A silicon-based wideband multisubpart profile grating reflector

In this paper, a multilayer configuration high-performance reflector utilizing a multisubpart profile grating structure is presented. Rigorous coupled-wave analysis (RCWA) for multilayered grating is adopted to design and optimize the structure. And experimental verification of theoretical design is accomplished. It is shown that, for transverse magnetic (TM) polarization, over a broadband spectrum from 1.65 to 1.72 μm, the reflector experimentally demonstrates combined merits of high reflectivity (>97%) and good angular insensitivity of about 24.6°. Moreover, it is found by RCWA that the reflector proposed here has a reasonably good tolerance of fabrication error, which provides a favorable advantage in the fabrication process.