Koike, Yasuhiro

写真a

Affiliation

University （Mita）

Position

Professor (Non-tenured)
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Other Affiliation 【 Display / hide 】

  • Keio Photonics Research Institute, Director

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Career 【 Display / hide 】

  • 1982.04
    -
    1983.03

    Keio University, Faculty of Science and Technology, 非常勤講師

  • 1983.04
    -
    1988.03

    Keio University, Faculty of Science and Technology,  助手

  • 1988.04
    -
    1992.03

    Keio University, Faculty of Science and Technology, 専任講師

  • 1989.04
    -
    1990.02

    AT&T Bell Laboratories, Visiting Researcher

  • 1992.04
    -
    1997.03

    Keio University, Faculty of Science and Technology,  助教授

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Academic Background 【 Display / hide 】

  • 1977.03

    Keio University, Faculty of Engineering, Department of Applied Chemistry

    University, Graduated

  • 1979.03

    Keio University, Graduate School, Division of Engineering

    Graduate School, Completed, Master's course

  • 1982.03

    Keio University, Graduate School, Division of Engineering

    Graduate School, Completed, Doctoral course

  • 2007.04

    Eindhoven University of Technology, Electrical Engineering

    5600MB, Eindhoven, Ｎ, Graduate School, Other, Doctoral course

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Academic Degrees 【 Display / hide 】

  • Engineering, Keio University, 1982.03

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Research Areas 【 Display / hide 】

  • Polymer chemistry (Photonics Polymer)

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Research Keywords 【 Display / hide 】

  • Graded Index Plastic Optical Fiber, Zero-Birefringence Polymers

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Books 【 Display / hide 】

  • Fundamentals of Plastic Optical Fibers

    Wiley-VCH, 2015.01

  • 透明ポリマーの材料開発と高性能化

    シーエムシー出版, 2015

    Scope: 第16章　プラスチック光ファイバー

  • Handbook of Fluoropolymer Science and Technology

    Y. Okamoto, F. Mikes, K. Koike, and Y. Koike, Wiley, 2014.05

    Scope: Amorphous Perfluoropolymers

  • 高分子ナノテクノロジーハンドブック～最新ポリマーABC技術を中心として～

    （株）エヌ・ティー・エス, 2014.03

    Scope: 第2章　IT・エレクトロニクスイノベーション：電気電子デバイスの高度化　第5節　フォトニクスポリマーデバイス

  • Optical Fibers; New Developments

    K. Koike, Y. Koike, and Y. Okamoto, Nova Science Publisher, 2013.09

    Scope: Graded-Index Plastic Optical Fibers: Materials and Fabrication Techniques

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Papers 【 Display / hide 】

  • 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

    　View Summary

    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.

  • 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

    　View Summary

    © 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.

  • 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

    　View Summary

    © 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.

  • 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

    　View Summary

    © 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.

  • 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

    　View Summary

    © 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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Reviews, Commentaries, etc. 【 Display / hide 】

  • 屈折率分布型ポリマー光導波路の歴史と展開

    小池康博

    光技術コンタクト (日本オプトメカトロニクス協会)   2017.05

    Introduction and explanation (scientific journal), Single Work

  • 新川崎タウンキャンパスの発展とこれからー研究活動を中心に

    小池康博

    三田評論 (慶應義塾)   2016.12

    Introduction and explanation (bulletin of university, research institution), Single Work

  • ボールペン技術から生まれたGI-POF用光コネクタ

    三井章仁、小池 康博

    光アライアンス2016年3月号 (日本工業出版)   2016.03

    Introduction and explanation (scientific journal), Joint Work

  • ディスプレイの高画質化のための光散乱ポリマー材料

    KOIKE YASUHIRO

    光学 (日本光学会)  44 ( 8 ) 310 - 315 2015.08

    Introduction and explanation (scientific journal), Joint Work

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Presentations 【 Display / hide 】

  • Recent Progress of GI-POF towards 8K and 5G Era

    Yasuhiro Koike

    14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO Pacific Rim, CLEO PR 2020) (Sydney, Australia (Virtual Conference)) , 2020.08, Oral Presentation(guest/special)

  • Proposal of Practical Polymeric Materials with No Birefringence over Wide Temperature Range for Real- Color Vehicle-Mounted Display

    K. Watanabe, Y. Kobayashi, and Y. Koike

    SID Display Week 2020 (San Francisco, USA (Virtual Conference)) , 2020.08, Poster (general)

  • Analysis of Random Depolarization Films with Birefringent Micro-particles for Liquid-Crystal and OLED Displays

    S. Sasaki, M. Udono, and Y. Koike

    SID Display Week 2020 (San Francisco, USA (Virtual Conference)) , 2020.08, Poster (general)

