Dynamical behaviour of unbounded spatial solitons in self-defocusing mediawith small chi((5)) self-focusing nonlinearity

A numerical study is made on dynamics of unbounded bright/dark spatial soli ton (UBSS/DSS) in self-defocusing Kerr media with small chi((5)) self-focus ing nonlinearity. Induced by the non-soliton part in the initial condition, soliton scattering process is followed by uneven energy redistribution bet ween the scattered wavepackets with the additional radiation taking parr in . Enhanced by the chi((5)) self-focusing effect with modification of the cu bic defocusing nonlinearity, the resultant propagation of the coupled UBSS/ DSS channels presents a striking contrast in brightness/blackness. Stable p ropagation of such soliton pair requires exacting physical conditions compo sed of appropriate ratio of cubic-quintic nonlinearity and initial repulsiv e force of sufficient strength matched with fitting input light power. (C) 2000 Elsevier Science B.V. All rights reserved.