Dual-dispersion-regime dual-comb mode-locked laser

TL;DR

This paper introduces the first solid-state dual-comb mode-locked laser operating simultaneously in different dispersion regimes, utilizing polarization multiplexing in a birefringent gain medium to generate two distinct pulse trains.

Contribution

It demonstrates a novel dual-comb laser in a single cavity with dual dispersion regimes and polarization multiplexing, enabling different pulse durations and dispersion characteristics.

Findings

Achieved dual pulse generation with 20-fold difference in duration.

Generated a 117 fs soliton-like pulse in anomalous dispersion.

Produced a strongly chirped pulse of 2360 fs in normal dispersion.

Abstract

We report on the first solid-state dual-comb mode-locked laser simultaneously operating in different dispersion regimes. Due to the intrinsic polarization-multiplexing in a birefringent Yb:Ca$_3$NbGa$_3$Si$_2$O$_{14}$ (Yb:CNGS) gain medium, the laser emits two cross-polarized pulse trains with a repetition rate offset of ~4.8 kHz from a single cavity. We obtain dual pulse generation with 20-fold difference in the duration, by setting the net cavity group delay dispersion to cross zero across the emission band of the employed gain medium. While the duration of the soliton-like pulses experiencing anomalous dispersion amounts to 117 fs, the second laser output that is spectrally located in the normal dispersion region, is strongly chirped with a pulse duration of 2360 fs.