WO2000046162A1 - Burner for fabricating aerosol doped waveguides - Google Patents

Burner for fabricating aerosol doped waveguides Download PDF

Info

Publication number
WO2000046162A1
WO2000046162A1 PCT/GB2000/000332 GB0000332W WO0046162A1 WO 2000046162 A1 WO2000046162 A1 WO 2000046162A1 GB 0000332 W GB0000332 W GB 0000332W WO 0046162 A1 WO0046162 A1 WO 0046162A1
Authority
WO
WIPO (PCT)
Prior art keywords
burner
inlet port
aerosol
inlet
angle
Prior art date
Application number
PCT/GB2000/000332
Other languages
French (fr)
Inventor
Paulo Vicente Da Silva Marques
James Ronald Bonar
James Stewart Aitchison
Original Assignee
The University Court Of The University Of Glasgow
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 The University Court Of The University Of Glasgow filed Critical The University Court Of The University Of Glasgow
Priority to GB0118724A priority Critical patent/GB2363637B/en
Priority to AU23084/00A priority patent/AU2308400A/en
Priority to EP00901786A priority patent/EP1150925A1/en
Publication of WO2000046162A1 publication Critical patent/WO2000046162A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00—Other methods of shaping glass
    • C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
    • C03B19/1415—Reactant delivery systems
    • C03B19/1423—Reactant deposition burners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
    • F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
    • C03B2201/34—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/20—Specific substances in specified ports, e.g. all gas flows specified
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/30—For glass precursor of non-standard type, e.g. solid SiH3F
    • C03B2207/32—Non-halide
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/30—For glass precursor of non-standard type, e.g. solid SiH3F
    • C03B2207/34—Liquid, e.g. mist or aerosol
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/42—Assembly details; Material or dimensions of burner; Manifolds or supports
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C2900/00—Special features of, or arrangements for combustion apparatus using fluid fuels or solid fuels suspended in air; Combustion processes therefor
    • F23C2900/9901—Combustion process using hydrogen, hydrogen peroxide water or brown gas as fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
    • F23L2900/07005—Injecting pure oxygen or oxygen enriched air
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

