Inverse-Designed Lithium Niobate Nanophotonics

Lithium niobate-on-insulator (LNOI) is an emerging photonic platform that exhibits favorable material properties (such as low optical loss, strong nonlinearities, and stability) enables large-scale integration with stronger confinement, showing promise for future networks, quantum processors, nonlinear systems. However, while photonics engineering has entered the era of automated “inverse design” via optimization in recent years, design LNOI integrated devices still mostly relies on intuitive models inefficient parameter sweeps, limiting accessible space, performance, functionality. Here, we implement a 3D gradient-based inverse-design model tailored topology based platform, which not only could efficiently search large but also takes into account practical fabrication constraints, including minimum feature sizes etched sidewall angles. We experimentally demonstrate spatial-mode multiplexer, waveguide crossing, compact bend, all insertion losses, tiny footprints, excellent agreement between simulation experimental results. The devices, together methodology, represent crucial step toward variety advanced device functionalities needed provide cost-effective solutions links, technologies, optics.