Modular Multi-Aperture Optical Phased Array System Enabling Solid-State Full-Space Beam Steering

Full-space perception capability is facilitating autonomous mobility devices to build more intelligent and safe systems. Silicon-based optical phased array (OPA) has emerged as a promising solid-state solution, offering chip-scale, non-mechanical beam steering. However, conventional single-aperture OPA architectures inherently suffer from unidirectional radiation and limited field of view (FOV), falling short of full-space coverage. Here, we propose and experimentally demonstrate a modular, multi-aperture OPA system combining chip-level FOV expansion and system-level spatial tiling to realize seamless 4π-steradian beam steering. At the chip level, a wide-FOV OPA is implemented by cascading multi-period grating antennas under a spatial-division multiplexing manner to enhance longitudinal steering capability. Meanwhile, a non-uniform-width waveguide array with half-wavelength spacing supports wide-angle lateral steering, resulting in a per-chip coverage of up to 90° × 90°. At the system level, we construct a multi-chip module arranged in a pyramid configuration. By spatially synthesizing the FOVs of four wide-FOV OPA chips, the system yields hemispherical coverage, and a mirror-symmetric counterpart enables seamless 4π-steradian beam steering. Finally, we validate the system through single-point ranging across representative full-space steering directions and multi-target, full-space three-dimensional (3D) imaging. This work paves the way for compact, fully integrated light detection and ranging (LiDAR) systems with omnidirectional spatial sensing.