CN109206006B - Torch and method for manufacturing core rod - Google Patents
Torch and method for manufacturing core rod Download PDFInfo
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- CN109206006B CN109206006B CN201710517571.6A CN201710517571A CN109206006B CN 109206006 B CN109206006 B CN 109206006B CN 201710517571 A CN201710517571 A CN 201710517571A CN 109206006 B CN109206006 B CN 109206006B
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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]
- C03B37/01413—Reactant delivery systems
- C03B37/0142—Reactant deposition burners
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/04—Multi-nested ports
- C03B2207/06—Concentric circular ports
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/04—Multi-nested ports
- C03B2207/12—Nozzle or orifice plates
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
- C03B2207/20—Specific substances in specified ports, e.g. all gas flows specified
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Abstract
The invention provides a blast lamp, which comprises an inner tube and an outer tube sleeved on the inner tube, wherein the outer tube is provided with an outer tube opening, the inner tube is provided with an inner tube opening, the inner tube opening is lower than the outer tube opening in the axial direction of the blast lamp, and the outer tube opening and the inner tube opening are used for ejecting raw material gas to perform combustion reaction. The invention also provides a method for manufacturing the core rod by using the blowtorch vapor deposition, which can effectively solve the problem of low slopes on two sides of the refractive index distribution of the optical fiber core rod, thereby improving the transmission quality of the optical fiber, reducing the exceeding rate of optical parameters of the optical fiber and having higher deposition rate.
Description
Technical Field
The invention relates to the field of manufacturing of optical fiber preforms, in particular to a blowtorch suitable for manufacturing a core rod of a single-mode optical fiber preform by a VAD method and a method for depositing the core rod of the single-mode optical fiber preform by the blowtorch.
Background
With the development of optical fiber preform technology, the methods for preparing the currently mature preform core rod mainly include axial vapor deposition (VAD), Modified Chemical Vapor Deposition (MCVD), and plasma chemical vapor deposition (MCVD).
The equipment for manufacturing the core rod by the VAD method mainly comprises a reaction cavity, a blast burner, a raw material gas supply part, a powder rod rotary lifting part and a PC machine. Among the most critical components are the torches, which are designed to spray SiCl4/GeCl4/H2/O2Etc. through combustion hydrolysis reaction to produce SiO2、GeO2Isopowder (SiCl)4+2H2+O2→SiO2+4HCl，GeCl4+2H2+O2→GeO2+4HCl), the powder is deposited on a quartz target rod in the center of the cavity through thermophoresis, and the target rod rotates along with the chuck and rises to be gradually deposited as a core rod powder rod. The blowtorch is generally divided into a quartz blowtorch and a metal blowtorch according to the material, and the quartz blowtorch has the characteristics of good temperature resistance, no metal impurity pollution and the like, and is always preferentially used by VAD technology.
The ideal refractive index profile for a single mode fiber is a step profile with a core refractive index higher than the cladding refractive index, and the refractive index is stepped and abrupt from the core to the cladding. However, it is difficult to produce an ideal step-type refractive index profile in the conventional VAD-method core rod because dopants such as Ge element for increasing the core refractive index are diffused toward the outer cladding layer by high temperature during deposition, and are diffused and volatilized by high temperature and halogen in the subsequent dehydration process, so that the refractive index profile has a slope with a certain slope. Such a cross-sectional shape affects optical performance of the optical fiber, particularly dispersion wavelength, and shifts the zero dispersion wavelength to the long wavelength side. The dispersion in a single-mode fiber is an important parameter for representing the signal degradation degree, so the shape of the refractive index profile directly influences the transmission speed and quality of the single-mode fiber. In addition, the dispersion and volatilization of Ge element as a fiber core dopant can cause the uniformity of the height of a refractive index profile to be poor, so that the refractive index value delta n is fluctuated, the main parameters of the manufactured optical fiber are influenced, the uniformity of the mode field diameter, the cut-off wavelength and the like is poor, and the optical parameters are easy to exceed the standard in the drawing process. Therefore, how to form the step-type refractive index distribution close to the ideal and improve the consistency has important significance on ensuring the quality of the optical fiber.
