High precision and sensitivity anti-interference 3D coherent ranging based on dual reversely chirped self-mixing lasers

Frequency-modulated continuous-wave light detection and ranging (FMCW lidar) is a powerful high-precision ranging and three-dimensional (3D) imaging technology with inherent immunity to ambient light and the ability to simultaneously yield distance and velocity information. However, the current withdraws of the traditional FMCW lidar systems are the poor resistance to environmental disturbance and high requirements for echo power, which greatly restrict their applications for high-precision ranging of noncooperative targets in dynamic measurement scenes. Here, we report an all-fiber anti-interference FMCW lidar system with high sensitivity and precision, employing a unique self-mixing stimulation radiation process for signal amplification, a special reversely chirped dual laser structure, and a common-path design for disturbance compensation. We evaluate the ranging accuracy, precision, and stability of the system completely. Finally, we demonstrate an ultralow echo detection limit of subpicowatts with a probe power of below 0.1 mW, a state-of-art localization accuracy of better than 50 μm, high stability with a standard deviation of 6.51 μm over 3 h, and high-quality 3D imaging of noncooperative objects in a fluctuating environment. With the advantages of high precision and stability, weak signal detection capability, and anti-interference ability, the proposed system has potential applications in space exploration, autodriving, and high-precision manufacturing.