Nonlinear optical beams carrying phase dislocations

We describe different types of self-trapped optical beams carrying phase dislocations, including vortex solitons and ring-like soliton clusters. We demonstrate numerically how to create such nonlinear singular beams by the interaction of several fundamental optical solitons. Mutual trapping of several solitons can be regarded as a synthesis of `soliton molecules', and it corresponds to a transfer of an initial orbital angular momentum of a system of solitons to a spin momentum of an optical vortex.