CN111116037A - Device and method for preparing rare earth element doped optical fiber preform by VAD (vapor deposition) method - Google Patents

Device and method for preparing rare earth element doped optical fiber preform by VAD (vapor deposition) method Download PDF

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CN111116037A
CN111116037A CN202010030359.9A CN202010030359A CN111116037A CN 111116037 A CN111116037 A CN 111116037A CN 202010030359 A CN202010030359 A CN 202010030359A CN 111116037 A CN111116037 A CN 111116037A
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rare earth
layer
vad
unit
optical fiber
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林傲祥
倪力
俞娟
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Chengdu Aoxiang Tuochuang Photoelectric Technology Partnership LP
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Chengdu Aoxiang Tuochuang Photoelectric Technology Partnership LP
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    • 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]
    • C03B37/01406—Deposition reactors therefor
    • 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]
    • C03B37/01413—Reactant delivery systems
    • 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]
    • C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
    • C03B37/0146—Furnaces therefor, e.g. muffle tubes, furnace linings
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2207/00—Glass deposition burners
    • C03B2207/04—Multi-nested ports
    • C03B2207/06—Concentric circular ports
    • 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

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  • Engineering & Computer Science (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Lasers (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

The invention discloses a device and a method for preparing a rare earth element doped optical fiber preform by a VAD method, wherein the device comprises a basic raw material supply unit, a doping device and a VAD device, the doping device comprises a rare earth compound volatilization unit, a co-doped volatilization unit and a high-temperature transmission unit, the VAD device comprises an inner-layer blast burner, a middle-layer blast burner, an outer-layer blast burner and a control unit, and output pipelines of the rare earth compound volatilization unit and the co-doped volatilization unit are respectively connected with a central feeding hole of the inner-layer blast burner through the high-temperature transmission unit; the control unit controls the movement of the guide rod in the VAD device and controls the inner layer blast lamp, the middle layer blast lamp, the outer layer blast lamp, the upper core layer, the middle layer and the cladding layer of the guide rod or the powder deposition of the core layer and the cladding layer, and the dehydration and sintering in the moving process. The method utilizes the device to prepare the rare earth element doped optical fiber preform. The invention can solve the preparation problem of the large fiber core rare earth doping prefabricated rod and simultaneously overcome the limitation problem of rare earth ion solution doping.

Description

Device and method for preparing rare earth element doped optical fiber preform by VAD (vapor deposition) method
Technical Field
The invention relates to the technical field of optical fiber preparation, in particular to a device and a method for preparing a rare earth element doped optical fiber preform by a VAD (vapor deposition) method.
Background
Rare earth doped specialty fibers have found widespread use in fiber lasers, amplifiers and sensors and have been greatly developed in recent years.
The optical fiber prefabricated rod is an important basic material for manufacturing optical fibers and optical cables, and is a key core technology in the optical fiber production flow. At present, the processes for preparing the preform in China mainly comprise a vapor axial deposition method (VAD), an outside vapor deposition method (OVD), a modified chemical outside vapor deposition Method (MCVD) and a plasma deposition method (PCVD), wherein the MCVD and the PCVD belong to an in-tube deposition method, and the VAD and the OVD belong to an outside deposition method. The deposition method in tube, although having some advantages in control accuracy, produces preforms with both core and cladding dimensions limited by the dimensions of the deposited quartz tube because of the deposition in the tube. The external deposition method gets rid of the size limitation of the quartz tube, and can prepare a large-size optical fiber preform, so that the large-size optical fiber preform has great advantages in manufacturing cost.
Among them, the VAD method has been widely used for the fabrication of the preform for the communication optical fiber due to its high deposition rate and low fabrication cost. However, the VAD and OVD methods are rarely applied in the field of preparation of rare earth doped special optical fiber preforms, and a method for manufacturing rare earth doped optical fiber preforms by using the VAD method is disclosed in patent CN102108008B, the method is to use large-size fiber core powder deposited by using VAD, and then immerse the fiber core powder in a solution containing rare earth ions to realize rare earth doping of the large-size fiber core powder, but the method is easy to introduce impurities in the processes of unloading the powder and immersing the rare earth solution as in the MCVD solution method.
