Pulse train uniformity and nonlinear dynamics of soliton crystals in mode-locked fiber ring lasers

The evolution of soliton crystal structures is analytically and numerically investigated in passively mode-locked fiber lasers by means of the nonlinear rotation of polarization. Four parameters are considered as fluctuating canonical variables of the light propagating along the fiber ring: the polarization, the phase, the amplitude, and the chirp. The stability criteria define pulse train uniformity in the soliton crystal via stable phase-locking regimes at 0 and pi/2, with polarization-locked regimes prohibited due to strong amplitude polarization coupling and the bounded nature of the pumped signal. Numerical investigations of the phase-locked regimes also reveal a novel phenomenon that is the generation of spatial soliton lattices. We suggest this remarkable phenomenon results from the amplitude-chirp interplay that transfers the elliptic soliton profile of temporal pumps into spatially localized excitations upon round-trip tours in the fiber ring. (C) 2016 Optical Society of America