Preparation of Ge20Se80 glasses with low hydrogen and oxygen impurities content for middle IR fiber optics

摘要

The method for preparation of high-purity Ge-Se glasses with the low content of hydrogen and oxygen impurities is developed. The method includes following stages: selenium purification by chemical-distillation technique; passing selenium vapors over a mixture of Ge batch and 2 wt% of Al for loading the components into the reactor; glass melting, quenching and cooling. Optical losses in the unclad fiber did not exceed 1 dB/m in the spectral ranges 2.0-4.3 mu m and 4.8-7.8 mu m; the minimum optical losses were 0.77 dB/m at 5.6 mu m. The fiber is characterized by the record low content of oxygen, chemically bound to germanium, which is 0.013 +/- 0.002 ppm(wt), the concentration of hydrogen in the form of Se-H groups is 1.77 +/- 0.12 ppm(at). The silica reactor is shown to be the source of impurities of hydrogen, metals and heterogeneous particles in Ge-Se glasses.