KITA, Tomohiro

写真a

Affiliation

Faculty of Science and Engineering, School of Advanced Science and Engineering

Job title

Associate Professor

Homepage URL

http://db.tohoku.ac.jp/whois/e_detail/0dc9e2aa0e65cadc7ebda3c6453f696e.html

Concurrent Post 【 display / non-display

  • Faculty of Science and Engineering   Graduate School of Advanced Science and Engineering

Research Institute 【 display / non-display

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Degree 【 display / non-display

  • Japan Advanced Institute of Science and Technology Hokuriku   工学博士(材料)

Professional Memberships 【 display / non-display

  •  
     
     

    日本物理学会

  •  
     
     

    The Institute of Electronics, Information and Communication Engineers

  •  
     
     

    応用物理学会

  •  
     
     

    Optical society, America

 

Research Areas 【 display / non-display

  • Electron device and electronic equipment   半導体工学

  • Optical engineering and photon science

Research Interests 【 display / non-display

  • 非線形光学効果

  • 半導体レーザ

  • 光エレクトロニクス

  • シリコンフォトニクス

  • 半導体工学

Papers 【 display / non-display

  • Tunable Dual-Wavelength Heterogeneous Quantum Dot Laser Diode with a Silicon External Cavity

    Tomohiro Kita, Atsushi Matsumoto, Naokatsu Yamamoto, Hirohito Yamada

    Journal of Lightwave Technology   36 ( 2 ) 219 - 224  2018.01  [Refereed]  [Invited]

     View Summary

    We propose a tunable dual-wavelength heterogeneous quantum dot laser diode. The tunable dual-wavelength laser consists of a quantum dot semiconductor optical amplifier as the optical gain medium and an external cavity fabricated from silicon photonics technology as the wavelength tunable filter. We successfully demonstrated dual-wavelength lasing oscillation by tuning the difference frequency from approximately 34 to 400 GHz.

    DOI

  • Narrow Spectral Linewidth Silicon Photonic Wavelength Tunable Laser Diode for Digital Coherent Communication System

    Tomohiro Kita, Rui Tang, Hirohito Yamada

    IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS   22 ( 6 )  2016.11  [Refereed]  [Invited]

     View Summary

    We demonstrated wavelength tunable laser diodes with Si-wire waveguide ring resonators as an external optical cavity. The footprint of the optical cavity including the semiconductor optical amplifier is as small as 0.8 mm x 0.6 mm which is less 1/10 of those made of silicon oxinitride material. Wavelength tuning range of approximately 55 nm was demonstrated, which covers entire L-band of the optical communication wavelength system. Furthermore, a spectral linewidth narrower than 100 kHz was obtained by optimizing the design of the external optical cavity. The optical nonlinearity of silicon is described and the influence on laser oscillation is also discussed.

    DOI

  • Heterogeneous quantum dot/silicon photonics-based wavelength-tunable laser diode with a 44 nm wavelength-tuning range

    Tomohiro Kita, Naokatsu Yamamoto, Atsushi Matsumoto, Tetsuya Kawanishi, Hirohito Yamada

    JAPANESE JOURNAL OF APPLIED PHYSICS   55 ( 4 ) 04EH11-1 - 04EH11-4  2016.04  [Refereed]

     View Summary

    A heterogeneous wavelength-tunable laser diode combining quantum dot and silicon photonics technologies is proposed. A compact wavelength-tunable filter with two ring resonators was carefully designed and fabricated using silicon photonics technology. The tunable laser combining the wavelength-tunable filter and an optical amplifier, which includes InAs quantum dots, achieved a 44.0 nm wavelength-tuning range at around 1250 nm. The broadband optical gain of the quantum dot optical amplifier was effectively used by the optimized wavelength-tunable filter. This heterogeneous wavelength-tunable laser diode could become a breakthrough technology for high-capacity data transmission systems. (C) 2016 The Japan Society of Applied Physics

    DOI

  • Ultra-compact wavelength-tunable quantum-dot laser with silicon-photonics double ring filter

    Tomohiro Kita, Naokatsu Yamamoto, Tetsuya Kawanishi, Hirohito Yamada

    APPLIED PHYSICS EXPRESS   8 ( 6 ) 062701 - 062704  2015.06  [Refereed]

     View Summary

    Compact, wavelength-tunable light sources are desired for the enhancement of information communication technology and bio-imaging applications. We propose a compact, wavelength-tunable laser diode with a wide wavelength-tunable range around 1230 nm consisting of a quantum-dot optical amplifier and a silicon photonic tunable filter. High-quality InAs quantum dots grown with the sandwiched sub-nano separator technique were used as the optical gain medium. The wavelength-tunable filter was constructed with ring resonators fabricated using silicon photonics. The single-mode laser oscillation was demonstrated with a 28.5-nm wavelength-tunable range. (C) 2015 The Japan Society of Applied Physics

    DOI

  • Optimum waveguide-core size for reducing device property distribution of Si-wire waveguide devices

    Munetoshi Soma, Tomohiro Kita, Yuichiro Tanushi, Munehiro Toyama, Miyoshi Seki, Nobuyuki Yokoyama, Minoru Ohtsuka, Hirohito Yamada

