WO2026007240A1 - 管内法光纤预制棒的制备方法 - Google Patents

管内法光纤预制棒的制备方法

Info

Publication number
WO2026007240A1
WO2026007240A1 PCT/CN2024/120104 CN2024120104W WO2026007240A1 WO 2026007240 A1 WO2026007240 A1 WO 2026007240A1 CN 2024120104 W CN2024120104 W CN 2024120104W WO 2026007240 A1 WO2026007240 A1 WO 2026007240A1
Authority
WO
WIPO (PCT)
Prior art keywords
quartz tube
optical fiber
mapping relationship
test
tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2024/120104
Other languages
English (en)
French (fr)
Inventor
肖武丰
王瑞春
王铁军
徐进
贺琳曼
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dongfeng Motor Group Co Ltd
Original Assignee
Dongfeng Motor Group Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dongfeng Motor Group Co Ltd filed Critical Dongfeng Motor Group Co Ltd
Publication of WO2026007240A1 publication Critical patent/WO2026007240A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C03B37/01807—Reactant delivery systems, e.g. reactant deposition burners
    • C03B37/01815—Reactant deposition burners or deposition heating means
    • 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
    • C03B37/07—Controlling or regulating

Definitions

  • This application relates to the field of optical fiber manufacturing technology, and in particular to a method for preparing an in-tube optical fiber preform.
  • Optical fiber preforms can be manufactured using in-tube PCVD (Plasma Chemical Vapor Deposition) or MCVD (Modified Chemical Vapor Deposition) or out-of-tube VAD (Vertical Axial Deposition) and OVD (Outside Vapor Deposition) processes.
  • PCVD Physical Vapor Deposition
  • MCVD Modified Chemical Vapor Deposition
  • VAD Very Axial Deposition
  • OVD Outside Vapor Deposition
  • the tube-based method involves introducing high-purity reactants such as SiCl4, O2, and GeCl4 into a high-purity quartz tube.
  • a microwave source resonant cavity or flame torch is used to excite the reaction, leading to chemical reaction and vapor deposition, forming a quartz glass deposition layer.
  • the refractive index distribution of the optical fiber is adjusted by incorporating dopants (such as Ge, P, F, B, Al, Ti, Zr, etc.) into SiO2.
  • dopants such as Ge, P, F, B, Al, Ti, Zr, etc.
  • the deposited quartz tube is then melted and shrunk in a high-temperature furnace to form a solid master rod.
  • the master rod is assembled with a matching sheath to form an optical fiber preform. This preform is then drawn into an optical fiber using a drawing machine.
  • the axial parameter fluctuations of optical fiber preforms directly affect the performance consistency of optical fibers; therefore, improving the uniformity of the axial parameters of the preform is crucial.
  • high-purity reactants undergo chemical reactions and vapor deposition within a quartz tube. Because the mixed gas flows from the inlet to the outlet within the tube, the uneven distribution of composition, temperature, pressure, density, and energy at various points within the tube leads to a certain axial deviation in the refractive index profile of the preform, thus affecting the consistency of the axial parameters and increasing the waste fiber rate.
  • This application proposes an in-tube method for fabricating optical fiber preforms to address these problems.
  • the main objective of this application is to propose a method for preparing optical fiber preforms using an in-tube method.
  • This method aims to address the problem that, during the traditional preform deposition process, the uneven distribution of composition, temperature, pressure, density, and energy at various points inside the tube leads to a certain deviation in the axial direction of the refractive index profile of the preform, which in turn affects the consistency of the axial parameters of the preform and increases the waste fiber rate.
  • the method for preparing an in-tube optical fiber preform proposed in this application includes the following preparation steps:
  • a preparation apparatus includes a rotatably mounted quartz tube, an excitation source for chemically depositing reactants within the quartz tube, and an exhaust structure located at the outlet end of the quartz tube.
  • the final mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube is determined.
  • the operation of the air extraction structure is controlled according to the actual discharge air pressure parameters of the quartz tube.
  • determining the final mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube includes:
  • Test master rods were fabricated multiple times using the aforementioned preparation equipment, and the test master rods were analyzed to establish a mapping relationship between the axial position of the excitation source and the discharge gas pressure parameters of the quartz tube.
  • the mapping relationship between the axial position of the excitation source and the discharge gas pressure parameters of the quartz tube was continuously adjusted.
  • the current mapping relationship corresponding to the test master rod is determined to be the final mapping relationship.
