Fiber Bragg grating stabilization of a passively mode-locked 28 μm Er^3+: fluoride glass fiber laser

We report the first stable mode-locking from an Er3+: fluoride glass fiber laser linear cavity operating near 3 μm to the best of our knowledge. The linear cavity includes a saturable absorber mirror and a fiber Bragg grating to provide a controlled and wavelength selective feedback. The pulse train has a 51.75 MHz repetition rate, an estimated 60 ps pulse duration, and an average power of 440 mW. The stable and self-starting mode-locking regime is confirmed by RF spectral measurements and is maintained over several hours.