Broadband focusing reflectors based on subwavelength gratings

Abstract

We have designed a reflector based on the hexagonal lattice of circular two-dimensional subwavelength gratings (2D SWG), which characterize high-reflectivity, polarization-independence and the ability of focusing. The focusing reflector has designed on a silicon-on-insulator (SOI) wafer to apply in mushroom-mesa photodetector to increase bandwidth as well as efficiency simultaneously. The focusing reflector with a diameter of 16um and a focal length of 6μm has been designed, which achieves normal incident light focusing at wavelength 1550nm.