Research On The Fabrication Of Telluride-based Chalcogenide Glasses And Micro-structure Optic Fibers

In recent decades, tremendous interest has been focused on the research of Te-basedchalcogenide glasses from universities and research institutions around the world, as long-cutoffedge of these glassy materials extends far beyond20μm indicating they have widely potentialapplication in exploration of outer space life, biochemical sensor, biomedical test and militaryfields. Currently, the effort of searching new components and network formers is essential toimprove the poor glass-forming ability and thermal stability of these Te-based glasses. Additionally,impurities such as water, oxygen affect the transmission property of Te-based chalcogenide glassand fiber. Thus, how to reduce the impurities is very important in Te-based chalcogenide glasspreparation. Combining the wide transmission range of chalcogenide glass, chalcogenide glassmicro-structure fibers offer many unique optical properties. However, more research in devicedesign and application based on chalcogenide micro-structure fibers, is confined by its immaturepreparation method. So new method should be advanced to fabricate chalcogenide micro-structurefibers.In view of the problems in Te based glass and chalcogenide micro-structrue fibers research,the main work of this thesis is focused on following aspects:（1） Heavy-metal Ag, Al and metal halide AlCl₃are introduced into Te based chalcogenideglasses to enlarge their glass-forming region. The thermal and physical properties, IR transmittingspectra, Vis-NIR absorption spectra and optical bandgap are investigated. The results show thatheavy metals Ag and Al could improve the thermal stability of Te based glasses, and the Te basedglass are very resistant against crystallization with the help of AlCl₃. Furthermore, Ge₁₅Te₇₅Ga₆Al₄glass has superior thermal stability （△T=126oC）. When the metal Al was replaced by AlCl₃, thestrong absorption in the range of15-20μm in Ge-Te-Ga glass or Al-O absorption at14.3μm inGe-Ga-Te-Al glass system was eliminated thoroughly. The transmitting range of studied glassesextends far beyond20μm, indicating the potential of these Te-rich glasses for far-IR application.（2） A novel quick-distilling method was advanced to purify Te-based chalcegenide glasscontaining Ga. Then, the dependences of optical losses on different oxygenic getters, quenchingtemperature and different contents of deoxidizers （Al or Mg） were investigated. The best result ofoptical loss of0.037dB/mm at12μm was obtained. Higher or lower quenching temperature couldalso result in optical loss. Reducing metal Al was much more functional to decrease the oxidecontent in the GGT glasses. Only with400ppm wt. of Al and vacuum fast distillation, it would be good enough to remove all oxide absorption bands, to expand the transmission spectrum and to flatthe spectra without any obvious absorption peak in all the range of8-20μm. In all, the results showmuch potential to develop a low-loss Ga-containing ChG fiber.（3） Ge₂₀Sb₁₅Se₆₅chalcogenide glass is adopted for its excellent plasticity to extrudemulti-hole fiber preforms using glass extruder. We test the infrared transmission spectra, theinfrared thermal image and fiber cross-section. The optical loss of extruded glass is calculatedbased on the infrared transmission spectra of glass disks with different thicknesses. The resultsshow that the infrared transmission spectra of extruded glass have not decrease obviously. Plasticpolymer is adopted as a protecting fiber coat that improves the strength of chalcogenide glass fiber,which promotes the development of chalcogenide micro-structure fibers.At the end of the thesis, all results of work are outlined, and some suggestions are given forthe succeeding works in the future.