Compagnie Generale D'electricite

Alcatel Fibres Optiques

Alcatel

Alcatel N.v.

Electricite De France - Service National

Alcatel Alsthom Compagnie Generale D'electricite

Societe Anonyme Dite: Compagnie Generale D'electricite

Alcatel Submarine Networks

Compagnie Lyonnaise De Transmissions

Alcatel Fibres Optques

Christian Le Sergent

Josiane Ramos

Gilles Barre

Michel Liegois

Pascale Nouchi

Emmanuel Desurvire

Laurent Gasca

Herve Fevrier

Jean-Francois Marcerou

Bertrand Desthieux

Christophe Sinet

Robert Pascal

Alain Drouart

The invention relates to an optical fiber having a core based on silica with at least one fluorescent dopant distributed over the entire section of the core, a central zone co-doped with a co-dopant chosen from Al and P, and a peripheral zone co-doped with the other co-dopant chosen from Al and P. The invention can be used in an optical fiber amplifier, and it guarantees good amplifier gain flatness over a wavelength band suitable for WDM transmission.

Optical fiber for a flat-gain optical amplifier

Optical fiber including a fluorescent dopant

A method of improving the symmetry of a cylindrical silica tube to be used in making a preform having a circular outside surface eccentric to a circular inside surface thereby providing a varying tube thickness throughout the circumference of the tube which includes the following steps. The first step is locating a longitudinal generator line of the cylindrical tube at a greatest thickness of the tube at a given circumferential point on the tube, and while preventing the tube from rotating, etching in at least one pass the inside of the tube with a gas capable of decomposing silica, while heating the outside of the tube along that longitudinal generator line.

Method of improving the geometrical shape of a tube used for making a

A method of manufacturing active optical fibers comprising preparing a preform and then drawing a fiber from the preform, wherein the method consists in using a preform having a doped peripheral outer zone, said zone being intended to constitute the outer cladding of the optical fiber, the doping of the peripheral zone giving it a refractive index greater than that of the optical cladding, and giving it a difference in softening temperature relative to that of the core of the optical fiber which is less than the difference that would exist if the outer zone were not doped.

Method of manufacturing active optical fibers

Method of outside plasma deposition onto a rod (17,22) of silica substantially free from hydroxyl ions, possibly doped to change its refractive index, by reaction with oxygen of a silicon compound and possibly of doping compounds, in the presence of a gas plasma raised to a very high temperature (16) by induction with the help of a high frequency generator (15). The rod on which the silica deposit is made is kept in a sealed chamber (19) separated from the surrounding atmosphere and supplied by a pipe (20) with atmospheric air that is successively passed through a filter (31), a compressor (32) a cooling means (33), a condensation water drain (35) and a final desiccation by adsorption (36, 38). A device for implementing the method is also claimed.

Method and device for outside plasma deposition of hydroxyl ion-free

A cylindrical piece of glass (4) is subjected to heating passes on a glassmaker's lathe. Possible opto-geometrical defects of said piece of glass are detected and measured and then said defects are corrected by machining the outside surface thereof during a correction pass performed on the same glassmaker's lathe.

Method of flame finishing optical fiber preforms

An optical amplifier in the 1.26 .mu.m to 1.34 .mu.m spectrum range, comprising a solid substrate of fluoride glass doped with praseodymium in which a three-dimensional monomode waveguide is formed having an index difference .DELTA.n relative to the index of the fluoride glass lying in the range 4.times.10.sup.-3 and 8.times.10.sup.-2, said waveguide being associated by coupling means to an optical pump having a wavelength equal to 1.02 .mu.m .+-.0.1 .mu.m.

Optical amplifier in the 1.26 .mu.m to 1.34 .mu.m spectrum range

A method of fabricating preforms for making optical fibers by drawing, in which a silica deposit, including a doping agent, is formed in successive layers inside a silica-based tube (1) from a chemical vapor containing a gaseous compound of silicon, oxygen, and a gaseous compound of an element for doping the silica, with the composite tube then being subjected to collapsing so as to cause the empty axial zone (3), the tube hollow, to disappear. The silica of the initial tube is then eliminated, by removal, after which a recharge of silica (5) is made around the remaining cylinder (4) by plasma torch deposition from a gas comprising oxygen and a halogen derivative of silica.

Method of fabricating preforms for making optical fibers by drawing

According to the present invention, a preform (7) for an optical fiber is made from a tube having a substrate layer (16) of fluorine-doped silica and a support layer (18) of non-doped silica. A cladding layer (8) of fluorine-doped silica and a core layer (10) of non-doped silica are formed on the inside surface of the tube by chemical vapor phase deposition. The optical fiber is subsequently obtained by collapsing the tube and drawing it. The invention is applicable to fabricating optical fibers.

Method of manufacturing an optical fiber preform having doped cladding

A mist is formed by an ultrasonic generator (5) from a liquid solution containing a dopant, and the mist is inserted into the tube blank to be doped (4) by means of a flexible pipe (2) in order to deposit microdrops on the inside surface of said tube blank. The flexible pipe is withdrawn progressively so that deposition takes place along the entire length of the tube blank. The deposit is dried and a new layer of glass is deposited thereon. The dopant from the deposit is heat diffused into the glass of the tube blank and of the new layer of glass. The invention is particularly applicable to fabricaitng rare-earth-doped silica preforms for the purpose of drawing optical fibers that can be used to constitute lasers or sensors.

Method of making an internally-doped tube of transparent glass, in

A method of fabricating an optical waveguide comprising a plane substrate made of a material having a relatively low refractive index, a plane light propagation layer made of a material having a higher refractive index than the substrate, inserted between two strips of a material having a lower refractive index than its own, and a plane light confining layer of a material having a lower refractive index than the propagation layer. At least one of the layer, meaning either the propagation or the confinement layer, is obtained by causing to circulate in a tube of pure silica the vapors of a gaseous compound of silicon transformable into silica and of a gaseous compound of a doping agent transformable into one of its own oxides and heating said vapors sufficiently to obtain the deposit of a layer of doped silica having a refractive index different from that of the pure silica. Modifacations to the refractive indices can be obtained by either diffusing or implanting dopants, or alternatively by selective elimination of dopants.

Optical waveguide fabrication method

The blank is made from a tube of silica with a layer of other glass coated on its inner surface. The said other glass is doped with P.sub.2 O.sub.5 for example to increase its refractive index. The blank is then reduced in diameter from a tube to a rod by heating a region of the tube while it rotates in a glassmaker's lathe. The heated region is moved back and forth along the length of the tube until it is finally reduced to a rod. One effect of the moving heated zone is to evaporate some of the doping material, and the vapour tends to move along the tube ahead of the heated zone until it is eventually shifted out of the ends of the tube. To minimize this loss the back and the forth movement of the heated zone includes a sudden step forward at the end of each pass before returning in the opposite direction. This has the effect of jumping the heated zone ahead of the escaping doping material which is then pushed back along the bore of the tube for the next pass, with the jump-ahead-and-reverse operation being repeated at each reversing point of the back and forth heated pass to conserve as much of the doping material as possible inside the tube and finally within the resulting glass fibre blank.

Method of producing an optical fibre blank

A reactive gaseous mixture which reacts in a localized heating zone to form a glass deposit on the inner wall of a tube is made to flow along the tube, and in the heating zone it is channelled around a cylindrical element which occupies much of the bore of the tube. The glass deposit is used for making glass fibres for telecommunications.

Growing community of inventors

Marcoussis, France

Christian Le Sergent