Compressibility of Dissipative Solitons in Mode-Locked All-Normal-Dispersion Fiber Lasers

We numerically investigated the compressibility of dissipative soliton pulses in an all-normal-dispersion fiber laser which was mode-locked with a nonlinear optical loop mirror. A transition state within the area between the traditional dissipative soliton regime and dissipative soliton resonance regime was revealed to have much higher dechirped peak power and shorter dechirped pulse duration than its vicinity. This phenomenon is reported for the first time to the best of our knowledge. The peak power and pulse width of the dechirped pulse were calculated using the linear compression method. The dynamics and the distribution of the transition state were systematically analyzed in laser parameter spaces. The nonlinear frequency chirp was mainly induced by self-phase modulation and the pulse formation mechanism, which influenced the linear compressibility of the dissipative. We demonstrated that there were optimal filter bandwidth values corresponding to the best pulse compressibility under different laser parameters. The simulation results indicate that dechirped pulses with a pulse peak power of 0.5-1 MW, a pulse duration of the 100-fs level, and a pulse energy of ~100 nJ can be obtained using the optimal parameters.