  • This invention relates to a burner for fabricating aerosol doped waveguides.
  • the invention relates to a modified burner which enables the in-situ delivery of dopant ions in a single step process to an optical waveguide during the deposition stage of fabrication.
  • silica based planar waveguides with high ion content by chemical vapour deposition (CVD) , and in particular flame hydrolysis deposition (FHD) methods, is already known in the art.
  • CVD chemical vapour deposition
  • FHD flame hydrolysis deposition
  • dopant ions In such fabrication methods it is often desired to introduce dopant ions during the deposition process.
  • the introduction of dopant ions is effected by a number of known methods which suffer to a greater or lesser degree from certain disadvantages. For example, solution doping requires the core which makes up the waveguide to be partially fused and this introduces several complications.
  • An alternative method is to use aerosol doping.
  • aerosol doping droplets of an aqueous solution of the dopant ions are transferred to a modified FHD burner.
  • the water is evaporated to leave submicron dopant ion particles.
  • the dopant ions are then oxidised in the burner flame and can be distributed during the deposition stage of fabricating the waveguide.
  • a burner for fabricating aerosol doped waveguides including: a plurality of inlet ports each connected to a respective torch conduit, said torch conduit connecting its respective inlet port to a gas mixing region; and including a gas expansion chamber provided for at least one of said inlet ports upstream of said gas mixing region.
  • the gas expansion chamber is in the form of a reservoir chamber.
  • the gas expansion chamber is located at the junction of an inlet port and the respective torch conduit .
  • the gas expansion chamber is located upstream of the junction between the inlet port and the respective torch conduit.
  • the gas expansion chamber is located downstream of the junction of an inlet port and the respective torch conduit.
  • said inlet ports feed oxygen, hydrogen, waveguide deposition material carried by a carrier gas, and aerosol droplets of a dopant ion solution carried by a carrier gas to the said burner.
  • the hydrogen port is located downstream of the waveguide deposition material inlet port.
  • the aerosol inlet port is located downstream of the hydrogen inlet port.
  • the oxygen inlet port is located downstream of the aerosol inlet port.
  • said at least one inlet port is located in a radial plane with respect to a longitudinal axis of the burner which differs from a radial plane containing said other inlet ports.
  • said at least one inlet port is located in a plane orientated at 180° to the radial plane of the other inlet ports .
  • said at least one inlet port is orientated at a first angle with respect to the burner axis, and wherein the other inlet ports are orientated at a second angle with respect to the burner axis, said first angle being less than said second angle.
  • said first angle lies in the range 5° to 45°.
  • said first angle lies in the range 5° to 25°.
  • said at least one inlet port is an aerosol inlet port for providing aerosol droplets of a dopant ion solution to said burner.
  • Fig. 1 is an FHD burner already known in the prior art
  • Fig. 2 is a cross-section through an FHD burner of the type shown in Fig. 1;
  • Fig. 3 is a cross-section through a modified FHD burner according to the present invention.
  • Fig. 1 illustrates a FHD burner 1 already known in the art.
  • the burner 1 has four feed inlet ports: a halide inlet port 2, a hydrogen inlet port 3 , an aerosol inlet port 4 , and an oxygen inlet port 5.
  • the halide inlet port 2 feeds the burner 1 with halide deposition materials, for example, SiCl 3 , PC1 3 , etc carried by a suitable carrier gas, for example, N 2 .
  • the inlet ports 2,3 4 and 5 communicate with a gas mixing region 8 at the output of the burner 1.
  • the aerosol inlet port 4 supplies aerosol droplets of a dopant ion solution, for example, 0.2 M aqueous ErCl 3 .
  • An atomizer 6 is used to generate the aerosol droplets of the dopant ion solution.
  • the aerosol droplets are carried by a carrier gas, for example, N 2 to the aerosol inlet port 4 of the burner 1.
  • the water solvent is then evaporated to leave submicron particles of the dopant ions (here Er +3 ) which are prone to condense at the inlet port 4.
  • the build up of condensed dopant ions can create a blockage 7 which can clog the inlet port 4.
  • This blockage 7 occurs before the dopant ions react in the gas mixing reaction zone 8, which affects the rate at which the dopant ions are incorporated during fabrication of a waveguide 9.
  • Fig. 2 there is shown a cross-section through this type of conventional burner 1.
  • the inlet ports 2, 3, 4 and 5 are all aligned at the same angle ⁇ to the torch axis X, and transfer the feed gases (the gas carrying the halide deposition materials, hydrogen, the gas carrying the dopant ions, and oxygen) into concentric torch conduits 10, 11, 12 and 13 respectively.
