Observation of dual-wavelength dissipative solitons in a figure-eight erbium-doped fiber laser.

We report on the generation of dual-wavelength dissipative solitons (DSs) in a passively mode-locked figure-eight fiber laser operating in the net-normal dispersion regime. DSs with central wavelengths of 1572 and 1587 nm can be achieved simultaneously or respectively. The dual-wavelength DSs, traveling at different round-trip time, exhibit double-rectangular spectral profile. The intensities of two mode-locked spectra decrease or increase simultaneously after passing through a polarization beam splitter, indicating that the dual-wavelength DSs almost share the same polarization state. Experimental results demonstrated that dual-wavelength mode locking strongly depends on birefringence-induced filtering effect.