Polarization-Independent Wavelength Conversion Using an Angled-Polarization Pump in a Silicon Nanowire Waveguide

A proposal for polarization-independent wavelength conversion is presented based on four-wave mixing in a silicon nanowire waveguide using an angled-polarization pump. The principle of polarization independence is introduced and the theoretical model is established. The optimized incident pump polarization angle is obtained for different waveguide geometries, and a polarization-independent bandwidth of 64 nm is achieved with the efficiency fluctuation of less than 1 dB in a 285 nm × 650 nm silicon waveguide. The polarization-independent bandwidth is limited by the larger one of the TE- and TM-mode phase mismatches, and can be enhanced further by carefully tailoring the dispersion characteristics of the silicon nanowire waveguide.