The current methods for preparing the rare earth element doped optical fiber preform mainly include a solution method, a gas phase method, a sol-gel method and the like, wherein the widely adopted method mainly includes the solution doping method and an evolution method thereof. Although the MCVD solution doping technology has the advantages of simple operation, high flexibility, etc., with the continuous rise of other doping technologies and technological optimization, the method for doping rare earth ions in the optical fiber has increasingly shown its limitations, especially its repeatability is difficult to control and it does not have the capability of preparing large core preform. The sol-gel method is always plagued by the problem of high optical fiber loss due to the difficulty in controlling impurities, and is not widely applied at present. Because the rare earth ion gas phase method doping has the consistency with the gas phase doping of the optical fiber preform basic raw material, the doping uniformity, the doping controllability, the interface optimization, the background loss, the optical fiber reliability and the simplification and repeatability of the preparation process are greatly improved, most of the rare earth ion gas phase doping is combined with MCVD or PCVD for use at present, the prepared preform has small size, the optical fiber drawn by a single preform is shorter, and the consistency of the batch performance of the rare earth doped optical fiber product is poorer. And because the rare earth doped preform has low preparation yield and small size, the rare earth doped optical fiber is high in cost, and the problems are needed to be solved for rare earth doped optical fiber products.
Disclosure of Invention
The invention aims to solve the preparation problem of a large-fiber-core rare earth doped preform rod in the background technology, simultaneously overcome the limitation problem of rare earth ion solution doping, and provide a device and a method for preparing a rare earth element doped optical fiber preform rod by a VAD method.
One aspect of the present invention provides an apparatus for preparing a rare earth doped optical fiber preform by VAD, comprising a doping apparatus and a VAD apparatus, wherein,
the doping device comprises a rare earth compound volatilization unit, a co-doping object volatilization unit and a high-temperature transmission unit, wherein output pipelines of the rare earth compound volatilization unit and the co-doping object volatilization unit respectively pass through the high-temperature transmission unit to be connected with the VAD device;
the VAD device comprises an inner layer blast burner, a middle layer blast burner, an outer layer blast burner and a control unit, wherein output pipelines of the rare earth compound volatilization unit and the co-doped volatilization unit are respectively connected with a central feeding hole of the inner layer blast burner through a high-temperature transmission unit, and the central feeding holes of the inner layer blast burner, the middle layer blast burner and the outer layer blast burner are also connected with an output pipeline of a basic raw material feeding unit of the VAD device; the control unit controls the movement of the guide rod in the VAD device and controls the inner layer blowtorch, the middle layer blowtorch and the outer layer blowtorch to finish the powder deposition of the upper core layer, the middle layer and the cladding layer of the guide rod or the core layer and the cladding layer and the dehydration and sintering in the moving process.
According to one embodiment of the device for preparing the rare earth element doped optical fiber preform rod by the VAD method, the rare earth compound volatilization unit and the co-dopant volatilization unit respectively comprise a charging bucket, a heater, a carrier gas input pipeline and an output pipeline, wherein the rare earth compound raw material contained in the charging bucket of the rare earth compound volatilization unit is organic metal chelate of rare earth element ions with atomic numbers of 57-71, the co-dopant raw material contained in the charging bucket of the co-dopant volatilization unit is organic metal chelate of Al, Ce, Na, K, Ti or Ba, and the carrier gas input by the carrier gas input pipeline is nitrogen or oxygen.
In one embodiment of the apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method of the present invention, the base material supplied from the base material supply unit connected to the central supply holes of the inner, middle and outer burners comprises SiCl4、GeCl4、C2F6、POCl3And/or O2。
According to one embodiment of the apparatus for manufacturing a rare earth element doped optical fiber preform by VAD of the present invention, the tail position of the central feeding hole of the inner layer torch comprises 3 holes and the port position is provided with only 1 hole, raw materials from the rare earth compound volatilization unit, the co-dopant volatilization unit and the base raw material supply unit respectively enter from the 3 holes at the tail position of the central feeding hole of the inner layer torch, and are converged and then ejected through the 1 hole at the port position of the central feeding hole of the inner layer torch to complete the mixing of all raw materials.
According to one embodiment of the apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method of the present invention, the inner layer torch is sequentially provided with a central feeding hole, a heating layer, a core layer isolation air hole, a core layer flame hole, an outer layer flame hole, and an outer layer isolation air hole from inside to outside, and the middle layer torch and the outer layer torch are sequentially provided with a central feeding hole, a core layer isolation air hole, a core layer flame hole, an outer layer flame hole, and an outer layer isolation air hole from inside to outside.
According to one embodiment of the apparatus for fabricating a rare earth doped optical fiber preform according to the VAD method of the present invention, the core flame holes include core flame hydrogen holes and core flame oxygen holes, and the outer flame holes include outer flame hydrogen holes and outer flame oxygen holes.
According to one embodiment of the device for preparing the rare earth element doped optical fiber preform rod by the VAD method, the high-temperature transmission unit is provided with a transmission cavity, a heating layer and a heat insulation layer from inside to outside, output pipelines of the rare earth compound volatilization unit and the co-doped volatilization unit penetrate through the transmission cavity to be connected with a central feeding hole of an inner-layer blast burner of the VAD device, and the number of the rare earth compound volatilization unit and the co-doped volatilization unit is at least one.
