Twenty-nine million Intrinsic Q-factor Monolithic Microresonators on Thin Film Lithium Niobate

TL;DR

This paper reports the fabrication of TFLN microresonators with a record-high intrinsic Q factor of 29 million, significantly reducing propagation loss and advancing integrated photonics capabilities.

Contribution

It demonstrates the highest intrinsic Q factor achieved in TFLN microresonators, approaching the material limit through improved fabrication techniques.

Findings

Intrinsic Q factor of 29 million achieved

Propagation loss reduced to 1.3 dB/m

Statistical analysis of Q factors across geometries

Abstract

The recent emergence of thin-film lithium niobate (TFLN) has extended the landscape of integrated photonics. This has been enabled by the commercialization of TFLN wafers and advanced nanofabrication of TFLN such as high-quality dry etching. However, fabrication imperfections still limit the propagation loss to a few dB/m, restricting the impact of this platform. Here, we demonstrate TFLN microresonators with a record-high intrinsic quality (Q) factor of twenty-nine million, corresponding to an ultra-low propagation loss of 1.3 dB/m. We present spectral analysis and the statistical distribution of Q factors across different resonator geometries. Our work pushes the fabrication limits of TFLN photonics to achieve a Q factor within one order of magnitude of the material limit.