Dissipative soliton trapping in normal dispersion-fiber lasers.

We report on the dissipative soliton (DS) trapping in a fiber ring laser mode locked with a semiconductor saturable absorber mirror and operated in normal dispersion regime. It was shown that despite the fact that a DS is strongly frequency chirped, two DSs formed along the two orthogonal polarization directions of a birefringent cavity fiber laser can incoherently couple and travel with the same group velocity in the laser. Numerical simulations have well confirmed the experimental observations.