Due to the popularization of 4G networks and the influence of the expiration of the service life of the first optical cables in China, the phenomenon of insufficient supply and demand appears in the market of the optical fiber preforms at present, and therefore factories of the optical fiber preforms select and improve the capacity of equipment in many ways. Since the productivity of the optical fiber preform depends on the core throughput, increasing the VAD deposition capacity is the most important aspect of increasing the productivity of the optical fiber preform enterprise. The deposition rate and efficiency of VAD deposition directly determines the throughput capacity of the plant, while deposition torches play a critical role in increasing deposition rate as a direct generator of deposition response.
In the conventional VAD core rod deposition process, a four-layer blowtorch is used for depositing a fiber core, which is formed by a central layer and three layers of pipe walls surrounding the central layer, wherein the pipe walls are concentrically distributed. Raw materials and various gases are introduced from the inner layer to the outer layer according to the following table 1, the raw materials are subjected to hydrolysis reaction in flame generated by burning the gases to generate SiO2 and GeO2 powder, and the powder is deposited to form a core rod powder rod. In current production, the deposition rate of this type of torch does not generally exceed 0.5 g/min.
[ Table 1]
The fiber core refractive index profile deposited by the blowtorch has certain slope gradient at the boundary part, which can affect the optical performance of the single-mode fiber, especially the dispersion wavelength, the output speed and the quality, and the deviation of optical parameters is easy to form over standard in the wire drawing process.
The invention patent CN200610129148.0 discloses a blowtorch for VAD to deposit fiber core, which has four-layer structure, and the core rod is deposited by introducing various gases according to the above table 1.
Chinese patent CN86103566A discloses a multi-layer burner suitable for VAD, which can stably manufacture a core with triangular refractive index profile, unlike a step-type refractive index profile burner.
The invention of Chinese patent CN200510050238.6 discloses a method for controlling the refractive index profile of a fiber core, which is mainly characterized in that the refractive index profile is closer to the step-type refractive index profile of a single-mode fiber by controlling the deposition temperature of a powder rod, adding O2 in the dehydration process and controlling the dehydration and vitrification temperature.
Disclosure of Invention
In view of the above, it is necessary to provide a torch comprising an inner tube and an outer tube sleeved on the inner tube, the outer tube having an outer tube opening, the inner tube having an inner tube opening lower than the outer tube opening in an axial direction of the torch, the outer tube opening and the inner tube opening being used for ejecting a raw material gas to perform a combustion reaction.
Further, the device is characterized in that the inner tube is provided with an inner tube feeding port, the outer tube is provided with an outer tube feeding port, and raw material gas is introduced into the inner tube and the outer tube to perform combustion reaction.
Furthermore, the outer tube comprises a first outer tube, a second outer tube, a third outer tube and a fourth outer tube which are sequentially sleeved from inside to outside, the first outer tube, the second outer tube, the third outer tube and the fourth outer tube are respectively provided with an outer tube opening, and the outer tube openings of the first outer tube, the second outer tube, the third outer tube and the fourth outer tube are on the same plane.
Further, the inner tube comprises a first inner tube, a second inner tube, a third inner tube and a fourth inner tube which are sequentially sleeved from inside to outside, the first inner tube, the second inner tube, the third inner tube and the fourth inner tube are respectively provided with the inner pipe ports, the inner pipe port of the first inner tube, the inner pipe port of the second inner tube, the inner pipe port of the third inner tube and the inner pipe port of the fourth inner tube and the outer pipe port are respectively provided with a first distance, a second distance, a third distance and a fourth distance, and the first distance, the second distance, the third distance and the fourth distance are gradually decreased one by one.
Further, the first distance, the second distance, the third distance and the fourth distance are gradually reduced one by one according to a reduction amount, the outer pipe orifice has a diameter, and the ratio of the reduction amount to the diameter of the outer pipe orifice is 0.02-0.04.
Further, the ratio of the fourth distance to the diameter of the outer pipe orifice is 0.6-1.0.
Further, the torch is made of quartz having a purity of 99.99% or more.
A method for manufacturing a core rod by using the blast lamp comprises the following steps:
rotating the target rod in a cavity at a speed of 10-40 r/min, and lifting the target rod at a speed of 30-60 mm/h;
and introducing raw material gas into the blowtorch, then ejecting the raw material gas from the blowtorch and combusting the raw material gas to generate a chemical reaction to generate silicon dioxide and germanium dioxide to be deposited on the target rod so as to form the core rod.
