Phase-noise-cancelled FMCW Lidar based on CS-DSB modulation and injection-locking technique

Based on carrier-suppressed dual-sideband (CS-DSB) modulation and injection-locking technique, a scheme of phase-noise-cancelled frequency-modulated continuous-wave (FMCW) Lidar is proposed and experimentally demonstrated. In the transmitted port, injection-locked upper-sideband and lower-sideband FMCW signals are generated by CS-DSB modulation and injection-locking technique, and then transmitted to a target. In the received port, two beat notes are extracted through homodyne detection method, and then multiplied to acquire a phase-noise-cancelled beat note. The feasibility of this scheme is verified via a fiber length measurement experiment. The tested fiber has a length of 4916.98 m, which is much larger than the laser coherence length of 637.90 m. The experimental results show that the measured fiber length is 4916.44 m, and the relative error is 0.011 %.