According to one embodiment of the apparatus for manufacturing the rare earth element-doped optical fiber preform according to the VAD method of the present invention, the VAD apparatus further comprises a dehydration atmosphere furnace and a sintering furnace disposed downstream of the outer layer torch, and the rod is sequentially dehydrated and sintered through the dehydration atmosphere furnace and the sintering furnace after deposition of the core layer, the intermediate layer and the cladding layer or powder of the core layer and the cladding layer is completed.
The invention also provides a method for preparing the rare earth element doped optical fiber preform by the VAD method, and the device for preparing the rare earth element doped optical fiber preform by the VAD method is adopted to prepare the rare earth element doped optical fiber preform.
In one embodiment of a method for making a rare earth doped optical fiber preform according to the VAD method of the present invention, the method comprises the steps of:
the first step is as follows: preparing a basic raw material supply unit, a doping device and a VAD device and enabling the basic raw material supply unit, the doping device and the VAD device to be in a state to be operated;
the second step is that: respectively adding a rare earth compound raw material and a co-dopant raw material to be doped into the charging buckets of the rare earth compound volatilization unit and the co-dopant volatilization unit, and heating the rare earth compound volatilization unit, the co-dopant volatilization unit and the high-temperature transmission unit after gas purging is completed;
the third step: the rare earth element doped fiber core powder deposition of the core layer is completed on the guide rod through the inner layer blast burner, the powder deposition of the middle layer is completed through the middle layer blast burner, and the powder deposition of the cladding layer is completed through the outer layer blast burner or the powder deposition of the cladding layer is completed through the outer layer blast burner directly;
the fourth step: and dehydrating the deposited preform powder, and sintering the preform powder in an upward moving process to form a transparent rare earth element doped optical fiber preform.
Compared with the prior art, the method can realize that the rare earth ions directly enter the fiber core area of the preform rod through gas phase doping, the fiber core and the cladding of the large-size preform rod can be prepared by adopting the VAD method, the problem of the proportion of the large-core cladding of the doped preform rod is effectively solved, the preparation cost of the rare earth doped optical fiber preform rod can be greatly reduced, the length of a drawn optical fiber is also increased due to the fact that the size of a single preform rod is increased, and the performance consistency of the rare earth doped optical fiber product.
Drawings
Fig. 1 is a schematic view showing the overall structure of an apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method in an exemplary embodiment of the present invention.
Fig. 2 is a schematic view showing a doping apparatus in an apparatus for manufacturing a rare earth element-doped optical fiber preform according to a VAD method according to an exemplary embodiment of the present invention.
Fig. 3 is a schematic diagram showing the structures of an inner layer torch, a middle layer torch and an outer layer torch of a VAD apparatus in an apparatus for manufacturing a rare earth doped optical fiber preform according to the VAD method of an exemplary embodiment of the present invention.
Fig. 4 is a schematic cross-sectional view showing the port positions of the middle layer torch and the outer layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth doped optical fiber preform according to the VAD method of the exemplary embodiment of the present invention.
Fig. 5 is a schematic cross-sectional view showing a port position of an inner burner of a VAD apparatus in an apparatus for manufacturing a rare earth doped optical fiber preform according to the VAD method of an exemplary embodiment of the present invention.
Fig. 6 is a schematic structural view showing a port position of a central feeding hole of an inner burner of a VAD apparatus in an apparatus for manufacturing a rare earth doped optical fiber preform according to a VAD method of an exemplary embodiment of the present invention.
Fig. 7 is a schematic view showing the configuration of the tail position of the central feeding hole of the inner burner of the VAD apparatus in the apparatus for manufacturing a rare earth element doped optical fiber preform according to the VAD method of the exemplary embodiment of the present invention.
Fig. 8 shows (a): a Yb chelate structure; (b) the method comprises the following steps An Al chelate structure; (c) ce chelate structure.
Description of reference numerals:
1-prefabricated rod powder, 2-doping device, 3-outer layer blast lamp, 4-middle layer blast lamp, 5-inner layer blast lamp, 6-high temperature transmission unit, 7-rare earth compound volatilization unit and codoped substance volatilization unit, 8-dehydration atmosphere furnace, 9-sintering furnace, 10-guide rod, 11-charging bucket, 12-heater, 13, 22-central feeding hole, 14, 24-core layer isolation air hole, 15, 25-core layer flame hydrogen hole, 16, 26-core layer flame oxygen hole, 17, 27-outer layer flame hydrogen hole, 18, 28-outer layer flame oxygen hole, 19, 29-outer layer isolation air hole, 20-tail position of blast lamp, 21-port position of blast lamp, 22-central feeding hole of inner layer blast lamp, 23-heating layer, 30-central feed hole a, 31-central feed hole B, 32-central feed hole C.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
Fig. 1 is a schematic view showing the overall structure of an apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method in an exemplary embodiment of the present invention.
