KEIO RESEARCHERS INFORMATION SYSTEM

Profile 【 Display / hide 】

Profile 【 Display / hide 】

• He received his B.S. in Electronics and Electrical Engineering from Keio University, Yokohama, Japan, in March 2000, and his M.S. and Ph. Design Engineering from the same institution in September 2001 and March 2004, respectively.
  He was a research associate of the 21st Century Center of Excellence (COE) program in optical and electronic device technology for access networks at Keio University from November 2002 to March 2004. He received a Certificate for Distinguished Activity as Research Assistant at Keio Information, Electronics, and Electrical Engineering Field COE. On April 2004, he joined NTT Basic Research Laboratories, NTT Corporation, in Atsugi, Japan. On April 2010, he moved to Electronics and Electrical Engineering at Keio University, where he is currently a professor. He received Scientific American 50 Award in 2007, and the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, The Young Scientists’ Prize in 2010. Dr. Tanabe is a member of the Optical Society, IEEE Photonics Society, SPIE, the Japan Society of Applied Physics, the Laser Society of Japan, and the Institute of Electronics, Information, and Communication Engineers. He is currently a Senior Editor for the IEEE Journal of Selected Topics in Quantum Electronics and Associate Editor for AIP Advances (APS) and Scientific Reports (NPG). He is also serving as a conference committee member in various conferences, including the general chair for CLEO:2022, program chair for CLEO:2020 and ALPS2023, vice-program chair for ICNN, sub-committee chair for CLEO:2018/2019 and CLEO Pacific Rim 2022, the committee in Optica Congress, LEOS, ALPS, APLS, ICO-24, ICNN, WOMBAT, LSJ, and JSAP.

Profile Summary 【 Display / hide 】

Profile Summary 【 Display / hide 】

• 微小光共振器を用いて光を強く閉じ込めることによって，微小な光強度で非線形光学効果を発現させます．それによって，微弱なエネルギーで動作する光スイッチ・光メモリや光トランジスタを実現させます．また，光を究極的に閉じ込めることによる新たな光物理の可能性についても探索します．

Career 【 Display / hide 】

Career 【 Display / hide 】

• 2002.11

  -

  2004.03

  Research associate of the 21st Century Center of Excellence (COE) program in optical and electronics device technology for access network

• 2004.04

  -

  2009.03

  NTT Basic Research Laboratories, NTT Corporation

• 2009.04

  -

  2010.03

  Research Engineer, NTT Basic Research Laboratories, NTT Corporation

• 2010.04

  -

  2012.03

  Lecturer, Department of Electronics and Electrical Engineering, Keio University

• 2012.04

  -

  2018.03

  Associate Professor, Department of Electronics and Electrical Engineering, Keio University

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Academic Background 【 Display / hide 】

Academic Background 【 Display / hide 】

• 2000.03

  Keio University, Faculty of Science and Engineering, Department of Electronics and Electrical Engineering

  University, Graduated

• 2001.09

  Keio University, Graduate School, Division of Science and Engineering, School of Integrated Design Engineering

  Graduate School, Completed, Master's course

• 2004.03

  Keio University, Graduate School, Division of Science and Engineering, School of Integrated Design Engineering

  Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide 】

Academic Degrees 【 Display / hide 】

• Ph.D., Keio University, Coursework, 2010.03

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

• Nanotechnology/Materials / Optical engineering and photon science (Applied Optics/Quantum Optical Engineering)

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• フォトニックナノ構造

• フォトニック結晶

• 光回路

• 微小光共振器

• 超高速光技術

Books 【 Display / hide 】

Books 【 Display / hide 】

• On-chip frequency comb

  Tetsumoto T., Fujii S., Tanabe T., On-Chip Photonics: Principles, Technology and Applications, 2024.01

  　View Summary

  An on-chip frequency comb is a light source on a chip that generates coherent multifrequency light whose frequencies are equidistant in the optical frequency domain. It even suggests the possible realization of chip-scale devices with metrological precision in terms of time and frequency. In particular, a microresonator-based frequency comb is a novel on-chip frequency comb device that exhibits intriguing features as experimental platforms on which to explore unique nonlinear phenomena and tools for practical applications. In this chapter, we first provide an overview of conventional frequency combs and on-chip frequency combs. Then, we describe the fundamentals of microresonator-based frequency combs, their key features, and applications. Finally, we summarize the chapter by discussing various challenges and future perspectives in relation to this emerging on-chip frequency comb.

