Tunable Polarization-Multiplexed Single-Cavity Dual-Comb.

Dual optical frequency combs exploiting two pulse trains with slightly different repetition rates have recently found applications in the distance ranging (LIDARs), structural health monitoring, gas sensing, optical communications, and instrumentation calibration for astronomy [1], [2]. To the date, there are various ways to generate dual optical frequency combs both in fiber lasers and solid-state lasers. Nonetheless, the traditional implementations based on two synchronized ultrafast lasers require addressing several technical challenges, such as the complexity of the phase-locking between both lasers. Therefore, most research efforts have been recently re-directed towards simpler systems based on a single laser. Single source dual-comb (dual-comb laser) has some advantages when it comes to common noise suppression and combs' coherence in a shared cavity [3], [4].