As shown in fig. 1, the apparatus for preparing a rare earth doped optical fiber preform according to the VAD method includes a doping apparatus 2 and a VAD apparatus, wherein the doping apparatus is used for generating a rare earth compound gas phase and a co-dopant gas phase and transmitting the rare earth compound gas phase and the co-dopant gas phase to the VAD apparatus to complete deposition; the VAD device can adopt the prior device to carry out corresponding modification, thus realizing corresponding VAD deposition.
Fig. 2 is a schematic view showing a doping apparatus in an apparatus for manufacturing a rare earth element-doped optical fiber preform according to a VAD method according to an exemplary embodiment of the present invention.
As shown in fig. 2, according to the present invention, the doping apparatus 2 includes a rare earth compound volatilization unit and a co-dopant volatilization unit 7 and a high temperature transmission unit 6, and output pipelines of the rare earth compound volatilization unit and the co-dopant volatilization unit 7 are respectively connected with the VAD apparatus through the high temperature transmission unit 6.
The rare earth compound volatilization unit and the co-doping material volatilization unit 7 respectively comprise a charging bucket 11, a heater 12, a carrier gas input pipeline and an output pipeline, wherein the raw material of the rare earth compound contained in the charging bucket 11 of the rare earth compound volatilization unit is organic metal chelate of rare earth element ions with atomic numbers of 57-71, such as organic metal chelate of Nd, Er, Ge, Pr, Ho, Eu, Yb, Dy, Tm and the like; the co-doping material raw material contained in the material tank of the co-doping material volatilization unit is an organic metal chelate of Al, Ce, Na, K, Ti or Ba elements, and the carrier gas input by the carrier gas input pipeline is nitrogen or oxygen. The number of the rare earth compound volatilization units and the number of the co-doped volatilization units are at least one, and the operator can specifically adjust the rare earth compound volatilization units and the co-doped volatilization units according to the product to be prepared.
FIG. 8 shows several structures of metal chelates, respectively, (a): a Yb chelate structure; (b) the method comprises the following steps An Al chelate structure; (c) the Ce chelate structure may specifically employ a rare earth compound raw material or a co-dopant raw material shown in fig. 8.
The high-temperature transmission unit 6 of the invention is provided with a transmission cavity, a heating layer and a heat insulation layer from inside to outside, the output pipeline transmission cavities of the rare earth compound volatilization unit and the codoped volatilization unit are connected with the central feeding hole of the inner blast burner of the VAD device,
the VAD device of the present invention comprises an inner layer torch 5, a middle layer torch 4, an outer layer torch 3, and a control unit (not shown), outputs of a rare earth compound volatilization unit and a co-dopant volatilization unit 7The pipelines are respectively connected with the central feeding hole of the inner layer blast lamp 5 through the high temperature transmission unit 6, and the central feeding holes of the inner layer blast lamp 5, the middle layer blast lamp 4 and the outer layer blast lamp 3 are also connected with the output pipeline of the basic raw material supply unit. That is, the central feeding hole of the inner layer torch is connected with the output pipeline of the rare earth compound volatilization unit, the output pipeline of the co-doped volatilization unit and the output pipeline of the base raw material supply unit so as to supply the rare earth compound raw material, the co-doped raw material and the base raw material through the inner layer torch; and the central feeding holes of the middle layer blast lamp and the outer layer blast lamp are connected with the output pipeline of the basic raw material supply unit so as to supply the basic raw materials through the middle layer blast lamp and the outer layer blast lamp. Specifically, the base material supplied from the base material supply unit connected to the central supply holes of the inner layer torch, the middle layer torch and the outer layer torch in the present invention may include SiCl4、GeCl4、C2F6、POCl3And/or O2And the like.
The control unit controls the movement of the guide rod 10 in the VAD device and controls the inner layer blowtorch 5, the middle layer blowtorch 4 and the outer layer blowtorch 3 to complete the powder deposition of the upper core layer, the middle layer and the cladding layer of the guide rod or the core layer and the cladding layer and the dehydration and sintering in the moving process. As shown in fig. 1, the VAD apparatus further includes a dehydration atmosphere furnace 8 and a sintering furnace 9 disposed downstream of the outer burner 3, and the rod 10 completes dehydration and sintering through the dehydration atmosphere furnace 8 and the sintering furnace 9 in this order after completion of deposition. Wherein the dehydration process is to remove OH contained in the preform soot-Ion, dehydration process is carried out after the deposition of the core layer, the middle layer and the cladding layer is finished and before the sintering of the prefabricated rod powder; the sintering process is to sinter the preform powder 1 at high temperature to form a transparent optical fiber preform.
