Multi-beam top-facing optical phased array enabling a 360° field of view

An optical phased array (OPA) featuring all-solid-state beam steering is a promising component for light detection and ranging (LiDAR). There exists an increasing demand for panoramic perception and rapid target recognition in intricate LiDAR applications, such as security systems and self-driving vehicles. However, the majority of existing OPA approaches suffer from limitations in field of view (FOV) and do not explore parallel scanning, thus restricting their potential utility. Here, we combine a two-dimensional (2D) grating with an FOV-synthetization concept to design a silicon-based top-facing OPA for realizing a wide cone-shaped 360° FOV. By utilizing four OPA units sharing the 2D grating as a single emitter, four laser beams are simultaneously emitted upwards and manipulated to scan distinct regions, demonstrating seamless beam steering within the lateral 360° range. Furthermore, a frequency-modulated dissipative Kerr-soliton (DKS) microcomb is applied to the proposed multi-beam OPA, exhibiting its capability in large-scale parallel multi-target coherent detection. The comb lines are spatially dispersed with a 2D grating and separately measure distances and velocities in parallel, significantly enhancing the parallelism. The results showcase a ranging precision of 1 cm and velocimetry errors of less than 0.5 cm/s. This approach provides an alternative solution for LiDAR with an ultra-wide FOV and massively parallel multi-target detection capability.