GB2235191A - Manufacture of preforms for optical fibres - Google Patents

Manufacture of preforms for optical fibres Download PDF

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Publication number
GB2235191A
GB2235191A GB9015290A GB9015290A GB2235191A GB 2235191 A GB2235191 A GB 2235191A GB 9015290 A GB9015290 A GB 9015290A GB 9015290 A GB9015290 A GB 9015290A GB 2235191 A GB2235191 A GB 2235191A
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GB
United Kingdom
Prior art keywords
tube
heating
course
blowpipe
treatment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9015290A
Other versions
GB9015290D0 (en
GB2235191B (en
Inventor
Sergent Christian Le
Josiane Ramos
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcatel Lucent NV
Original Assignee
Alcatel NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcatel NV filed Critical Alcatel NV
Publication of GB9015290D0 publication Critical patent/GB9015290D0/en
Publication of GB2235191A publication Critical patent/GB2235191A/en
Application granted granted Critical
Publication of GB2235191B publication Critical patent/GB2235191B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
    • C03B37/01—Manufacture of glass fibres or filaments
    • C03B37/012—Manufacture of preforms for drawing fibres or filaments
    • C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
    • C03B37/018—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD] by glass deposition on a glass substrate, e.g. by inside-, modified-, plasma-, or plasma modified- chemical vapour deposition [ICVD, MCVD, PCVD, PMCVD], i.e. by thin layer coating on the inside or outside of a glass tube or on a glass rod
    • C03B37/01876—Means for heating tubes or rods during or immediately prior to deposition, e.g. electric resistance heaters
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
    • C03C17/22—Surface treatment of glass, not in the form of fibres or filaments, by coating with other inorganic material
    • C03C17/23—Oxides
    • C03C17/245—Oxides by deposition from the vapour phase
    • C03C17/2456—Coating containing TiO2
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C25/00—Surface treatment of fibres or filaments made from glass, minerals or slags
    • C03C25/10—Coating
    • C03C25/104—Coating to obtain optical fibres
    • C03C25/106—Single coatings
    • C03C25/1061—Inorganic coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/105—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type having optical polarisation effects
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2203/00—Fibre product details, e.g. structure, shape
    • C03B2203/30—Polarisation maintaining [PM], i.e. birefringent products, e.g. with elliptical core, by use of stress rods, "PANDA" type fibres

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

Optical fibre preform is manufactured by the rotation of a silica tube (4) about horizontal axis (A). Reactive gases are supplied and discharged through (1) and (9) respectively, while oxygen and hydrogen are supplied to blowpipe (22), which is capable of moving along lathe slide (7). Gravitational deformation of the tube is avoided by varying the speed of rotation and/or the heat supplied to the tube. <IMAGE>

