CN115180817B - Online doping method and device for preparing active optical fiber preform - Google Patents
Online doping method and device for preparing active optical fiber preform Download PDFInfo
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- CN115180817B CN115180817B CN202211008522.7A CN202211008522A CN115180817B CN 115180817 B CN115180817 B CN 115180817B CN 202211008522 A CN202211008522 A CN 202211008522A CN 115180817 B CN115180817 B CN 115180817B
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 96
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 62
- 239000010453 quartz Substances 0.000 claims abstract description 60
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- 238000010438 heat treatment Methods 0.000 claims description 26
- 239000012159 carrier gas Substances 0.000 claims description 22
- 239000007787 solid Substances 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 20
- 238000005245 sintering Methods 0.000 claims description 16
- RLOWWWKZYUNIDI-UHFFFAOYSA-N phosphinic chloride Chemical compound ClP=O RLOWWWKZYUNIDI-UHFFFAOYSA-N 0.000 claims description 15
- 229910003902 SiCl 4 Inorganic materials 0.000 claims description 14
- 238000005137 deposition process Methods 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 11
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 10
- 238000007524 flame polishing Methods 0.000 claims description 10
- 239000011521 glass Substances 0.000 claims description 10
- 239000001301 oxygen Substances 0.000 claims description 10
- 239000000428 dust Substances 0.000 claims description 9
- 238000005530 etching Methods 0.000 claims description 9
- 239000002994 raw material Substances 0.000 claims description 9
- 238000003466 welding Methods 0.000 claims description 5
- 230000003647 oxidation Effects 0.000 claims 1
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- 238000000151 deposition Methods 0.000 abstract description 128
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- 238000004519 manufacturing process Methods 0.000 abstract description 9
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- 238000007789 sealing Methods 0.000 description 38
- 239000002585 base Substances 0.000 description 36
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 31
- 229910052761 rare earth metal Inorganic materials 0.000 description 20
- 150000002910 rare earth metals Chemical class 0.000 description 18
- 229910052757 nitrogen Inorganic materials 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 13
- 238000005229 chemical vapour deposition Methods 0.000 description 8
- 239000000306 component Substances 0.000 description 8
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- 230000001590 oxidative effect Effects 0.000 description 8
- 239000011162 core material Substances 0.000 description 7
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 239000000460 chlorine Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- -1 rare earth ion Chemical class 0.000 description 5
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- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000013522 chelant Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
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- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- XHXFXVLFKHQFAL-UHFFFAOYSA-N phosphoryl trichloride Chemical compound ClP(Cl)(Cl)=O XHXFXVLFKHQFAL-UHFFFAOYSA-N 0.000 description 2
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- 238000003756 stirring Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- IEXRMSFAVATTJX-UHFFFAOYSA-N tetrachlorogermane Chemical compound Cl[Ge](Cl)(Cl)Cl IEXRMSFAVATTJX-UHFFFAOYSA-N 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910052691 Erbium Inorganic materials 0.000 description 1
- YKIKHUWCDJLQGB-UHFFFAOYSA-N [Er].[La] Chemical compound [Er].[La] YKIKHUWCDJLQGB-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- CUJRVFIICFDLGR-UHFFFAOYSA-N acetylacetonate Chemical compound CC(=O)[CH-]C(C)=O CUJRVFIICFDLGR-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
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- 238000005260 corrosion Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- HDGGAKOVUDZYES-UHFFFAOYSA-K erbium(iii) chloride Chemical compound Cl[Er](Cl)Cl HDGGAKOVUDZYES-UHFFFAOYSA-K 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229940119177 germanium dioxide Drugs 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000012994 industrial processing Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- ICAKDTKJOYSXGC-UHFFFAOYSA-K lanthanum(iii) chloride Chemical compound Cl[La](Cl)Cl ICAKDTKJOYSXGC-UHFFFAOYSA-K 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 239000000843 powder Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
- 238000005491 wire drawing Methods 0.000 description 1
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
-
- 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
- C03B37/01853—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geochemistry & Mineralogy (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
The invention discloses an online solution doping method and device for preparing an active optical fiber preform, wherein the online solution doping method comprises a preparation tube, an MCVD lathe and a liquid storage device; the preparation pipe is fixedly connected to the MCVD lathe; the liquid storage device is connected with the preparation pipe; the preparation pipe comprises an air inlet pipe, a deposition pipe and a tail gas pipe; the online solution doping method and device for preparing the active optical fiber preform disclosed by the invention have the advantages that the problems of bubbles, uneven local components, multiple impurities and the like in the preform caused by the fact that undeposited particles are easily introduced by inserting a solution conduit from a quartz tail gas end are avoided, the operation is convenient, the practicability is good, the success rate of preparing the preform is high, the cost is saved, the production effect is improved, the quality and the yield of the active optical fiber preform are improved, the condition is mild, and the industrialized wide popularization and application are facilitated.
Description
Technical Field
The invention relates to the field of manufacturing of optical fiber preforms, in particular to an on-line doping method and device for preparing an active optical fiber preform.
Background
The rare earth doped active optical fiber can be used as the gain optical fiber of the oscillation level and the amplification level in the optical fiber laser system, and with the deep application fields of the high-power optical fiber laser system such as industrial processing, national defense and military, scientific research and the like, the performance requirements (such as high absorption, high gain, low numerical aperture and the like) of the rare earth doped active optical fiber are more and more strict. The performance of the rare earth doped active optical fiber can be fundamentally improved by improving and optimizing the preparation process of the active optical fiber. While developing rare earth doped active optical fiber preform is a prerequisite for drawing high quality rare earth doped optical fiber, the mainstream techniques developed for this purpose are vapor deposition, sol-gel, nanoparticle direct deposition (DND). Among them, the most widely used is the modified chemical vapor deposition method, abbreviated as MCVD.
In the prior art, the publication patent CN109293249A discloses that an improved chemical vapor deposition (MCVD) combined with a rare earth ion vapor phase doping method is adopted to enable all materials to be deposited under vapor phase conditions, chemical reaction is carried out in a reaction zone to generate oxide particles, the purpose of doping rare earth and co-doped oxide in a matrix is achieved, then the large-core optical fiber preform is obtained through sintering and shrinking processes, and in the preparation method of the prior art, the gaseous rare earth chelate can be decomposed in advance due to overhigh pipeline temperature or can be condensed and blocked due to overhigh pipeline temperature in pipeline transportation; the rare earth chelate contains C, H element in chemical structure, H generated by reaction 2 O can corrode a metal air inlet pipe at high temperature, and metal impurities or a large number of-OH groups are introduced to cause excessive optical fiber loss.
