LAUSR

Abstract The grating structure and its performance for coupling between fiber and silicon-based waveguide are studied and analyzed. The coupling mechanism is illustrated through the grating Bragg diffraction condition, and the effect of physical parameters and alignment parameters of the grating coupler on the coupling efficiency is analyzed by FDTD (Finite-difference time-domain). The optimum design values of the period, duty cycle, etching depth and alignment parameters of the grating coupler are obtained, and at the same time, the deviation analysis on the optimal size is carried out. We present high-efficiency grating couplers fabricated both in EBL (Electron Beam Lithography) and Deep Silicon Etching through process optimization on device dimension, which can be useful for grating coupler fabrication.