METHOD FOR MANUFACTURING OPTICAL FIBER USING ISOTHERMAL AND LOW-PRESSURE PLASMA DEPOSITION TECHNIQUE

PROBLEM TO BE SOLVED: To provide a method of improving the quality of material deposited in a substrate tube of an optical fiber preform. SOLUTION: An isothermal, low pressure-based process of depositing a material in a substrate creates a narrow deposition zone within which a more uniform and efficient deposition will occur. Sets of isothermal plasma operating conditions assure that the deposited material is clear glass rather than soot particles. The exhaust end of the tube is connected to a vacuum system which is in turn connected to a gas scrubber apparatus for removal and neutralization of reaction by-products. The operating conditions are selected such that the hot plasma does not transfer a substantial amount of heat to the substrate tube, where the presence of such heat results in vaporizing the reactant material (creating soot) and developing hot spots. COPYRIGHT: (C)2009,JPO&INPIT