The prior solution doping method is to soak the loose layer in the solution, and the doping substance achieves the purpose of doping through the permeation and adsorption effects. The solution doping method is divided into an off-line solution doping method and an on-line solution doping method. The prior art discloses a patent CN102086089A, a method for manufacturing a rare earth doped optical fiber preform, a prior art discloses a patent CN104556674A, a preparation method for a rare earth ion co-doped optical fiber preform, a prior art discloses a patent CN106698920A, an ion solution doping method for preparing an active optical fiber, a prior art discloses a patent CN102515501A, an off-line solution doping method for realizing a solution doping method in rare earth doping based on an MCVD technology is disclosed in the method for manufacturing the doped optical fiber preform by adopting the MCVD technology, a deposition tube is required to be taken down from a deposition lathe by the off-line solution doping method, and the deposition tube is welded on the lathe again after the deposition tube is soaked; the off-line solution doping method is extremely prone to introduce contamination during operation, and the preparation process is complex and time-consuming.
In the prior art, the patent CN102815866a discloses an on-line solution doping method for realizing a solution doping method in rare earth doping based on an MCVD process in a doping device of an optical fiber preform, the existing disclosed on-line solution doping method does not need to take down a deposition tube, and solution doping can be completed only by introducing a feeding tube into a tail gas tube, but the solution feeding mode may bring oxide particles which are not deposited in the tail gas system into a loose layer, thereby causing adverse results such as uneven local components, bubbles, particle impurities and the like in a core region of the preform, and finally affecting the performance of the preform.
Accordingly, those skilled in the art have been directed to developing an on-line solution doping method and apparatus for preparing an active optical fiber preform to solve the above-mentioned disadvantages of the related art.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, the present invention aims to solve the technical problems that the solution doping method and the off-line solution doping method in the active optical fiber preform disclosed in the prior art can cause adverse results such as uneven local components, bubbles, particulate impurities and the like in the core region of the preform, and meanwhile, pollution is very easy to be introduced in the operation process, and the off-line solution doping has the technical bottleneck problems of complex preparation process and time consumption.
In order to achieve the above object, a first aspect of the present invention provides an on-line doping apparatus for preparing an active optical fiber preform, including a preparation tube, an MCVD lathe, and a liquid storage device; the preparation pipe is fixedly connected to the MCVD lathe; the liquid storage device is connected with the air inlet end of the preparation pipe, so that doping solution enters the preparation pipe from the air inlet end for doping;
further, the MCVD lathe comprises a lathe base, a pitching device, a metal air inlet pipe, a metal hose, a VCR joint and a supporting rod; the pitching device is fixedly connected to the left end and the right end below the lathe base and is used for tilting the lathe; the support rods comprise two support rods which are respectively and fixedly connected with the left end and the right end above the lathe base; the top end of the left supporting rod is fixedly connected with the side wall of the metal air inlet pipe; the metal hose is connected to the metal air inlet pipe through a VCR connector;
further, the preparation pipe comprises an air inlet pipe, a deposition pipe and a tail gas pipe; the right part of the air inlet pipe is fixedly connected with a deposition pipe; the right part of the deposition tube is fixedly connected with a tail gas tube; the right end of the tail gas pipe is connected with a right end supporting rod;
further, the air inlet pipe is an air inlet pipe with a T-shaped opening on the surface or an air inlet pipe without a T-shaped opening on the surface;
Further, the air inlet pipe with the T-shaped opening comprises a sealing plug;
further, the number of T-shaped holes of the air inlet pipe is 1-4;
further, the liquid storage device comprises a solution storage tank, a solution conduit, a high-purity nitrogen pipeline, a solution conduit valve, a nitrogen pipeline valve and a conduit ring; the solution storage tank air inlet is connected with a high-purity nitrogen pipeline; the high-purity nitrogen pipeline comprises a nitrogen pipeline valve; the nitrogen pipeline valve is used for controlling the switch of the gas circuit; the liquid supply end in the solution storage tank is connected with one end of the solution conduit; the other end of the solution conduit is connected with an air inlet pipe; the solution conduit comprises a solution conduit valve and a flowmeter; the solution conduit valve is used for controlling the switch of the liquid path; the flowmeter is used for monitoring and controlling the flow rate of the liquid in real time; the guide ring is positioned at the corner of the solution conduit and is used for uniformly winding the solution conduit in the rotation process of the preparation pipe;
further, a rare earth-containing solution or a co-doped element-containing solution is placed in the solution storage tank;
further, the fixed connection is welding, bonding and integrated forming;
in a specific embodiment of the present invention, the metal air inlet pipe is SiCl 4 、POCl 3 、GeCl 4 An air inlet pipe;
In the specific embodiment of the invention, the air inlet pipe, the deposition pipe and the tail gas pipe are quartz pipes;
in the specific embodiment of the invention, the number of T-shaped openings of the air inlet pipe with the T-shaped openings on the surface is 1;
in the specific embodiment of the invention, the air inlet pipe is an air inlet pipe with a T-shaped opening on the surface;
in another specific embodiment of the invention, the air inlet pipe is an air inlet pipe with no T-shaped opening on the surface;
in a specific embodiment of the invention, the air inlet pipe is a straight air inlet pipe;
in another specific embodiment of the present invention, the air inlet pipe is a straight air inlet pipe with a spherical bulge;
in the specific embodiment of the invention, the solution conduit is a hose, and one end of the solution conduit penetrates through the center of the sealing plug and is connected with the T-shaped opening end of the air inlet pipe; the other end is connected with a liquid supply end in the solution storage tank;
in another specific embodiment of the invention, the solution conduit is a hose, one end of the solution conduit is connected with a liquid supply end in the solution storage tank, and the other end of the solution conduit directly penetrates into the air inlet pipe from the air inlet of the air inlet pipe;
in the specific embodiment of the invention, a rare earth-containing solution is placed in the solution storage tank;
in another specific embodiment of the invention, the solution containing co-doping element is placed in the solution storage tank;
In a specific embodiment of the present invention, the fixed connection is a weld.
