Twenty-nine million intrinsic <i>Q</i>-factor monolithic microresonators on thin-film lithium niobate
Xinrui Zhu, Yaowen Hu, Shengyuan Lu, Hana Warner, Xudong Li, Yunxiang Song, Letícia Magalhães, Amirhassan Shams‐Ansari, Andrea Cordaro, Neil Sinclair, Marko Lončar
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 1 order of magnitude of the material limit.