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Optical fiber is mostly made from silicon dioxide(SiO 2 ) but some little amount of other materials are also used such as s fluorozirconate, fluoroaluminate, and chalcogenide glasses as well as crystalline materials like sapphire, are used for longer-wavelength infrared or other specialized applications.Chemical compounds such as germanium tetrachloride (GeCl 4 ) and phosphorus oxychloride (POC1 3 ) can be used to produce core fibers and outer shells, or claddings, with function-specific optical properties. Because the purity and chemical composition of the glass used in optical fibers determine the most important characteristic of a fiber,degree of attenuation,research now focuses on developing glasses with the highest possible purity. Glasses with a high fluoride content hold the most promise for improving optical fiber performance because they are transparent to almost the entire range of visible light frequencies. This makes them especially valuable for multimode optical fibers, which can transmit hundreds of discrete light wave signals concurrently.
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Refrences
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http://www.thefoa.org/tech/fibr-mfg.html
http://www.madehow.com/Volume-1/Optical-Fiber.html
http://www.fiberoptics4sale.com/wordpress/the-manufacturing-of-optical-fiber/