BRIGHT AND DARK SOLITARY WAVE-PROPAGATION AND BISTABILITY IN THE ANOMALOUS-DISPERSION REGION OF OPTICAL WAVE-GUIDES WITH 3RD-ORDER AND 5TH-ORDER NONLINEARITIES

A unified analysis of all existing solitary wave solutions - bright, b lack and gray - of the cubic-yuintic nonlinear Schrodinger equation (C QNLSE) is made concretely, considering a monomode step-index optical f ibre with third- and fifth-order nonlinearities in the anomalous dispe rsion frequency region. Different aspects of the effect of the fifth-o rder nonlinearity, such as the existence of bright and gray solitary w aves in the same parameter range and dark solitary wave bistability ar e considered. The influence of the distributions modified by the nonli nearity radial fields on the quintic dispersion coefficient in the CQN LSE is calculated. The results obtained are applicable to the cases of spatial solitons and optical beam self-action in highly nonlinear med ia.