  • Access to Document (DOI)

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Mechanically Actuated Kerr Soliton Microcombs

  Fujii S., Wada K., Kogure S., Kumazaki H., Tanabe T.

  Laser and Photonics Reviews 18 ( 9 )  2024.09

  ISSN  18638880

  　View Summary

  Mode-locked ultrashort pulse sources with a repetition rate of up to several tens of gigahertz greatly facilitate versatile photonic applications such as frequency synthesis, metrology, radar, and optical communications. Dissipative Kerr soliton microcombs provide an attractive solution as a broadband, high-repetition-rate compact laser system in this context. However, its operation usually requires sophisticated pump laser control to initiate and stabilize the soliton microcombs, particularly in millimeter-sized ultrahigh-Q whispering-gallery resonators. Here, a mechanically actuated soliton microcomb oscillator is realized with a microwave repetition rate of 15 GHz. This enables direct initiation, subsequent long-term stabilization, and fine tuning of soliton combs without pump laser tunability that is generally required for soliton microcomb operation. The prospects for using this method with a wide range of applications are revealed that will benefit from mechanical soliton actuation such as optical clocks, spectral extension, and dual-comb spectroscopy.

  • Access to Document (DOI)

• Exceptional point proximity-driven mode-locking in coupled microresonators

  Imamura R., Fujii S., Nakashima A., Tanabe T.

  Optics Express 32 ( 13 ) 22280 - 22290 2024.06

  　View Summary

  We show theoretically and numerically that mode-locking is feasible with a coupled-cavity system with gain and loss, notably, without any natural saturable absorber. We highlight that in the vicinity of the exceptional point, system Q exhibits substantial modulation even with minor refractive index changes and a minimal Kerr effect contribution. Leveraging this unique behavior, we propose an unprecedented approach wherein the lossy auxiliary cavity functions as an efficient artificial saturable absorber, thus facilitating mode-locking. This approach is not only novel, but also presents considerable advantages over conventional systems where both gain and saturable absorption are contained within a single microcavity. These benefits include reduced operational power and ease of post-adjustment, achievable through the manipulation of the coupling strength between the two microcavities.

  • Access to Document (DOI)

• Compact photonic crystal spectrometer with resolution beyond the fabrication precision

  Sugano R., Kokubu J., Jin S., Kodama T., Hofs J.J., Zhang J., Okano M., Tanabe T.

  Optics Express 32 ( 12 ) 21563 - 21576 2024.06

  　View Summary

  We present a compact silicon photonic crystal spectrometer with a footprint of 740 × 9 μm2 and excellent wavelength resolution (∼0.01 nm at single and <0.03 nm at multiple wavelength operation) across a telecom bandwidth of 10 nm. Although our design targets a wavelength resolution of 1.6 nm, within the current state-of-the-art fabrication precision of 2 nm, we achieve a resolution that exceeds these limits. This enhanced resolution is made possible by leveraging the random localization of light within the device.

  • Access to Document (DOI)

• Synchronization of two chaotic microresonator frequency combs

  Moreno D., Fujii S., Nakashima A., Lemcke D., Uchida A., Sanchis P., Tanabe T.

  Optics Express 32 ( 2 ) 2460 - 2472 2024.01

  　View Summary

  We explore the synchronization of chaotic microresonator frequency combs, emphasizing the modulation instability state, which is known for its inherent chaotic behaviors. Our study confirms that the synchronization of two such combs is feasible by injecting the output from the lead microresonator into the next microresonator’s input. We also identify the optimal parameters for this synchronization. Remarkably, even partial injection from the leader is sufficient for synchronization, paving the way for versatile future system configurations. Such systems could simultaneously utilize distinct spectral components for synchronization and transmission. This work advances our understanding of chaotic microresonator combs, showing them to be pivotal elements in next-generation optical communication systems.

  • Access to Document (DOI)

• Soliton Comb Generation Using a Small Prism Coupling Module

  Mototani Y., Fujii S., Kimura S., Hashimoto Y., Yamakawa T., Imamura R., Tanabe T.

  16th Pacific Rim Conference on Lasers and Electro-Optics, CLEO-PR 2024  2024

  　View Summary

  We developed a compact prism coupling module conforming to the 1U CubeSat standard and demonstrated soliton microcomb generation with an ultrahigh-Q MgF resonator to explore the robustness of the miniaturized multi-wavelength light source.