Further, the outer tube comprises a first outer tube, a second outer tube, a third outer tube and a fourth outer tube which are sequentially sleeved from inside to outside, the first outer tube, the second outer tube, the third outer tube and the fourth outer tube are respectively provided with a feed inlet for introducing the raw material gas, argon is introduced into the feed inlet of the first outer tube and the feed inlet of the third outer tube, hydrogen is introduced into the feed inlet of the second outer tube, and oxygen is introduced into the feed inlet of the fourth outer tube.
Further, the inner tube includes from interior to first inner tube, second inner tube, third inner tube and the fourth inner tube of establishing of outer cover in proper order, first inner tube the second inner tube the third inner tube with the fourth inner tube disposes a feed inlet respectively and is used for letting in raw materials gas, to the feed inlet of first inner tube lets in silicon tetrachloride and hydrogen, to the feed inlet of second inner tube lets in germanium tetrachloride and hydrogen, to the feed inlet of third inner tube lets in argon, to the feed inlet of fourth inner tube lets in oxygen.
Compared with the traditional four-layer blast burner, the blast burner provided by the invention changes the structure and the material feeding mode of the blast burner, and changes the reaction in combustion flame to generate SiO2、GeO2The distribution of the powder improves the refractive index distribution and improves the deposition rate, so that the single-mode optical fiber preform core rod with better quality can be deposited more quickly.
Drawings
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, wherein:
FIG. 1 is a schematic diagram of a conventional four-layer torch for VAD mandrel deposition;
FIG. 2 is a cross-sectional view of a conventional four-layer torch for VAD mandrel deposition;
FIG. 3 is a schematic view of a torch in an embodiment of the invention;
FIG. 4 is a cross-sectional view of a torch in an embodiment of the invention;
FIG. 5 is a schematic diagram of an ideal refractive index profile of a single mode optical fiber;
FIG. 6 is a schematic diagram of an apparatus of a VAD deposition apparatus;
FIG. 7 is a cross-sectional comparison of the refractive indices of cores deposited using a torch of an embodiment of the invention and a conventional four-layer torch;
FIG. 8 is a graph comparing deposition rates for deposition of a mandrel in a VAD process using a torch according to an embodiment of the present invention and a conventional four-layer torch;
FIG. 9 is a graph showing the comparison of the zero dispersion wavelength excess ratio between the conventional four-layer blowtorch and the single-mode optical fiber preform manufactured by the blowtorch of the present invention after drawing.
Fig. 10 is a graph comparing the fluctuation of the refractive index Δ n of the conventional four-layer torch and the torch manufacturing core rod in the embodiment of the present invention.
FIG. 11 is a graph showing the comparison of the mode field diameter overshoot of a single mode optical fiber preform drawn by a conventional four-layer torch and a torch according to an embodiment of the present invention.
FIG. 12 is a graph showing the comparison of the cut-off wavelength excess ratio of a single-mode optical fiber preform drawn by a conventional four-layer torch and a torch according to an embodiment of the present invention.
Description of the main elements
The following detailed description will further illustrate the invention in conjunction with the above-described figures.
Detailed Description
Before describing the present invention, it should be noted that the present invention is not limited to the specific embodiments described below. It will be appreciated by those skilled in the art that changes and modifications may be made to the embodiments described below without departing from the spirit of the invention as defined by the appended claims.
Fig. 1 and 2 are a schematic and cross-sectional view, respectively, of a conventional four-layer torch for VAD core rod deposition processes. In fig. 1 and 2, a conventional four-layer torch is formed of a central tube 14 and three outer tubes 15, 16, 17 surrounding the central tube, which are sequentially arranged from inside to outside. The central tube 14 and the three outer tubes 15, 16 and 17 are provided with feed inlets, namely, a first feed inlet 10, a second feed inlet 11, a third feed inlet 12 and a fourth feed inlet 13, the central tube 14 and the three outer tubes 15, 16 and 17 are provided with tube orifices, namely, a central tube orifice, a first outer tube orifice, a second outer tube orifice and a third outer tube orifice, and the central tube orifice, the first outer tube orifice, the second outer tube orifice and the third outer tube orifice are on the same plane.
The embodiment of the invention provides a blast lamp, which comprises an inner tube and an outer tube sleeved on the inner tube, wherein the outer tube is provided with an outer tube opening, the inner tube is provided with an inner tube opening, the inner tube opening is lower than the outer tube opening in the axial direction of the blast lamp, and the outer tube opening and the inner tube opening are used for ejecting raw material gas to perform combustion reaction.
