Weakly nonparaxial spatial solitons in a medium with Kerr nonlinearity

A version of perturbation theory is developed that intends to determine the field distribution of spatial solitons with a 2D transverse profile in a K err medium in the case of small deviations from paraxial conditions. An app roximate master equation for transverse components of the electric field in the case of wide solitons is derived. By solving this equation starting fr om the unperturbed soliton, i.e., Townes mode with linear polarization of r adiation, a solution with an axially symmetric field distribution is found. Dependences of the main soliton characteristics on the degree of paraxiali ty are determined. (C) 2000 MAIK "Nauka/Interperiodica".