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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.
why silca?
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_ Fig. 2. Silica molecule_ *_\[1\]_* |
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Protection coating consist of two parts: a soft inner + hard outer coating. “The overall thickness of the coating varies between 62.5 and 187.5 μm, depending on fiber applications” *\[3\]* |
After the fiber is taken from the preform, a coating is applied fast after the formation of the thin fiber as shown below on the scheme.
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!http://www.fiberoptics4sale.com/wordpress/wp-content/uploads/2009/06/opticalfibercoatingprocess.gif|border=1!
Fig. 7. Coating the fiber *\[3\]* |
Test & Measurement
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Then the drawn fiber goes through compulsory tests, where all optical and geometrical parameters are checked to meet strict quality requirements.
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!http://www.flukenetworks.com/sites/flukenetworks.com/files/assets/FT_FiberTestSimpliFiber.jpg|border=1!
Fig. 8. Fiber testing in environment *\[6\]*
Tensile strength of fiber is tested first: reel of drawn fiber is clamped through a series of capstans and loaded to test the minimal tensile strength required. The fiber is then placed onto reels for distribution and separated equally to required lengths. |
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