Low mode-locking threshold and sub-90 fs Er-doped Mamyshev oscillator

We demonstrated an all-fiber Er-doped Mamyshev oscillator with short pulse-duration and low mode-locking threshold based on an external seed. In experiments, the proposed laser generated stable pulses with 5.45 MHz repetition rate and 47.4 nm bandwidth at 10-dB. The pulse duration is 83 fs, which is the first time to our knowledge, that the sub-90 fs pulse output was observed directly from the Mamyshev oscillator output coupler (OC) without extra compression. Incorporating suitable setting of the cavity structure, the mode-locking operation could be achieved easily along with the two pumps beyond mode-locking threshold of 33.9 mW and 28.8 mW, respectively. To our knowledge, this is by far the shortest pulse duration and lowest mode-locking threshold Er-doped Mamyshev oscillator. The experimental results suggest that the proposed laser shows potential applications in laser communication and biosensing fields.