Nonlinear Optics in Hydrogenated Amorphous Silicon

Nonlinear photonic circuits with the ability to generate and process signals all-optically have emerged in the past decade with superior performance to electronic chips. In particular, crystalline silicon has become a leading platform for integrated nonlinear optics. More recently, hydrogenated amorphous silicon emerged as a promising alternative to crystalline silicon due to its large nonlinearity. In this paper, we review recent research on nonlinear optical interactions in and applications of hydrogenated amorphous silicon nanophotonic devices. This new material platform enables the capability of multilayer CMOS-compatible photonic-integrated circuits with low-power requirements for high-speed optical signal processing.