We present a comprehensive, numerically oriented investigation of spatially nonstationary, TE-polarized optical field distributions guided by a thin film that can support both TE and TE waves. The film is asymmetrically bounded by a Kerr-like nonlinear cladding that may exhibit linear material losses. All field distributions have been generated by exciting different guided waves at one of the film end faces and tracing them down the film with the help of an extended propagating beam method. The long-distance asymptotic behavior is of particular interest. The numerical-stability analysis of the dispersion curve for nonlinear guided waves (NGW's) indicates that the positively sloped TE0 branches are stable; this is not strictly true for the TE1 branch. Unstable NGW's display a rich set of nonstationary phenomena, including soliton formation and nonlinear beating effects. Characteristic transformation lengths depend strongly on the definite, unstable initial NGW profile. The main effect of cladding losses is that the field tries to avoid the lossy region, leading to a considerable loss reduction. This property may destroy characteristic NGW features for propagation lengths approaching the absorption length of the lossy cladding. Phase-locked single-soliton and multisoliton emission can be induced by launching linear guided modes with the appropriate power flow through one of the film end faces.
© 1988 Optical Society of America
L. Leine, C. Wächter, U. Langbein, and F. Lederer, "Evolution of nonlinear guided optical fields down a dielectric film with a nonlinear cladding," J. Opt. Soc. Am. B 5, 547-558 (1988)