Heterogeneously integrated widely tunable laser using lattice filter and ring resonator on Si photonics platform

Takuma Aihara*, Tatsurou Hiraki, Takuro Fujii, Koji Takeda, Tai Tsuchizawa, Takaaki Kakitsuka, Hiroshi Fukuda, Shinji Matsuo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We fabricated a tunable laser consisting of a Si lattice filter, a Si ring resonator, and a III-V gain region. The lattice filter, a cascade of interferometers with the same delay length, has periodic transmission peaks with a wide free spectral range (FSR). By connecting the lattice filter to a ring resonator with a narrow FSR, the lasing mode is selected from one of the resonance modes of the ring resonator. The lasing wavelength can be tuned by changing the transmission peak wavelength of the lattice filter, in which an integrated micro heater controls the refractive index of the longer or shorter arm. Since the length of the refractive index control region on both arms of the lattice filter can be extended while maintaining a wide FSR, a wide tuning range can be obtained. This laser facilitates the control of the lasing wavelength because of the simple configuration. The Si lattice filter and the Si ring resonator were fabricated on a Si photonics platform by a Si photonics foundry, and III-V gain region was heterogeneously integrated. The lasing wavelength is shifted to a longer (shorter) one by heating the longer (shorter) arm of the lattice filter, in which the tuning wavelength is 1529 to 1561 nm and side-mode suppression ratio is more than 40 dB. A Lorentzian linewidth for lasing wavelengths narrower than 40 kHz is also demonstrated.

Original languageEnglish
Pages (from-to)15820-15829
Number of pages10
JournalOptics Express
Volume30
Issue number10
DOIs
Publication statusPublished - 2022 May 9
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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