Resonance- and phase-induced window sequences in vector-soliton collisions

In this Letter, we report two new discoveries in vector-soliton collisions of the nonintegrable coupled nonlinear Schrodinger equations. The first dis covery is that, at low cross-phase-modulational coefficients, a sequence of reflection windows similar to that in the phi (4) model appears in the col lision of two orthogonally polarized and equal-amplitude solitons. This win dow sequence is caused by a resonance between the translational motion and width oscillations of vector solitons. Analytically, we explain these colli sion behaviors by a variational model which qualitatively reproduces this w indow sequence. The second discovery is that, when initial solitons are not orthogonally polarized, their collision can generate a different sequence of reflection windows. This window sequence is induced by the collision's d ependence on solitons' phase differences. Our analytical formula for the lo cations of these phase-induced windows agrees well with our numerics. To ou r knowledge, this is the first report of phase-induced window sequences in solitary-wave collisions in the literature. (C) 2001 Elsevier Science B.V. All rights reserved.