BOUND-STATES OF SOLITARY PULSES IN LINEARLY COUPLED GINZBURG-LANDAU EQUATIONS

We investigate the existence, formation and stability of multipulse bo und states in a system of two Ginzburg-Landau equations coupled by lin ear terms. The system includes linear gain, diffusion, dispersion, and cubic nonlinearity in one component, and only linear losses in the ot her. This is a straightforward model of a doped dual-core nonlinear op tical fiber in which only one core is pumped. The model supports exact stable solitary-pulse solutions. By means of systematic numerical sim ulations, we find that bound states of two, three, and more pulses wit h a uniquely determined separation between them exist. The three-pulse bound states are stable against symmetric perturbations, but prove to be unstable against asymmetric ones. Only the two-pulse states are fo und to be fully stable. (C) 1998 Elsevier Science B.V.