Generalized Tappert transformation in femtosecond nonlinear optics

We present the generalized Tappert transformation for the higher-order nonlinear Schrodinger equation model of femtosecond nonlinear optics, in which the gravitational-like potential is introduced with the aim of the effective parameterization of the Raman soliton self-scattering effect. By means of the nonlinear change of variables and nontrivial reversible gauge transformation the higher-order forced nonlinear Schrodinger equation model is turning into the free higher-order nonlinear SchrOdinger equation without external potential, but with varying in time dispersion and nonlinearity. The proposed generalized Tappert transformations allow one to find the direct relationships between the soliton solutions of the forced nonisospectral equations and the corresponding isospectral equations without external potential, but with varying in time dispersion and nonlinearity coefficients.