Fig. 3 is a schematic structural view showing the inner layer torch, the middle layer torch and the outer layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth element doped optical fiber preform according to the VAD method of the exemplary embodiment of the present invention, fig. 6 is a schematic structural view showing the port position of the central feeding hole of the inner layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth element doped optical fiber preform according to the VAD method of the exemplary embodiment of the present invention, and fig. 7 is a schematic structural view showing the tail position of the central feeding hole of the inner layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth element doped optical fiber preform according to the VAD method of the exemplary embodiment of the present invention.
As shown in fig. 3, 6 and 7, the end position 20 of the central feeding hole of the inner layer burner of the present invention comprises 3 holes and the port position 21 is provided with only 1 hole, and the raw materials from the rare earth compound volatilization unit, the co-dopant volatilization unit and the base raw material supply unit enter from the 3 holes at the end position of the central feeding hole of the inner layer burner 5 respectively, for example, through the central feeding hole a30, the central feeding hole B31 and the central feeding hole C32, and then are ejected through the 1 hole at the end position of the central feeding hole of the inner layer burner 5 to complete the mixing of all the raw materials.
Fig. 4 is a schematic cross-sectional view showing the port positions of the middle layer torch and the outer layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method, and fig. 5 is a schematic cross-sectional view showing the port positions of the inner layer torch of the VAD apparatus in the apparatus for manufacturing a rare earth element-doped optical fiber preform according to the VAD method.
As shown in fig. 4 and 5, the inner layer blowtorch 5 is sequentially provided with a central feeding hole 22, a heating layer 23, a core layer isolation air hole 24, a core layer flame hole, an outer layer flame hole and an outer layer isolation air hole 29 from inside to outside, wherein the heating layer of the inner layer blowtorch is used for heating and insulating the high-temperature doped raw material; the middle layer blowtorch 4 and the outer layer blowtorch 3 are sequentially provided with a central material supply hole 13, a core layer isolation air hole 14, a core layer flame hole, an outer layer flame hole and an outer layer isolation air hole 19 from inside to outside, and the basic raw materials conveyed by the middle layer blowtorch and the outer layer blowtorch do not need to be heated at too high temperature, so that a heating layer is not needed.
The core layer flame holes of the inner layer blowtorch 5, the middle layer blowtorch 4 and the outer layer blowtorch 3 comprise a core layer flame hydrogen hole and a core layer flame oxygen hole, and the outer layer flame hole comprises an outer layer flame hydrogen hole and an outer layer flame oxygen hole, if the inner layer blowtorch 5 comprises the core layer flame hydrogen holes 25, the core layer flame oxygen holes 26, the outer layer flame hydrogen holes 27 and the outer layer flame oxygen holes 28 which are alternately arranged, the middle layer blowtorch 4 and the outer layer blowtorch 3 comprise the core layer flame hydrogen holes 15, the core layer flame oxygen holes 16, the outer layer flame hydrogen holes 17 and the outer layer flame oxygen holes 18 which are alternately arranged, and the inner layer blowtorch 5, the middle layer blowtorch 4 and the outer layer blowtorch 3 all utilize the combustion of hydrogen and oxygen to provide a reaction heat source.
And (3) adopting a doping device to enable the rare earth compound raw material and the co-dopant raw material to generate gas phase and transmit the gas phase to an inner layer blast lamp of a VAD device to finish the deposition of the rare earth element doped fiber core powder. Meanwhile, the middle layer raw material is transmitted to a middle layer blast lamp through a basic raw material supply unit of the VAD device, the middle layer blast lamp is used for depositing middle layer powder, the cladding raw material is also transmitted to an outer layer blast lamp through a basic raw material supply unit of the VAD device, and the cladding powder is deposited through the outer layer blast lamp. And after the deposited preform rod powder is dehydrated, sintering the preform rod powder to form a transparent optical fiber preform rod in an upward moving process under the high-temperature action of a sintering furnace. Wherein, only the core layer and the cladding layer can be deposited, and the core layer, the middle layer and the outer layer can also be deposited, and are specifically selected according to the product requirements.
The invention also provides a method for preparing the rare earth element doped optical fiber preform by the VAD method, and the device for preparing the rare earth element doped optical fiber preform by the VAD method is used for preparing the rare earth element doped optical fiber preform.
Preferably, the method of the invention comprises the steps of:
the first step is as follows: preparing a basic raw material supply unit, a doping device and a VAD device and enabling the basic raw material supply unit, the doping device and the VAD device to be in a state to be operated;
the second step is that: respectively adding a rare earth compound raw material and a co-dopant raw material to be doped into the charging buckets of the rare earth compound volatilization unit and the co-dopant volatilization unit, and heating the rare earth compound volatilization unit, the co-dopant volatilization unit and the high-temperature transmission unit after gas purging is completed;
the third step: the rare earth element doped fiber core powder deposition of the core layer is completed on the guide rod through the inner layer blast burner, the powder deposition of the middle layer is completed through the middle layer blast burner, and the powder deposition of the cladding layer is completed through the outer layer blast burner or the powder deposition of the cladding layer is completed through the outer layer blast burner directly;
the fourth step: and dehydrating the deposited preform powder, and sintering the preform powder in an upward moving process to form a transparent rare earth element doped optical fiber preform.