  • A Wide Color Gamut LCD with a Polarized Laser Backlight

    Yasuhiro Koike

    SID Display Week 2020 (San Francisco, USA (Virtual Conference)) , 2020.08, Oral Presentation(guest/special)

  • Recent progress in photonics polymer for ultrahigh-definition imaging system

    Y. Koike

    SPIE Photonics West 2020 OPTO (San Francisco, USA) , 2020.02, Oral Presentation(guest/special)

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Works 【 Display / hide 】

  • 日本経済新聞 15面 低ノイズの光ファイバー　プラ製　慶大と日東電工が開発

    日本経済新聞15面, 

    2020.01
    , 

    Other

  • 電波タイムズ　2面「一般社団法人サービス高度化推進協会が実証実験を公開　新4K8K衛星放送の光配信方式の実用化」

    2019.03
    , 

    Other

  • 電波新聞　3面「A-PAB POFシステムによる実証実験　簡単に現場施工、低コスト　外観損なわず既存設備に追加」

    2019.02
    , 

    Other

  • 日本経済新聞　9面「サングラスでも液晶画面鮮明に　慶大が専用フィルム」

    2019.02
    , 

    Other

  • 日本経済新聞　15面「光ファイバ量産に500億円　日東電工、8K・5G対応」

    2018.05
    , 

    Other

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Awards 【 Display / hide 】

  • 高分子科学功績賞

    小池康博, 2019.02, 高分子学会, フォトニクスポリマーの基礎と機能創出

  • SID Special Recognition Awards

    2015.06

  • 第２４回「向井賞」

    KOIKE YASUHIRO, 2013.05, 公益財団法人東京応化科学技術振興財団, Fundamental Studies and Creation of Functions of Photonics Polymer

  • 第13回「神奈川イメージアップ大賞」

    KOIKE YASUHIRO, 2011.01, 毎日新聞社

  • 科学技術への顕著な貢献2009「ナイスステップな研究者」

    KOIKE YASUHIRO, 2009.12, 文部科学省　科学技術政策研究所, 高速通信用プラスチック光ファイバーの研究および実用化

    　View Description

    従来より200倍以上の高速伝送を可能とした低損失・高速プラスチック光ファイバーを世界に先駆け発明・提案した。プラスチックは曲げに強く、安全で、ビル内、家庭内のような狭い場所への配線に大変適している。現在、旭硝子（株）と共同開発を進め、伝送速度を40ギガビットを越える全フッ素化プラスチック光ファイバーの試作に成功し、臨場感溢れるFace-to-Faceコミュニケーションへ向けての研究開発を行っている。

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Courses Taught 【 Display / hide 】

  • APPLIED PHYSICS AND PHYSICO-INFORMATICS LABORATORY C

    2019

  • APPLIED PHYSICS AND PHYSICO-INFORMATICS LABORATORY D

    2019

  • BACHELOR'S THESIS

    2019

  • GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 1

    2019

  • GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 2

    2019

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Social Activities 【 Display / hide 】

  • カイロス株式会社　テクニカル・アドバイザー

    2016.12
    -
    2017.12

  • 第22回微小光学国際会議（MOC'17) 組織委員

    2016.08
    -
    2017.11

  • 国立大学法人　神戸大学　非常勤講師

    2016.08

  • 市村学術賞　審査委員

    2015.11
    -
    2018

  • 独立行政法人科学技術振興機構　研究成果展開事業「戦略的イノベーション創出推進プログラム（S-イノベ）」研究開発テーマ「フォトニクスポリマーによる先進情報通信技術の開発」プログラムオフィサー補佐

    2014.04
    -
    2015.03

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Memberships in Academic Societies 【 Display / hide 】

  • The International Society for Optics and Photonics, 

    2016.01
    -
    Present

  • SPIE, 

    2016
    -
    Present

  • The Society for Information Display, 

    2011.04
    -
    Present

  • 一般社団法人　電子情報通信学会, 

    2011.01
    -
    2015.03

  • Japan Responsinble Care Council, 

    2008.10
    -
    2010.05

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Committee Experiences 【 Display / hide 】

  • 2019.12
    -
    2020.03

    国際科学技術共同研究推進事業（戦略的国際共同研究プログラム）アドバイザー, 国立研究開発法人科学技術振興機構

  • 2018.09
    -
    2018.11

    Organizing Committee Member, the 24th Microoptics Conference (MOC2019)

  • 2018.03
    -
    2019.04

    日本国際賞審査部会委員, 公益財団法人　国際科学技術財団　

  • 2018.02
    -
    2018.03

    国際科学技術共同研究推進事業（戦略的国際共同研究プログラム）アドバイザー, 国立研究開発法人　科学技術振興機構

  • 2017.10
    -
    2018.03

    戦略的情報通信研究開発推進事業（SCOPE）専門評価委員, 総務省

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