Papers - Koike, Yasuhiro

ＰＯＦ

NIHEI EISUKE, KOIKEYASUHIRO

工業材料 Vol. 44 ( No. 4 ) 29-34 1996.04

Research paper (other academic), Joint Work

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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

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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

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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

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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

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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

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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

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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

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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

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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

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　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 ; 100µm, 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

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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

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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

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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-µm 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

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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

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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

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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

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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

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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

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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

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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.