CN109133608B - Doping equipment for optical fiber preform - Google Patents
Doping equipment for optical fiber preform Download PDFInfo
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- CN109133608B CN109133608B CN201811369389.1A CN201811369389A CN109133608B CN 109133608 B CN109133608 B CN 109133608B CN 201811369389 A CN201811369389 A CN 201811369389A CN 109133608 B CN109133608 B CN 109133608B
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- rotary sealing
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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]
- C03B37/018—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
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- 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
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Abstract
The invention relates to doping equipment for an optical fiber preform, which is characterized by comprising a long cylindrical heating holding furnace, wherein the outer sides of two ends of the heating holding furnace are respectively provided with an air inlet rotary sealing chuck and an air outlet rotary sealing chuck, the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are respectively communicated with a doping gas source and a tail gas collecting and processing device, the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are combined into pairs, 2 pairs or more than 2 pairs are arranged, and the axes of each pair of the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are coincided. The invention can heat the whole doped prefabricated rod glass liner tube, has uniform heating and good doping quality, and can carry out batch treatment simultaneously, thereby greatly shortening the processing time, effectively improving the production efficiency and improving the doping uniformity. The repeated rise and fall of the temperature of the prefabricated rod glass liner tube are avoided, and the crystallization risk and the stress unevenness of the glass liner tube are reduced. The invention has simple structure and convenient use and operation.
Description
Technical Field
The invention relates to doping equipment for an optical fiber preform, and belongs to the technical field of optical fiber preform manufacturing.
Background
Optical fibers are widely used in optical communication systems such as long-distance trunk lines, metropolitan area networks, and access networks. In recent years, with the explosive growth of IP traffic, optical communication networks are advancing toward next-generation systems, and building an optical fiber infrastructure with a large transmission capacity is the foundation of the next-generation networks.
In the actual production of optical fibers, optical fibers having excellent properties can be produced by adding specific dopant substances to an optical fiber preform. The existing doping methods mainly comprise doping in the deposition process and doping in the rod forming process, and doping in SiO2Doping in the powder of SOOT and doping in the solidification of SOOT. Germanium and fluorine are incorporated primarily by deposition, mostly using tubesThe inner deposition or outer deposition method introduces doping elements of germanium and fluorine with different contents, and the doping elements react under the action of high temperature to form required doping components, so that different refractive index distributions can be obtained. Still other element dopings are by diffusion methods, such as alkali metals and phosphorus. The diffusion method is mainly characterized in that the optical fiber preform is heated by a movable furnace at present so that corresponding doping is diffused to a designated interval, and the diffusion method has the defects of poor uniformity of preform heating, long time consumption in the whole doping process and low production efficiency.
In Chinese patents CN 102627398A, CN102627400A and CN106458696, a glass tube is heated to 1500-2200 ℃ to perform diffusion doping of alkali metal elements in the tube. The heat source moving speed is 30mm/min-100mm/min, the reciprocating movement times are 15-30 times, and the doping time is at least 5 hours if the length of the liner tube is 1 m. The diffusion time is long, the production efficiency is low, and the large-scale production is not facilitated. In addition, the movement of the heating furnace causes the temperature of the liner tube to circularly rise and fall, so that the crystallization is easier, and the longitudinal distribution of the doped alkali metal is also easy to be uneven.
Disclosure of Invention
The technical problem to be solved by the invention is to provide doping equipment for an optical fiber preform aiming at the defects in the prior art, which has the advantages of uniform heating, short doping time and high production efficiency.
The technical scheme adopted by the invention for solving the problems is as follows: including long cylindric heating heat preservation stove, the outside at heating heat preservation stove both ends sets up the rotary seal chuck of admitting air and the rotary seal chuck of exhausting respectively, the rotary seal chuck of admitting air and the rotary seal chuck of exhausting be linked together with doping gas air supply and tail gas collection processing apparatus respectively, the rotary seal chuck of admitting air and the rotary seal chuck of exhausting constitute in pairs, be provided with 2 pairs or more than 2 pairs, every axis of the rotary seal chuck of admitting air and the rotary seal chuck of exhausting coincide mutually.
According to the scheme, the heating and heat-preserving furnace comprises a long cylindrical furnace shell, a heat-preserving layer is arranged on the inner wall of the furnace shell, heating elements are circumferentially arranged in a furnace cavity on the outer side of the heat-preserving layer, and the heating and heat-preserving furnace is formed by folding two furnace shells which are opened and closed in half or hinging one side of the furnace shells.
According to the scheme, the two ends of the heating holding furnace are provided with openings, the outer sides of the openings are respectively provided with an air inlet rotary sealing chuck and an air outlet rotary sealing chuck, a heat insulation baffle is arranged between the air inlet rotary sealing chuck and the openings, and a heat insulation baffle is also arranged between the air outlet rotary sealing chuck and the openings.
