High-Precision Silicon-Integrated Frequency-Modulated Continuous Wave LiDAR Calibrated Using a Microresonator

Abstract

Frequency-modulated continuous wave (FMCW) LiDAR can achieve long-distance and high-precision measurement, and the ranging error mainly comes from the nonlinearity of the laser frequency sweep. In this study, a high-precision silicon-integrated FMCW LiDAR is proposed. An equal frequency hypercube network is established by the stable free spectral range (FSR) of the microresonator to calibrate the nonlinearity of FMCW, and the distance matrix is obtained by analyzing the phase difference matrix of the FMCW signal. A standard length-based microresonator FSR calibration scheme is used to further improve the LiDAR accuracy. The feasibility of the scheme is verified by ranging and three-dimensional (3D) imaging. The ranging is carried out indoors and outdoors. In the indoor environment of a distance of 4 m, the minimum Allan deviation is 65 nm at 10.24 s. In the outdoor environment, the minimum Allan deviation at 438 m is 420 nm at 10.24 s. The 3D imaging can reconstruct the spatial point cloud of the objects and identify the spatial targets. This scheme has good on-chip integration capability and can be further combined with lens-assisted beam steering and optical phased array, laying the foundation for compact, large bandwidth, long-range, and high-precision LiDAR.