High-Energy Square Pulses in a Mode-Locked Yb-Doped Fiber Laser Operating in DSR Region

We report the experimental observation of high-energy square pulses in all-normal-dispersion passively mode-locked Yb-doped fiber laser under dissipative soliton resonance (DSR) condition using a nonlinear polarization rotation technique. The generated square pulses are mode locked with fundamental cavity repetition rate of 1.86 MHz. The maximum output average power and the corresponding pulse energy are 62.1 mW and 34 nJ, respectively. The output square pulses are wave-breaking-free and can be tuned in pulsewidth from hundreds of picoseconds to several nanoseconds by changing the pump power. The multistability of DSR in all-normal-dispersion cavity has been first demonstrated in experiment, which is in agreement with theoretical prediction. The observed experimental results will enhance the understanding of fundamental physics of DSR phenomenon.