Observation of Bright-Dark Soliton Pair in a Fiber Laser With Topological Insulator

The bright-dark soliton pair in a passively mode-locked fiber laser based on the topological insulator: Bi ₂ Se ₃ /polyvinyl alcohol (PVA) film in the proper polarization state and the pump power is experimentally demonstrated. By carefully adjusting the pump power and the polarization state, the bright-dark soliton pair could be easily observed. Furthermore, it is found experimentally that the formation of the bright-dark soliton pair is mainly due to the polarization effect based on the high nonlinear effect of topological insulator: Bi ₂ Se ₃ /PVA film. We also demonstrate that the pulse shape of the bright-dark soliton pair can be affected by the total net cavity dispersion in the fiber laser.