  • the process of repeatedly fabricating a test master rod using the preparation equipment, analyzing the test master rod to establish a mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube, and continuously adjusting the mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube includes:
  • the initial test master rod is analyzed to establish an initial mapping relationship between the axial position of the excitation source and the discharge gas pressure parameter of the quartz tube;
  • the process test master rod was fabricated using the fabrication equipment according to the initial mapping relationship
  • the process test master rod is analyzed to determine the process mapping relationship between the axial position of the excitation source and the discharge gas pressure parameter of the quartz tube;
  • the process test master rod is fabricated again using the same process mapping relationship from the previous preparation equipment until the process test master rod meets the qualification conditions.
  • the method further includes:
  • test master rod that meets the qualification conditions is drawn into fiber to form an optical fiber
  • the cross-sectional parameters of the optical fiber are analyzed, and the position of the cross-sectional parameters of the optical fiber on the mother rod is obtained based on the location of the optical fiber and the total drawing length of the test mother rod.
  • the final mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube is corrected by the profile parameters of the optical fiber.
  • a test master rod is fabricated using the aforementioned preparation equipment, and the test master rod is analyzed to establish a mapping relationship between the axial position of the excitation source and the outlet gas pressure parameters of the quartz tube, including:
  • test master rod was fabricated using the preparation equipment
  • test mother rod is cut at preset intervals to obtain different cross-sections
  • test mother rod is divided into multiple sub-regions along its axis according to multiple profile parameters
  • the variation value of the discharge air pressure parameter in each of the sub-regions is determined based on the multiple profile parameters located in each of the sub-regions;
  • the preset interval is D, and D ⁇ 20mm.
  • the number of the plurality of said sub-regions is a positive integer, and greater than or equal to 3; and/or,
  • the quartz tube used for depositing the test master rod has a total length of Lt, and the plurality of sub-regions include end sub-regions near the feed end and discharge end of the test master rod, the length of the end sub-regions being L1, and 0.05Lt ⁇ L1 ⁇ 0.3Lt; and/or,
  • the total length of the quartz tube used to deposit the test master rod is Lt, and Lt ⁇ 500 mm.
  • the outlet air pressure parameter of the quartz tube is between 8 mbar and 25 mbar.
  • the discharge air pressure parameter of the quartz tube fluctuates by less than 30% in each of the sub-regions.
  • the total length of the quartz tube used to deposit the test master rod is Lt;
  • the axial variation parameter of the discharge end pressure of the quartz tube in at least one of the multiple sub-regions remains unchanged, and the length of the sub-region is L2, L2 ⁇ 0.2Lt.
  • the outlet gas pressure parameter of the quartz tube changes continuously and gradually within each of the sub-regions as the axial displacement of the microwave resonant cavity or flame torch in the preparation equipment changes.
  • the profile parameters include at least one of the relative refractive index difference, diameter, and distribution index ⁇ of the layers of the test master rod.
  • the technical solution of this application by dividing the master rod into test zones, can treat the positions corresponding to the various profile parameters as the positions of the excitation source. Then, the mapping relationship between the axial position of the excitation source and the outlet gas pressure parameter of the quartz tube is obtained. Through multiple test master rod iterations, the mapping relationship between the excitation source position and the outlet pressure parameter under the current deposition conditions is optimized. The final mapping relationship is used as the control parameter for actual production. This method, because it is continuously iterated and optimized based on actual production data, results in a highly reliable mapping relationship, significantly improving the consistency of axial parameters after core rod production.
  • the consistency of axial parameters at the two ends of the core rod is poor, and this portion typically accounts for a large portion of the total rod length.
  • the production method in this solution can produce core rods with near-ideal profiles over a long axial region, particularly with a significantly reduced slope at the left and right ends, increasing the effective rod length and improving the yield of qualified optical fibers, thus possessing significant practical application value.
  • Figure 1 is a process flow diagram of the method for preparing the in-tube optical fiber preform provided in this application;
  • Figure 2 is a detailed process flow diagram of "determining the final mapping relationship between the axial position of the excitation source and the discharge gas pressure parameter of the quartz tube" in Figure 1.
  • FIG. 3 is a detailed process flow diagram of some of the processes shown in Figure 2;
  • Figure 4 is a partial process flow diagram after "when the test mother rod meets the qualification conditions, the current mapping relationship corresponding to the test mother rod is determined to be the final mapping relationship" in Figure 2;
  • Figure 5 is a schematic diagram of the specific process in Figure 2, which is "using the preparation equipment to make a test master rod, analyzing the test master rod, and establishing the mapping relationship between the position of the excitation source in the axial direction and the discharge gas pressure parameter of the quartz tube".