The present invention will be described in more detail hereinafter with the aid of examples and schematic drawings, which are given by way of illustration only, the drawings being intended to illustrate details of the design and the concept of the invention and not to limit the scope of protection of the invention to these embodiments.
Example 1: yb doped preform
Firstly preparing a VAD device to be in a state to be operated, then preparing 200 g of rare earth Yb chelate (tris (2,2,6, 6-tetramethyl-3, 5-heptanedionate) ytterbium) and 400 g of codoped Al chelate (2, 6-aluminum acetylacetonate) required by a preform, respectively adding the raw materials of the rare earth Yb chelate and the codoped Al chelate into two material tanks 11 in a rare earth compound volatilization unit and a codoped volatilization unit 7 of a doping device 2, then exhausting air in the material tanks by using He, after gas purging is completed, heating a Yb chelate material tank to 240 ℃, heating an Al chelate material tank to 240 ℃, heating a high-temperature transmission unit to 280 ℃, and after the temperature is controlled and stabilized for 2 hours, enabling the doping device to be in a state to be operated.
Fiber core powder deposition: using O2Taking chelate steam of the rare earth Yb and the Al as carrier gas, respectively carrying out the chelate steam from a charging bucket 11 of the doping device 2, entering a central material spraying hole 22 of the inner layer blast burner 5 through the high-temperature transmission unit 6 and spraying out, and simultaneously using O2Taking SiCl as a base material as a carrier gas4、POCl3The rare earth chelate steam, the co-dopant steam and the base material steam are subjected to gas phase reaction under the action of oxyhydrogen flame sprayed from the core layer flame holes and the outer layer flame holes of the inner layer blowtorch 5 and are deposited to form fiber core powder. It reacts as follows:
SiCl4+2H2O→SiO2+4HCl
2POCl3+3H2O→P2O5+6HCl
2C33H57O6Yb+90O2→Yb2O3+66CO2+57H2O
2C15H21O6Al+36O2→Al2O3+30CO2+21H2O
and (3) deposition of cladding powder: mixing the base material SiCl4、C2F6、POCl3The steam is transmitted into the central feeding hole 13 of the outer layer blowtorch 3 to be sprayed out, the basic material steam is reacted with the gas phase under the action of the oxyhydrogen flame sprayed out from the core layer flame hole and the outer layer flame hole of the outer layer blowtorch 3 together, and the cladding powder is formed by deposition. It reacts as follows:
SiCl4+2H2O→SiO2+4HCl
2POCl3+3H2O→P2O5+6HCl
3SiCl4+2C2F6+O2+6H2O→3SiF4+4CO2+12HCl
finally, the Yb doped prefabricated rod is prepared.
Example 2: preparation of Yb doped fiber core GeSi step type doping prefabricated rod
After the VAD device is prepared to be in a state to be operated, 200 g of rare earth Yb chelate (tris (2,2,6, 6-tetramethyl-3, 5-heptanedionate) ytterbium) required by the preparation of a preform rod, 400 g of co-doped Al chelate (2, 6-aluminum acetylacetonate) and 200 g of co-doped Ce chelate (cerium acetylacetonate) are prepared, the raw materials of the rare earth Yb chelate, the co-doped Al chelate and the co-doped cerium chelate are respectively added into three material tanks 11 of a doping device 2, and exhausting the air in the material tank by using the carrier gas He, heating the Yb chelate material tank to 240 ℃ after gas purging is completed, heating the Al chelate material tank to 240 ℃, heating the Ce chelate material tank to 280 ℃, heating the high-temperature transmission device of the high-temperature transmission unit 6 to 300 ℃, and keeping the doping device in a state to be operated after the temperature is controlled to be stable for 2 hours.