Referring to fig. 3 and 4, the outer tube includes a first outer tube 30, a second outer tube 31, a third outer tube 32 and a fourth outer tube 33, which are sequentially sleeved from inside to outside, the first outer tube 30, the second outer tube 31, the third outer tube 32 and the fourth outer tube 33 respectively have a first outer tube opening, a second outer tube opening, a third outer tube opening and a fourth outer tube opening, and the first outer tube opening, the second outer tube opening, the third outer tube opening and the fourth outer tube opening are on the same plane.
The inner pipe comprises a first inner pipe 26, a second inner pipe 27, a third inner pipe 28 and a fourth inner pipe 29 which are sequentially sleeved from inside to outside, the first inner pipe 26, the second inner pipe 27, the third inner pipe 28 and the fourth inner pipe 29 are respectively provided with a first inner pipe orifice, a second inner pipe orifice, a third inner pipe orifice and a fourth inner pipe orifice, and the distances between the first inner pipe orifice, the second inner pipe orifice, the third inner pipe orifice and the fourth inner pipe orifice and the outer pipe orifice are gradually decreased. In the embodiment of the present invention, the first inner pipe orifice 26, the second inner pipe orifice 27, the third inner pipe orifice 28 and the fourth inner pipe orifice 29 and the outer pipe orifice respectively have a first distance, a second distance, a third distance and a fourth distance, the first distance, the second distance, the third distance and the fourth distance are gradually decreased according to a decreased amount L1, the outer pipe orifice has a diameter D, and a ratio of the decreased amount L1 to the outer pipe orifice diameter D is 0.02-0.04. In this embodiment, the outer nozzle diameter D is the diameter of the fourth outer nozzle.
Referring to fig. 5, fig. 5 is a schematic diagram of an ideal refractive index profile of a single mode optical fiber, which is a step profile having a core refractive index higher than a cladding refractive index, and a step-like abrupt change in refractive index from the core to the cladding. In fig. 4, the distances between the first inner pipe orifice 26, the second inner pipe orifice 27, the third inner pipe orifice 28 and the fourth inner pipe orifice 29 and the outer pipe orifice are gradually decreased according to the decreased amount L1, and the ratio of the decreased amount L1 to the diameter D of the outer pipe orifice is 0.02-0.04, so that the refractive index profile formed by the hydrolysis reaction of the raw materials of silicon tetrachloride and germanium tetrachloride is closer to a step-type refractive index distribution.
In this embodiment, the ratio of the distance between the fourth inner tube orifice and the outer tube orifice (i.e., the fourth distance L2) to the diameter D of the outer tube orifice is 0.6 to 1.0, so that the hydrolysis reaction pressure of the raw materials silicon tetrachloride and germanium tetrachloride at the burner orifice is higher, the reaction is more sufficient, and the deposition rate can be increased.
In fig. 3, the first inner tube 26, the second inner tube 27, the third inner tube 28, the fourth inner tube 29, the first outer tube 30, the second outer tube 31, the third outer tube 32, and the fourth outer tube 33 are all provided with feed inlets, which are the first inner tube feed inlet 18, the second inner tube feed inlet 19, the third inner tube feed inlet 20, the fourth inner tube feed inlet 21, the first outer tube feed inlet 22, the second outer tube feed inlet 23, the third outer tube feed inlet 24, and the fourth outer tube feed inlet 25 in sequence.
In an embodiment of the present invention, the torch is made of quartz having a purity of 99.99% or more. The quartz blowtorch has the characteristics of good temperature resistance, no metal impurity pollution and the like.
The invention also provides a device for manufacturing a core rod by using the blast burner for manufacturing the optical fiber preform, which comprises a quartz cavity 1, blast burners 6 and 7, a raw material gas supply part 8, a powder rod rotary lifting part and a PC (personal computer) 9, wherein the powder rod rotary lifting part comprises a lifting part motor 4, a chuck 5 and a metal suspender 2.
