Alcatel

Draka Comteq B.v.

Jacques Jolly

Jean-Florent Campion

R&eacute;mi Fauche

Jean-Maxime Saugrain

Christelle Lavallade

Jean-Fran&ccedil;ois Chariot

Pierryle Jourdier

Rosine Meilleur

Virginie Herchuelz

Rémi Fauche

Eric Tutin

The present invention provides an installation for fabricating or overcladding an optical fiber preform, which installation includes an inductive torch for producing a plasma from a plasma generating gas and material feed means and is characterized in that said plasma generating gas is a mixture of a first gas chosen from diatomic gases and mixtures of at least two gases and argon in a proportion by volume from 0.5% to 10%.

Overcladding an optical fiber preform using an air-argon plasma torch

The method is designed to be implemented in an installation provided with means enabling a preform held between two points by supporting end-pieces to be rotated and to be moved in translation. Heater means for heating the preform by means of a plasma torch are associated with material supply means, so as to enable the preform to be manufactured in layers. Preform/torch relative displacements, with or without material being supplied, lead either to a new layer of material being deposited on the preform, or to the most recent layer deposited being glazed. Said method interposes a one-ended reduction in layer length, starting from one of the intermediate layers, while a succession of concentric layers are being deposited on the preform in a manner such that the lengths of the layers are progressively reduced so that the preform tapers towards it ends. The one-ended reduction leads to a limitation of the thickness of a determined segment at the level of the layer deposited immediately prior to the reduction.

Making an optical fiber preform including reducing the length of a deposition layer

A method of manufacturing an optical fiber preform ( ) comprising: forming at least one silica-based outer deposition layer ( ) by depositing silica on a primary preform ( ) constituted by a bar mainly comprising silica and including a silica-based outer peripheral portion ( ), the method being characterized in that the viscosity of the outer deposition layer ( ) is adjusted to be substantially identical to the viscosity of the outer peripheral portion ( ) of the primary preform ( ) by adding to the silica, over a substantial portion of the outer deposition layer ( ), at least one compound selected from the group formed by the following compounds: CaF , MgF , AlF , B O , and Al O .

Method of depositing a layer of silica followed by a step of adding dopant to the layer

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Saint Ouen l'Aumone, France

Jacques Jolly