Development of vector modulation technique using spin-controlled semiconductor lasers

• Project/Area Number: 19H02186
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Tohoku University
• Principal Investigator: YOKOTA Nobuhide 東北大学, 電気通信研究所, 助教 (00734542)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥18,070,000 (Direct Cost: ¥13,900,000、Indirect Cost: ¥4,170,000); Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2020: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2019: ¥13,910,000 (Direct Cost: ¥10,700,000、Indirect Cost: ¥3,210,000)
• Keywords: 面発光レーザ / スピン偏極 / ベクトル変調

Outline of Research at the Start

コストや消費電力に厳しい要求が課せられる短距離光通信において、周波数利用効率の高いベクトル変調方式（光の振幅と位相を制御する方式）の導入が求められている。本研究では、面発光レーザに電流注入する電子のスピン偏極（上向き or 下向き）を制御する特殊な変調法を活用することで、面発光レーザからベクトル変調光を直接生成する技術を開発する。また、本技術によって光通信と無線通信を融合させる手法を開発する。

Outline of Final Research Achievements

A vector modulation scheme in which both amplitude and phase of light are modulated is promising for next-generation optical communication systems, because it can densely allocate signal points in a complex plane. In this study, the vector modulation of light using an injection-locked semiconductor laser under modulation of electron spin polarization was theoretically confirmed, and a preliminary experimental setup for evaluation of the vector modulation waveforms was developed. Moreover, application of the spin-controlled semiconductor laser to radio over fiber systems and local oscillators in coherent optical communication systems was proposed and demonstrated.

Academic Significance and Societal Importance of the Research Achievements

光通信等で用いられる通常の半導体レーザでは電流注入される電子の密度のみが変調され、電子の有するスピン偏極状態の自由度は制御されない。本研究は半導体レーザにおける注入電子のスピン偏極度を高速に変調することが通常の半導体レーザの高速動作限界を突破する切り口になることを明らかにしたものであり、今後の光通信の大容量化や次世代無線通信技術（Beyond 5G）の発展に貢献するものである。

Research Products

• [Journal Article] Spin Laser Local Oscillators for Homodyne Detection in Coherent Optical Communications (2021)
  • Author(s): Yokota Nobuhide、Yasaka Hiroshi
  • Journal Title: Micromachines Volume: 12 Issue: 5 Pages: 573-573
  • DOI: 10.3390/mi12050573
  • Peer Reviewed / Open Access
• [Journal Article] Spin-Injected Birefringent VCSELs for Analog Radio-Over-Fiber Systems (2021)
  • Author(s): Yokota Nobuhide、Ikeda Kazuhiro、Yasaka Hiroshi
  • Journal Title: IEEE Photonics Technology Letters Volume: 33 Issue: 6 Pages: 297-300
  • DOI: 10.1109/lpt.2021.3059697
  • Peer Reviewed
• [Presentation] 注入同期による面発光レーザのスピン偏極変調特性制御 (2022)
  • Author(s): 横田信英，池田和浩，八坂洋
  • Organizer: 第69回応用物理学会春季学術講演会
• [Presentation] pin-VCSELs for analog radio-over-fiber systems in 5G and beyond (2021)
  • Author(s): N. Yokota, K. Ikeda, and H. Yasaka
  • Organizer: SPIE OPTICS+PHOTONICS
  • Int'l Joint Research / Invited
• [Presentation] Numerical investigation of direct IQ modulation of spin-VCSELs for coherent communications (2020)
  • Author(s): N. Yokota, K. Ikeda, and H. Yasaka
  • Organizer: SPIE OPTICS+PHOTONICS
  • Int'l Joint Research / Invited
• [Presentation] Spin polarization modulation of 1.55-μm VCSELs for high-speed data communications (2019)
  • Author(s): N. Yokota, K. Nisaka, K. Ikeda, and H. Yasaka
  • Organizer: SPIE OPTICS+PHOTONICS
  • Int'l Joint Research / Invited