The invention also provides a method for manufacturing a core rod by using the blast burner for manufacturing the optical fiber preform, which comprises the following steps: depositing a core rod under VAD technology, suspending a quartz target rod 3 at the tail end of a metal suspension rod 2 and extending into a quartz cavity 1, controlling the rising and the rotation of a chuck 5 by a lifting part motor 4, keeping the core rod rotating (the rotating speed is generally 10-40 r/min) in the deposition process, and lifting at a certain speed (generally 30-60 mm/h). The quartz torches 6 and 7 of the present invention are installed at the right side of the chamber and connected to a raw gas disk 8 through a pipe. Because of SiCl as a raw material4And GeCl4Is liquid at ordinary temperature, so SiCl is contained in the raw gas disk 84And GeCl4The gas is transported in a heated pipeline by adopting an evaporation method, the temperature of the pipeline is generally kept between 80 and 120 ℃, and the flow is controlled by a mass flow Meter (MFC). Thus, SiCl4/GeCl4/H2/O2Raw material gas such as/Ar is blown out from quartz torches 6 and 7 and burned to generate chemical reaction to produce SiO2、GeO2Powder is deposited on the quartz target rod 3 which is put in advance, and the quartz target rod 3 is continuously rotated and lifted up to carry out core rod deposition.
When the burner in the embodiment of the invention is used for depositing the core rod, raw materials and various gases are respectively introduced into the inner tube and the outer tube through the feed inlets.
Silicon tetrachloride and hydrogen are introduced into a feed inlet 18 of the first inner tube, the silicon tetrachloride is used as raw material gas, the flow of the introduced silicon tetrachloride is 2.0-10.0 g/min, the hydrogen is used as combustible gas, and the flow of the introduced hydrogen is 1.0-10.0L/min.
Germanium tetrachloride and hydrogen are introduced into a feed port 19 of the second inner tube, the germanium tetrachloride is used as raw material gas, the flow of introduced silicon tetrachloride is 80.0-600.0 mg/min, the hydrogen is used as combustible gas, and the flow of introduced hydrogen is 1.0-10.0L/min.
Argon is introduced into a feed inlet 20 of the third inner tube, the argon is used as isolation gas, and the flow of the introduced argon is 1.0-8.0L/min.
Oxygen is introduced into a feed port 21 of the fourth inner tube, the oxygen is used as combustion-supporting gas, and the flow rate of the introduced oxygen is 8.0-30.0L/min.
Argon is introduced into the feeding hole 22 of the first outer tube, the argon is used as isolation gas, and the flow of the introduced argon is 1.0-10.0L/min.
The second outer tube feeding port 23 is filled with hydrogen which is used as combustible gas, and the flow rate of the hydrogen is 5.0-20.0L/min.
Argon is introduced into the third outer tube feeding port 24, the argon is used as isolation gas, and the flow of the introduced argon is 1.0-10.0L/min.
Oxygen is introduced into the feed inlet 25 of the fourth outer tube, the oxygen is used as combustion-supporting gas, and the flow rate of the oxygen is 10.0-40.0L/min.
The first inner tube 26 is fed with silicon tetrachloride and hydrogen through the first inner tube feeding hole 18, and the second inner tube 27 is fed with germanium tetrachloride and hydrogen through the second inner tube feeding hole 19, so that the refractive index profile formed by the feeding mode is closer to a step-type refractive index distribution, and the raw materials and the hydrogen are fed together to have a higher deposition rate.
And (3) performance testing:
1. refractive index testing of fiber core
A typical core rod deposited using a torch of the present invention and a core rod deposited using a conventional four-layer torch were selected, the core refractive index profiles were plotted and the patterns were overlaid and compared, and fig. 7 is a graph comparing the core refractive index profiles deposited using a torch of the present invention and a conventional four-layer torch. Where 34 is the core index profile deposited using the torch of the present embodiment, 35 is the core index profile deposited using a conventional four-layer torch, and 36 is the ideal index profile for a single mode fiber. It can be seen that the core refractive index profile of the VAD process using the torch deposited core rod of the present invention is closer to a step-index profile than the core refractive index profile using the conventional four-layer torch deposited core rod.
2. Deposition rate testing of core rods
The deposition rates of 50 core rods deposited by using the torch of the present invention and 50 core rods deposited by using the conventional four-layer torch are randomly extracted, and the deposition rates are calculated by adopting a formula of "deposition rate is equal to the weight of the core rod/deposition time", fig. 8 is a comparison graph of the deposition rates of the deposition core rods by using the torch of the present embodiment and the conventional four-layer torch in the VAD process, and it can be seen that the average deposition rate of the deposition core rods by using the torch of the present embodiment is 0.86g/min, and the average deposition rate of the deposition core rods by using the conventional four-layer torch is 0.44 g/min. The deposition rate of the torch deposition core rod in the embodiment of the invention is about 2 times that of the conventional four-layer torch.
