Design and analysis of SiN optical waveguide for 2D beam steering

Abstract

This paper presents a method for achieving 2D beam steering using 16-phased array grating couplers through FDTD simulation. The method begins by designing a single grating coupler with a silicon nitride material (depth = 0.15 um, width = 0.2 um, grating pitch = 0.34 um) to achieve 1D beam steering of around 7.6° by changing the input wavelength from 500 nm to 550 nm and changing the TE or TM mode source. The grating pitch of 0.34 um was selected because the input wavelength at 532 nm through the NV center can measure the magnitude field, resulting in a reflected angle of 0°. By changing the input wavelength, positive and negative beam steering directions can be achieved. Subsequently, a total of 16 phased arrays were established, and a multimode interferometer (MMI) was used to split the input beam into 16 grating couplers. With the 16 waveguides, the phase can be changed from 0 to π/8, allowing the 2D steering angle to be altered from 0° to 1.72°. The method was validated using 3D simulations to ensure that the results match those obtained through 2D simulation.