An integrated electro-optically tunable multi-channel interference cavity laser

TL;DR

This paper presents a hybrid integrated laser system combining a reflective semiconductor optical amplifier with a lithium niobate multi-channel interference cavity, enabling fine wavelength tuning with high side-mode suppression.

Contribution

It introduces a novel integrated laser with precise tunability and high spectral purity, fabricated using advanced chemo-mechanical etching techniques.

Findings

Wavelength tuning range of 1538-1560 nm with 0.014 nm resolution

Side-mode suppression ratio exceeding 30 dB

Output power up to 10 μW, amplified to 70 mW

Abstract

We demonstrated a continuously tunable laser system 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 lasers allows for fine-tuning of the laser wavelength from 1538 nm to 1560 nm with a resolution of 0.014 nm and a side-mode suppression ratio (SMSR) 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 approximately 10 {\mu}W, which can be further amplified to 70 mW using a commercial erbium-doped fiber amplifier (EDFA) without significant broadening of the laser linewidth.