  • Figure 6 is a schematic diagram of the equipment structure used in the fabrication method of the in-tube optical fiber preform in Figure 1.
  • Figure 7 shows the relationship between the cross-sectional parameters of the mother rod and the discharge end pressure in Embodiment 2 of the preparation method of the optical fiber preform in Figure 1.
  • Figure 8 shows the relationship between the effective length of the mother rod and the total length of the mother rod in Figure 1.
  • Figure 9 shows the relationship between the cross-sectional parameters of the mother rod and the discharge end pressure in Embodiment 1 of the preparation method of the optical fiber preform in the tube method in Figure 1.
  • Figure 10 shows the relationship between the pressure change in the sub-region and the change of ⁇ 0 in Example 1 of the preparation method of the optical fiber preform in the tube in Figure 1.
  • Figure 11 shows the effect of pressure fluctuation at the discharge end on the deposition rate in Example 1 of the preparation method of the optical fiber preform in the tube in Figure 1.
  • Figure 12 shows the relationship between the cross-sectional parameters of the mother rod and the discharge end pressure in Embodiment 3 of the preparation method of the optical fiber preform in Figure 1.
  • the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.
  • Optical fiber preforms can be manufactured using in-tube PCVD (Plasma Chemical Vapor Deposition) or MCVD (Modified Chemical Vapor Deposition) or out-of-tube VAD (Vertical Axial Deposition) and OVD (Outside Vapor Deposition) processes.
  • PCVD Physical Vapor Deposition
  • MCVD Modified Chemical Vapor Deposition
  • VAD Very Axial Deposition
  • OVD Outside Vapor Deposition
  • the tube-in-tube method involves introducing high-purity reactants such as SiCl4, O2, and GeCl4 into a high-purity quartz tube 6 through a specific pathway.
  • a chemical reaction and vapor deposition are then induced using a microwave source resonant cavity or a flame torch to form a quartz glass deposition layer.
  • the reaction formula for the optical fiber master rod preparation is as follows:
  • the refractive index distribution of the optical fiber is adjusted by incorporating dopants (such as Ge, P, F, B, Al, Ti, Zr, etc.) into SiO2.
  • dopants such as Ge, P, F, B, Al, Ti, Zr, etc.
  • the deposited quartz tube 6 is then melted and shrunk in a high-temperature furnace to form a solid master rod.
  • the master rod is assembled with a matching sheath to form an optical fiber preform. This preform is then drawn into an optical fiber using a drawing machine.
  • the axial parameter fluctuations of optical fiber preforms directly affect the performance consistency of optical fibers; therefore, improving the uniformity of the axial parameters of the preforms is crucial.
  • high-purity reactants undergo chemical reactions and vapor deposition within a quartz tube 6. Because the mixed gas flows from the inlet to the outlet within the tube, the uneven distribution of composition, temperature, pressure, density, and energy at various points within the tube leads to a certain axial deviation in the refractive index profile of the preform, thus affecting the consistency of the axial parameters and increasing the waste fiber rate.
  • This application proposes an in-tube method for preparing optical fiber preforms to address these problems.
  • This application proposes a method for preparing an in-tube optical fiber preform to solve the above problems.
  • Mass Flow Controller A gas flow stabilization device that provides precise automatic control of the flow rate of reactants (such as GeCl4, C2F6, etc.) in the preparation of master rods.
  • the refractive index of the optical fiber preform can be divided into multiple layers.
  • the radius of each layer is the distance from the outer edge to the axis.
  • the relative refractive index of each layer is the refractive index relative to the cladding, and is usually also the refractive index relative to pure silicon dioxide.
  • the geometric parameters of the section include the diameter, roundness, and concentricity of each layer, while the optical parameters include the relative refractive index and distribution index.
  • the core refractive index profile of graded-index optical fibers needs to be designed with a refractive index distribution that gradually decreases continuously from the center to the edge of the core, commonly referred to as the " ⁇ profile". That is, a refractive index distribution that satisfies the following power-law function:
  • n1 represents the refractive index of the fiber axis
  • r indicates the distance from the fiber axis
  • ⁇ Represents the distribution index
  • ⁇ 0 Represents the refractive index of the fiber core center relative to the cladding.
