LINEAR-APPROACH FOR APPROXIMATING SPATIAL SOLITONS AND NONLINEAR GUIDED MODES

A new (to our knowledge) conceptual approach is advanced for finding approximation to nonlinear guided modes and spatial solitons. It shows that the standard stationary expression for the linear wave equation can be used to find nonlinear guided modes, provided that it is linked with a physically insightful consistency condition. Because nonlinear modes have their linear-optical waveguide counterpart, solutions can be borrowed directly from previous applications of the variational procedure to linear-optical waveguides. Examples include spatial solitons in a Kerr-law medium and idealized saturation nonlinearities.