Apparatus for manufacture of a silica optical fiber

Abstract

An article for use in producing silica optical fibers doped with a metal de obtained by synthesis from low pressure vapor reactants is made from an outer supporting tube extending along a longitudinal axis and having first and second longitudinally opposite ends and an inner surface on which silica and a dopant formed by a reaction between vapor-state reactants can be deposited over a longitudinally extending silica-deposition zone. Respective first and second joints engage the ends of the supporting tube and each have a fixed part and a rotating part. Each rotating part supports the respective end for rotation relative to the respective fixed part about the axis. At least one of the reactants is introduced into the supporting tube through the first joint and depleted gases are discharged through the second joint. An inner tube extends through one of the joints into the outer tube and is formed between the outer-tube ends with a radially throughgoing and axially extending slit in which is held a high-purity wool of wires of metal. The inner tube is supplied internally with a gaseous compound reactive with the metal wool to form the oxide and forming a compound therewith constituting one of the reactants.