Erbium-ytterbium co-doped lithium niobate single-mode microdisk laser with an ultralow threshold of 1 uW

TL;DR

This paper reports the development of a single-mode erbium-ytterbium co-doped lithium niobate microdisk laser operating at 1530 nm with an ultra-low threshold of 1 μW, demonstrating significant improvements in efficiency and threshold compared to prior work.

Contribution

The study introduces a high-Q, single-mode microdisk laser on TFLN with an ultra-low threshold and high conversion efficiency, advancing integrated photonics technology.

Findings

Threshold as low as 1 μW, ten times lower than previous records.

Conversion efficiency of 0.406%, the highest in similar TFLN lasers.

Successful suppression of multi-mode lasing through polygon mode excitation.

Abstract

We demonstrate single-mode microdisk lasers in the telecom band with ultra-low thresholds on erbium-ytterbium co-doped thin-film lithium niobate (TFLN). The active microdisk were fabricated with high-Q factors by photo-lithography assisted chemo-mechanical etching. Thanks to the erbium-ytterbium co-doping providing high optical gain, the ultra-low loss nanostructuring, and the excitation of high-Q coherent polygon modes which suppresses multi-mode lasing and allows high spatial mode overlap factor between pump and lasing modes, single-mode laser emission operating at 1530 nm wavelength was observed with an ultra-low threshold, under 980-nm-band optical pump. The threshold was measured as low as 1 uW, which is one order of magnitude smaller than the best results previously reported in single-mode active TFLN microlasers. And the conversion efficiency reaches 0.406%, which is also the highest value reported in single-mode active TFLN microlasers.