Lithium niobate (LN) is a material with a wide range of applications in optical and microwave technologies. Conventional LN devices, including fiber-optic modulators and periodically poled frequency converters, has been the workhorse of the optoelectronics industries. However, one of the longstanding chanlledge for LN is the difficulty of etching. Recently developed thin-film LN-on-insulator technology has made it possible to obtain thin-film LN wafer. Based on this, our group has developed high-quality etching of lithium niobate. This breakthrough leads to the current field of integrated lithium nioabte photonics. Building upon this breakthrough, we are working a variety of different projects using lithium niobate, including high-performance electro-optic device, microwave-to-optical transduction, photonic quantum networking and computing, nonlinear optics and frequency combs, lithium niobate - III-V laser integrations, visible lithium niobate photonics, photonic synthetic dimension, etc.
[Di Zhu, et al. Advances in Optics and Photonics 13, 242 (2021)]