The second aspect of the invention provides an on-line doping preparation method of an active optical fiber preform, comprising the steps of introducing components to be doped from an air inlet pipe end of a preparation pipe, and carrying out on-line doping in the preparation process of the active optical fiber preform to obtain a doped active optical fiber preform;
further, the components to be doped adopt gas phase doping and online solution doping;
further, the on-line doping preparation method of the active optical fiber preform comprises single doping and mixed doping;
further, the single doping is that when the active optical fiber preform is prepared by chemical vapor deposition, the chemical vapor deposition is followed by one-time on-line solution doping;
further, the mixing is that when the active optical fiber preform is prepared by chemical vapor deposition, chemical vapor deposition layers and on-line solution doping layers are alternately performed;
in the specific embodiment of the invention, the on-line doping preparation method of the active optical fiber preform adopts a chemical vapor deposition method to carry out single doping on-line solution doping to prepare the doped active optical fiber preform, and the specific steps are as follows:
Step 1-1, fixing pitching devices at the left end and the right end below a lathe base, and adjusting the pitching devices of the MCVD lathe to enable the MCVD lathe base to be in a horizontal state; fixedly connecting an air inlet pipe, a deposition pipe and a tail gas pipe to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe extends into the pipe orifice of the air inlet pipe, and the other end of the metal air inlet pipe is connected with a metal hose through a VCR joint; the air inlet pipe comprises a T-shaped opening; the T-shaped opening is sealed by using a solid sealing plug;
step 1-2, performing high-temperature flame polishing on the deposition tube and introducing SF 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the deposition tube by oxidizing and etching;
step 1-3, adding a solution to be doped which is prepared in advance into a solution storage tank; connecting an air inlet of a solution storage tank with a high-purity nitrogen pipeline; connecting a liquid supply end in the solution storage tank with one end of the solution conduit; the other end of the solution conduit is not connected;
step 1-4, introducing continuous oxygen from a metal air inlet pipe as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, carrier gas flow, loose layer deposition temperature and flame moving speed during loose layer deposition are set, and deposition operation is carried out to obtain a plurality of deposition layers; in the deposition process, the flame moving range does not cover the position of the sealing plug so as to avoid damaging the air tightness of the system in the heating process;
Step 1-5, stopping flame heating after the deposition is finished, adjusting a pitching device of the MCVD lathe to incline a MCVD lathe base, and inclining a preparation tube so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit valve and a flowmeter of the solution conduit, replacing a sealing plug with a T-shaped opening with a sealing plug with an opening, connecting the other end of the solution conduit with the T-shaped opening, leading in solution to be doped from an air inlet pipe, setting a rotation mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to rotate for a certain time in a certain direction, then rotating for the same time in the opposite direction repeatedly, matching with a guide ring to prevent the solution conduit from being entangled, and doping deposited prefabricated bars with online solution in a single doping mode;
step 1-6, after doping is finished, removing the solution conduit, connecting the T-shaped opening by adopting a solid sealing plug, and adjusting a lathe pitching device to enable the MCVD lathe base to recover to a horizontal state;
step 1-7, adopting high temperature and Cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
further, in the step 1-1, the air inlet pipe, the deposition pipe and the tail gas pipe are quartz pipes;
Further, in the step 1-1, the air inlet pipe is an air inlet pipe with a T-shaped opening on one end surface; the T-shaped opening comprises a sealing plug;
further, in the step 1-2, the polishing high temperature is 1950 ℃ or higher;
further, in the step 1-3, the solution to be doped is a solution containing rare earth or a solution containing co-doping elements;
further, in the steps 1 to 4, the metal air inlet pipe is SiCl 4 、POCl 3 、GeCl 4 An air inlet pipe;
further, in the step 1-4, the set carrier gas flow is 100-2000 ml/s, the loose layer deposition temperature is 1300-1600 ℃, and the flame moving speed is 100-150 mm/min during loose layer deposition;
further, in the step 1-5, the inclination angle of the preparation pipe is 15-45 degrees;
further, in the step 1-7, the sintering high temperature is 1800-2100 ℃;
in the specific embodiment of the present invention, in the step 1-1, the air inlet pipe is a straight air inlet pipe;
in another specific embodiment of the present invention, in the step 1-1, the air inlet pipe is a straight air inlet pipe with a spherical bulge;
in a specific embodiment of the present invention, in the step 1-2, the polishing high temperature is 2000 ℃;
In the specific embodiment of the invention, in the step 1-3, the solution to be doped is a solution containing rare earth;
in another specific embodiment of the present invention, in the step 1-3, the solution to be doped is a solution containing co-doping elements;
in the specific embodiment of the invention, in the step 1-3, the solution conduit is a hose, and one end of the solution conduit penetrates through the center of the sealing plug and is connected with the T-shaped opening end of the air inlet pipe; the other end is connected with a liquid supply end in the solution storage tank;
in another specific embodiment of the present invention, in the step 1-3, the solution conduit is a hose, one end of the solution conduit is connected to the liquid supply end in the solution storage tank, and the other end of the solution conduit directly penetrates into the air inlet pipe from the air inlet of the air inlet pipe;
in the specific embodiment of the invention, in the steps 1-4, the carrier gas flow rate is 1450ml/s, the loose layer deposition temperature is 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition;
in the specific embodiment of the invention, in the steps 1-5, the preparation tube is firstly rotated leftwards for 1min, then rotated rightwards for 1min, and repeated for a plurality of times;
in another specific embodiment of the present invention, in the steps 1 to 5, the continuous rotation of the preparation tube is first rotated rightward for 1min, and then rotated leftward for 1min;
In a specific embodiment of the present invention, in the steps 1 to 5, the inclination angle is 25 °;
in a specific embodiment of the present invention, in the steps 1 to 7, the sintering temperature is 1850 ℃;
in a specific embodiment of the present invention, the step 1-1 specifically operates as follows:
fixing pitching devices at the left end and the right end below the lathe base, and adjusting the pitching devices of the MCVD lathe to enable the MCVD lathe base to be in a horizontal state; fixedly connecting a quartz air inlet pipe, a quartz deposition pipe and a quartz tail gas pipe to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe extends into the pipe orifice of the quartz air inlet pipe, and the other end of the metal air inlet pipe is connected with a metal hose through a VCR joint; the quartz air inlet pipe comprises a T-shaped opening; the T-shaped opening is sealed by using a solid sealing plug;
in a specific embodiment of the present invention, the step 1-2 specifically operates as follows:
high-temperature flame polishing at 2000 ℃ and SF feeding into a quartz deposition tube 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube by oxidizing etching;
in a specific embodiment of the present invention, the steps 1-3 specifically operate as:
