Aliasing-free dual-comb ranging system based on free-running fiber lasers

A dual-comb ranging (DCR) system without spectral aliasing based on free-running fiber lasers was proposed. By monitoring the repetition frequency over time, we compensate for the instability of the optical pulse train from the free-running fiber lasers. We demonstrated a double-channel filtering structure that eliminates the aliasing between multiheterodyne beats in radio frequency interferograms. Without any frequency locking, the DCR system implements stable running for at least 60 min. The system realizes a 6-µm repetition precision without averaging and shows good consistency with a commercial interferometer.