Drawing of Preformed Glass

Drawing of Preformed Glass 165 Chemical Vapour Deposition (CVD) Process... 

Recently a new preform-based fiber-processing technique has emerged that allows the simultaneous drawing of ChG glasses in combination with metallic electrodes and polymers [180]. 

Optical fibers are usually made of glass, and most often this is an oxide glass based on silica (Si02) and some additives. A rod of glass (called preform) is heated until soft, and then a fiber is drawn from its end. This fiber consists only of a core. The preform itself may consist of two glasses, of different indices of refraction, such as shown schematically in Fig. 2(b). In this case a core/clad fiber is fabricated by drawing. In both cases the outer diameter of the fiber is less fhan 0.1 mm, in order to obtain flexibility. Fibers in use today are generally core/clad fibers. 

While there are many reports on sol-gel-derived oxide glass fibers, few works have been done on fluoride glass fibers. Fiber drawing of multi-component precursor oxide gels and their fluorination appear to be much less viable. Heavy-metal fluoride glass fibers are usually produced by the preform drawing technique. 

Figure 7.11 Thermal drawing of a core-only preform into a single-index fiber (pictures glass As2Se3].

Savage S. D., Miller C. A., Furniss D., and Seddon A. B., Extrusion of chalcogenide glass preforms and drawing to multimode optical fibers, /. Non-Cryst. Solids, 354, 3418-3427 (2008). 

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