Research on Dual-Comb Ranging Technology Based on Si3N4 Microcomb

To promote the transition of microresonator dual-comb ranging (DCR) technology from the laboratory to practical applications, we have developed a DCR system based on two self-developed, self-starting silicon nitride (Si3N4) microcombs with repetition-rate-locking. By integrating servo-control circuits and employing an all-polarization-maintaining fiber design, we have achieved long-term stable operation of the system. To validate the system’s performance parameters, we conducted two verification experiments at the National Institute of Metrology, China (NIM): a comparison against the indoor national long-base comparator and a repeatability test at an outdoor field baseline. Over the indoor test range of 0–60 m, measurement results showed deviations within 6 μm when compared against the indoor national long-base comparator. At the outdoor field baseline location of 618 m, with a signal acquisition duration of 1 ms per measurement, the ranging standard deviation was 2.38 μm. During outdoor ranging experiments, the system operated continuously for over 4 h without the need for specialized thermal insulation or vibration isolation measures. These results demonstrate the exceptional measurement accuracy and stability of the microresonator DCR system.