Optical soliton perturbation with anti-cubic nonlinearity by semi-inverse variational principle

The perturbed nonlinear Schrödinger's equation with anti-cubic nonlinearity is studied with the aid of semi-inverse variational principle. The perturbation terms that are included are inter-modal dispersion, third and fourth order dispersion, nonlinear dispersion and self-steepening term, the last two of which appear with full nonlinearity.