According to the scheme, the heating element is arranged between the air inlet rotary sealing chuck and the heat insulation baffle plate and used for heating the preform glass extension tube.
According to the scheme, the temperature thermocouple is arranged in the furnace chamber.
According to the scheme, the cross section of the furnace body is rectangular or oval.
According to the scheme, the axes of each pair of the air inlet rotary sealing chuck and the air exhaust rotary sealing chuck are parallel and are parallel to the central axis of the heating and heat-preserving furnace chamber.
According to the scheme, the heating holding furnace is horizontal or vertical, 2-6 pairs of air inlet rotary sealing chucks and air outlet rotary sealing chucks are arranged, and each pair is arranged in parallel at intervals.
According to the scheme, the air inlet rotary sealing chuck is connected with a doped gas source through an air inlet pipe, an impurity filter is arranged on the air inlet pipe, and the air supply pressure of the doped gas source is 10-10000 Pa, preferably 10-2000 Pa.
According to the scheme, the gas inlet pipe is connected with a raw material gas concentration detection device.
According to the scheme, the heating element is plasma, a resistance wire, a carbon rod or an induction coil, and the heating temperature of the furnace chamber is 800-2200 ℃.
The invention has the beneficial effects that: 1. can carry out many integral heating to doping prefabricated stick glass lining pipe, the heating is even, and doping quality is good. 2. The whole heating and the whole doping can be carried out on the doped prefabricated rod glass liner tube, and the batch processing can be carried out simultaneously, so that the processing time is greatly shortened, the production efficiency is effectively improved, and the doping uniformity is also improved. The repeated rise and fall of the temperature of the prefabricated rod glass liner tube are avoided, and the crystallization risk and the stress unevenness of the glass liner tube are reduced. 3. The invention has simple structure and convenient use and operation. The device of the invention provides a good solution for the optical fiber perform rod and the optical fiber perform rod intermediate body which need special doping and special heat treatment.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a heat retention furnace in accordance with one embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following drawings and examples.
One embodiment of the invention is shown in figures 1 and 2, and is of a horizontal structure and comprises a long cylindrical heating and heat-preserving furnace and a frame, wherein the long cylindrical heating and heat-preserving furnace comprises a long cylindrical furnace shell 6, a heat-preserving layer 11 is arranged on the inner wall of the furnace shell, heating elements 12 are arranged on two sides of a furnace chamber outside the heat-preserving layer, the cross section of the furnace body is rectangular, the height of the furnace body is 0.5-1 m, the width of the furnace body is 0.2-1 m, the length of the furnace body is 1-1.8 m, the heating and heat-preserving furnace is formed by combining two furnace shells which are opened and closed in half-and-half, the heat-preserving layer is formed by heat-preserving cotton or heat-preserving bricks, and the thickness of the heat-preserving layer is more than 5 mm; the heating elements are carbon rods, 2 heating elements are arranged on two sides of the furnace chamber respectively, the temperature of the furnace chamber reaches 1600 ℃, and a temperature thermocouple is arranged in the furnace chamber and connected with a temperature control device, so that the temperature of the whole furnace body can be controlled, and the temperature can be controlled more uniformly. The top of the heating and heat-preserving furnace is provided with a fixing and control element 7, the two ends of the heating and heat-preserving furnace are provided with openings, the outer sides of the openings are respectively provided with 3 pairs of air inlet rotary sealing chucks 2 and air outlet rotary sealing chucks 3, the axes of each pair of air inlet rotary sealing chucks and air outlet rotary sealing chucks are overlapped and synchronously rotated, the axes of the 3 pairs of air inlet rotary sealing chucks and air outlet rotary sealing chucks are parallel, and each pair of air inlet rotary sealing chucks and air outlet rotary sealing chucks are arranged in parallel at intervals and are parallel to the central axis of the furnace chamber of the heating and heat-preserving furnace. And 3 pairs of air inlet rotary sealing chucks and air outlet rotary sealing chucks are respectively clamped with the two end heads of the 3 prefabricated rod glass liner tubes 4 in a sealing way to drive the glass liner tubes to rotate at a constant speed. Glass liner tubeThe two ends of the heat-insulating furnace body are connected with extension pipes, the extension pipes extend out of the two ends of the heating heat-insulating furnace body, a heat-insulating baffle plate 5 is arranged between the air inlet rotary sealing chuck and the opening, and a heat-insulating baffle plate is also arranged between the air outlet rotary sealing chuck and the opening. The gas inlet rotary sealing chuck and the gas outlet rotary sealing chuck are respectively communicated with a doped gas source 13 and a tail gas collecting and processing device through a gas inlet pipe 1 and a gas outlet pipe 8. An impurity filter and a raw material gas concentration detection device are arranged on the gas inlet pipe, and the raw material gas concentration detection device is used for on-line detection and real-time control. The gas supply pressure of the doping gas source is 1000Pa, the doping gas source mainly comprises pure oxygen, phosphorus oxychloride gas, Freon, compressed gas and other auxiliary gases, the auxiliary gases are mainly used for constantly keeping the stable positive pressure of the whole gas supply source, and the doping gas is P2O5For phosphorus doping of the glass liner 4. And (3) gradually diffusing the P element into a glass body of the prefabricated rod through the inner surface at the furnace temperature of 1600 ℃ in a heat preservation state of 40min, necking and fusing the intermediate containing the P element to obtain a core rod with a core layer containing the P element, and drawing the core rod by matching with a proper outer sleeve to obtain the optical fiber with the core layer containing a small amount of the P element.
