OFC-enabled high-accuracy and real-time AMCW LiDAR for absolute laser ranging

An amplitude-modulated continuous-wave (AMCW) LiDAR based on an optical frequency comb (OFC) is proposed and demonstrated. We employ an OFC for ranging signal down-conversion, ensuring high ranging, accuracy, and speed while alleviating the requirements for large-bandwidth photodetectors (PDs) and high-performance analog-to-digital converters (ADCs). In addition, we intensity-modulate a reference electrical pulse sequence onto the OFC to extend the measurable range and eliminate range ambiguity according to the pulse time difference in the time domain. The experiments achieved a repeatability of 10.5 nm at an average time of 427 ms, an accuracy of ±0.8 µm, and an update rate of 150 Hz. Additionally, three-dimensional (3D) laser imaging, with a standard deviation (STD) of 3.7 µm, was achieved using a micro-electro-mechanical system (MEMS) scanning mirror.