Lens-assisted beam steering chip based on micro-ring optical switch array

Light detection and ranging (LiDAR) technique is always a building block in the fields of sensing, mapping and autonomous driving navigation. Beam steering devices, which are used for light emission and reception, play a key role in LiDAR system. Lens-assisted beam-steering (LABS) is one of the most competitive candidates among various beam steering technologies. Compared with conventional integrated optical phased array (OPA), LABS unit is with lower optical loss and meanwhile lower control complexity. In this paper, we demonstrate a highly integrated LABS chip based on micro-ring optical switch array with a wide field of view (FoV, 30°×40°) and a narrow beam divergence (<0.1°). A 32×32 micro-ring optical switch array connected with a 1×1024 optical antenna array is integrated in the silicon photonic chip with an overall size of 6×14 mm2. Incident light is routed to one antenna by the micro-ring optical switch array and emitted into the free space, and the emergent light is collimated and steered by a cylindrical lens fixed above the optical antenna array subsequently. On this basis, one-dimensional steering is achieved by switching light to different antennas, while steering in the other dimension is realized via wavelength tuning. Under this circumstance, only two micro-ring switches need to be turned on at one time, leading to a significant reduction of optical loss and control complexity of the proposed chip. Notably, our work demonstrates the feasibility of large-scale integration of optical switch array within LABS chip by adopting compact micro-ring switches, paving a new path for miniatured beam scanners.