  • the halide torch conduit 10, hydrogen torch conduit 11, aerosol torch conduit 12, and oxygen torch conduit 13 deliver the feed gases to the gas mixing reaction zone 8 located in the burner nozzle 14 where the dopant ions are oxidised in the burner flame.
  • the oxidised dopant ions are then incorporated during the deposition of the layers (not shown) which form the waveguide 9 (shown in Fig.l) a single step process.
  • a modified burner 15 made in accordance with the invention for introducing rare earth dopant ions, for example, Er +3 , during fabrication of a waveguide (not shown) .
  • the burner 15 has four feed inlet ports: a halide inlet port 16, a hydrogen inlet port 17, an aerosol inlet port 18, and an oxygen inlet port 19.
  • the halide inlet port 16 supplies the deposition materials, for example, SiCl 3 , PC1 3 , etc, which are carried by a suitable carrier gas, for example, N 2 .
  • the aerosol inlet port 18 supplies aerosol droplets of a dopant ion solution, for example, aqueous ErCl 3 .
  • the halide inlet port 16, hydrogen port 17, and oxygen port 19 are located in the same radial plane radiating from the torch axis Y and can be all aligned at the same angle ⁇ l to the torch axis Y.
  • the aerosol inlet port 18 is located in a different radial plane (for example, it may be displaced by 180° from the plane in which the inlet ports 16, 17 and 19 are located) and is positioned at a different angle ⁇ 2 with respect to the torch axis Y.
  • the inlet ports 16, 17, 18 and 19 transfer the feed gases into respective concentric torch conduits 20, 21, 22 and 23.
  • the halide torch conduit 20, hydrogen torch conduit 21, aerosol torch conduit 22, and oxygen torch conduit 23 deliver their respective feed gases to a gas mixing reaction zone 24 where the dopant ions, in this example Er +3 , are oxidised in the burner flame (not shown) .
  • the aerosol inlet port 18 has a modified structure, compared to the aerosol inlet port 4 of prior art burner 1.
  • the aerosol conduit 22 is expanded at the region where it connects with aerosol inlet port 18 to form a gas expansion chamber 25 (here in the form of a reservoir chamber) .
  • the gas expansion chamber 25 provides an increase in the volume of the aerosol inlet port 18 and helps to maintain the concentration of dopant ions and to mitigate the build up of condensed dopant ions during evaporation of the aqueous dopant ion solution.
  • the gas expansion chamber 25 enables the evaporation of the dopant ion solvent to occur without the dopant ions condensing at the base of the aerosol inlet port 18 forming a blockage at the base of the aerosol inlet port 18.
  • a suitable volume for the gas expansion chamber lies in the range of 2500 mm 3 to 5000 mm 3 for an aerosol feed carrier gas flow rate of 3 litres/min, an aerosol inlet port 18 internal diameter of 5.5 mm, and an aerosol conduit 22 internal diameter of 14 mm.
  • the gas expansion chamber 25 is circular in radial cross-section and elliptical in axial cross-section and is provided at the junction of the aerosol inlet port 18 with the aerosol torch conduit 22 by expanding the internal diameter of the aerosol conduit 22.
  • the gas expansion chamber may have a different shape and/or configuration. It can also be located at other points where evaporation of the dopant ion solution occurs, for example upstream along the aerosol inlet port 18 or downstream along the aerosol conduit 22.
  • the prevention of a blockage occurring as the dopant ions enter the aerosol conduit 22 is further assisted by reducing the angle of directionality ⁇ 2 (the angle the aerosol inlet port makes with the torch axis (Y in Fig. 3)).
  • ⁇ 2 being substantially equal to 10°, which is in a preferred range of 5° to 25°.
  • a reduction in the amount of condensation is also achieved if ⁇ 2 is in the range of 25° to 45°.
  • the dimensions of the aerosol conduit 22 are selected to optimise the dopant process and to provide directionality to the flame whilst reducing the burner nozzle 26 temperature to below 1300°C. This prevents devitrification of the nozzle 26 which would otherwise provide unwanted contaminants.
  • dopant ions for example, rare earth or heavy metal ions and combinations of ions can incorporated using the burner 15 into the deposition stage.
  • Suitable solutions including rare earth and/or heavy metal ions can be prepared at much higher concentrations than were hitherto known in the art without any accretion clogging the burner 15.
  • a Nd doped planar silica (Si0 2 - P 2 0 5 ) waveguide can be fabricated using the burner 15.
  • An Nd/Al aqueous solution of 0.5M/0.4M can be used to provide the waveguide with dopant ion concentrations of 0.25 wt% for Nd and 0.04 wt% for Al .
  • the modified FHD burner 15 therefore enables greater control of the ion doping process during the deposition stage of fabricating the waveguide.
  • One or more ion species can be introduced during the deposition stage of fabricating the waveguide in a controlled manner to produce waveguides with more uniform and much higher dopant ion concentrations than known from the prior art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Gas Burners (AREA)

