Self-starting triple-wavelength vector dark soliton with a bismuth-doped fiber saturable absorber.

We report on the generation of a triple-wavelength vector dark soliton in an all-fiber ring cavity of erbium-doped fiber laser mode-locked with a bismuth-doped fiber saturable absorber. The formation of the triple-wavelength vector dark soliton is due to the cross-phase coupling derived from the cavity birefringence. The mode-locked laser operated at a 1.89 MHz repetition rate with a 335 ns pulse width, and its robustness is confirmed.