Scaling the repetition rate of thulium-doped ultrafast soliton fiber lasers to the GHz regime

GHz high repetition rate compact sources with femtosecond pulse durations and stable performance can enable a wide range of applications. In this paper, several high repetition rate ultrafast thulium fiber lasers with repetition rates varying between 532 MHz to 1.25 GHz are demonstrated with femtosecond pulse durations down to 426 fs. An approach of maintaining comparable pulse energies while scaling the repetition rates allows high-quality femtosecond mode-locking performance with low noise performance in thulium soliton lasers for the first time.