Fabrication and characterization of chalcogenide glass for hollow Bragg fibers

Low- and high-refractive-index chalcogenide glasses are studied for their potential use in the fabrication of one-dimensional hollow Bragg fibers. The low-index glasses are based on the GeSe-glass systems with indices varying from 2.0 to 2.5, while the high-index glasses are formed from the AgAsSe glasses with indices ranging from 2.8 to 3.8. High-purity elemental starting materials are distilled and the surface oxides removed prior to mixing in a rocking furnace. The refractive indices of the AgAsSe glasses, measured using a CO₂ laser reflectometer, were near 3.10 for the compositions most compatible with the low-index Ge₂₀Se₈₀ glass (n 1/4 2:46). Spectral measurements show impurity absorption bands between 12 and 16 μm. The loss at 10:6 μmfor the Ag₂₅As₄₀Se₃₅ glass measured using CO₂ laser calorimetry was 1:16 × 10^-3 cm ^-1.