adding the solution containing the co-doping element prepared in advance into a solution storage tank; connecting an air inlet of a solution storage tank with a high-purity nitrogen pipeline; connecting a liquid supply end in the solution storage tank with one end of the solution conduit; the other end of the solution conduit is not connected;
In a specific embodiment of the present invention, the steps 1-4 specifically operate as:
introducing continuous oxygen from a metal air inlet pipe as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing deposition operation to obtain a plurality of deposition layers; in the deposition process, the flame moving range does not cover the position of the sealing plug so as to avoid damaging the air tightness of the system in the heating process;
in a specific embodiment of the present invention, the steps 1-5 specifically operate as:
stopping flame heating after the deposition is finished, and adjusting a pitching device of the MCVD lathe to incline a MCVD lathe base, wherein the inclination angle of the preparation tube is 25 degrees, so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit valve and a flowmeter of the solution conduit, replacing a sealing plug with a T-shaped opening with a sealing plug with an opening, connecting the other end of the solution conduit with the T-shaped opening, leading in solution to be doped from an air inlet pipe, setting a rotation mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to be firstly rotated rightwards for 1min, then rotated leftwards for 1min, repeating for a plurality of times, matching with a guide ring to prevent the solution conduit from being entangled, and carrying out online solution doping by using a single doping mode on the deposited preform;
In a specific embodiment of the present invention, the steps 1-6 specifically operate as:
after doping is finished, removing the solution conduit, connecting the T-shaped opening by adopting a solid sealing plug, and adjusting a lathe pitching device to enable the MCVD lathe base to recover to a horizontal state;
in a specific embodiment of the present invention, the steps 1-7 specifically operate as:
high temperature 1850 ℃ and Cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
in the specific embodiment of the invention, the on-line doping preparation method of the active optical fiber preform adopts a chemical vapor deposition method to carry out on-line solution doping of mixed doping to prepare the doped active optical fiber preform, and the specific steps are as follows:
step 2-1, fixing pitching devices at the left end and the right end below a lathe base, and adjusting the pitching devices of the MCVD lathe to enable the MCVD lathe base to be in a horizontal state; fixedly connecting an air inlet pipe, a deposition pipe and a tail gas pipe to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe extends into the pipe orifice of the air inlet pipe, and the other end of the metal air inlet pipe is connected with a metal hose through a VCR joint; the air inlet pipe comprises a T-shaped opening; the T-shaped opening is sealed by using a sealing plug;
Step 2-2, performing high-temperature flame polishing on the deposition tube andSF is introduced 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the deposition tube by oxidizing and etching;
step 2-3, adding the solution to be doped prepared in advance into a solution storage tank; connecting an air inlet of a solution storage tank with a high-purity nitrogen pipeline; connecting a liquid supply end in the solution storage tank with one end of the solution conduit; the other end of the solution conduit is not connected;
step 2-4, introducing continuous oxygen from a metal air inlet pipe as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, and the carrier gas flow, the loose layer deposition temperature and the flame moving speed during loose layer deposition are set to carry out deposition operation; in the deposition process, the flame moving range does not cover the position of the sealing plug so as to avoid damaging the air tightness of the system in the heating process; after a deposition layer is obtained, stopping flame heating;
step 2-5, adjusting a pitching device of the MCVD lathe to incline a MCVD lathe base, and preparing a tube to incline so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit valve and a flowmeter of the solution conduit, replacing a sealing plug with a T-shaped opening with a sealing plug with an opening, connecting the other end of the solution conduit with the T-shaped opening, leading in solution to be doped from an air inlet pipe, setting a rotation mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to rotate for a certain time in a certain direction firstly, then rotating for the same time in the opposite direction, repeating for a plurality of times, and matching with a guide ring to prevent the solution conduit from being entangled; carrying out online solution doping on the deposition layer obtained in the step 2-4;
Step 2-6, after the doping for the first time is finished, removing the solution conduit, connecting the T-shaped opening by adopting a solid sealing plug, and adjusting a lathe pitching device to enable the MCVD lathe base to be restored to a horizontal state; continuously heating the deposition tube to perform next deposition;
step 2-7, repeating the steps 2-4, 2-5 and 2-6 for a plurality of times to obtain an optical fiber preform doped with an online solution in a mixing mode; according to actual requirements, the mixing mode can be one doping time for each deposited layer or one doping time for a plurality of deposited layers;
step 2-8, adoptHigh temperature, cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
further, in the step 2-1, the air inlet pipe, the deposition pipe and the tail gas pipe are quartz pipes;
further, in the step 2-1, the air inlet pipe is an air inlet pipe with a T-shaped opening on one end surface; the T-shaped opening comprises a sealing plug;
further, in the step 2-2, the polishing high temperature is 1950 ℃ or higher;
further, in the step 2-3, the solution to be doped is a solution containing rare earth or a solution containing co-doping elements;
Further, in the step 2-4, the metal air inlet pipe is SiCl 4 、POCl 3 、GeCl 4 An air inlet pipe;
further, in the step 2-4, the set carrier gas flow is 100-2000 ml/s, the loose layer deposition temperature is 1300-1600 ℃, and the flame moving speed is 100-150 mm/min during loose layer deposition;
further, in the step 2-5, the inclination angle of the preparation pipe is 15-45 degrees;
further, in the step 2-8, the sintering high temperature is 1800-2100 ℃;
in the specific embodiment of the present invention, in the step 2-1, the air inlet pipe is a straight air inlet pipe;
in another specific embodiment of the present invention, in the step 2-1, the air inlet pipe is a straight air inlet pipe with a spherical bulge;
in a specific embodiment of the present invention, in the step 2-2, the polishing high temperature is 2000 ℃;
in the specific embodiment of the invention, in the step 2-3, the solution to be doped is a solution containing rare earth;
in another specific embodiment of the present invention, in the step 2-3, the solution to be doped is a solution containing co-doping elements;
in the specific embodiment of the invention, in the step 2-3, the solution conduit is a hose, and one end of the solution conduit passes through the center of the sealing plug and is connected with the T-shaped opening end of the air inlet pipe; the other end is connected with a liquid supply end in the solution storage tank;
In another specific embodiment of the present invention, in the step 2-3, the solution conduit is a hose, one end of the solution conduit is connected to the liquid supply end in the solution storage tank, and the other end of the solution conduit directly penetrates into the air inlet pipe from the air inlet of the air inlet pipe;
in the specific embodiment of the invention, in the steps 2-4, the carrier gas flow rate is 1450ml/s, the loose layer deposition temperature is 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition;