Abstract

A burner for fabricating aerosol doped planar waveguides which includes a plurality of inlet ports (16, 17, 18, 19) each connected to a respective torch conduit (20, 21, 22, 23); said torch conduit connecting its respective inlet feed to a gas mixing region (24); wherein a gas expansion chamber (25) is provided between at least one of said inlet ports (16, 17, 18, 19) and said gas mixing region (24).

Description

BURNER FOR FABRICATING AEROSOL DOPED WAVEGUIDES
FIELD OF THE INVENTION
This invention relates to a burner for fabricating aerosol doped waveguides. In particular, the invention relates to a modified burner which enables the in-situ delivery of dopant ions in a single step process to an optical waveguide during the deposition stage of fabrication.
BACKGROUND OF THE INVENTION
The fabrication of silica based planar waveguides with high ion content by chemical vapour deposition (CVD) , and in particular flame hydrolysis deposition (FHD) methods, is already known in the art.
In such fabrication methods it is often desired to introduce dopant ions during the deposition process. The introduction of dopant ions is effected by a number of known methods which suffer to a greater or lesser degree from certain disadvantages. For example, solution doping requires the core which makes up the waveguide to be partially fused and this introduces several complications.
An alternative method is to use aerosol doping. In aerosol doping droplets of an aqueous solution of the dopant ions are transferred to a modified FHD burner. The water is evaporated to leave submicron dopant ion particles. The dopant ions are then oxidised in the burner flame and can be distributed during the deposition stage of fabricating the waveguide.
It is known to modify conventional FHD burners to incorporate an extra port for the aerosol feed. A problem arises, however, when such burners are used in the fabrication of heavily doped waveguides. High dopant ion levels require high concentrations of the aqueous dopant ion solution. During the evaporation of the solvent in highly concentrated solutions, more dopant ions condense around the aerosol inlet port than would do with a less concentrated solution. This build up of condensed ions can create blockages. The present invention seeks to provide a modified burner design which obviates or mitigates the problems heretofore mentioned.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a burner for fabricating aerosol doped waveguides, the burner including: a plurality of inlet ports each connected to a respective torch conduit, said torch conduit connecting its respective inlet port to a gas mixing region; and including a gas expansion chamber provided for at least one of said inlet ports upstream of said gas mixing region. Preferably, the gas expansion chamber is in the form of a reservoir chamber.
Preferably, the gas expansion chamber is located at the junction of an inlet port and the respective torch conduit .
Alternatively, the gas expansion chamber is located upstream of the junction between the inlet port and the respective torch conduit.
Alternatively, the gas expansion chamber is located downstream of the junction of an inlet port and the respective torch conduit.
Preferably, said inlet ports feed oxygen, hydrogen, waveguide deposition material carried by a carrier gas, and aerosol droplets of a dopant ion solution carried by a carrier gas to the said burner.
Preferably, the hydrogen port is located downstream of the waveguide deposition material inlet port.
Preferably, the aerosol inlet port is located downstream of the hydrogen inlet port.
Preferably, the oxygen inlet port is located downstream of the aerosol inlet port.
Preferably, said at least one inlet port is located in a radial plane with respect to a longitudinal axis of the burner which differs from a radial plane containing said other inlet ports.
Preferably, said at least one inlet port is located in a plane orientated at 180° to the radial plane of the other inlet ports .
Preferably, said at least one inlet port is orientated at a first angle with respect to the burner axis, and wherein the other inlet ports are orientated at a second angle with respect to the burner axis, said first angle being less than said second angle.
Preferably, said first angle lies in the range 5° to 45°.
Preferably, said first angle lies in the range 5° to 25°.
Preferably, said at least one inlet port is an aerosol inlet port for providing aerosol droplets of a dopant ion solution to said burner.
DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described by way of example only, with reference to the drawings in which:
Fig. 1 is an FHD burner already known in the prior art;
Fig. 2 is a cross-section through an FHD burner of the type shown in Fig. 1; and
Fig. 3 is a cross-section through a modified FHD burner according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, Fig. 1 illustrates a FHD burner 1 already known in the art. The burner 1 has four feed inlet ports: a halide inlet port 2, a hydrogen inlet port 3 , an aerosol inlet port 4 , and an oxygen inlet port 5. The halide inlet port 2 feeds the burner 1 with halide deposition materials, for example, SiCl3, PC13, etc carried by a suitable carrier gas, for example, N2. The inlet ports 2,3 4 and 5 communicate with a gas mixing region 8 at the output of the burner 1.
The aerosol inlet port 4 supplies aerosol droplets of a dopant ion solution, for example, 0.2 M aqueous ErCl3. An atomizer 6 is used to generate the aerosol droplets of the dopant ion solution. The aerosol droplets are carried by a carrier gas, for example, N2 to the aerosol inlet port 4 of the burner 1. The water solvent is then evaporated to leave submicron particles of the dopant ions (here Er+3) which are prone to condense at the inlet port 4. For solution strengths above 0.2M, the build up of condensed dopant ions can create a blockage 7 which can clog the inlet port 4. This blockage 7 occurs before the dopant ions react in the gas mixing reaction zone 8, which affects the rate at which the dopant ions are incorporated during fabrication of a waveguide 9. The blockage 7 arises due to the combination of an abrupt reduction in pipe volume and the change in directionality of the carrier gas flow (θ = 68° from the torch axis (X in Fig. 1)) .
