFR was related to the heterogeneity of the copolymer composition and the compatibility between the M1 and M2 polymers. The comparison of the light scattering theory with the experimental data indicated that the much less scattering intensity from the MMA-VPAc LFR than the MMA-VB LFR should be attributed to the good compatibility between MMA and VPAc polymers, and scarcely attributed to the index difference between the VPAc and VB polymers.

Studies on The Light-Focusing Plastic Rod.12: The GRIN Fiber Lens of Methyl Methacrylate-Vinyl Phenylacetate Copolymer

KOIKE YASUHIRO, KIMOTO YOSHIHIKO, OHTSUKA YASUJI

Applied Optics Vol.21 ( No.6 ) 1057-1062 1982.03

Research paper (scientific journal), Joint Work, Accepted

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The light-focusing plastic rod (LFR) and fiber (LFF) were fabricated by Photocopolymerization of MMA with VPAc. The MMA-VPAc LFR has much higher clarity than that of the MMA-VB LFR reported previously. Using the BME as the initiator, which initiates photopolymerization preferentially, led to a much steeper index distribution than using BPO, which initiates thermal- and photochemical polymerization simultaneously. The relationship between preparation condition and optical characteristics were clarified in terms of the index distribution, light scattering, lens function, and attenuation of light transmission.

Studies on The Light-Focusing Plastic Rod.7: Estimation of The Refractive-Index Profile of The Doubly Imaging Fiber-Lens

OHTSUKA YASUJI, KOIKE YASUHIRO

Journal of Society of Fiber Science and Technology Vol.37 ( No.11 ) 439-447 1981.11

Research paper (scientific journal), Joint Work

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A doubly-imaging fiber-lens (DIF) was fabricated by the Photocopolymerization of MMA with VB. The core and the outer portions of the DIF form two refractive-index distributions with different gradient-indexes from one another. The DIF, assuring a meridional ray under paraxial condition, led to a simple and feasible method estimating the index-profile of DIF on a basis of its lens function. The validity of this method was verified by the measurement in various conditions and the comparison with the index-profile determined interferometrically.

Studies on The Light-Focusing Plastic Rod.10: A Light-Focusing Plastic Fiber of Methyl Methacrylate-Vinyl Benzoate Copolymer

OHTSUKA YASUJI, KOIKE YASUHIRO, YAMAZAKI HIROTAKA

Applied Optics Vol.20 ( No.15 ) 2726-2730 1981.08

Research paper (scientific journal), Joint Work, Accepted

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A light-focusing plastic fiber (LFF) with a parabolic refractive-index distribution was obtained by the continuous heat drawing of the preform prepared from the Photocopolymerization of MMA with VB. The relation between the preparation conditions and the optical and mechanical properties of the LFFs was clarified. The index profile of LFFs is found to be scarcely affected by the continuous heat drawing process compared with that of original preforms. The resulting LFF would be suitable for short-distance communication system due to its attenuation being higher than 103 dB/km.

Studies on The Light-Focusing Plastic Rod.6: The Photocopolymer Rod of Methyl Methacrylate with Vinyl Benzoate

OHTSUKA YASUJI, KOIKE YASUHIRO, YAMAZAKI HIROTAKA

Applied Optics Vol.20 ( No.2 ) 280-285 1981.01

Research paper (scientific journal), Joint Work, Accepted

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The Photocopolymerization of MMA with VB containing BPO was carried out in a glass tube to fabricate a light-focusing plastic Rod (LFR, radius Rp) with a parabolic refractive-index distribution (distribution constant A) in the region near the center axis (radius Rc). The dependence of A and Rc/Rp on MMA/VB, BPO concentration and the velocity of the UV lamp was clarified. These relations could be explained using a computer simulation based on the polymerization mechanism.

Determination of The Refractive-Index Profile of Light-Focusing Rods: Accuracy of a Method Using Interphako Interference Microscopy

OHTSUKA YASUJI, KOIKE YASUHIRO

Applied Optics Vol.19 ( No.16, ) 2866-2872 1980.08

Research paper (scientific journal), Joint Work, Accepted

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Two analysis procedures to determine the refractive-index profile using Interphako interference microscopy are compared for accuracy: (I) express the profile as a five-nominal equation; (II) considering ray bending due to the index gradient and using Abel inversion. Computer simulation indicate that the errors of both procedures are comparable except for mismatching between the specimen periphery (np) and immersion oil (n2) where Analysis (I) is more accurate than Analysis (II). The partial splitting method is more practicable than total spotting for a rodlike specimen. In addition, improved partial splitting procedure facilitates reduction of error. The index profiles of the two selected light-focusing plastic rods (LFR) were calculated with these two procedures in various conditions. It is concluded that Analysis (I) is preferable to Analysis (II) when np≠n2 and that the improved partial splitting procedure is a practicable method for determining the index profile of LFR.