Monolithically integrated silicon photonic biaxial FMCW LiDAR system.

Three-dimensional sensing is critical for autonomous systems, robotics and industrial monitoring, motivating compact frequency-modulated continuous-wave (FMCW) LiDARs, which optically measure distance and velocity. However, current integrated designs using optical phased arrays (OPAs) for beam steering or focal-plane arrays (FPAs) for parallel reception face trade-offs in optical power, aperture and acquisition speed. Here we show a biaxial FMCW LiDAR that monolithically integrates an OPA transmitter and coherent FPA receiver with over 4500 functional components on separate optical paths, eliminating the need for circulators. A line-shaped beam enables agile steering, while a lens-assisted FPA provides a large receiving aperture and parallel single-wavelength readout. The system images at 20 m using 3.7 mW of emitted power, with 5 cm depth resolution and 1.4 mm/s velocity resolution. It produces point clouds at 10 frames per second (fps) and supports acquisition rates up to 41 fps, offering a compact and practical route towards integrated FMCW LiDAR.