in the specific embodiment of the invention, in the step 2-5, the preparation tube is firstly rotated leftwards for 1min, then rotated rightwards for 1min, and repeated for a plurality of times;
in another specific embodiment of the present invention, in the step 2-5, the continuous rotation of the preparation tube is first rotated rightward for 1min, and then rotated leftward for 1min;
in a specific embodiment of the present invention, in the step 2-5, the inclination angle is 25 °;
in a specific embodiment of the present invention, in the step 2-8, the sintering temperature is 1850 ℃;
in a specific embodiment of the present invention, the step 2-1 specifically operates as follows:
fixing pitching devices at the left end and the right end below the lathe base, and adjusting the pitching devices of the MCVD lathe to enable the MCVD lathe base to be in a horizontal state; fixedly connecting a quartz air inlet pipe, a quartz deposition pipe and a quartz tail gas pipe to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe extends into the pipe orifice of the quartz air inlet pipe, and the other end of the metal air inlet pipe is connected with a metal hose through a VCR joint; the quartz air inlet pipe comprises a T-shaped opening; the T-shaped opening is sealed by using a sealing plug;
In the specific embodiment of the invention, the step 2-2 specifically comprises the following steps:
high-temperature flame polishing at 2000 ℃ and SF feeding into a quartz deposition tube 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube by oxidizing etching;
in a specific embodiment of the present invention, the step 2-3 specifically operates as follows:
adding the solution containing the co-doping element prepared in advance into a solution storage tank; connecting an air inlet of a solution storage tank with a high-purity nitrogen pipeline; connecting a liquid supply end in the solution storage tank with one end of the solution conduit; the other end of the solution conduit is not connected;
in a specific embodiment of the present invention, the steps 2-4 specifically operate as:
introducing continuous oxygen from a metal air inlet pipe as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing deposition operation, wherein the flame moving range does not cover the position of the sealing plug in the deposition process, so as to avoid damaging the air tightness of the system in the heating process; after a deposition layer is obtained, stopping flame heating;
in a specific embodiment of the present invention, the steps 2-5 specifically operate as:
Adjusting a pitching device of the MCVD lathe to incline a MCVD lathe base, and inclining a preparation tube so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit valve and a flowmeter of the solution conduit, replacing a sealing plug with a T-shaped opening with a sealing plug with an opening, connecting the other end of the solution conduit with the T-shaped opening, leading in solution to be doped from an air inlet pipe, setting a rotating mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to be firstly rotated rightwards for 1min, then rotated leftwards for 1min, repeating for a plurality of times, matching with a guide ring to prevent the solution conduit from being entangled, and carrying out online solution doping on the deposition layer obtained in the step 2-4;
in a specific embodiment of the present invention, the steps 2-6 specifically operate as:
after the primary doping is finished, removing the solution conduit, connecting the T-shaped opening by adopting a solid sealing plug, and adjusting a lathe pitching device to enable the MCVD lathe base to recover to a horizontal state; continuously heating the quartz deposition tube to perform next deposition;
in a specific embodiment of the present invention, the steps 2-7 specifically operate as:
repeating the steps 2-4, 2-5 and 2-6 for a plurality of times to obtain an optical fiber preform doped with an online solution in a mixed doping mode; according to actual requirements, the mixing mode can be one doping time for each deposited layer or one doping time for a plurality of deposited layers;
In a specific embodiment of the present invention, the steps 2-8 specifically operate as:
high temperature 1850 ℃ and Cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
the invention also provides an active optical fiber preform obtained by the preparation method according to any one of the second aspects of the invention;
by adopting the scheme, the online solution doping method and device for preparing the active optical fiber preform have the following advantages:
(1) Compared with the existing doping method, the on-line solution doping method and device for preparing the active optical fiber preform have the advantages that the problems of bubbles, uneven local components, multiple impurities and the like in the preform caused by the fact that undeposited particles are easily introduced by inserting a solution conduit from a quartz tail gas end are avoided, the operation is convenient, the practicability is good, and the success rate of preparing the preform is improved;
(2) Compared with the off-line solution doping method, the on-line solution doping method and the on-line solution doping device for preparing the active optical fiber preform have the advantages that the on-line solution doping mode is adopted, cutting and re-welding of a deposition tube are avoided, the cost is saved, and the production effect is improved. The quality and the yield of the active optical fiber preform are improved;
(3) The on-line solution doping method and device for preparing the active optical fiber preform are simple and convenient, easy to operate, mild in condition and beneficial to realizing industrial expansion production application.
(4) The doping mode of the active optical fiber preform device comprises single doping and mixed doping, and the doping mode can be freely selected and is applied to manufacturing various optical fiber preforms;
in summary, the online solution doping method and device for preparing the active optical fiber preform disclosed by the invention avoid the problems of bubbles, uneven local components, multiple impurities and the like in the preform caused by the fact that undeposited particles are easily introduced by inserting a solution conduit from a quartz tail gas end, are convenient to operate, good in practicability, high in success rate of preparing the preform, cost-saving, improved in production effect, beneficial to the quality and yield improvement of the active optical fiber preform, mild in condition, and beneficial to the wide popularization and application in industrialization.
The conception, specific technical scheme, and technical effects produced by the present invention will be further described in conjunction with the specific embodiments below to fully understand the objects, features, and effects of the present invention.
Drawings
FIG. 1 is a schematic view of a prepared active optical fiber preform according to example 1 of the present invention;
FIG. 2 is a schematic view of an active optical fiber preform prepared according to embodiment 2 of the present invention;
FIG. 3 is a schematic view of an active optical fiber preform prepared according to embodiment 3 of the present invention;
in the figure, 1, a lathe base; 2. a pitching device; 3. a metal air inlet pipe; 4. a metal hose; 5. a VCR joint; 6. a support rod; 7. an air inlet pipe; 8. a deposition tube; 9. a tail gas pipe; 10. t-shaped openings; 11. a sealing plug; 12. a solution storage tank; 13. a solution conduit; 14. a high purity nitrogen line; 15. a solution conduit valve; 16. a nitrogen line valve; 17. a guide ring.
Detailed Description
The following describes a number of preferred embodiments of the present invention to make its technical contents more clear and easy to understand. This invention may be embodied in many different forms of embodiments which are exemplary of the description and the scope of the invention is not limited to only the embodiments set forth herein.
If there are experimental methods for which specific conditions are not specified, the experimental methods are usually carried out according to conventional conditions, such as the related instructions or manuals.
