Controlling Microring Resonator Extinction Ratio via Metal-Halide Perovskite Nonlinearity

The exceptionally high optical nonlinearities, wide bandgap, and homogeneity in solution-processed metal-halide perovskite media are utilized as optical nonlinear elements on a silicon photonic platform for low-power-active components, such as all-optical switches, modulators, and lasers. With room temperature back-end-of-line compatible processing, a hybrid metal-halide perovskite (CH₃NH₃PbI₃) microring resonator (MRR) structure is fabricated on a foundry-processed low-loss silicon photonic platform. With in-plane excitation near the light intensity of 110 W m⁻², strong two-photon absorption and free-carrier absorption saturation are observed. With 10³ field enhancements by MRRs, the photorefractive effect in the metal-halide perovskite reduces linear absorption, represented by 10² improvement of the MRR's intrinsic quality factor and 20 dB enhancement of the extinction ratio.