Details of a Researcher - Koike, Yasuhiro

Papers - Koike, Yasuhiro

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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

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

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–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 −2.6. This optode responded to sodium ion in the concentration range from 10−5 to 10−1 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 4.5µm 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.

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