Heterogeneous Thin-Film Lithium Niobate Integrated Photonics for Electrooptics and Nonlinear Optics

Ion-sliced thin-film lithium niobate (LN) compact waveguide technology has facilitated the resurgence of integrated photonics based on the material. The thin-film waveguides offer over an order of magnitude improvement in optical confinement and bending radius compared to conventional LN waveguides. The thin-film technology can also be implemented on versatile silicon substrates. Harnessing the improved confinement, a variety of miniaturized and efficient photonic devices has been realized. The state of the art of thin-film LN integrated photonics is reviewed, focusing on heterogeneous integration, electrooptic modulation, and nonlinear frequency conversion. The potential applications and associated challenges of next-generation LN-based integrated photonics are discussed.