Example 1 preparation of active optical fiber preform
As shown in figure 1 of the drawings,
step 1, fixing pitching devices 2 at left and right ends below a lathe base 1, and adjusting the pitching devices 2 of an MCVD lathe to enable the MCVD lathe base 1 to be in a horizontal state; the quartz air inlet pipe 7, the quartz deposition pipe 8 and the quartz tail gas pipe 9 are fixedly connected to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe 3 extends into the pipe orifice of the quartz air inlet pipe 7, and the other end of the metal air inlet pipe 3 is connected with the metal hose 4 through the VCR joint 5; the quartz air inlet pipe 7 is a straight air inlet pipe with bulges;
Step 2, performing 2000 ℃ high-temperature flame polishing on the quartz deposition tube 8, and introducing SF 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube 8 by oxidizing and etching;
step 3, adding the solution containing the co-doping elements prepared in advance into a straight air inlet pipe with bulges;
step 4, introducing continuous oxygen from the metal air inlet pipe 3 as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing deposition operation to obtain a plurality of deposition layers; in the deposition process, the flame moving range does not cover the bulge position of the straight air inlet pipe;
step 5, stopping flame heating after the deposition is finished, and adjusting a pitching device 2 of the MCVD lathe to incline a MCVD lathe base 1, wherein the inclination angle of the preparation tube is 25 degrees, so that the inlet tube end is relatively higher than the tail gas tube end; performing on-line solution doping by using a single doping mode on the deposited preform;
step 6, after doping is finished, adjusting a lathe pitching device 2 to enable the MCVD lathe base 1 to be restored to a horizontal state;
step 7, using 1850 ℃ high temperature, cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
Results: the optical fiber preform obtained by the embodiment 1 has uniform structure, no bubbles and less impurities;
example 2 preparation of active optical fiber preform
As shown in the figure 2 of the drawings,
step 1, fixing pitching devices 2 at left and right ends below a lathe base 1, and adjusting the pitching devices 2 of an MCVD lathe to enable the MCVD lathe base 1 to be in a horizontal state; the quartz air inlet pipe 7, the quartz deposition pipe 8 and the quartz tail gas pipe 9 are fixedly connected to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe 3 extends into the pipe orifice of the quartz air inlet pipe 7, and the other end of the metal air inlet pipe 3 is connected with the metal hose 4 through the VCR joint 5; the quartz air inlet pipe 7 is a straight air inlet pipe without a T-shaped opening 10;
step 2, performing 2000 ℃ high-temperature flame polishing on the quartz deposition tube 8, and introducing SF 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube 8 by oxidizing and etching;
step 3, adding the solution containing the co-doping element prepared in advance into a solution storage tank; connecting the air inlet of the solution storage tank 12 with a high-purity nitrogen pipeline 14; connecting the liquid supply end in the solution storage tank 12 with one end of the solution conduit 13; the other end of the solution conduit 13 is not connected;
Step 4, introducing continuous oxygen from the metal air inlet pipe 3 as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing deposition operation to obtain a plurality of deposition layers; the flame moving range does not cover the position of the sealing plug 11 in the deposition process so as not to damage the air tightness of the system in the heating process;
step 5, stopping flame heating after the deposition is finished, and adjusting a pitching device 2 of the MCVD lathe to incline a MCVD lathe base 1, wherein the inclination angle of the preparation tube is 25 degrees, so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit 13 valve and a flowmeter of the solution conduit 13, directly connecting the other end of the solution conduit 13 into an air inlet pipe, leading in solution to be doped from the air inlet pipe, and carrying out on-line solution doping by using a single doping mode on the deposited preform;
step 6, after doping is finished, removing the solution guide pipe 13, and adjusting the lathe pitching device 2 to enable the MCVD lathe base 1 to recover to a horizontal state;
step 7, using 1850 ℃ high temperature, cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
Results: the optical fiber preform obtained in the embodiment 2 has a uniform structure, no bubbles and few impurities;
example 3 preparation of active optical fiber preform
As shown in the figure 3 of the drawings,
step 1, fixing pitching devices 2 at left and right ends below a lathe base 1, and adjusting the pitching devices 2 of an MCVD lathe to enable the MCVD lathe base 1 to be in a horizontal state; the quartz air inlet pipe 7, the quartz deposition pipe 8 and the quartz tail gas pipe 9 are fixedly connected to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe 3 extends into the pipe orifice of the quartz air inlet pipe 7, and the other end of the metal air inlet pipe 3 is connected with the metal hose 4 through the VCR joint 5; the quartz air inlet pipe 7 comprises a T-shaped opening 10; the T-shaped opening 10 is sealed with a solid sealing plug 11;
step 2, performing 2000 ℃ high-temperature flame polishing on the quartz deposition tube 8, and introducing SF 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube 8 by oxidizing and etching;
step 3, adding the solution containing the co-doping element prepared in advance into a solution storage tank; connecting the air inlet of the solution storage tank 12 with a high-purity nitrogen pipeline 14; connecting the liquid supply end in the solution storage tank 12 with one end of the solution conduit 13; the other end of the solution conduit 13 is not connected;
Step 4, introducing continuous oxygen from the metal air inlet pipe 3 as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to carry out layer-by-layer deposition, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the deposition temperature of a loose layer is set to 1550 ℃, and the flame moves during the deposition of the loose layerThe moving speed is 125mm/min; performing deposition operation to obtain a plurality of deposition layers; the flame moving range does not cover the position of the sealing plug 11 in the deposition process so as not to damage the air tightness of the system in the heating process;
step 5, stopping flame heating after the deposition is finished, and adjusting a pitching device 2 of the MCVD lathe to incline a MCVD lathe base 1, wherein the inclination angle of the preparation tube is 25 degrees, so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit 13 valve and a flowmeter of the solution conduit 13, replacing a sealing plug 11 of the T-shaped opening 10 with the sealing plug 11 with the opening, connecting the other end of the solution conduit 13 with the T-shaped opening 10 to enable solution to be doped to be introduced from an air inlet pipe, setting a rotating mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to be firstly right-handed for 1min, then left-handed for 1min, repeating for a plurality of times, matching with a guide ring 17 to prevent the solution conduit 13 from being entangled, and carrying out online solution doping by using a single doping mode on deposited preformed rod;
