Output analysis of sandwiched two-layer arrays for cancellation of zeroth order

In this paper, a sandwich structure two-port transmission beam splitter with two-layer array is proposed. By using rigorous coupled-wave analysis and simulated annealing algorithm, the structure and parameters of the grating are analyzed and optimized to achieve high efficiency diffraction and zero order suppression. At normal incidence of 800 nm incident light, the diffraction efficiency of the grating at +/- 1st transverse magnetic polarization and transverse polarization is 48.83% and 49.12% respectively. In addition, the grating can still maintain high efficiency within the process tolerance range of some parameters (including incident wavelength, duty cycle, incident angle and grating period).