Dual-comb mode-locked laser simultaneously operating in two different dispersion regimes

Generation of two separate mode-locked pulse trains from a single laser cavity enables to maintain high mutual coherence between the two frequency combs. Consequently, even without any active locking their relative stability can be sufficient for demanding applications requiring two phase-stable sources like dual-comb spectroscopy or ranging [1] . As the two signals share the same cavity, their parameters are usually very similar. Yet, it has been recently shown on the example of Yb-doped fiber laser, that if the combs are emitted at different wavelengths, they can even experience various pulse formation mechanisms [2] . Here, we present a single-cavity dual-comb bulk Yb:CNGS laser based on our recently demonstrated intrinsic polarization-multiplexing scheme [3] . The net cavity dispersion crosses zero across the emission bandwidth of the gain medium, which enabled to simultaneously generate two mode-locked pulse trains operating in a conservative and chirped soliton regimes.