Integrated silicon photonic nanocircuits and technologies for optical interconnect and optical sensing

Abstract

Silicon-on-insulator (SOI) nanowires give a very promising way to realize ultrasmall photonic integrated devices because of the ability for ultrasharp bending as well as the CMOS compatibility. As a typical integrated-type (de)multiplexer, ultrasmall arrayed-waveguide gratings (AWG) are very attractive for many applications. We have developed several types of ultrasmall SOI-nanowire AWG with novel layouts. SOI nanowires also give a good platform for optical sensing with high sensitivity because of the enhanced evanescent field. We have developed SOI-nanowire- based optical sensors by using MZI (Mech-Zehnder interferometer)-coupled microrings and cascaded rings. We also note that the size of an SOI nanowire is still limited to the order of wavelength in each direction. In contrast, surface plasmon (SP) waveguides could provide a nano-scale waveguiding and confinement of light. However, the conventional nano-scale SP waveguides are usually quite lossy. We have proposed two types of novel hybrid plasmonic waveguides to achieve nano-scale optical confinement and low-loss light propagation. Due to the ultra-high optical confinement, sub- μm² hybrid plasmonic devices (e.g., power splitters) are presented. It is also shown that hybrid plasmonic waveguide enables sub-μm bending and thus sub-μm resonator has been also demonstrated. The hybrid plasmonic waveguides offer a way to transfer both photonic and electronic signals along the same circuit, which is attractive for active components, e.g., tunable filters and optical modulators.