Fiber core powder deposition: using O2Taking chelate steam of Yb, Al and Ce as carrier gas to be respectively carried out from a charging bucket 11 of the doping device 2 and enter an inner layer blast burner 5 through a high-temperature transmission unit 6The core material spraying hole 22 is used for spraying O2Taking SiCl as a base material as a carrier gas4、POCl3The rare earth compound steam, the co-doped steam and the base material steam are transmitted into the central feeding hole 22 of the inner layer blowtorch 5 to be sprayed out, and the rare earth compound steam, the co-doped steam and the base material steam are subjected to gas phase reaction and are deposited to form the fiber core powder under the action of oxyhydrogen flames sprayed out of the core layer flame holes and the outer layer flame holes of the inner layer blowtorch 5. It reacts as follows:
SiCl4+2H2O→SiO2+4HCl
2POCl3+3H2O→P2O5+6HCl
2C33H57O6Yb+90O2→Yb2O3+66CO2+57H2O
2C15H21O6Al+36O2→Al2O3+30CO2+21H2O
2C15H21O6Ce+36O2→Ce2O3+30CO2+21H2O
deposition of the interlayer of the step layer: the vapor of the basic raw materials SiCl4 and GeCl4 are transmitted into the central feeding hole 13 of the middle layer blast burner 4 to be sprayed out, the vapor of the basic raw materials jointly generate gas phase reaction under the action of oxyhydrogen flame sprayed out from the core layer flame holes and the outer layer flame holes of the middle layer blast burner 4, and the cladding powder is formed through deposition. It reacts as follows:
SiCl4+2H2O→SiO2+4HCl
GeCl4+2H2O→GeO2+4HCl
and (3) deposition of cladding powder: mixing the basic raw materials SiCl4 and C2F6、POCl3The steam is transmitted into the central feeding hole 13 of the outer layer blowtorch 3 to be sprayed out, and the basic raw material steam jointly generates gas phase reaction and deposits to form cladding powder under the action of oxyhydrogen flame sprayed out from the core layer flame holes and the outer layer flame holes of the outer layer blowtorch 3. It reacts as follows:
SiCl4+2H2O→SiO2+4HCl
2POCl3+3H2O→P2O5+6HCl
3SiCl4+2C2F6+O2+6H2O→3SiF4+4CO2+12HCl
finally, the Yb doped fiber core GeSi step type doped prefabricated rod is prepared.
In conclusion, the invention provides the doping device for effectively preparing the rare earth optical fiber preform, the method can realize that the rare earth ions directly enter the fiber core area of the preform by gas phase doping, and simultaneously, the VAD method can be used for preparing the fiber core and the cladding of the large-size preform, thereby effectively meeting the problem of the proportion of the large core cladding of the doped preform.
The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims (10)

1. A device for preparing rare earth element doped optical fiber preform by VAD method is characterized by comprising a doping device and a VAD device, wherein,
the doping device comprises a rare earth compound volatilization unit, a co-doping object volatilization unit and a high-temperature transmission unit, wherein output pipelines of the rare earth compound volatilization unit and the co-doping object volatilization unit respectively pass through the high-temperature transmission unit to be connected with the VAD device;
the VAD device comprises an inner layer blast burner, a middle layer blast burner, an outer layer blast burner and a control unit, wherein output pipelines of the rare earth compound volatilization unit and the co-doped volatilization unit are respectively connected with a central feeding hole of the inner layer blast burner through a high-temperature transmission unit, and the central feeding holes of the inner layer blast burner, the middle layer blast burner and the outer layer blast burner are also connected with an output pipeline of a basic raw material feeding unit of the VAD device; the control unit controls the movement of the guide rod in the VAD device and controls the inner layer blowtorch, the middle layer blowtorch and the outer layer blowtorch to finish the powder deposition of the upper core layer, the middle layer and the cladding layer of the guide rod or the core layer and the cladding layer and the dehydration and sintering in the moving process.
2. The VAD-method-based device for preparing the rare earth element-doped optical fiber preform according to claim 1, wherein the rare earth compound volatilization unit and the co-dopant volatilization unit respectively comprise a charging bucket, a heater, a carrier gas input pipeline and an output pipeline, wherein the rare earth compound raw material contained in the charging bucket of the rare earth compound volatilization unit is an organic metal chelate of rare earth element ions with atomic numbers of 57-71, the co-dopant raw material contained in the charging bucket of the co-dopant volatilization unit is an organic metal chelate of Al, Ce or Ba, and the carrier gas input by the carrier gas input pipeline is nitrogen or oxygen.
3. The VAD method for producing a rare earth element-doped optical fiber preform according to claim 1, wherein the base material supplied from the base material supply unit connected to the central supply holes of the inner layer torch, the middle layer torch and the outer layer torch comprises SiCl4、GeCl4、C2F6、POCl3And/or O2。
4. The apparatus for preparing a rare earth element-doped optical fiber preform according to the VAD of claim 1, wherein the end position of the central feeding hole of the inner burner comprises 3 holes and only 1 hole is provided at the end position, and the raw materials from the rare earth compound volatilization unit, the co-dopant volatilization unit and the base raw material supply unit respectively enter from the 3 holes at the end position of the central feeding hole of the inner burner, are converged and then are ejected through the 1 hole at the end position of the central feeding hole of the inner burner, and complete the mixing of all the raw materials.
5. The apparatus for VAD fabrication of a rare earth doped optical fiber preform according to claim 1, wherein the inner burner is sequentially provided with a central feeding hole, a heating layer, a core isolation air hole, a core layer flame hole, an outer flame hole, and an outer isolation air hole from inside to outside, and the middle burner and the outer burner are sequentially provided with a central feeding hole, a core isolation air hole, a core layer flame hole, an outer flame hole, and an outer isolation air hole from inside to outside.
