CHALCOGENIDE GLASSES GE-SN-SE, GE-SE-TE, AND GE-SN-SE-TE FOR INFRARED OPTICAL FIBERS

Chalcogenide glasses of the systems Ge-Sn-Se, Ge-Se-Te, and Ge-Sn-Se-Te have been prepared. Several compositions were found suitable for drawing fibers for CO2 laser radiation (λ = 10.6 μm) transmission. The glasses were characterized by x-ray diffraction, DSC (Differential Scanning Calorimetry), SEM with EDX analysis, FTIR spectrometry, density, and microhardness measurements. The glass transition temperature and microhardness of Ge-Se-Sn and Ge-Sn-Se-Te glasses decreased with increasing Sn content, for most of the samples. The region of high IR transparency of Ge-Se-Sn, Ge-Se-Te, and Ge-Sn-Se-Te glasses was slightly expanded (1–2 μm) toward longer wavelengths, compared to Ge-Se glasses, mainly for the glasses containing ⩽70 at.% Se. The intensity of the impurity absorption peak of Ge-O (at λ ~ 12.8 μm), which usually appears in Ge-Se glasses, was reduced or absent in Ge-Sn-Se-Te glasses. The best fibers were produced with the glass composition Ge0.8Sn0.2Se3.5Te0.5. An attenuation of 20 dB/m at 10.6 μm, and a transmitted maximum power density of 2.4 × 106 W/m2 were measured. The mechanical and optical characteristics of these glasses have been related to the glasses structure. Corresponding to the reduced masses of the bonds formed in the Ge-Sn-Se-Te system (in the amorphous region), it is expected that the multiphonon edge is slightly shifted. As a consequence, as was measured, the transparency region has been expanded by less than 2 μm toward longer wavelengths. © 1990, Materials Research Society. All rights reserved.