3. Testing zero dispersion wavelength exceeding rate of optical fiber preform manufactured by core rod after wire drawing
The method comprises the steps of randomly extracting 50 core rods deposited by using the blowtorch and 50 core rods deposited by using the traditional four-layer blowtorch, manufacturing an optical fiber preform rod by adopting the same process in the same equipment, drawing the optical fiber by adopting the same drawing equipment, and calculating the zero dispersion wavelength exceeding rate by adopting a formula of exceeding rate, namely exceeding length/total drawing length, wherein fig. 9 is a comparison graph of the zero dispersion wavelength exceeding rate of the single-mode optical fiber preform rod manufactured by using the traditional four-layer blowtorch and the blowtorch. The average value of the zero dispersion wavelength standard exceeding rate of the optical fiber preform manufactured by the blowtorch deposition core rod in the VAD process in the embodiment of the invention after drawing is 0.19 percent, and the average value of the zero dispersion wavelength standard exceeding rate of the optical fiber preform manufactured by the traditional four-layer blowtorch deposition core rod after drawing is 0.36 percent. It is shown that the optical fiber preform drawn by the optical fiber obtained by depositing the core rod by the torch in the embodiment of the present invention has better transmission quality.
4. Refractive index delta n fluctuation of core rod, standard exceeding rate of die field diameter after drawing of optical fiber preform rod manufactured by core rod and standard exceeding rate test of cut-off wavelength after drawing of optical fiber preform rod manufactured by core rod
Randomly extracting 50 core rods deposited by using the blowtorch and 50 core rods deposited by using the traditional four-layer blowtorch, measuring and calculating the refractive index value delta n of 10 fiber cores at equal intervals by each core rod, and representing the fluctuation condition of the refractive index value delta n of one core rod by adopting the standard deviation of the 10 refractive index values delta n. Then, the same equipment is adopted to manufacture an optical fiber preform, the optical fiber preform is drawn by the same drawing equipment, the exceeding rate of the mode field diameter and the exceeding rate of the cut-off wavelength are calculated by adopting a formula of the exceeding rate being the exceeding length/the total drawing length, and referring to fig. 10, fig. 11 and fig. 12, the VAD process adopts the standard deviation mean value of the refractive index value delta n of the fiber core of the spray lamp deposition core rod in the embodiment of the invention to be 0.0075%, the standard deviation mean values of the mode field diameter and the cut-off wavelength of the manufactured optical fiber preform after drawing are respectively 0.32% and 0.38%, the standard deviation mean value of the refractive index value delta n of the fiber core of the conventional four-layer spray lamp deposition core rod is 0.0126%, and the exceeding rate mean values of the mode field diameter and the cut-off wavelength of the manufactured optical fiber preform after drawing are respectively 0.47% and 0.70%. It is shown that the optical fiber preform drawn by the optical fiber preform obtained by depositing the core rod by the torch in the embodiment of the present invention has better transmission quality.
The refractive index distribution of the core rod of the single-mode optical fiber preform manufactured in the embodiment of the invention is closer to the ideal step-type refractive index distribution of the single-mode optical fiber, the dispersion performance is better, and the transmission speed and the quality are higher; the refractive index value delta n of the single-mode optical fiber preform core rod is smaller in fluctuation, the consistency of main parameters of the manufactured optical fiber, such as mode field diameter, cut-off wavelength and the like, is high, and the optical parameter exceeding in the drawing process is reduced; the deposition rate can be improved, the output capacity of equipment is improved, and the economic benefit is higher.
Although the present invention has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.
Claims (8)
1. A torch comprising an inner tube and an outer tube fitted over the inner tube, the outer tube having an outer orifice and the inner tube having an inner orifice, wherein the inner orifice is lower than the outer orifice in an axial direction of the torch, and the outer orifice and the inner orifice are used to eject a raw material gas to perform a combustion reaction;
the inner pipe consists of a first inner pipe, a second inner pipe, a third inner pipe and a fourth inner pipe which are sequentially sleeved from inside to outside, the first inner pipe, the second inner pipe, the third inner pipe and the fourth inner pipe are respectively provided with an inner pipe orifice, the inner pipe orifice of the first inner pipe, the inner pipe orifice of the second inner pipe, the inner pipe orifice of the third inner pipe and the inner pipe orifice and the outer pipe orifice of the fourth inner pipe are respectively provided with a first distance, a second distance, a third distance and a fourth distance, and the first distance, the second distance, the third distance and the fourth distance are gradually decreased one by one;
the first distance, the second distance, the third distance and the fourth distance are gradually reduced one by one according to a reduction amount, the outer pipe orifice has a diameter, and the ratio of the reduction amount to the diameter of the outer pipe orifice is 0.02-0.04.
