Bound-vector solitary waves in isotropic nonlinear dispersive media

On the basis of a simple analysis of the coupled nonlinear Schrödinger equations that govern pulse propagation in isotropic nonlinear dispersive media, we show the existence of a novel class of bound-vector solitary waves. These solitary waves are novel in exhibiting elliptical polarization that varies across the pulse and evolves periodically during propagation while the pulse intensity envelope remains unchanged. Simple physical arguments allow us to understand the existence and the features of these particular solutions.