The second embodiment of the invention is 3 pieces of prefabricated glass liner tubes simultaneously doped with alkali metal oxide, the glass liner tubes rotate at a constant speed, a heating element 10 is arranged between an air inlet rotary sealing chuck and a heat insulation baffle plate and used for heating the prefabricated glass extension tube, alkali metal salt 9 is arranged in the prefabricated glass extension tube corresponding to the heating element and generates alkali metal ion gas under the action of high temperature as doping gas, required gas raw materials, mainly oxygen, alkali metal source gas, auxiliary gas such as Freon, compressed gas and the like, are introduced through an air inlet end 1 in the doping process, the auxiliary gas is mainly used for constantly keeping the stable positive pressure of the whole air supply source, the pressure value range is 1000Pa, the temperature of a silicon carbon rod in a furnace body is raised to 1800 ℃ and is kept for 40min, the alkali metal element is gradually diffused into the glass body through the inner surface under the action of high temperature, and then necking and fusing the intermediate containing the alkali metal element to obtain three core rods containing the alkali metal element in the middle, and drawing the core rods matched with a proper outer sleeve to obtain the optical fiber with the core rods containing a small amount of the alkali element.
Comparative examples of the invention are as follows:
and depositing a core layer, an inner cladding and a sunken cladding required by the optical fiber on the fluorine-doped silica glass liner tube by PCVD deposition processing to form an intermediate body of the optical fiber preform. The method adopts the conventional in-tube diffusion method for doping, and comprises the following steps:
1) 5-50g of alkali metal raw material KBr (purity 99.99%) is placed in a large-diameter glass tube;
2) doping: the air inlet end of the glass liner tube is introduced with O2(the flow rate is 2SLM), turning on a heater to heat the large-diameter glass tube, setting the temperature of the heater to be 750 ℃, enabling the alkali metal raw material to form a gas state due to heating, and carrying the gas into the glass lining tube, and moving the heating equipment at the speed of 30mm/min for 20 times of reciprocating to carry out diffusion;
3) after doping, heating at high temperature for collapsing to obtain a solid core rod, and combining the core rod and the outer sleeve to obtain a prefabricated rod.
Table 1: results of comparison of examples with comparative examples
The above examples show the method and results of preparing an optical fiber preform containing a specific doping element using the present invention, and it can be seen from table 1 that: the P element and the alkali metal element can be added into the silica glass tube by the diffusion method through the equipment, and three diffusions can be simultaneously carried out, because the hot zone of the equipment is longer and is at least 1 meter, the effective part in the silica glass tube can be simultaneously doped, and the advantages that firstly, the time is saved, the heating time of the previous moving heat source is greatly shortened, and the time is reduced from a plurality of hours to less than one hour. And secondly, the temperature is uniform, the temperature in the whole furnace body is uniform, the whole region is diffused simultaneously, the temperature does not rise or fall, the repeated rise and fall of the temperature are avoided, and the crystallization risk and the stress are not uniform. And thirdly, three treatments are carried out simultaneously, and through uniform temperature control, good doping effect can be realized for three treatments, and the yield can be improved without occupying more space for the equipment. Therefore, the equipment is very suitable for large-scale mass production of the optical fiber preform, and the overall production efficiency is improved.
Claims (7)
1. A doping device for an optical fiber preform is characterized by comprising a long cylindrical heating holding furnace, wherein the outer sides of two ends of the heating holding furnace are respectively provided with an air inlet rotary sealing chuck and an air outlet rotary sealing chuck, the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are respectively communicated with a doping gas source and a tail gas collecting and processing device, the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are combined into pairs, 2 pairs or more than 2 pairs are arranged, and the axes of each pair of the air inlet rotary sealing chuck and the air outlet rotary sealing chuck are coincided; the heating and heat-preserving furnace comprises a long cylindrical furnace shell, a heat-preserving layer is arranged on the inner wall of the furnace shell, heating elements are circumferentially arranged in a furnace cavity outside the heat-preserving layer, and the heating and heat-preserving furnace is formed by folding or hinging two furnace shells which are opened and closed in half; openings are formed in the two end heads of the heating and heat-preserving furnace, an air inlet rotary sealing chuck and an air outlet rotary sealing chuck are respectively arranged on the outer sides of the openings, a heat insulation baffle is arranged between the air inlet rotary sealing chuck and the openings, and a heat insulation baffle is also arranged between the air outlet rotary sealing chuck and the openings; and a heating element is arranged between the air inlet rotary sealing chuck and the heat insulation baffle plate and used for heating the preform glass extension tube.
