Glasses and Optical IR Fibers of As₂Se_3−xTe_x

Abstract

Chalcogenide glasses of As₂Se_3−xTe_x (O<x<3) were made with special care, using very pure raw materials in order to avoid traces of oxygen. From these materials optical fibers were pulled, and the attenuation of CO₂ laser light (wavelength λ = 10.6 μm) transmitted through these fibers was measured as a function of the Te content (x). The fiber’s surface and cross-section were examined, using both the scanning electron and optical microscopes, and they directly revealed the increase in the concentration of the defects while x was increasing. The influence of the physical and mechanical properties on the concentration of defects was studied by measuring the optical absorption (α) and the microhardness (V_H) of the raw materials. Slabs of As₂Se_3−xTe_x were made, and in these samples the α, V_H, and glass transition temperature (T_g) as a function of x were measured. In the infrared region of the spectra at λ = 10.6 μm, the α in both the slabs and pulled fibers increased, and the V_H and T_g decreased with the increase of x. This can be explained by the increase of the concentration of the defects (small crystallites) which appeared during the fiber pulling.