Heterogeneously Integrated Photonics Based on Thin Film Lithium Niobate Platform

Abstract The emergence of high‐quality thin film lithium niobate on an insulator has opened up new research opportunities in the field of integrated photonics devices. Through heterogeneous integration, it is possible to integrate light sources, electro‐optic modulators, photodetectors, and other key components onto a single chip, achieving multifunctionality. This is an accomplishment beyond the capability of standalone thin film lithium niobate. Heterogeneous integration offers an effective approach to develop photonic integrated circuits based on thin film lithium niobate platform. This review article summarizes recent advances in heterogeneously integrated photonics based on thin film lithium niobate platform. This work provides an overview of basic heterogeneously integrated photonics materials, including silicon, silicon nitride, III–V semiconductors, and 2D materials, and basic devices such as waveguides, grating couplers, lasers, microring resonators, electro‐optic modulators, and photodetectors. This work discusses the operating mechanism, design principle, fabrication methodology, and performance metrics of each device. Finally, this work summarizes the recent key advances in heterogeneously integrated photonics based on thin film lithium niobate platform and addresses the challenges that need to be tackled for the future development.