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Optical fiber is a single, hair fine filament drawn from molten silca glass. Today, this has replaced metal wires in high speed communication.In a fiber optic communications system, cables made of optical fibers connect datalinks that contain lasers and light detectors. To transmit information, a datalink converts an analog electronic signal into digital pulses of laser light. These travel through the optical fiber to another datalink, where a light detector reconverts them into an electronic signal. It makes people to wonder how something only 1/8 of a mm - 0.005 inches - in diameter can be made with such precison. So here is breif explanation of how optical fiber is made. 
Raw Materials
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Optical fiber is mostly made from silicon dioxide(SiO 2 ) but some little amount of other materials such as 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 (GeCl4 ) and phosphorus oxychloride (POCl3 ) can be used to produce core fibers and outer shells, or claddings, with function-specific optical properties.
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