6. The apparatus for fabricating a rare earth doped optical fiber preform according to the VAD method of claim 5, wherein the core flame holes comprise core flame hydrogen holes and core flame oxygen holes, and the outer flame holes comprise outer flame hydrogen holes and outer flame oxygen holes.
7. The apparatus for preparing the rare earth element doped optical fiber preform according to the VAD method of claim 1, wherein the high temperature transmission unit is provided with a transmission cavity, a heating layer and a thermal insulation layer from inside to outside, output pipelines of the rare earth compound volatilization unit and the co-doped volatilization unit penetrate through the transmission cavity to be connected with a central feeding hole of an inner layer blowtorch of the VAD apparatus, and the number of the rare earth compound volatilization unit and the co-doped volatilization unit is at least one.
8. The apparatus for fabricating a rare earth doped optical fiber preform according to the VAD method of claim 1, wherein the VAD apparatus further comprises a dehydration atmosphere furnace and a sintering furnace disposed downstream of the outer layer torch, and the rod is sequentially dehydrated and sintered through the dehydration atmosphere furnace and the sintering furnace after the deposition of the core layer, the intermediate layer and the clad layer or the soot of the core layer and the clad layer is completed.
9. A method for preparing a rare earth element doped optical fiber preform by VAD, characterized in that the preparation of the rare earth element doped optical fiber preform is carried out by using the apparatus for preparing the rare earth element doped optical fiber preform by VAD according to any one of claims 1 to 8.
10. The VAD method of claim 9, wherein the method comprises the steps of:
the first step is as follows: preparing a basic raw material supply unit, a doping device and a VAD device and enabling the basic raw material supply unit, the doping device and the VAD device to be in a state to be operated;
the second step is that: respectively adding a rare earth compound raw material and a co-dopant raw material to be doped into the charging buckets of the rare earth compound volatilization unit and the co-dopant volatilization unit, and heating the rare earth compound volatilization unit, the co-dopant volatilization unit and the high-temperature transmission unit after gas purging is completed;
the third step: the rare earth element doped fiber core powder deposition of the core layer is completed on the guide rod through the inner layer blast burner, the powder deposition of the middle layer is completed through the middle layer blast burner, and the powder deposition of the cladding layer is completed through the outer layer blast burner or the powder deposition of the cladding layer is completed through the outer layer blast burner directly;
the fourth step: and dehydrating the deposited preform powder, and sintering the preform powder in an upward moving process to form a transparent rare earth element doped optical fiber preform.
CN202010030359.9A 2020-01-13 2020-01-13 Device and method for preparing rare earth element doped optical fiber preform by VAD (vapor deposition) method Pending CN111116037A (en)

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JPS63134531A (en) * 1986-11-21 1988-06-07 Furukawa Electric Co Ltd:The Device for synthesizing glass fine particle
JPH02275724A (en) * 1989-04-17 1990-11-09 Nippon Telegr & Teleph Corp <Ntt> Production of optical fiber matrix
CN1623941A (en) * 2003-09-29 2005-06-08 利基有限公司 System for forming a gas flow of reactants for a doped glass material
CN103359927A (en) * 2013-07-22 2013-10-23 中国科学院西安光学精密机械研究所 Optical fiber perform doper and doping method
KR20140006712A (en) * 2012-07-05 2014-01-16 한국전자통신연구원 Method for doping rare earth in vapor axial deposition process
CN106396362A (en) * 2016-08-29 2017-02-15 长飞光纤光缆股份有限公司 Production method of prefabricated fiber rod
CN110395900A (en) * 2019-08-02 2019-11-01 长飞光纤光缆股份有限公司 A kind of outer method of pipe prepares the precipitation equipment and method of low transmission loss optical fiber prefabricated rods

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63134531A (en) * 1986-11-21 1988-06-07 Furukawa Electric Co Ltd:The Device for synthesizing glass fine particle
JPH02275724A (en) * 1989-04-17 1990-11-09 Nippon Telegr & Teleph Corp <Ntt> Production of optical fiber matrix
CN1623941A (en) * 2003-09-29 2005-06-08 利基有限公司 System for forming a gas flow of reactants for a doped glass material
KR20140006712A (en) * 2012-07-05 2014-01-16 한국전자통신연구원 Method for doping rare earth in vapor axial deposition process
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CN106396362A (en) * 2016-08-29 2017-02-15 长飞光纤光缆股份有限公司 Production method of prefabricated fiber rod
CN110395900A (en) * 2019-08-02 2019-11-01 长飞光纤光缆股份有限公司 A kind of outer method of pipe prepares the precipitation equipment and method of low transmission loss optical fiber prefabricated rods

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