Alcatel

Alcatel Alsthom Compagnie Generale D'electricite

Alcatel Fibres Optiques

Jacques Goudeau

Jean-Florent Campion

Christelle Lavallade

Jean-Philippe Francois

Michel Hertz

Jean-Francois Chariot

Helene Jameron

Patrick McKenzie

Henri Marc Michaud

Thierry Auvray

In the method, a suspension of silica particles in water is provided, the suspension is gelled, the resulting gel is dried under microwaves, the dried gel is fractioned into silica granules having a diameter lying in the range 10 .mu.m to 1000 .mu.m, having an apparent density of about 0.5 g/cm.sup.3 to 0.6 g/cm.sup.3, and a porosity of less than 20%, and the granules are screened in the range 100 .mu.m to 500 .mu.m. The suspension in water of silica particles is made by mixing silica soots having a size of less than 0.1 .mu.m and silica grains having a size greater than 1 .mu.m. Its maximum concentration in total weight is greater than that of a suspension of synthetic soots on their own, thereby making it possible to increase the production capacity of the method. Advantageously, the out-of-range granules rejected by the screening are recycled as silica grains for the aqueous suspension, thereby making it possible to increase the accumulated production efficiency of the method.

Method of manufacturing a silica powder

The method of manufacturing a preform having a supporting core by effecting successive passes with a plasma torch while material is being supplied, and by effecting at least one glazing step with the plasma torch and without material being supplied includes:

Method of separating and glazing an optical fiber preform

The fiber-drawing furnace includes a graphite tube positioned vertically, heated by induction, and subjected internally to an inert atmosphere, said tube internally defining a fiber-drawing chamber. In the furnace said graphite tube is a double-walled tube having an inner wall and an outer wall, its inner wall is porous and separates the fiber-drawing chamber from a peripheral chamber defined between the walls and subjected to a flow of inert gas which diffuses through said porous wall into said fiber-drawing chamber. Application to drawing down an optical-fiber preform.

Fiber-drawing furnace for drawing down an optical-fiber preform into an

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Hickory, NC, United States of America

Jacques Goudeau