Referring now to Fig. 2, there is shown a cross-section through this type of conventional burner 1. The inlet ports 2, 3, 4 and 5 are all aligned at the same angle θ to the torch axis X, and transfer the feed gases (the gas carrying the halide deposition materials, hydrogen, the gas carrying the dopant ions, and oxygen) into concentric torch conduits 10, 11, 12 and 13 respectively. The halide torch conduit 10, hydrogen torch conduit 11, aerosol torch conduit 12, and oxygen torch conduit 13 deliver the feed gases to the gas mixing reaction zone 8 located in the burner nozzle 14 where the dopant ions are oxidised in the burner flame. The oxidised dopant ions are then incorporated during the deposition of the layers (not shown) which form the waveguide 9 (shown in Fig.l) a single step process.
Referring now to Fig. 3, there is shown a modified burner 15 made in accordance with the invention for introducing rare earth dopant ions, for example, Er+3, during fabrication of a waveguide (not shown) .
The burner 15 has four feed inlet ports: a halide inlet port 16, a hydrogen inlet port 17, an aerosol inlet port 18, and an oxygen inlet port 19. The halide inlet port 16 supplies the deposition materials, for example, SiCl3, PC13, etc, which are carried by a suitable carrier gas, for example, N2. The aerosol inlet port 18 supplies aerosol droplets of a dopant ion solution, for example, aqueous ErCl3.
The halide inlet port 16, hydrogen port 17, and oxygen port 19 are located in the same radial plane radiating from the torch axis Y and can be all aligned at the same angle θl to the torch axis Y. The aerosol inlet port 18 is located in a different radial plane (for example, it may be displaced by 180° from the plane in which the inlet ports 16, 17 and 19 are located) and is positioned at a different angle Θ2 with respect to the torch axis Y. The inlet ports 16, 17, 18 and 19 transfer the feed gases into respective concentric torch conduits 20, 21, 22 and 23. The halide torch conduit 20, hydrogen torch conduit 21, aerosol torch conduit 22, and oxygen torch conduit 23 deliver their respective feed gases to a gas mixing reaction zone 24 where the dopant ions, in this example Er+3, are oxidised in the burner flame (not shown) .
The aerosol inlet port 18 has a modified structure, compared to the aerosol inlet port 4 of prior art burner 1. The aerosol conduit 22 is expanded at the region where it connects with aerosol inlet port 18 to form a gas expansion chamber 25 (here in the form of a reservoir chamber) . The gas expansion chamber 25 provides an increase in the volume of the aerosol inlet port 18 and helps to maintain the concentration of dopant ions and to mitigate the build up of condensed dopant ions during evaporation of the aqueous dopant ion solution.
The gas expansion chamber 25 enables the evaporation of the dopant ion solvent to occur without the dopant ions condensing at the base of the aerosol inlet port 18 forming a blockage at the base of the aerosol inlet port 18.
A suitable volume for the gas expansion chamber lies in the range of 2500 mm3 to 5000 mm3 for an aerosol feed carrier gas flow rate of 3 litres/min, an aerosol inlet port 18 internal diameter of 5.5 mm, and an aerosol conduit 22 internal diameter of 14 mm.
In the preferred embodiment, the gas expansion chamber 25 is circular in radial cross-section and elliptical in axial cross-section and is provided at the junction of the aerosol inlet port 18 with the aerosol torch conduit 22 by expanding the internal diameter of the aerosol conduit 22. Alternatively, the gas expansion chamber may have a different shape and/or configuration. It can also be located at other points where evaporation of the dopant ion solution occurs, for example upstream along the aerosol inlet port 18 or downstream along the aerosol conduit 22.
The prevention of a blockage occurring as the dopant ions enter the aerosol conduit 22 is further assisted by reducing the angle of directionality Θ2 (the angle the aerosol inlet port makes with the torch axis (Y in Fig. 3)). In the preferred embodiment, significant reduction in the amount of condensation is provided by Θ2 being substantially equal to 10°, which is in a preferred range of 5° to 25°. A reduction in the amount of condensation is also achieved if Θ2 is in the range of 25° to 45°.
The dimensions of the aerosol conduit 22 are selected to optimise the dopant process and to provide directionality to the flame whilst reducing the burner nozzle 26 temperature to below 1300°C. This prevents devitrification of the nozzle 26 which would otherwise provide unwanted contaminants.
In the preferred embodiment, with a deposition rate of 1 μm of base material per traversal of the FHD burner, it is possible to achieve doping levels of up to 0.72 wt% for an ErCl3 solution strength of IM with a carrier gas flow rate of 2.4 litre min"1. Higher dopant levels can be achieved, for example, by maintaining the rare earth dopant conditions and reducing the halide flow rates or by increasing the concentration of the rare earth dopant solution.
Other dopant ions, for example, rare earth or heavy metal ions and combinations of ions can incorporated using the burner 15 into the deposition stage. Suitable solutions including rare earth and/or heavy metal ions can be prepared at much higher concentrations than were hitherto known in the art without any accretion clogging the burner 15.
For example, a Nd doped planar silica (Si02 - P205) waveguide can be fabricated using the burner 15. An Nd/Al aqueous solution of 0.5M/0.4M can be used to provide the waveguide with dopant ion concentrations of 0.25 wt% for Nd and 0.04 wt% for Al .
The modified FHD burner 15 therefore enables greater control of the ion doping process during the deposition stage of fabricating the waveguide. One or more ion species can be introduced during the deposition stage of fabricating the waveguide in a controlled manner to produce waveguides with more uniform and much higher dopant ion concentrations than known from the prior art.
While several embodiments of the present invention have been described and illustrated, it will be apparent to those skilled in the art once given this disclosure that various modifications, changes, improvements and variations may be made without departing from the spirit or scope of this invention.

