The modified nonlinear Schroedinger equation: Facts and artefacts
  It is argued that the integrable modified nonlinear Schroedinger equation with the nonlinearity dispersion term is the true starting point to analytically describe subpicosecond pulse dynamics in monomode fibers. Contrary to the known assertions, solitons of this equation are free of self-steepining and the breather formation is possible. 
E.V. Doktorov