Description

MANUFACTURE OF PREFORMS FOR ROTATIONALLY ASYMMETRIC OPTICAL FIBRES This invention relates to the manufacture of preforms for rotationally asymmetric optical fibres.
The present invention can be applied in particular to the production of preforms for special optical fibres, the composition and the physical properties of which must, at every point, depend upon the angular position of the point under consideration about the axis of the fibre. It is a matter of, for example, polarising or polarisation-maintaining fibres, that is to say, double refracting fibres.
A known method for producing double refracting fibres is described in an article by R.D.Birch et al, "Fabrication of polarisation-maintaining fibres using gas-phase etching" in Electronics Letters (Vol. 18 No.24).
According to the known method, certain reactions for depositing optically active elements are carried out on the internal surface of an initial tube with the help of a blowpipe which moves longitudinally under this tube.
Deposition then takes place substantially along the lower generatrix of the tube.
This known method, however, does not appear to permit the desired angular variation in the optical properties of a final optical fibre to be easily obtained. It is known that this fibre will subsequently be obtained from the preform by the necking and stretching thereof.
An object of the present invention is more easily to obtain angular variations desired in the composition of a preform, without running any risk of deformation of this preform in the course of hot deposition operations.
The invention provides a method of manufacturing preforms for rotationally asymmetric optical fibres comprising the steps of: - positioning an initial tube having a longitudinal axis, an internal space and internal and external cylindrical surfaces, on a glass maker's lathe, so that the axis of this tube is aligned with a substantially horizontal lathe axis, the lathe being suitable for imparting to the tube rotational motion about this axis at a controllable speed, the lathe comprising a lathe slide carrying a blowpipe for heating the external surface of the tube, the heating of this surface by means of the blowpipe being, at any moment, particularly intense in the region, of this surface which is, at that moment, opposite the blowpipe, the lathe slide and blowpipe being able to perform heating passes, in the course of each one of which it moves in the longitudinal direction along the length of the tube, and - carrying out at least one coating treatment for forming an optically active coating on the internal surface of the initial tube, this treatment being carried out in the course of a heating pass, the said treatment or a further treatment being carried out in the course of a selective heating pass, in the course of which the heating power is distributed in an angularly selective manner over the external surface of the initial tube, so that an effect of this treatment on the internal surface of the tube is obtained in an angularly selective manner and affects in an angularly selective manner an optical property of an optically active coating, - characterised in that, in the course of the selective heating pass, the tube is caused to rotate in a substantially continuous manner at a rotational speed which is sufficient substantially to avoid any gravitational deformation of this tube, and a course of periodic variation synchronised with the rotation of the tube is applied to the speed of rotation of the tube and/or to the heating power, so that the heating of the external cylindrical surface of the tube is selectively intense along pre-determined generatrices of this surface, so that an effect is obtained with particular characteristics along corresponding generatrices of the internal cylindrical surface of the tube.
Preferably, the coating treatment operation is an operation for depositing, etching or impregnating a coating, and is performed with a sweep of the internal space of the initial tube by reagents suitable for bring about a depositing, etching or impregnating reaction, as the case may be, which depends upon temperature.
The usefulness of the present invention becomes apparent from the following considerations: The incorporation of the germanium into, or the volatilisation of other dopes in, a coating of silica is very sensitive to temperature, enabling the concentration of the substance to be controlled.
The thickness of a deposited coating can also be easily controlled, since the phenomena of thermophoresis governing the deposition are very sensitive to temperature.
The rate of vitrification and consequently the porosity of a deposited coating can also thus be controlled with a view to impregnation of this coating, for example by means of a doping solution of salts of nobel earths.
The depositing conditions can be chosen independently for various sheathing or core coatings.
The present invention will be better understood with the description which is given in the following with the help of the attached drawings and is by way of example.
In the drawings: FIGURE 1 shows an elevation of a glass-maker's bench for the implementation of the present invention, FIGURE 2 shows a transverse section of a fibre optic obtained from a preform produced by the method of this invention, and FIGURE 3 shows a diagram of a variation, in dependence upon the angular co-ordinate of a constant radial co-ordinate point in a property of the material at this point or in the region adjacent to the centre of an optical fibre or preform.
In accordance with Figure 1, the glassmaker's lathe comprises two headstocks, one upstream 10 and one downstream 11, provided with upstream and downstream gripping jaws 10A and llA, respectively, for rotating a tube of silica such as 4 about a horizontal axis A, which tube of silica constitutes the initial tube. This tube is retained by these gripping jaws by means of connection sleeves made of silica which are welded to the tube at its upstream and downstream ends 14 and 16 respectively.
An intake revolving joint 8 permits reactive gas mixtures to be supplied through the upstream headstock 10.
The supply and the discharge of the reactive gas mixtures are shown by the arrows 1 and 9.
The glass-maker's lathe also comprises a table 12 provided with a lathe slide 7 which moves in the longitudinal direction, that is to say, parallel to the axis A.
A depositing operation of impregnation with titanium is for example carried out on a previously deposited coating by supplying a suitable reactive gas mixture by way of the revolving joint 8, and by carry out a heating pass by means of an oxygen and hydrogen blowpipe 22. The blowpipe is attached for this purpose to the lathe slide 7. In certain cases, the reactive gas mixture can advantageously comprise liquid droplets in suspension and can thus form a mist.
Various operations for depositing coatings of glass are carried out in a similar manner before and after such an operation of impregnation with a doping element.
The method according to the invention fits into the usual depositing method, "MCVD", used for manufacturing conventional preforms.
In accordance with the present invention, an angular position detector 20 is located on the upstream headstock 10 and controls the supply and delivery of the oxygen and hydrogen to the blowpipe 22 through flexible tubes 26 and 28.
The fibre shown in Figure 2 comprises a core 30, an optical sheath 32 and an external coating 34 which is derived from the initial tube 4.
In two diametrically opposite angular sectors of the sheath 32, deposits 36 of titanium oxide Ti 2 are formed. A polarising fibre optic is produced in this way.
The variation in the concentration C of this titanium sheath is shown in ordinates in Figure 3 in dependence upon the angular position D of the point under consideration, this position being shown in abscissae.
A similar curve could show a thickness deposited, or the depth of a chemical attack on a coating deposited previously on the internal surface of an initial tube.
Alternatively the speed of rotation of the tube or both the speed of rotation and the heating power of the blowpipe 22 may be varied in relation to the angular position of the tube.
Although only the cases of polarising and double refracting fibres have been mentioned above, it will be seen that very varied objects can be produced by the method according to the present invention.

