Directly modulated membrane lasers with 108 GHz bandwidth on a high-thermal-conductivity silicon carbide substrate

Suguru Yamaoka, Nikolaos Panteleimon Diamantopoulos, Hidetaka Nishi, Ryo Nakao, Takuro Fujii, Koji Takeda, Tatsurou Hiraki, Takuma Tsurugaya, Shigeru Kanazawa, Hiromasa Tanobe, Takaaki Kakitsuka, Tai Tsuchizawa, Fumio Koyama, Shinji Matsuo

Research output: Contribution to journalArticlepeer-review

Abstract

Increasing the modulation speed of semiconductor lasers has attracted much attention from the viewpoint of both physics and the applications of lasers. Here we propose a membrane distributed reflector laser on a low-refractive-index and high-thermal-conductivity silicon carbide substrate that overcomes the modulation bandwidth limit. The laser features a high modulation efficiency because of its large optical confinement in the active region and small differential gain reduction at a high injection current density. We achieve a 42 GHz relaxation oscillation frequency by using a laser with a 50-μm-long active region. The cavity, designed to have a short photon lifetime, suppresses the damping effect while keeping the threshold carrier density low, resulting in a 60 GHz intrinsic 3 dB bandwidth (f3dB). By employing the photon–photon resonance at 95 GHz due to optical feedback from an integrated output waveguide, we achieve an f3dB of 108 GHz and demonstrate 256 Gbit s−1 four-level pulse-amplitude modulations with a 475 fJ bit−1 energy cost of the direct-current electrical input.

Original languageEnglish
JournalNature Photonics
DOIs
Publication statusAccepted/In press - 2020

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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