Step 6, after doping is finished, removing the solution conduit 13, connecting the T-shaped opening by adopting the solid sealing plug 11, and adjusting the lathe pitching device 2 to enable the MCVD lathe base 1 to recover to a horizontal state;
step 7, using 1850 ℃ high temperature, cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
results: the optical fiber preform obtained in the embodiment 3 has a uniform structure, no bubbles and few impurities;
example 4 preparation of active optical fiber preform
As shown in the figure 3 of the drawings,
step 1, fixing pitching devices 2 at left and right ends below a lathe base 1, and adjusting the pitching devices 2 of an MCVD lathe to enable the MCVD lathe base 1 to be in a horizontal state; the quartz air inlet pipe 7, the quartz deposition pipe 8 and the quartz tail gas pipe 9 are fixedly connected to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe 3 extends into the pipe orifice of the quartz air inlet pipe 7, and the other end of the metal air inlet pipe 3 is connected with the metal hose 4 through the VCR joint 5; the quartz air inlet pipe 7 comprises a T-shaped opening 10; the T-shaped opening 10 is sealed with a sealing plug 11;
step 2, performing 2000 ℃ high-temperature flame polishing on the quartz deposition tube 8, and introducing SF 6 Removing scratches, dust, oil stains and other impurities on the inner wall of the quartz deposition tube 8 by oxidizing and etching;
step 3, adding the solution containing the co-doping element prepared in advance into a solution storage tank; connecting the air inlet of the solution storage tank 12 with a high-purity nitrogen pipeline 14; connecting the liquid supply end in the solution storage tank 12 with one end of the solution conduit 13; the other end of the solution conduit 13 is not connected;
step 4, introducing continuous oxygen from the metal air inlet pipe 3 as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing a deposition operation, wherein the flame moving range does not cover the position of the sealing plug 11 in the deposition process, so as to avoid damaging the air tightness of the system in the heating process; after a deposition layer is obtained, stopping flame heating;
step 5, adjusting a pitching device 2 of the MCVD lathe to incline a MCVD lathe base 1, and preparing a tube to incline so that the inlet tube end is relatively higher than the tail gas tube end; opening a solution conduit 13 valve and a flowmeter of the solution conduit 13, replacing a sealing plug 11 of the T-shaped opening 10 with the sealing plug 11 with the opening, connecting the other end of the solution conduit 13 with the T-shaped opening 10 to enable solution to be doped to be introduced from an air inlet pipe, setting a rotating mode of a preparation pipe in a process formula, enabling the continuous rotation of the preparation pipe to be firstly right-handed for 1min, then left-handed for 1min, repeating for a plurality of times, matching with a guide ring 17 to prevent the solution conduit 13 from being entangled, and carrying out online solution doping on the deposition layer obtained in the steps 2-4;
Step 6, after the doping for one time is finished, removing the solution conduit 13, connecting the T-shaped opening by adopting the solid sealing plug 11, and adjusting the lathe pitching device 2 to enable the MCVD lathe base 1 to recover to a horizontal state; continuing heating the quartz deposition tube 8 for next deposition;
step 7, repeating the steps 2-4, 2-5 and 2-6 for a plurality of times to obtain an optical fiber preform doped with an online solution in a mixing mode; according to actual requirements, the mixing mode can be one doping time for each deposited layer or one doping time for a plurality of deposited layers;
step 8, adopting 1850 ℃ high temperature and Cl 2 Dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining a solid optical fiber preform through a rod shrinking process;
results: the optical fiber preform obtained in example 4 has a uniform structure, no bubbles and few impurities;
comparative example 5,
Preparing an optical fiber preform by adopting a patent CN 109293249A;
step 1, the core component SiO of the optical fiber preform rod 2 、Al 2 O 3 、Yb 2 O 3 、CeO 2 And F content is converted into flow of gaseous reactant during deposition, and the flow of the gaseous reactant and the number of deposition layers are set in a control system of the MCVD equipment; wherein the gaseous reaction material used comprises SiCl 4 、Al(acac) 3 、Yb(thd) 3 、Ce(hfa) 4 、SiF 4 And O 2 ；
Step 2, connecting the cleaned quartz tube to an MCVD deposition bed, and preheating the quartz tube by oxyhydrogen flame; the quartz tube is in a rotating state while preheating; after preheating is completed, SF is introduced 6 Gas erodes the inner wall of the quartz tube;
step 3, after the corrosion is finished, introducing gaseous reaction materials into the rotating quartz tube to perform core rod deposition; the heating temperature of the quartz tube is 1750-1850 ℃;
step 4, when the set deposition layer number is reached, starting shrinkage pipe, and introducing chlorine gas in the shrinkage pipe process; and (5) after the quartz tube is contracted into a solid rod from the hollow tube, the optical fiber preform is manufactured.
Results: the optical fiber preform obtained in comparative example 7 has a nonuniform structure and contains more bubbles and impurities;
comparative example 6,
Preparing a rare earth doped optical fiber preform by adopting a patent CN 102086089A;
and step 1, performing high-temperature flame polishing on the quartz deposition tube to eliminate scratch impurities, surface unevenness and shrinkage bubbles on the surface of the deposition tube.
Step 2, depositing a plurality of layers of SiO-containing layers on the inner surface of the deposition tube at 1870 DEG C 2 -P 2 O 5 -inner cladding of F. Reverse deposition is adopted at 1550 ℃ and SiCl is introduced 4 And POCl 3 The gas deposits a loose soot core.
Step 3, soaking the deposition tube containing the loose ash core layer in YbCl containing 0.07mol/L 3 ·6H 2 O and 0.5mol/L AlCl 3 ·6H 2 O in aqueous solution for about 1.5 hours. And then discharging the redundant solution, putting the deposition tube into a sintering furnace, introducing nitrogen gas, blowing for 30min, then gradually raising the temperature to 600-1300 ℃, introducing oxygen, chlorine and helium gas, dehydrating and drying for 2 hours.
Step 4, after drying and dewatering, introducing He and O 2 The loose soot core layer was sintered at 1550 deg.c. POCl is introduced during sintering 3 The gas flows through the porous soot core.
And 5, finally, reinstalling the deposition tube 12 on the MCVD lathe, and fusing and shrinking the deposition tube 12 into a transparent solid glass rod at 2200 ℃.
