Rotation of polarization vector in graded index waveguide

Abstract

Evolution of the polarization vector in an isotropic multi-mode graded-index optical fiber is investigated theoretically. It is shown that the rotation of the polarization vector increases with increasing axial displacement and the angle of inclination of the incident beam to the waveguide axis according to the quadratic law. The influence of polarization of light beam on its geometrical characteristics at propagation in a two-dimensional isotropic graded-index medium using the methods of coherent states is investigated. In a paraxial approximation taking into account the second order terms in a vector wave equation the expressions for the trajectory and width of linear- and circularly- polarized radiation are obtained. It is shown that the circular polarization leads to the rotation of the propagation plane of the meridional rays and additional rotation of sagittal rays, depending on the axial shift of the incident beam.