On the limits of validity of nonparaxial propagation equations in Kerr media

Recent generalizations of the standard nonlinear Schroedinger equation (NLSE), aimed at describing nonparaxial propagation in Kerr media are examined. An analysis of their limitations, based on available exact results for transverse electric (TE) and transverse magnetic (T M) (1+1)-D spatial solitons, is presented. Numerical stability analysis reveals that nonparaxial TM soltions are unstable to perturbations and tend to catastrophically collapse while TE solitons are stable even in the extreme nonparaxial limit. (c) 2006 Optical Society of America.