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US 4,125,389 AGranted
Method for manufacturing an optical fibre with plasma activated deposition in a tube
AssigneeNorthern Telecom Limited
InventorFrederick D. King
Life of this patent
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Abstract
An optical fibre is manufactured by forming a layer of fused silica, which may or may not be doped, on the inner wall of a fused silica tube by producing a plasma in the reactant gases flowing through the tube. By this means a higher temperature can be maintained inside the tube than at the tubes outer wall. The plasma is produced at substantially atmospheric pressure. Cooling gas is passed along the outer wall of the tube.
Claims6
A method of manufacturing an optical fibre, comprising:
- providing a fused silica tube;
- positioning said tube in a microwave cavity;
- feeding a carrier gas through said tube;
- applying a microwave field to said cavity to produce a plasma in said tube at a position in said cavity and maintain a temperature on the inner wall of said tube of at least 1000.degree. C.;
- passing a cooling gas along the outside wall of said tube;
- feeding a reactant gas into said tube, and
- traversing said tube through said cavity to form a fused layer on the inner wall of the tube.
4 more elements
Dependencies are inferred from the claim text.