Rotary dissipative spatial solitons in cylindrical lattices

Abstract

We study both the stability and rotational dynamics of dissipative spatial solitons in optical media described by the cubic-quintic complex Ginzburg–Landau equation in the presence of periodic cylindrical lattices. We consider three kinds of cylindrical lattices, which are generated by (a) the refractive index modulation, (b) the linear-loss modulation, and (c) the combined modulation of both refractive index and linear-loss coefficient. The solitons can be trapped inside each concentric lattice ring (circular “trough”) and can be set into rotary motion by imposing onto the input field distribution a phase slope (or angle), which is proportional to the initial momentum imparted to the soliton in the tangential direction. The rotary motion can be effectively controlled by tuning the amplitude of the modulation profile. For either refractive index or linear-loss modulated cylindrical lattices, the spatial soliton can exhibit stably persistent rotation along the circular lattice orbit only if its initial momentum does not exceed a certain allowable maximum value. But for cylindrical lattices generated by combined refractive index modulation and linear-loss modulation, soliton rotary motion only appears in the initial propagation stage and then stops at certain spatial position. When the initial momentum imparted to the soliton is absent we find that for cylindrical lattices with only linear-loss modulation profile, by varying the modulation depth, the dissipative spatial soliton can display a transverse drift, can spread out into a stable multi-ring-shaped mode, or can decay.