Plasma torch and preform fabrication system using the method

Abstract

A system for fabricating an optical fiber preform including glazing the outside surface of the preform using inductive heating, the system including a plasma torch for localized heating of the preform during the glazing, and an injector for injecting into the plasma in the area of the outside face of the preform on which the plasma impinges a gas which is substantially free of silica particles to reduce the power of the plasma during the glazing operation.

1 . A plasma torch for localized heating of an optical fiber preform during a glazing operation when a plasma of said plasma torch is substantially free of injected silica particles, said plasma torch including: 
 means for generating said plasma; and    means for injecting a gas which is substantially free of silica particles between the plasma torch and said preform in the area of an outside surface of said preform to be heated during said glazing operation, to thereby reduce the power of said plasma in said area during said glazing operation.    
   
   
       2 . A system for fabricating an optical fiber preform, said system including: 
 means for holding said preform, and    a plasma torch for localized heating of said preform during a glazing operation when said plasma is substantially free of injected silica particles, said plasma torch including means for injecting a gas which is substantially free of silica particles between the plasma torch and said preform in the area of an outside surface of said preform on which said plasma impinges during said glazing operation, to thereby reduce the power of said plasma in said area during said glazing operation,    
   
   
       3 . The system claimed in  claim 2  wherein said means for injecting includes an injector nozzle fixed relative to said torch and positioned in the vicinity of said torch so as to orient a jet of gas at a particular flowrate onto said area of the outside surface of said preform on which said plasma impinges