An Integrated Electro‐Optically Tunable Multi‐Channel Interference Cavity Laser

Abstract A quasi‐continuous tunable laser system is demonstrated by butt coupling a reflective semiconductor optical amplifier (RSOA) chip with a thin‐film lithium niobate (TFLN) based multi‐channel interference (MCI) cavity chip. This hybrid integrated laser allows for fine‐tuning of the laser wavelength from 1538 to 1560 nm with side‐mode suppression ratios (SMSRs) exceeding 30 dB. The MCI cavity chip is fabricated using the photolithography‐assisted chemo‐mechanical etching (PLACE) technique. The developed laser has an output power of ≈10 µW, which can be further amplified to 70 mW using a commercial erbium‐doped fiber amplifier (EDFA) without significant broadening of the laser linewidth.