2. The torch according to claim 1, wherein the inner tube is provided with an inner tube feed opening, and the outer tube is provided with an outer tube feed opening for feeding a raw material gas into the inner tube and the outer tube to perform a combustion reaction.
3. The torch according to claim 1, wherein the outer tube comprises a first outer tube, a second outer tube, a third outer tube and a fourth outer tube, which are sequentially sleeved from inside to outside, the first outer tube, the second outer tube, the third outer tube and the fourth outer tube respectively have an outer tube opening, the outer tube openings of the first outer tube, the second outer tube, the third outer tube and the fourth outer tube are on the same plane, and the ratio of the reduction amount to the tube opening diameter of the fourth outer tube is 0.02-0.04.
4. The torch according to claim 1, wherein a ratio of the fourth distance to the diameter of the outer nozzle is 0.6 to 1.0.
5. The torch of claim 1, wherein the torch is made of quartz having a purity of 99.99% or more.
6. A method of manufacturing a mandrel using the torch according to claim 1, comprising the steps of:
rotating the target rod in a cavity at a speed of 10-40 r/min, and lifting the target rod at a speed of 30-60 mm/h;
and introducing raw material gas into the blowtorch, then ejecting the raw material gas from the blowtorch and combusting the raw material gas to generate a chemical reaction to generate silicon dioxide and germanium dioxide to be deposited on the target rod so as to form the core rod.
7. The method according to claim 6, wherein the outer tube comprises a first outer tube, a second outer tube, a third outer tube and a fourth outer tube which are sequentially sleeved from inside to outside, the first outer tube, the second outer tube, the third outer tube and the fourth outer tube are respectively provided with a feed inlet for introducing the raw material gas, argon is introduced into the feed inlet of the first outer tube and the feed inlet of the third outer tube, hydrogen is introduced into the feed inlet of the second outer tube, oxygen is introduced into the feed inlet of the fourth outer tube, and the ratio of the reduction amount to the diameter of the orifice of the fourth outer tube is 0.02-0.04.
8. The method according to claim 7, wherein the inner tube comprises a first inner tube, a second inner tube, a third inner tube and a fourth inner tube which are sequentially sleeved from inside to outside, wherein the first inner tube, the second inner tube, the third inner tube and the fourth inner tube are respectively provided with a feed inlet for feeding the raw material gas, silicon tetrachloride and hydrogen are fed into the feed inlet of the first inner tube, germanium tetrachloride and hydrogen are fed into the feed inlet of the second inner tube, argon is fed into the feed inlet of the third inner tube, and oxygen is fed into the feed inlet of the fourth inner tube.
Priority Applications (1)
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|---|---|---|---|
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| JPH04260616A (en) * | 1991-02-08 | 1992-09-16 | Sumitomo Electric Ind Ltd | Production of glass body |
| JP2003212560A (en) * | 2002-01-18 | 2003-07-30 | Sumitomo Electric Ind Ltd | Method for manufacturing fine glass deposit |
| CN1468822A (en) * | 2002-07-05 | 2004-01-21 | 株式会社藤仓 | Multitube burner and method for producing glass preform with the same multitube burner |
| CN110248900A (en) * | 2017-02-22 | 2019-09-17 | 古河电气工业株式会社 | Porous body synthesis multiple pipe burner and porous body synthesizer |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04260616A (en) * | 1991-02-08 | 1992-09-16 | Sumitomo Electric Ind Ltd | Production of glass body |
| JP2003212560A (en) * | 2002-01-18 | 2003-07-30 | Sumitomo Electric Ind Ltd | Method for manufacturing fine glass deposit |
| CN1468822A (en) * | 2002-07-05 | 2004-01-21 | 株式会社藤仓 | Multitube burner and method for producing glass preform with the same multitube burner |
| CN110248900A (en) * | 2017-02-22 | 2019-09-17 | 古河电气工业株式会社 | Porous body synthesis multiple pipe burner and porous body synthesizer |
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