Lithium niobate microring with ultra-high Q factor above 10^8

TL;DR

This paper reports the fabrication of lithium niobate microring resonators with an ultra-high Q factor exceeding 10^8, achieved through a novel fabrication process that minimizes lattice damage and waveguide loss.

Contribution

The study introduces a new fabrication method for lithium niobate microrings that achieves record-high Q factors close to the material's absorption limit.

Findings

Q factor up to 10^8 at 1550 nm wavelength

Waveguide propagation loss of about 0.28 dB/m

Fabrication without ion slicing or etching damage

Abstract

We demonstrate ultra-high Q factor microring resonators close to the intrinsic material absorption limit on lithium niobate on insulator. The microrings are fabricated on pristine lithium niobate (LN) thin film wafer thinned from LN bulk via chemo-mechanical etching without ion slicing and ion etching. A record-high Q factor up to times ten to the power of 8th at the wavelength of 1550 nm is achieved because of the ultra-smooth interface of the microrings and the absence of ion induced lattice damage, indicating an ultra-low waveguide propagation loss of about 0.28 dB per meter. The ultra-high Q microrings will pave the way for integrated quantum light source, frequency comb generation, and nonlinear optical processes.