Analysis of Bound-Soliton States in a Dual-Wavelength Mode-Locked Fiber Laser Based on Bi2Se 3
Wavelength switchable and dual-wavelength soliton operations are demonstrated in an erbium-doped fiber laser with three pieces of TI Bi<sub>2</sub>Se<sub>3</sub> polyvinyl alcohol (Bi<sub>2</sub>Se<sub>3</sub>-PVA) film. Wavelength switchable operation from 1532 to 1557 nm could be achieved just by adjusting the pump power. With the appropriate settings of PC and pump power, a novel dual-wavelength soliton operation was observed. The dual-wavelength pulses operate at different mode-locked states. One is the single pulse mode-locking operation at 1532 nm, and the other one is the bound-soliton states at 1557 nm. However, the dual-wavelength soliton operation cannot be stable for a long time. The numerical results demonstrate that the separations of bound pulses have small variation and that the phase difference of bound pulses appear jumping change of <inline-formula><tex-math notation="LaTeX">$\pi $</tex-math></inline-formula>.