We show the existence of stable two- and three-dimensional vortex solitons carrying multiple, spatially separated, single-charge topological dislocations nested in a common vortex-ring core. Such nonlinear states are supported by elliptical gain landscapes in focusing nonlinear media with two-photon absorption. The separation between the phase dislocations is dictated mostly by the geometry of the gain landscape, and it only slightly changes upon variation of the gain or absorption strength.
Borovkova, O. [et al.]. Stable vortex-soliton tori with multiple nested phase singularities in dissipative media. "Physical review A", 2012, vol. 85, núm. 2, p. 1-4.