Scattering losses in optic fiber materials. II. Numerical estimates

Abstract

Applying the theoretical results outlined in the first paper of this series, numerical estimates have been obtained for density fluctuation, Raman, and concentration fluctuation scattering losses in a number of materials which are under consideration as candidates for ultralow loss fiber-optic applications. The materials include single-component oxide, halide, and chalcogenide glasses as well as a few multicomponent glasses and single component halide crystals. Attenuation estimates (in dB/km) are given both at the minimum dispersion wavelength and, whenever possible, at minimum total attenuation (including scattering and absorption mechanisms). Raman attenuation is found to be small in all cases, typically a few percent of the total at most, but concentration fluctuation attenuation is potentially dominant in some multicomponent samples. The broad conclusion is that a significant improvement over silicate glasses can only be obtained by use of halide glasses or by single crystal fibers. Ideal minimum values of ∼0.01 and ∼0.001 dB/km are indicated for vitreous BeF2 and ZnCl2, respectively, while values of the order 0.003–0.007 dB/km seem to be attainable using fluorozirconate glasses. Possible minimum attenuation as low as 10−4 dB/km is indicated for quasiperfect single crystal chloride fibers if they can be fabricated.