The vector soliton associated with polarization modulational instability in the normal dispersion regime

When accounting for the polarization of the electromagnetic field, light propagation in isotropic Kerr materials is described by two incoherently coupled nonlinear Schrodinger (NLS) equations. The fundamental importance of this phenomenon is that a soliton must exist that is associated with modulational instability (MI) in the normal dispersion regime in the same way as the bright NLS soliton is associated with MI of the scalar NLS equation in anomalous dispersion. The aim of our analysis is to confirm the existence and describe the features of this fundamental soliton. In dimensionless units the evolution of the circular polarization components of light propagating in a normally dispersive Kerr medium is ruled by the incoherently coupled NLS equations