Controlling Dual-Comb Soliton Motion inside a single Fiber Laser Cavity

Abstract: Ultrafast science builds on dynamic compositions of precisely timed light pulses1 and evolving sequences of pulses are observed inside almost every mode-locked laser. However, the underlying physics remains barely controlled and utilized until now. Here, we demonstrate the fast and deterministic control of soliton motion for the generation of programmable ultrashort pulse patterns from a dual-comb mode-locked Er:fiber laser. Specifically, we harness intra-cavity modulation of individual solitons and their laser-intrinsic dynamics to facilitate the rapid tuning of two interlaced soliton combs. Upon extra-cavity temporal recombination of both combs, we obtain reconfigurable pulse patterns at arbitrary delays. Using high-throughput real-time spectral interferometry, we resolve the short-range inter-soliton motion upon external stimuli and we demonstrate the high-speed sweeping of picosecond pump-probe-delays and programmable free-form trajectories. This work introduces a novel approach to soliton control and paves the way for ultrafast instruments at unprecedented high tuning, cycling and acquisition speeds.