BISTABLE BRIGHT SOLITONS IN DISPERSIVE MEDIA WITH A LINEAR AND QUADRATIC INTENSITY-DEPENDENT REFRACTION INDEX CHANGE

An exact analytical bistable (or two-state) soliton solution of the generalized nonlinear Schrodinger equation has been found for a medium with a linear and quadratic intensity depending refraction index change of the form DELTA-n = n2\A\2+n4\A\4. It is shown that for negative nonlinear coefficients n2n4 < 0 and k(L)"n2 < 0 two possible soliton states exist, which describe undistorted pulses with the same duration but different peak power. It is proven that both solution branches are stable against small fluctuations.