Claims

Claims :
1. A burner for fabricating aerosol doped waveguides, the burner including: a plurality of inlet ports each connected to a respective torch conduit, said torch conduit connecting its respective inlet port to a gas mixing region; and including a gas expansion chamber provided for at least one of said inlet ports upstream of said gas mixing region.
2. A burner as claimed in Claim 1, wherein the gas expansion chamber is in the form of a reservoir chamber .
3. A burner as claimed in either preceding claim, wherein the gas expansion chamber is located at the junction of an inlet port and the respective torch conduit.
4. A burner as claimed in Claim 1 or 2 , wherein the gas expansion chamber is located upstream of the junction between the inlet port and the respective torch conduit.
5. A burner as claimed in Claim 1 or 2 , wherein the gas expansion chamber is located downstream of the junction between the inlet port and the respective torch conduit.
6. A burner as claimed in any preceding claim, wherein said inlet ports feed oxygen, hydrogen, waveguide deposition material carried by a carrier gas, and aerosol droplets of a dopant ion solution carried by a carrier gas to the said burner.
7. A burner as claimed in Claim 6, wherein the hydrogen port is located downstream of the waveguide deposition material inlet port .
8. A burner as claimed in Claim 6 or 7, wherein the aerosol inlet port is located downstream of the hydrogen inlet port .
9. A burner as claimed in any one of Claims 6 to 8 , wherein the oxygen inlet port is located downstream of the aerosol inlet port .
10. A burner as claimed in any preceding claim, wherein said at least one inlet port is located in a radial plane with respect to a longitudinal axis of the burner which differs from a radial plane containing said other inlet ports.
11. A burner as claimed in Claim 10, wherein said at least one inlet port is located in a plane orientated at 180° to the radial plane of the other inlet ports.
12. A burner as claimed in any preceding claim, wherein said at least one inlet port is orientated at a first angle with respect to the burner axis, and wherein the other inlet ports are orientated at a second angle with respect to the burner axis, said first angle being less than said second angle.
13. A burner as claimed in Claim 12, wherein said first angle lies in the range 5° to 45°.
14. A burner as claimed in Claim 13, wherein said first angle lies in the range 5° to 25°.
15. A burner as claimed in any preceding claim, wherein said at least one inlet port is an aerosol inlet port for providing aerosol droplets of a dopant ion solution to said burner.
16. A burner substantially as described herein and with reference to Fig. 3 of the accompanying drawings.
PCT/GB2000/000332 1999-02-05 2000-02-07 Burner for fabricating aerosol doped waveguides WO2000046162A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB0118724A GB2363637B (en) 1999-02-05 2000-02-07 Burner for fabricating aerosol doped waveguides
AU23084/00A AU2308400A (en) 1999-02-05 2000-02-07 Burner for fabricating aerosol doped waveguides
EP00901786A EP1150925A1 (en) 1999-02-05 2000-02-07 Burner for fabricating aerosol doped waveguides

