Unidirectional SiN antenna based on dual-layer gratings for LiDAR with optical phased array

A novel unidirectional SiN antenna for LiDAR is proposed. It is designed as a sandwich structure composed of two layers of gratings and a slab waveguide. The highest upward directionality is 96.7% at 957 nm and upward directionality exceeds 53% in the wavelength range of 875 nm to 1100 nm. With an antenna aperture size of 15.5 mm × 2.048 mm, a small divergence angle of 0.0037° × 0.027° (Δθ×Δφ) is achieved. It is able to get higher output than silicon-based optical phased arrays to increase the detection range of integrated optical phased array LiDAR chips.