Two-state bright solitons in doped fibers with saturating nonlinearity

Fundamental bright soliton solutions are studied numerically in a model for pulse propagation in semiconductor-doped glass fibers with exponential saturation of the nonlinear dielectric function. It is shown that the given model possesses two-state soliton solutions in the sense that for a given set of fiber parameters there exist two soliton solutions with the same pulse width but with different peak amplitudes, i.e., with different peak powers. The stability of these solitons under weak perturbations and the effect of the fiber loss are also investigated. A comparison with earlier results for such solitons is made. © 1996 The American Physical Society.