Influence of the geometry and mode composition of radiation on the scattering properties of a silica-polymer optical fiber with a reflective coating Tefzel

A numerical solution of the characteristic equation is performed for a silica-polymer optical fiber with a light-carrying core diameter of 400 microns and a scattering reflective coating made of a thermoplastic copolymer of tetrafluoroethylene with ethylene Tefzel. For the hybrid modes studied, the radial profiles and the scattering – determining value $\chi$-the relative fraction of the mode energy propagating through the light-reflecting coating were calculated. The function $\chi(m,s)$ increases monotonically with increasing azimuthal number m and decreases with increasing radial number $s$. The highest value of $\chi$ is achieved for the mode with the maximum possible value for a given optical fiber $m$ = 953, at which there is only one mode with $s$ = 1. As the diameter of the light-carrying core decreases, the scattering increases. A qualitative substantiation of the previously conducted experiments on the measurement of scattering in the studied optical fibers is also carried out.