Alekseev A. Geometrical analysis of a phase singularity structure of a the optical fibers' radiation field

Dissertation is dedicated to analysis of phase singularities appearing in a radiation field of cylindrical isotropic optical fibers and highly birefringent fibers. It was shown that in the case of isotropic fiber being excited with circularly polarized light the radiation can be represented as a superposition of two guided optical vortices and mode. For the case of anisotropic fiber being excited with linearly polarized light along it's anisotropic axis the radiated field, having a view of mixed dislocation, can be represented by superposition of three LP modes. Equal intensity lines close to the singularity is elliptic like. This ellipse parameters determined the amplitude coefficients of fiber's eigen modes excitation. It was experimentally and theoretically found the dependence of eigen mode excitation coefficients from the displacement of laser beam on the optical fiber input. It was raveled experimentally and theoretically character of rotational Doppler effect manifestation in radiation of optical fiber radiation field. It was shown that the singularity motion in radiation field determined by topological charge and polarization of modes. The excitation of optical fiber with right circular polarization light leads to the elliptical trajectory of singularity in radiation field, which has the doubled frequency of rotation opposite to the direction of polarizer rotation. It was found three methods of calculation the rotation angle of interference spiral, which results from the superposition of optical vortex and fundamental mode.