  • Access to Document (DOI)

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Development of small light source with extended-nano space processing

  Tanabe, Takasumi

  科学研究費補助金研究成果報告書 2019

• Sensing of volatile organic compounds in breathing air by using packaged optical microcavity device

  Tanabe, Takasumi

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2018

• Study on energy-saving optical frequency comb source based on an optical microcavity

  Tanabe, Takasumi

  科学研究費補助金研究成果報告書 2018

• Sensing of volatile organic compounds in breathing air by using packaged optical microcavity device

  Tanabe, Takasumi

  学事振興資金研究成果実績報告書 (慶應義塾大学)  2017

• Nonlinear optics in coupled resonators

  Tanabe, Takasumi

  科学研究費補助金研究成果報告書 2017

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• Increased performance of nanophotonic devices by utilizing structural fluctuation information with deep learning

  2021.07

  -

  2023.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory), Principal investigator

• Development of high-repetition optical pulse source by miroresonator

  2019.04

  -

  2024.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A) , Principal investigator

• 拡張ナノ領域プロセシングが実現させる微小光源開発

  2018.06

  -

  2020.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Research (Exploratory) , Principal investigator

• Nonlinear optics in coupled resonators

  2016.04

  -

  2018.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research, Principal investigator

• Study on energy-saving optical frequency comb source based on an optical microcavity

  2015.04

  -

  2019.03

  MEXT,JSPS, Grant-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (A), Principal investigator

Awards 【 Display / hide 】

Awards 【 Display / hide 】

• Poster Awards

  Hiroshi Kudo, Yohei Ogawa, Takasumi Tanabe, and Atsushi Yokoo, 2012.03, International Conference on Optical and Optoelectronic Properties of Materials and Applications (ICOOPMA), Fabrication of Whispering Gallery Mode Cavities using Crystal Growth

  Type of Award： Other

• 第24回安藤博記念学術奨励賞

  TANABE Takasumi, 2011.06

  Type of Award： Award from publisher, newspaper, foundation, etc.

• 文部科学大臣表彰 若手科学者賞

  TANABE Takasumi, 2011.04

  Type of Award： Other

• The 6th Annual Scientific American 50 Award

  TANABE Takasumi, 2007.11, Scientific American, Light Manipulation

  Type of Award： Other

• 第31回レーザー学会業績賞 論文賞(オリジナル部門)

  TANABE Takasumi, 2007.05, シリコンフォトニック結晶共振器を用いた全光スイッチおよび5GHz RZ光パルス列変調

  Type of Award： Award from Japanese society, conference, symposium, etc.

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Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• LABORATORIES IN ELECTRONICS AND INFORMATION ENGINEERING(2)

  2024

• INDEPENDENT STUDY ON INTEGRATED DESIGN ENGINEERING

  2024

• GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 2

  2024

• GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 1

  2024

• COMPREHENSIVE EXERCISE OF ELECTRONICS AND ELECTRICAL ENGINEERING

  2024

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Courses Previously Taught 【 Display / hide 】

Courses Previously Taught 【 Display / hide 】

• フォトニックナノ構造

  Keio University

  2014.04

  -

  2015.03

  , 

  Spring Semester, Lecture

• フォトニクス

  Keio University

  2014.04

  -

  2015.03

  , 

  Autumn Semester, Lecture

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• AIP Advances, 

  2013.04

  -

  Present

• 電子情報通信学会超高速光エレクトロニクス研究会, 

  2013.04

  -

  Present

• レーザー学会 編集委員会, 

  2011.04

  -

  Present

• 電子情報通信学会レーザ・量子エレクトロニクス, 

  2011.04

  -

  Present

• 電子情報通信学会超高速光エレクトロニクス研究会, 

  2011.04

  -

  2013.03

Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2017.04

  -

  Present

  Subcommittee Chair, CLEO:2018

• 2017.04

  -

  Present

  Associate Editor, Scientific Reports, Nature Publishing Group

• 2013.04

  -

  Present

  編集委員, AIP Advances

• 2013.04

  -

  Present

  専門委員, 電子情報通信学会超高速光エレクトロニクス研究会

• 2013.04

  -

  Present

  Accosiate Editor, AIP Advances

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