All-fiber fast coherent LiDAR for ranging and velocimetry based on optical comb injection

Frequency-modulated continuous-wave light detection and ranging (LiDAR) is a powerful ranging technique that offers inherent resistance to ambient light and the capability to simultaneously measure both distance and velocity. However, conventional LiDAR systems often face challenges with environmental interference and achieving a balance between demodulation complexity, data-refresh rate, and precision. Here, we introduce an all-fiber LiDAR system that utilizes optical comb injection for high-precision ranging and velocimetry. Owing to the injection locking process, the beam output from slave lasers inherits the linear and fast frequency modulation features of the injected optical comb sidebands generated through an electro-optics modulator while maintaining a stable output power with little phase noise, solving a big concern in traditional external modulation schemes. The unique dual-sideband locking and common-path design enhance stability and anti-interference ability, enabling the system to possess a high data-refresh rate of over 10 kHz and a high precision of 500 μm without complex algorithms or compensation circuits. Dynamic ranging and imaging of noncooperative targets are also demonstrated. With the advantages of fast and noncontact measurement, high precision and stability, and anti-interference ability, the proposed system has potential applications in automatic driving, machine control, and intelligent robotics.