Apparatus for manufacture of a silica optical fiber

Claim 1

An apparatus for fabricating silica optical fibers doped with a metal oxide, the apparatus comprising: 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 two vapor-state reactants can be deposited over a longitudinally extending silica-deposition zone; heating means for heating the supporting tube and thereby causing the reaction; respective first and second joints engaging said first and second ends of said supporting tube, each joint having a fixed part and a rotating part, each of the rotating parts supporting a respective end of said supporting tube for rotation relative to each of the fixed parts about the axis of the supporting tube; means for introducing at least one of the reactants into the supporting tube through the first joint; means for discharging depleted gases through the second joint; an inner tube extending within the outer tube and of a diameter smaller than that of the outer tube, the inner tube extending through one of the joints, being axially fixed in the outer tube, and being formed between the outer-tube ends with a radially throughgoing and axially extending slit; a high-purity wool of wires of metal received in the inner tube along the slit; and means for internally supplying the inner tube with a gaseous compound reactive with the metal of the wool to form the metal oxide and forming a compound therewith constituting one of the reactants, the slit having a width which increases in a direction of flow of the gaseous compound therethrough.

Claim 2

An apparatus for fabricating silica optical fibers doped with a metal oxide, the apparatus comprising: 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 two vapor-state reactants can be deposited over a longitudinally extending silica-deposition zone; heating means for heating the supporting tube and thereby causing the reaction; respective first and second joints engaging said first and second ends of said supporting tube, each joint having a fixed part and a rotating part, each of the rotating parts supporting a respective end of said supporting tube for rotation relative to each of the fixed parts about the axis of the supporting tube; means for introducing at least one of the reactants into the supporting tube through the first joint; means for discharging depleted gases through the second joint; an inner tube extending within the outer tube and of a diameter smaller than that of the outer tube, the inner tube extending through one of the joints, being axially fixed in the outer tube, and being formed between the outer-tube ends with a radially throughgoing and axially extending slit; a high-purity wool of wires of metal received in the inner tube along the slit; and means for internally supplying the inner tube with a gaseous compound reactive with the metal of the wool to form the metal oxide and forming a compound therewith constituting one of the reactants, the slit having a width which increases in a direction of flow of the gaseous compound therethrough.