    JAPANESE JOURNAL OF APPLIED PHYSICS   54 ( 4 ) 04DG03  2015.04  [Refereed]

     View Summary

    We investigated the waveguide-core size distribution of ring resonators fabricated on a 300mm silicon-on-insulator (SOI) wafer using a CMOS-compatible process featuring ArF immersion lithography. These ring resonators were constructed in a Si-wire waveguide with a standard core size of 400nm width and 220nm height. The group refractive indices of the waveguide were derived from the transmission spectra of the ring resonators. From the deviation of these group refractive indices, the waveguide-core width distribution was estimated to be 5 nm, and the waveguide-core height distribution was estimated to be 1 nm. Moreover, the device property distribution of various Si-wire waveguide depended on the estimated fabrication error was calculated. The waveguide core with the smallest device property distribution had a 540nm width and a 160nm height, and this waveguide has a device property distribution of 2/3 value compared with the standard core size. (C) 2015 The Japan Society of Applied Physics

    DOI

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Misc 【 display / non-display

  • Demonstration of 1-μm-band Si-photonics-based quantum dot heterogeneous tunable laser

    A. Matsumoto, K. Akahane, T. Umezawa, N. Yamamoto, H. Yamada, T. Kita

    2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings    2018.08

     View Summary

    © 2018 OSA. We present a Si-photonics-based quantum dot heterogeneous tunable lasers in the 1-μm band. Optical devices using Si-photonics-based PIC in the 1-μm band probably have not been reported yet.

  • Tunable Dual-Wavelength Heterogeneous Quantum Dot Laser Diode with a Silicon External Cavity

    Tomohiro Kita, Atsushi Matsumoto, Naokatsu Yamamoto, Hirohito Yamada

    Journal of Lightwave Technology   36 ( 2 ) 219 - 224  2018.01

     View Summary

    We propose a tunable dual-wavelength heterogeneous quantum dot laser diode. The tunable dual-wavelength laser consists of a quantum dot semiconductor optical amplifier as the optical gain medium and an external cavity fabricated from silicon photonics technology as the wavelength tunable filter. We successfully demonstrated dual-wavelength lasing oscillation by tuning the difference frequency from approximately 34 to 400 GHz.

    DOI

  • Silicon photonic wavelength tunable laser diode with low loss direct heating phase shifter

    Tomohiro Kita, Yuto Chiba, Hirohito Yamada

    14th International Conference on Group IV Photonics, GFP 2017     125 - 126  2017.10

     View Summary

    We proposed and demonstrated a compact and low propagation loss thermo-optical phase shifter using a multi-mode interference. The calculated insertion loss of designed MMI phase shifter was approximately 0.05 dB. The fabricated phase shifter shows high speed and low power consumption. The wavelength tunable laser diode with two ring resonators loaded the MMI phase shifters was fabricated. The wavelength tuning operation with low power consumption was successfully demonstrated.

    DOI

  • Silicon photonic wavelength-tunable lasers for high-capacity optical communication systems

    Tomohiro Kita, Hiroyuki Yamazaki, Naokatsu Yamamoto, Hirohito Yamada

    2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings    2017.05

     View Summary

    © 2017 Optical Society of America. Silicon photonic wavelength-tunable laser diodes consist of a wavelength-tunable filter with double silicon ring resonators and a compound semiconductor optical amplifier. Narrow spectral linewidth lasers for digital coherent optical communication systems and quantum dot heterogeneous laser diodes were demonstrated. The combination of silicon photonics and compound semiconductor technology leads to a breakthrough in the development of effective and compact integrated light sources for a wide range of application fields.

  • Heterogeneous lasers with silicon photonic external cavity

    Tomohiro Kita, Shotaro Takei, Atsushi Matsumoto, Naokatsu Yamamoto, Hirohito Yamada

    Optics InfoBase Conference Papers   Part F78-JSAP 2017  2017.01

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Other 【 display / non-display

  • 高い環境耐性を有するキャリアコンバータ技術の研究開発

    2016.05
     
     

     View Summary

    5G時代に対応した大容量・低遅延・シームレスな光/ミリ波変換デバイ
    スの開発と実証評価

  • ナノハイブリッド電気光学ポリマーを用いた光インターコネクト技術

    2016.04
     
     

     View Summary

    本課題では、電気光学ポリマーとシリコン光導波路を複合化する事で、これまでにない機能性を有する導波路デバイスを作製する。本研究の目的は、車載通信に用いるインターコネクトデバイスへの製品化を目的として高機能・小型光導波路を作製する。

  • 狭線幅波長可変レーザの開発

    2015.12
     
     

     View Summary

    次世代の大容量光通信方式として実用化の始まっているデジタル・コヒーレント光通信用狭線幅波長可変レーザーをシリコンフォトニクスによって独自に開発した超小型波長可変フィルターを用いて実現する。波長可変動作、狭線幅発振といった個々の特性に関しては、すでに十分な特性が得られているが本技術が実用化に耐えうる特性を持つことを証明するために高出力、省スペース、安定した波長可変動作といった特性を満足する波長可変レーザーモジュールを開発する。

