Coherent mode-combined ultra-narrow-linewidth single-mode micro-disk laser

TL;DR

This paper presents a novel ultra-high Q Erbium-doped lithium niobate micro-disk laser that achieves single-mode operation with an ultra-narrow linewidth of 98 Hz, promising for integrated photonic applications.

Contribution

It demonstrates a controllable, cost-effective method to generate ultra-narrow-linewidth single-mode microlasers using coherently combined polygon modes in a lithium niobate micro-disk.

Findings

Achieved 98 Hz linewidth in the microlaser.

Demonstrated coherent mode combination at pump and laser wavelengths.

Enabled on-chip integration for high-precision photonic circuits.

Abstract

Integrated single-mode microlasers with ultra-narrow linewidths play a game-changing role in a broad spectrum of applications ranging from coherent communication and LIDAR to metrology and sensing. Generation of such light sources in a controllable and cost-effective manner remains an outstanding challenge due to the difficulties in the realization of ultra-high Q active micro-resonators with suppressed mode numbers. Here, we report a microlaser generated in an ultra-high Q Erbium doped lithium niobate (LN) micro-disk. Through the formation of coherently combined polygon modes at both pump and laser wavelengths, the microlaser exhibits single mode operation with an ultra-narrow-linewidth of 98 Hz. In combination with the superior electro-optic and nonlinear optical properties of LN crystal, the mass-producible on-chip single-mode microlaser will provide an essential building block for the photonic integrated circuits demanding high precision frequency control and reconfigurability.