TeX glass fibers with a core-cladding structure

摘要

TeX glass fibers with a core-cladding structure are prepared by one of three methods: modified crucible method, preform method, or double crucible method. The raw elements are purified in order to eliminate some oxide impurities. They are then all distilled. The Te-Se-As-I system was chosen for the core and cladding glasses because of its stability against crystallization. The numerical aperture (N.A.) of the fiber is typically between 0.15 and 0.4. The diameter ratio of the core and cladding can be varied in the range of 0.15 - 0.9. These fibers are covered with a thermal plastic, to improve their mechanical properties. The optical losses of the fibers are measured between 2 and 13 micrometers by the cut-back method. The modified crucible method was the best to reduce the loss due to structural imperfections at the interface of the core and cladding. The lowest loss of 0.5 dB/m was achieved in the 7 - 9 micrometer region. Many applications of TeX glass fibers are actually tested in our laboratory such as thermal imaging, laser power delivery and remote spectroscopy. This last technology allows in-situ detection and quantification of several chemical compounds which have their characteristic absorptions in the 3 - 13 micrometer region.