  • シリコンフォトニック波長可変レーザを用いた医療イメージング用光源の開発

    2015.04
     
     

     View Summary

    光断層イメージングに必要な広波長帯域可変レーザをシリコンフォトニクスを用いて作製した波長可変フィルタと量子ドット光増幅器を用いて実現する。

  • 大容量光通信用高機能シリコンフォトニック波長可変レーザの開発

    2014.08
     
     

     View Summary

    次世代の大容量光通信技術であるデジタル・コヒーレント光通信、フォトニックネットワーク、超広周波数帯域波長分割多重といった通信方式において使用できる実用的な特性を持つ高機能波長可変レーザをシリコンフォトニクスを用いて開発する。

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Awards 【 display / non-display

  • 石田實記念財団研究奨励賞

    2014.11   石田寛記念財団   大容量光通信用シリコンフォトニック波長可変レーザに関する研究

  • 第23回応用物理学会 講演奨励賞

    2007.10   応用物理学会  

Presentations 【 display / non-display

  • シリコンフォトニクスチップを外部共振器とした機能性レーザの開発

    電子情報通信学会 

    Presentation date: 2017.09

  • Heterogeneous Lasers with Silicon Photonic External Cavity

    Tomohiro Kita, Shotaro Takei, Atsushi Matsumoto, Naokatsu Yamamoto, Hirohito Yamada

    応用物理学会ーOSA joint symposia 

    Presentation date: 2017.09

  • Silicon Photonic Wavelength Tunable Lasers for high-capacity optical communication system

    Optical Fiber Communication Conference and Exhibition (OFC) 2017  (United States Los Angeles) 

    Presentation date: 2017.03

  • Heterogeneous silicon photonic wavelength tunable laser diodes

    The 6th Annual World Congress of Nano Science and Technology-2016(Nano S&T-2016)  (Singapore) 

    Presentation date: 2016.10

  • Ultra-compact Wavelength Tunable Quantum Dot Laser with Silicon Photonic External Cavity

    Tomohiro Kita, Naokatsu Yamamoto, Tetsuya Kawanishi, Hirohito Yamada

    The Conference on Lasers and Electro-Optics(CLEO)  (United States サンノゼ) 

    Presentation date: 2015.05

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Specific Research 【 display / non-display

  • 1チップレーザービームスキャナの作製

    2020  

     View Summary

    経路差を用いたシリコンアレイ導波路及びブラッグ回折格子構造によってレーザ光の波長によってレーザビームの出射方向を二次元的に制御できることを確認した。さらに光増幅チップとシリコンフォトニクスチップとを光学接着剤を用いて結合し良好なレーザ発振特性が得られた。これらの成果によって1チップ二次元ビームスキャナ実現への道筋を得ることができた。

  • 光波制御ユニットの高精度制御に関する研究

    2019  

     View Summary

    シリコンフォトニクスチップ上に試作した多数のヒーターを同時に制御する計測システムを構築した。複数の直流安定化電源、ファンクションジェネレータ等を独立に制御することでハイブリッドレーザーから出力した二波長のレーザー光を用いてマイクロ波を発生させることに成功した。

  • 非常に広い可変波長域を有するヘテロジニアス波長可変レーザの開発

    2018  

     View Summary

    シリコンフォトニクスによって作製した外部共振器と化合物半導体光増幅器とを組み合わせたヘテロジニアス波長可変レーザをより広い波長範囲に適用するために波長依存性の小さな導波路型波長可変フィルタを開発した。本研究においては、リング共振器とバス導波路とを結合する方向性結合器に曲がり導波路構造を用いることで、従来型の波長可変フィルタの1.5倍程度の波長可変範囲で使用可能な波長フィルタの設計、試作した。方向性結合の結合効率の波長依存性が小さいためリング共振器のQ値といった特性の波長依存性が低減されることが確認できた。

 

Syllabus 【 display / non-display

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Committee Memberships 【 display / non-display

  • 2014.12
    -
    Now

    電子情報通信学会シリコンフォトニクス時限研究専門委員会  専門委員

  • 2014.12
    -
    Now

    電子情報通信学会シリコンフォトニクス時限研究専門委員会  専門委員

  • 2016.06
    -
    2019.05

    電子情報通信学会  和文論文誌C編集委員

  • 2016.06
    -
    2019.05

    電子情報通信学会  和文論文誌C編集委員

Media Coverage 【 display / non-display

  • Quantum dots and silicon photonics combine in broadband tunable laser

    Newspaper, magazine

    Laser focus world  

    2015.11

  • Tunable laser diode taps NIR for data transmission

    Newspaper, magazine

    Photonics Spectra  

    2015.08

  • 波長可変、広範に 東北大 情通機構 小型レーザー開発

    Newspaper, magazine

    2015.05

  • 東北大とNICT ヘテロジニアス波長可変レーザの開発に成功 超小型・広帯域光デ

    Newspaper, magazine

    電波タイムズ  

    2015.05

  • 光ファイバー波長数2倍 東北大など レーザー部品開発

    Newspaper, magazine

    日経産業新聞  

    2015.05