Integrated Electro-Optics on Thin-Film Lithium Niobate

Electro-optics serves as the crucial bridge between electronics andphotonics, unlocking a wide array of applications ranging from communicationsand computing to sensing and quantum information. Integrated electro-opticsapproaches in particular enable essential electronic high-speed control forphotonics while offering substantial photonic parallelism for electronics.Recent strides in thin-film lithium niobate photonics have usheredrevolutionary advancements in electro-optics. This technology not only offersthe requisite strong electro-optic coupling but also boasts ultra-low opticalloss and high microwave bandwidth. Further, its tight confinement andcompatibility with nanofabrication allow for unprecedented reconfigurabilityand scalability, facilitating the creation of novel and intricate devices andsystems that were once deemed nearly impossible in bulk systems. Building uponthis platform, the field has witnessed the emergence of various groundbreakingelectro-optic devices surpassing the current state of the art, and introducingfunctionalities that were previously non-existent. This technological leapforward provides a unique framework to explore various realms of physics aswell, including photonic non-Hermitian synthetic dimensions, active topologicalphysics, and quantum electro-optics. In this review, we present the fundamentalprinciples of electro-optics, drawing connections between fundamental scienceand the forefront of technology. We discuss the accomplishments and futureprospects of integrated electro-optics, enabled by thin-film lithium niobateplatform.