Controlled Generation of Bright or Dark Solitons in a Fiber Laser by Intracavity Nonlinear Absorber

We numerically found that an intracavity nonlinear absorber (saturable absorber or reversed saturable absorber) plays a crucial role in the formation of dissipative bright or dark solitons in a fiber laser. The operation of an all-normal-dispersion fiber laser could evolve from a bright-soliton emission state to a black-soliton emission state, purely by changing the intracavity nonlinear absorber from a saturable absorber to an antisaturable absorber. Our simulation results are well supported by the experimental observations. The result suggests a new way to control the dissipative soliton operation of lasers and deepens our understanding of the properties of dissipative solitons.