Wide range linearization calibration method for DFB Laser in FMCW LiDAR

Abstract

In this paper, a solution based on a hybrid electro-optic phase-locked loop (HEO-PLL) is proposed to address the nonlinearity of the continuous sweep frequency of the light source in Frequency Modulated Continuous Wave (FMCW) LiDAR. This nonlinearity leads to large measurement errors, low accuracy, and poor system adaptability. The proposed solution uses a HEO-PLL to control the frequency sweep linearity of the distributed feedback (DFB) laser when it undergoes continuous, rapid, and wide-range frequency modulation through current tuning. The system is designed to allow the DFB laser to be used as a high-quality source for FMCW LiDAR. This enhances the resolution and ranging capability of the FMCW LiDAR with the DFB laser as the source, while avoiding issues such as difficult tuning of the loop bandwidth and central frequency and being highly susceptible to temperature and voltage variations caused by the charge pump phase-locked loop.