Papers - Koike, Yasuhiro

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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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µm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

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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

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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 ≏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

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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

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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

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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

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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.