Pulse shaping effects of fast saturable absorbers in dissipative soliton fiber lasers

We present a numerical study on the relationship between output pulse parameters and fast saturable absorber (SA) in dissipative soliton fiber lasers. It is found that both the modulation depth and the saturation power of the SA can affect the pulse parameters significantly in dissipative soliton fiber lasers. Distinctive temporal and spectral shapes can be achieved via changing the SA's parameters. Pulse shaping effect of SAs saturating at high instantaneous power is stronger than those saturating at low power. Different trends of pulse parameters variation are found in nonlinear polarization rotation mode-locked lasers and real SA mode-locked lasers. The results can be used for the optimization of building environmentally stable all-fiber dissipative soliton lasers with real SAs.