Rapidly and widely repetition-rate-tunable free-running dual-comb fiber laser with a bidirectional polarization-multiplexing configuration

Abstract

Repetition-rate-tunable fiber lasers are practical in addressing aliasing issue and exploring optimization parameters for dual-comb metrology and 3D surface profilometry. However, the tuning speed of typical delay lines is not very high, which limits the frame rate. Meanwhile, wide-range tunability is desired to extend non-ambiguity distances and eliminate dead zones. Here, we developed a dual-comb fiber laser based on a resonate piezoelectric motorized delay line that shows a tuning speed up to 493.5 kHz/s over 329-kHz tuning range, which is the fastest to the best of our knowledge. Benefiting from the mechanically shared polarization-maintaining oscillator, the proposed laser is stable with low crosstalk in full free-running, while this bidirectional polarization multiplexing configuration endows good flexibility and tunability. Consequently, the 1-hour variation of repetition rate difference is 0.52 Hz, with a standard deviation of 0.10 Hz. The dual combs are further pulled closer to 184.5 Hz by roughly compensating for fiber length. These results demonstrate a promising solution for developing accordion-comb seed light sources that can contribute to dual-comb metrology and 3D surface profilometry.