Abstract

In the presence of weak nonlinearity and dispersion, an envelope of a single (quasi-monochromatic) wave is known to obey the nonlinear Schrodinger (NLS) equation, which supports bright or dark solitons depending on the type of dispersion. What happens to solitary waves of different modes when they become coupled? It has been shown by several authors that nonlinear coupling between the modes with dispersions of opposite sign usually leads to instabilities of the coupled dark-bright solitons [1,2], and until now the existence of stable solitons of this type has not been reported. We present here the analysis of dark-bright solitons in two nonresonantly coupled NLS equations with dispersion coefficients of the same and opposite signs. We find general families of these solitons and reveal an important physical mechanism of their stabilisation.

© 1996 Optical Society of America