The problems of optical loss reduction in arsenic sulfide glass IR fibers

Abstract The actively developed direction at the present time is the production of chalcogenide glasses with a low content of impurities and the manufacture of optical fibers with low optical losses on their basis. The transparency of glasses, characterized in optical fibers by the level of optical losses, refers to the key parameters of optical fibers and determines the attenuation of the signal passing through the fiber. The lowest optical losses that were achieved in multimode fibers from sulfide, selenide, and arsenic sulfoselenide glasses are 12–14; 60 and 67 dB/km, respectively. Real level of optical losses in chalcogenide glass fibers are two or more orders higher than theoretically predicted. The magnitude of this discrepancy contains the constituent parts associated with the nature and properties of glass, with the conditions for the manufacture of glass and optical fibers as well as with the methodology for the theoretical evaluation of the magnitude of intrinsic optical losses in glass. In this paper the structure, the main sources of excessive losses, the ways of approximation of real and theoretically predicted losses are considered on the example of optical fibers produced from arsenic-based chalcogenide glasses.