Results: the optical fiber preform obtained in comparative example 8 has a non-uniform structure, more bubbles and more impurities; comparative example 7,
The doping device of the optical fiber preform is prepared by adopting a patent CN 102815866A;
step 1, carrying silicon tetrachloride, germanium tetrachloride and phosphorus oxychloride liquid into a reaction tube by using an MCVD material cabinet system through a bubbling mode; wrapping aluminum chloride or aluminum oxide solid blocks or powder with gold foil or copper foil with meshes, and placing into a specially prepared gas phase doping tube wrapping groove for high-temperature gas phase doping;
step 2, closing a gas phase heating device to set the heating temperature at 185 ℃, wherein the core material of the heating device is a periodically arranged resistance wire; preparing erbium trichloride ion solution according to the doping concentration of 0.7 mol/L, adding lanthanum chloride into the solution to improve the doping concentration of erbium ions in an optical fiber, filtering the prepared erbium lanthanum solution, injecting the solution into a solution tank, and carrying out online liquid phase doping from the rear end of a reaction tube by utilizing a micropore injection tube;
Step 3, setting a system air inlet and tail gas system, after adjusting the pressure in a reaction tube, the rotating speed of the reaction tube, the running speed of a main lamp and other series of parameters, starting a gas phase heating device to heat aluminum chloride, starting a silicon tetrachloride valve and a germanium tetrachloride valve when the aluminum chloride gas is stably output, starting a solution tank and a spraying device connecting valve to enable a solution to enter a spraying tube for spraying, keeping micro-positive pressure in the solution tank, and starting a stirring device of the solution tank to stir the solution;
step 4, synchronously depositing silicon dioxide, aluminum oxide, germanium dioxide and erbium trichloride serving as reaction products on the inner wall of the reaction tube, and carrying out vitrification at 1900 ℃ together, thereby completing the deposition of the whole reaction tube core layer along the axial direction;
and 5, closing a valve of the liquid containing tank after the deposition is finished, stopping heating of all the heating devices, and keeping the reaction tube to rotate. Taking out the liquid-phase spraying device after the reaction tube is cooled;
and 6, finally, fusing the doped reaction tube into a solid preform rod in 7 times at the temperature of 1980-2000 ℃. Preparing the erbium-doped optical fiber through high-temperature high-speed wire drawing;
results: the optical fiber preform obtained in comparative example 9 was not uniform in structure, had a small amount of bubbles, and had many impurities;
Test example 8:
comparing the active optical fiber preform obtained in example 3 with the optical fiber preform obtained in comparative example 5, the optical fiber preform obtained in comparative example 6, and the erbium-doped optical fiber obtained in comparative example 7;
results: the active optical fiber preform obtained in example 3 was free from the problems of bubbles, local component non-uniformity, impurity bright spots, and the like, as compared with the optical fiber preform obtained in comparative example 5, the optical fiber preform obtained in comparative example 6, and the erbium-doped optical fiber obtained in comparative example 7;
compared with the preparation methods of comparative examples 7, 5 and 6, the preparation method of the active optical fiber preform prepared by the method of the invention in example 3 avoids the defects of bubbles, uneven local components, impurity bright spots and the like in the preform caused by the fact that undeposited particles are easily introduced by inserting a solution conduit from a quartz tail gas end in the traditional online solution doping method. The cutting and re-welding of the deposition tube are avoided, the cost is saved, the production effect is improved, and the method is suitable for improving the quality and the yield of the active optical fiber preform;
the obtained active optical fiber preform according to other embodiments of the present invention has similar advantageous effects as described above;
the active optical fiber preform according to other embodiments of the present invention has similar advantageous effects as described above.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention without requiring creative effort by one of ordinary skill in the art. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by a person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (4)
1. An on-line doping device for preparing an active optical fiber preform is characterized by comprising a preparation tube and an MCVD lathe; the preparation pipe is fixedly connected to the MCVD lathe;
the MCVD lathe comprises a lathe base (1), a pitching device (2), a metal air inlet pipe (3), a metal hose (4), a VCR joint (5) and a supporting rod (6); the pitching device (2) is fixedly connected to the left end and the right end below the lathe base (1) and is used for tilting a lathe; the two support rods (6) are respectively and fixedly connected to the left end and the right end above the lathe base (1); the metal hose (4) is connected to the metal air inlet pipe (3) through a VCR connector (5);
the preparation pipe comprises an air inlet pipe (7), a deposition pipe (8) and a tail gas pipe (9); the left end of the air inlet pipe (7) is fixedly connected with a support rod (6) at the left end, and the right part of the air inlet pipe (7) is fixedly connected with a deposition pipe (8); the right part of the deposition tube (8) is fixedly connected with a tail gas tube (9); the right end of the tail gas pipe (9) is fixedly connected with the right end supporting rod (6), the air inlet pipe (7) is a straight air inlet pipe with a spherical bulge, the solution containing the co-doping element prepared in advance is added into the straight air inlet pipe with the bulge, the deposition pipe is heated by oxyhydrogen flame in the deposition process, and the flame moving range does not cover the bulge position of the straight air inlet pipe in the deposition process.
2. An in-line doping apparatus for preparing an active optical fiber preform as defined in claim 1,
the fixed connection is welding, bonding and integrated forming.
3. An in-line doping apparatus for preparing an active optical fiber preform as defined in claim 1,
the metal air inlet pipe (3) is SiCl 4 、POCl 3 、GeCl 4 An air inlet pipe; the air inlet pipe (7), the deposition pipe (8) and the tail gas pipe (9) are quartz pipes;
the fixed connection is welding.
4. An on-line doping preparation method of an active optical fiber preform based on an on-line doping apparatus for preparing an active optical fiber preform as claimed in claim 1, characterized by comprising the steps of:
step 1, fixing the pitching devices (2) at the left end and the right end below a lathe base (1), and adjusting the pitching devices (2) of the MCVD lathe to enable the MCVD lathe base (1) to be in a horizontal state; fixedly connecting the air inlet pipe (7), the deposition pipe (8) and the tail gas pipe (9) to form a preparation pipe; fixedly connecting the left end and the right end of the preparation tube to an MCVD lathe; one end of the metal air inlet pipe (3) extends into the pipe orifice of the air inlet pipe (7), and the other end of the metal air inlet pipe (3) is connected with a metal hose (4) through a VCR joint (5); the air inlet pipe (7) is a straight air inlet pipe with a drum bag;
Step 2, performing 2000 ℃ high-temperature flame polishing on the deposition tube (8), and introducing SF 6 Removing scratches, dust and oil stains on the inner wall of the deposition tube (8) by oxidation etching;
step 3, adding the solution containing the co-doping elements prepared in advance into a straight air inlet pipe with bulges;
step 4, introducing continuous oxygen from the metal air inlet pipe (3) as carrier gas to carry SiCl 4 、POCl 3 Raw materials enter a deposition tube to be deposited layer by layer, the deposition tube is heated by oxyhydrogen flame, the carrier gas flow rate is set to 1300ml/s, the loose layer deposition temperature is set to 1550 ℃, and the flame moving speed is 125mm/min during loose layer deposition; performing deposition operation to obtain a plurality of deposition layers; in the deposition process, the flame moving range does not cover the bulge position of the straight air inlet pipe;
step 5, stopping flame heating after the deposition is finished, and adjusting a pitching device (2) of the MCVD lathe to incline a MCVD lathe base (1), wherein a preparation pipe inclines by 25 degrees, so that the air inlet pipe (7) is relatively higher than the tail gas pipe (9); performing on-line solution doping by using a single doping mode on the deposited preform;
step 6, after doping is finished, adjusting the lathe pitching device (2) to enable the MCVD lathe base (1) to be restored to a horizontal state;
step 7, using 1850 ℃ high temperature, cl 2 And dehydrating and drying the obtained loose layer, sintering the loose layer to a transparent glass state, and obtaining the solid optical fiber preform through a rod shrinking process.
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| KR101310761B1 (en) * | 2012-04-23 | 2013-09-25 | 한국광기술원 | Apparatus for adding doping solution for optical fiber core |
| CN110606657A (en) * | 2018-06-15 | 2019-12-24 | 华中科技大学 | A large core diameter rare earth doped optical fiber preform and its preparation method |
| CN211367413U (en) * | 2019-09-25 | 2020-08-28 | 法尔胜泓昇集团有限公司 | Solution soaking device of loose body tube based on MCVD (modified chemical vapor deposition) process special optical fiber |
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| JPS63501711A (en) * | 1985-08-13 | 1988-07-14 | ブリティッシュ・テクノロジー・グループ・リミテッド | Optical fiber manufacturing |
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