Nonstationary self-focusing of modal fields in guiding structures with sharp discontinuities

Spatial-temporal transient process of optical pulse propagation through nonlinear discontinuities of planar dielectric waveguide is analysed numerically. Nonlinear equation for the slowly varying pulse envelope in a moving frame coordinate system is solved in quasi-static approximation and with account of self-steepening effect and small material dispersion. Soliton-like propagation of the optical pulse is observed provided that quasi-static approximation is used.