Comb-calibrated Frequency-modulated Continuous-wave Lidar

Frequency-modulated continuous-wave FMCW laser detection and ranging technology is very suitable for absolute distance measurement of large-scale, non-cooperative targets with high resolution, and precision. However, the precision of ranging often decreased because of the frequency modulation nonlinearity of FMCW laser. In order to solve this problem, we propose a method for eliminating the nonlinearity by real-time measurement of the relative frequency of the FMCW laser with an optical frequency comb. The scanning range of the FMCW laser spans from 1556 nm to 1562 nm with a scanning speed of 2000 nm/s. The measurement resolution of the ranging system is about 220 μm, and the repeatability is below 100 nm.