The Effect of the Geometry and Mode Composition of Radiation on the Diffusing Properties of a Quartz-Polymer Optical Fiber with a Tefzel Light-Reflecting Shell

摘要

Numerical calculation of the hybrid modes is performed for a quartz-polymer optical fiber with the diameter of the optical fiber core of 400 mu m and a diffusing light-reflecting shell made of a thermoplastic copolymer of tetrafluoroethylene and ethylene of the Tefzel brand. The radial profile and quantity chi, the relative fraction of the energy of the mode which propagates along the light-reflecting shell, which determines diffusion are calculated for the selected modes. The function chi(m, s) monotonically increases with the increase in the azimuthal number m and decreases with the increase in the radial number s. The highest value of chi is achieved in the mode with the maximum possible for this optical fiber value of m = 953, at which only one mode with s = 1 exists. Diffusion increases upon decreasing the diameter of the optical fiber core. The obtained calculation theoretical results are qualitatively confirmed by the experiments on the measurement of diffusion in quartz-polymer optical fibers with a Tefzel light-reflecting shell with the diameters of the optical fiber core of 400 and 200 mu m.