Exact Solutions for Wave Propagation in Birefringent Optical Fibers
  We carry out a group-theoretical study of the pair of nonlinear Schr\"{o}dinger equations describing the propagation of waves in nonlinear birefringent optical fibers. We exploit the symmetry algebra associated with these equations to provide examples of specific exact solutions. Among them, we obtain the soliton profile, which is related to the coordinate translations and the constant change of phase. 
E. Alfinito, M. Leo, R.A. Leo, G. Soliani and L. Solombrino