Details of a Researcher - Koike, Yasuhiro

Papers - Koike, Yasuhiro

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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

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

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

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

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. % 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

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

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

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

FRANTISˇEK MIKESˇ, YU YANG, TERAOKA IWAO, ISHIGURE TAKAAKI, KOIKE YASUHIRO, OKAMOTO YOSHIYUKI

Macromolecules Vol. 38 ( No. 10 ) 4237 – 4245 2005.05

Research paper (scientific journal), Joint Work, Accepted

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

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

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

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

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

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

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

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

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

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

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

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