Narrowband Dual-Wavelength Silicon Waveguide Bragg Reflectors

We demonstrate two device concepts based on cladding-modulated (CladMod) waveguide grating for simultaneous dual-wavelength reflection with narrow and equal bandwidths on silicon-on-insulator for the first time. With misaligned corrugations on core waveguide of CladMod waveguide grating, as-realized grating device generates two stopbands with identical bandwidth of 0.8 nm and an interval of 11 nm. With slowly-varying envelope on cladding waveguides of CladMod waveguide gratings, as-realized moiré grating enables two stopbands with a bandwidth of 0.262 nm and an interval of 0.34 nm. The first grating design enables dual-wavelength reflection with flexible bandwidth while the latter one allows two reflecting wavelengths with controllable stopband interval. Those approaches find their respective applications in either wavelength/mode division multiplexing or microwave/millimeter wave generation and sensors.