Claims (4)

Claims:
1. A method of manufacturing rotationally asymmetric preforms for optical fibres comprising the steps of: - positioning an initial tube having a longitudinal axis, an internal space and internal and external cylindrical surfaces, on a glass-maker's lathe, so that the axis of this tube is aligned with a substantially horizontal lathe axis, about which axis the tube can be caused to rotate at a controllable speed, the lathe comprising a lathe slide carrying a blowpipe for heating the external surface of the tube, the heating of this surface by means of the blowpipe being, at any moment, particularly intense in a region of this surface which is, at that moment, opposite the blowpipe, with the lathe slide and blowpipe being able to perform heating passes, in the course of each one of which the blowpipe moves in the longitudinal direction along the length of the tube, and - carrying out at least one coating treatment for forming an optically active coating on the internal surface of the initial tube, this treatment being carried out in the course of a heating pass, the said treatment or a further treatment being carried out in the course of a selective heating pass, in the course of which the heating power is distributed in an angularly selective manner over the external surface of the initial tube, so that an effect of this treatment on the internal surface of the tube is obtained in an angularly selective manner and affects in an angularly selective manner an optical property of an optically active coating, - characterised in that, in the course of the selective heating pass, the tube is caused to rotate in a substantially continuous manner at a rotational speed which is sufficient substantially to avoid any gravitational deformation of this tube, and there is applied, to the speed of rotation of the tube and/or the heating power, a variation which is related to the angular position of the tube.
2. A method according to claim l, characterised in that the coating treatment operation, carried out in the course of the selective heating pass, is an operation of depositing, etching or impregnating a coating, and is carried out with a sweep of the internal space of the initial tube by reagents suitable for bringing about the depositing, etching or impregnating reactions, as the case may be, which depends upon temperature.
3. A method of manufacturing rotationally asymmetric preforms substantially as hereinbefore described with reference to the accompanying drawings.
4. A rotationally asymmetric preform for an optical fibre as manufactured in accordance with claim 1, 2 or 3.
GB9015290A 1989-07-11 1990-07-11 Manufacture of preforms for rotationally asymmetric optical fibres Expired - Lifetime GB2235191B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR8909297A FR2649690B1 (en) 1989-07-11 1989-07-11 PROCESS FOR MANUFACTURING PREFORMS FOR OPTICAL FIBERS WITHOUT REVOLUTION SYMMETRY

Publications (3)

Publication Number Publication Date
GB9015290D0 GB9015290D0 (en) 1990-08-29
GB2235191A true GB2235191A (en) 1991-02-27
GB2235191B GB2235191B (en) 1992-11-11

