Trapping of Soliton Molecule in a Graphene-Based Mode-Locked Ytterbium-Doped Fiber Laser

We reported on the trapping of soliton molecule in a passively mode-locked ytterbium-doped fiber laser with a microfiber-based graphene saturable absorber (GSA). By virtue of the highly nonlinear effect of microfiber-based GSA, the multipulse formation, such as the soliton molecule, is greatly enhanced despite of the all-normal dispersion regime. Depending on the cavity parameter selections, it was found that the conventional multisoliton could be reconstructed and then evolve into the soliton molecule. The soliton molecule trapping of two polarization components with a 0.65-nm wavelength separation was observed, which propagated as a group-velocity locked vector soliton despite of the cavity birefringence. The obtained results provide an enhanced understanding of dynamics of the soliton molecule.