Study on angle detection capability of silicon waveguide grating coupler

Silicon waveguide grating coupler is one of the most important optoelectronic devices in optical communication system. We study on the angle detection capability of silicon waveguide grating coupler. The silicon on insulator (SOI) waveguide grating coupler is designed based on slab waveguide theory firstly. The parameters of the grating structure, which cannot be determined by slab waveguide theory, are optimized by finite difference time-domain (FDTD) solution, such as the grating length, the etch depth and the duty cycle. Simulations are carried out to test the angle detection capability of the silicon waveguide grating coupler. It is demonstrated that the silicon waveguide grating coupler can be used as an angular sensor, with a detection range of 25°.