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9902476.2 1999-02-05
GB9902476A GB2346683A (en) 1999-02-05 1999-02-05 Flame hydrolysis deposition burner

Publications (1)

Publication Number Publication Date
WO2000046162A1 true WO2000046162A1 (en) 2000-08-10

Family

ID=10847094

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2000/000332 WO2000046162A1 (en) 1999-02-05 2000-02-07 Burner for fabricating aerosol doped waveguides

Country Status (4)

Country Link
EP (1) EP1150925A1 (en)
AU (1) AU2308400A (en)
GB (2) GB2346683A (en)
WO (1) WO2000046162A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU776420B2 (en) * 2000-09-14 2004-09-09 Sumitomo Electric Industries, Ltd. Burner for synthesizing glass particles and method for producing porous glass body

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002098805A1 (en) * 2001-05-30 2002-12-12 Pirelli & C. S.P.A. Method and burner for manufacturing a glass optical fibre preform by vapour deposition

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5595638A (en) * 1979-01-10 1980-07-21 Hitachi Ltd Production of glass soot block
JPS56155034A (en) * 1980-04-26 1981-12-01 Nippon Telegr & Teleph Corp <Ntt> Synthetic torch for fine glassy particle
EP0160858A1 (en) * 1984-05-11 1985-11-13 Licentia Patent-Verwaltungs-GmbH Method and apparatus for producing an aerosol flue
EP0463783A1 (en) * 1990-06-25 1992-01-02 AT&T Corp. Method and apparatus for making glass
JPH0421536A (en) * 1990-05-16 1992-01-24 Hitachi Cable Ltd Preparation of rare earth element-doped glass
WO1997022553A1 (en) * 1995-12-19 1997-06-26 Corning Incorporated Method and apparatus for forming fused silica by combustion of liquid reactants
EP0978486A1 (en) * 1998-08-07 2000-02-09 Corning Incorporated Method and burner for forming silica-containing soot

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4440558A (en) * 1982-06-14 1984-04-03 International Telephone And Telegraph Corporation Fabrication of optical preforms by axial chemical vapor deposition
JPS62187135A (en) * 1986-02-12 1987-08-15 Furukawa Electric Co Ltd:The Torch for synthesizing fine glass particle

