Sub-100 fs Passively Mode-locked Holmium-doped Fiber Oscillator Operating at 2.06 μm

摘要

We demonstrate a simple and compact Holmium-doped fiber (HDF) femtosecond oscillator with 35 MHz repetition rate. The oscillator is pumped by a Tm-doped fiber laser. A dispersion compensating fiber was utilized to set the net-intra-cavity dispersion to zero at 2.06 μm. The output pulses had an maximum average power of 40 mW and 160 fs FWHM pulse duration. To further shorten the pulse duration, we implemented a nonlinear compressor consisting of a solid core highly nonlinear fiber (HNLF) for SPM broadening and single mode fiber (SMF) for pulse compression. Sub-100 fs pulses were achieved.