2. A doping apparatus for an optical fiber preform according to claim 1, wherein a temperature thermocouple is installed in the furnace chamber.
3. A doping apparatus for an optical fiber preform according to claim 1 or 2, wherein the furnace body has a rectangular or elliptical cross-section.
4. A doping apparatus for an optical fiber preform according to claim 1 or 2, wherein each pair of the gas-in spin seal chuck and the gas-out spin seal chuck has an axis parallel to a central axis of the furnace chamber of the heating and holding furnace.
5. A doping apparatus for an optical fiber preform according to claim 1 or 2, wherein the heating and holding furnace is horizontal or vertical, and the pair of the air-intake rotary sealing chuck and the air-exhaust rotary sealing chuck is provided in 2 to 6 pairs, each pair being disposed in parallel at an interval.
6. A doping apparatus for an optical fiber preform according to claim 1 or 2, wherein the gas-feeding rotary sealing chuck is connected to a source of dopant gas through a gas-feeding tube, on which an impurity filter is installed, and the source of dopant gas has a gas-feeding pressure of 10 to 10000 Pa.
7. A doping apparatus for an optical fiber preform according to claim 1 or 2, wherein the heating element is a plasma, a resistance wire, a carbon rod, or an induction coil, and the furnace chamber is heated at a temperature of 800 ℃ to 2200 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811369389.1A CN109133608B (en) | 2018-11-16 | 2018-11-16 | Doping equipment for optical fiber preform |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811369389.1A CN109133608B (en) | 2018-11-16 | 2018-11-16 | Doping equipment for optical fiber preform |
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| CN109133608A CN109133608A (en) | 2019-01-04 |
| CN109133608B true CN109133608B (en) | 2022-02-01 |
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| CN112794638B (en) * | 2021-01-13 | 2022-09-30 | 烽火通信科技股份有限公司 | Air inlet end rotary sealing device for chemical deposition of optical fiber preform |
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| JP2003321238A (en) * | 2002-04-30 | 2003-11-11 | Fujikura Ltd | Method and apparatus for producing optical fiber preform |
| CN101182114A (en) * | 2006-11-14 | 2008-05-21 | 德雷卡通信技术公司 | Apparatus and mentod for carrying out a pcvd deposition process |
| CN102249532A (en) * | 2011-04-15 | 2011-11-23 | 长飞光纤光缆有限公司 | Optical fiber preform deposition lathe for PCVD (plasma chemical vapor deposition) processing |
| CN203866201U (en) * | 2014-04-17 | 2014-10-08 | 中天科技精密材料有限公司 | Manufacturing equipment for optical fiber preform sleeve with complicated refractive-index section |
| CN107032595A (en) * | 2017-05-31 | 2017-08-11 | 长飞光纤光缆股份有限公司 | The preparation method and device of a kind of preform alkali-metal-doped |
| CN108002698A (en) * | 2017-11-29 | 2018-05-08 | 长飞光纤光缆股份有限公司 | A kind of manufacture method of preform |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040118164A1 (en) * | 2002-12-19 | 2004-06-24 | Boek Heather D. | Method for heat treating a glass article |
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- 2018-11-16 CN CN201811369389.1A patent/CN109133608B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003321238A (en) * | 2002-04-30 | 2003-11-11 | Fujikura Ltd | Method and apparatus for producing optical fiber preform |
| CN101182114A (en) * | 2006-11-14 | 2008-05-21 | 德雷卡通信技术公司 | Apparatus and mentod for carrying out a pcvd deposition process |
| CN102249532A (en) * | 2011-04-15 | 2011-11-23 | 长飞光纤光缆有限公司 | Optical fiber preform deposition lathe for PCVD (plasma chemical vapor deposition) processing |
| CN203866201U (en) * | 2014-04-17 | 2014-10-08 | 中天科技精密材料有限公司 | Manufacturing equipment for optical fiber preform sleeve with complicated refractive-index section |
| CN107032595A (en) * | 2017-05-31 | 2017-08-11 | 长飞光纤光缆股份有限公司 | The preparation method and device of a kind of preform alkali-metal-doped |
| CN108002698A (en) * | 2017-11-29 | 2018-05-08 | 长飞光纤光缆股份有限公司 | A kind of manufacture method of preform |
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