Vortex clusters in coupled nonlinear waveguides

Abstract

We study vortex clusters in a circular array of nonlinear waveguides coupled to a central waveguide. Multivortex solitons are found analytically and numerically and their linear stability is determined. A seven-waveguide coupler can support two distinct types of multivortex breathers, involving either the coordinated charge flipping of vortices or the rotation of vortices around the central waveguide.