Tunable single-mode laser on thin film lithium niobate

TL;DR

This paper demonstrates a tunable single-mode whisper gallery laser on thin film lithium niobate, achieving wavelength tuning and mode suppression, with potential for further electro-optic tuning enhancements.

Contribution

The work introduces a novel integrated tunable whisper gallery single-mode laser on LNOI using coupled microdisk and microring structures, with demonstrated wavelength tuning and mode suppression.

Findings

Achieved a 31.4 dB side mode suppression ratio (SMSR).

Wavelength tuning from 1560.30 nm to 1560.40 nm via temperature regulation.

Demonstrated wavelength adjustments to 1560.60 nm and 1565.00 nm by changing coupling gap.

Abstract

Erbium-doped lithium niobate on insulator (LNOI) laser plays an important role in the complete photonic integrated circuits (PICs). Here, we demonstrate an integrated tunable whisper galley single mode laser (WGSML) by making use of a pair of coupled microdisk and microring on LNOI. A 974 nm single-mode pump light can have an excellent resonance in the designed microdisk, which is beneficial to the whisper gallery mode (WGM) laser generation. The WGSML at 1560.40 nm with a maximum 31.4 dB side mode suppression ratio (SMSR) has been achieved. By regulating the temperature, WGSMLs output power increased and the central wavelength can be changed from 1560.30 nm to 1560.40 nm. What's more, 1560.60 nm and 1565.00 nm WGSMLs have been achieved by changing the coupling gap width between microdisk and microring. We can also use the electro-optic effect of LNOI to obtain more accurate adjustable WGSMLs in further research.