High-performance integrated silicon LiDAR enabled by combined shallow and full etching.

Light detection and ranging (LiDAR) systems that rely on wavelength tuning typically employ gratings to realize wavelength-dependent beam steering. In this work, we propose a subwavelength grating (SWG) antenna incorporating shallow-etched auxiliary blocks. These auxiliary blocks break the vertical structural symmetry of the antenna, thereby effectively suppressing downward optical power leakage into the substrate. The geometric parameters are optimized using a particle swarm optimization (PSO) algorithm, resulting in a transmission of 66.2%, a scanning rate of -0.233∘/nm, and transmission fluctuations confined within 6.42%. The system uses a coarse wavelength-division multiplexing (CWDM) laser array as the light source and supports bidirectional waveguide propagation, achieving a 28° scanning field of view (FOV) over a 60 nm wavelength range.