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5595638A (en) * 1979-01-10 1980-07-21 Hitachi Ltd Production of glass soot block
JPS56155034A (en) * 1980-04-26 1981-12-01 Nippon Telegr & Teleph Corp <Ntt> Synthetic torch for fine glassy particle
EP0160858A1 (en) * 1984-05-11 1985-11-13 Licentia Patent-Verwaltungs-GmbH Method and apparatus for producing an aerosol flue
JPH0421536A (en) * 1990-05-16 1992-01-24 Hitachi Cable Ltd Preparation of rare earth element-doped glass
EP0463783A1 (en) * 1990-06-25 1992-01-02 AT&T Corp. Method and apparatus for making glass
WO1997022553A1 (en) * 1995-12-19 1997-06-26 Corning Incorporated Method and apparatus for forming fused silica by combustion of liquid reactants
EP0978486A1 (en) * 1998-08-07 2000-02-09 Corning Incorporated Method and burner for forming silica-containing soot

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 16, no. 176 27 April 1992 (1992-04-27) *
PATENT ABSTRACTS OF JAPAN vol. 4, no. 151 23 October 1980 (1980-10-23) *
PATENT ABSTRACTS OF JAPAN vol. 6, no. 35 3 March 1982 (1982-03-03) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU776420B2 (en) * 2000-09-14 2004-09-09 Sumitomo Electric Industries, Ltd. Burner for synthesizing glass particles and method for producing porous glass body
CN100473618C (en) * 2000-09-14 2009-04-01 住友电气工业株式会社 Burner of synthetic glass particles and method for fabricating porous vitreous body

Also Published As

Publication number Publication date
GB9902476D0 (en) 1999-03-24
EP1150925A1 (en) 2001-11-07
AU2308400A (en) 2000-08-25
GB2346683A (en) 2000-08-16
GB0118724D0 (en) 2001-09-26
GB2363637A (en) 2002-01-02
GB2363637B (en) 2003-09-24

Similar Documents

Publication Publication Date Title
US5692087A (en) Optical fiber with low OH impurity and communication system using the optical fiber
CA1165551A (en) Optical fiber fabrication and resulting product
US5106402A (en) Method of manufacturing a monomode optical fiber
JP3182730B2 (en) Precision burner for oxidizing halide-free silicon-containing compounds
EP0463783A1 (en) Method and apparatus for making glass
US4235616A (en) Optical waveguide manufacturing process and article
KR20010053022A (en) Method and apparatus for manufacturing a rare earth metal doped optical fiber preform
US6682339B2 (en) Flame stabilizer for flame hydrolysis deposition
CN1490267A (en) Method for manufacturing rare earth extended fibre-optical prefabricated bar
EP0245716A1 (en) Method and apparatus for forming doped optical preforms
GB2059944A (en) Fabrication method of optical fiber preforms
WO2003093182A1 (en) Burner assembly for producing glass preforms and corresponding production process
WO2000046162A1 (en) Burner for fabricating aerosol doped waveguides
US20030115909A1 (en) Plasma chemical vapor deposition methods and apparatus
US7891217B2 (en) Method of producing an optical fiber preform
US4312654A (en) Method and apparatus for making large diameter optical waveguide preforms
JPH06234537A (en) Method for forming optical fiber preform
NO147948B (en) METHOD AND APPARATUS FOR MANUFACTURING OPTICAL GLASS FIBERS
CN1623941B (en) System for forming a gas flow of reactants for a doped glass material
US20020028415A1 (en) Co-flow diffusion flame burner device used for fabricating an optical waveguide
CN114455828A (en) Method for manufacturing boron-doped stress rod
US7441416B2 (en) Method for manufacturing optical fibre preforms
CN112596151A (en) Erbium-doped polarization-maintaining active optical fiber and preparation method thereof
US20020073734A1 (en) Apparatus and method of doping silica with fluorine during laydown
CN114637068B (en) Gain-balanced few-mode erbium-doped optical fiber and preparation method thereof

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

WWE Wipo information: entry into national phase

Ref document number: 2000901786

Country of ref document: EP

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref country code: GB

Ref document number: 200118724

Kind code of ref document: A

Format of ref document f/p: F

WWP Wipo information: published in national office

Ref document number: 2000901786

Country of ref document: EP

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWE Wipo information: entry into national phase

Ref document number: 09890681

Country of ref document: US

WWW Wipo information: withdrawn in national office

Ref document number: 2000901786

Country of ref document: EP