Low-threshold power and tunable integrated optical limiter based on an ultracompact VO2/Si waveguide

Optical limiters are nonlinear devices that encompass applications from device protection to activation functionalities in neural networks. In this work, we report an optical limiter on silicon photonics based on an ultracompact VO2/Si waveguide. Our 20-μm-long experimental device features a thermal tunable threshold power of only ∼3.5 mW while being spectrally broadband. Our work provides a new pathway to achieve integrated optical limiters for dense and low-power photonic integrated circuits.