Monolithically integrated silicon photonic biaxial FMCW LiDAR system

The increasing demand for three-dimensional dynamic environmental perception is driving interest in solid-state frequency-modulated continuous-wave (FMCW) LiDAR technologies. However, integrated FMCW LiDAR based on either optical phased arrays (OPAs) or focal-plane arrays (FPAs) face intrinsic trade-offs that have not yet been addressed simultaneously. Here, we present a biaxial FMCW LiDAR architecture that monolithically integrates an OPA transmitter with a coherent FPA receiver, comprising over 4500 functional components and implemented on separate optical paths in a circulator-free configuration. The architecture combines the complementary strengths of OPAs and FPAs. The OPA easily supports high optical power handling and provides agile line-by-line steering enabled by an engineered line-shaped beam. The FPA can form a large receiving aperture assisted by an imaging lens and enables parallel coherent signal readout at a single wavelength. The system achieves single-wavelength three-dimensional imaging with a ranging distance of 20 m using 3.7 mW of emitted optical power. A depth resolution of 5 cm and a velocity resolution of 1 mm/s are obtained. Parallel point-cloud at 10 frames per second (fps) is demonstrated, while acquisition rates of up to 62 fps are supported by the architecture. These results position the biaxial OPA-FPA architecture as a compact and practical system-level approach for integrated FMCW LiDAR.