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Family Applications (1)

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GB9015290A Expired - Lifetime GB2235191B (en) 1989-07-11 1990-07-11 Manufacture of preforms for rotationally asymmetric optical fibres

Country Status (3)

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FR (1) FR2649690B1 (en)
GB (1) GB2235191B (en)
NL (1) NL9001538A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4140765A1 (en) * 1991-12-11 1993-06-17 Kabelmetal Electro Gmbh METHOD AND DEVICE FOR PRODUCING A PREFORM FOR FIBERGLASS FIBER-WAVE GUIDES

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1554314A (en) * 1975-08-16 1979-10-17 Heraeus Schott Quarzschmelze Manufacture of light-conducting fibres
EP0182250A1 (en) * 1984-11-13 1986-05-28 Sumitomo Electric Industries Limited Method for producing glass preform for optical fiber
US4631079A (en) * 1984-09-26 1986-12-23 At&T Technologies, Inc. Method for stretching a glass rod

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3982916A (en) * 1975-12-24 1976-09-28 Bell Telephone Laboratories, Incorporated Method for forming optical fiber preform
US4076380A (en) * 1976-10-28 1978-02-28 Bell Telephone Laboratories, Incorporated Graded index optical fiber
DE2930781A1 (en) * 1979-07-28 1981-02-12 Licentia Gmbh Glass optical waveguide fibre - with non-symmetrical profile of refractive index used to separate two light waves polarised in orthogonal directions
JPS6047216B2 (en) * 1980-07-29 1985-10-21 日本電信電話株式会社 Method for producing base material for optical fiber
CA1177297A (en) * 1981-03-30 1984-11-06 Michael G. Blankenship Polarization retaining single-mode optical fibers and methods of making
JPS57170830A (en) * 1981-04-08 1982-10-21 Sumitomo Electric Ind Ltd Manufacture of optical fiber containing ellipsoidal core
US4428761A (en) * 1981-12-22 1984-01-31 Bell Telephone Laboratories, Incorporated Lithographic method of making optical fibers
DE3369675D1 (en) * 1982-06-25 1987-03-12 Nat Res Dev Method of making optical fibre preforms and optical fibre preform
JPS5939736A (en) * 1982-08-25 1984-03-05 Hitachi Cable Ltd Production of base material for optical fiber retaining plane of polarization
JPS5950037A (en) * 1982-09-10 1984-03-22 Furukawa Electric Co Ltd:The Production of base material for optical fiber
JPS5969436A (en) * 1982-10-09 1984-04-19 Hitachi Cable Ltd Manufacture of optical fiber material capable of retaining polarized face
JPS59141436A (en) * 1983-02-03 1984-08-14 Nippon Telegr & Teleph Corp <Ntt> Manufacture of optical fiber preform
JPS605034A (en) * 1983-04-12 1985-01-11 Fujikura Ltd Manufacture of single polarization optical fiber
US4528009A (en) * 1983-06-01 1985-07-09 Corning Glass Works Method of forming optical fiber having laminated core
FR2551881B1 (en) * 1983-09-13 1986-06-27 Thomson Csf METHOD FOR MANUFACTURING MULTI-CORE OPTICAL FIBER
GB2180232B (en) * 1985-09-13 1989-10-04 Stc Plc Optical fibre

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1554314A (en) * 1975-08-16 1979-10-17 Heraeus Schott Quarzschmelze Manufacture of light-conducting fibres
US4631079A (en) * 1984-09-26 1986-12-23 At&T Technologies, Inc. Method for stretching a glass rod
EP0182250A1 (en) * 1984-11-13 1986-05-28 Sumitomo Electric Industries Limited Method for producing glass preform for optical fiber

Also Published As

Publication number Publication date
FR2649690B1 (en) 1994-01-28
GB9015290D0 (en) 1990-08-29
GB2235191B (en) 1992-11-11
NL9001538A (en) 1991-02-01
FR2649690A1 (en) 1991-01-18

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20000711