  • Relative refractive index i.e., ⁇ i:
  • ni represents the refractive index at a distance i from the center of the fiber core
  • n0 represents the minimum refractive index of the fiber core, which is usually also the refractive index of the fiber cladding.
  • Core rod A prefabricated component containing a core layer and a partial cladding layer.
  • the total length of the mandrel is the distance between the inflection points at both ends of the reciprocating motion.
  • the effective length of the mandrel is the length of each section parameter that meets the requirements of the production control range.
  • Mother rod A reference mandrel used to test the axial distribution of profile parameters.
  • Figure 1 shows a schematic diagram of the PCVD production equipment and reactant supply for the master rod.
  • the reaction gas enters the preparation equipment 100 through a control valve (this device is a constant temperature control device).
  • the flow rate of a certain gaseous reactant e.g., GeCl4
  • the gaseous reactants are mixed in the pipeline and then enter the holding furnace 3 and high-purity quartz tube 6 through the infeed end rotating chuck assembly 4 and the extension tube for further heating. They then react in the reciprocating high-speed excitation source 2 (resonant cavity/flame torch) to form a glass deposition layer on the inner wall of the high-purity quartz tube 6.
  • the reaction exhaust gas is extracted from the outlet end extension tube and the outlet end rotating chuck assembly 4. After deposition, the master rod is shrunk and prepared into an optical fiber preform.
  • the MCVD (modified chemical vapor deposition) production equipment replaces the high-frequency resonant cavity in the figure with a flame torch and eliminates the need for the holding furnace 3.
  • This application provides a method for preparing an in-tube optical fiber preform, which improves the axial consistency of the core rod and can greatly increase the effective length of the mother rod and the yield of qualified optical fibers.
  • the axial distribution of the master rod parameters is affected by high-frequency equipment, motion systems, and high-temperature distribution, resulting in a certain degree of axial fluctuation. Due to the back-and-forth movement of the resonant cavity or flame torch, there are acceleration and deceleration processes and fluctuations in movement speed at both ends, leading to changes in the axial temperature distribution curve within the deposition holding furnace 3. Furthermore, the heating process of the reaction gas at the feed end causes the parameters of the master rod near the feed end (IS) to deviate from the ideal situation and fluctuate drastically. On the other hand, airflow fluctuations caused by the extraction at the discharge end and the gradual accumulation of dust in the discharge end pipe during deposition further exacerbate the parameter fluctuations of the master rod near the discharge end (OS).
  • the inventors discovered that when the excitation source 2 (resonant cavity/flame torch) moves along its axial position, the pressure at the discharge end can affect the flow and distribution of gas, the shape of plasma, etc., directly affecting the reaction efficiency of the mixed gas, and thus affecting the refractive index profile of the master rod.
  • precise axial control of the diameter, refractive index, or distribution index ⁇ of each layer of the profile can be achieved, improving the axial consistency of the master rod.
  • the effect of discharge end pressure on profile parameters is influenced by deposition conditions, including the flame torch opening, resonant cavity power, resonant cavity/flame torch moving speed, total flow rate and component ratio of the mixed gas inside the pipe, discharge end pressure, and total deposition time.
  • deposition conditions including the flame torch opening, resonant cavity power, resonant cavity/flame torch moving speed, total flow rate and component ratio of the mixed gas inside the pipe, discharge end pressure, and total deposition time.
  • deposition conditions including the flame torch opening, resonant cavity power, resonant cavity/flame torch moving speed, total flow rate and component ratio of the mixed gas inside the pipe, discharge end pressure, and total deposition time.
  • deposition conditions including the flame torch opening, resonant cavity power, resonant cavity/flame torch moving speed, total flow rate and component ratio of the mixed gas inside the pipe, discharge end pressure, and total deposition time.
  • an increase of 1 mbar in discharge end pressure leads to a 0.008 increase in the distribution index
  • this solution explores the mapping relationship between the position of the excitation source 2 along the axis of the quartz tube 6 and the discharge end pressure under a specific production condition to determine the production parameters of the discharge end pressure under this condition.
  • the mapping relationship between the excitation source 2 and the discharge end pressure under different conditions is determined, then during production, the mapping relationship parameters corresponding to the current production condition can be directly used for control to obtain a mother rod quality with better axial consistency under the current production condition.
  • This application provides a method for preparing an in-tube optical fiber preform, comprising the following steps:
  • a preparation apparatus 100 comprising a rotatably mounted quartz tube 6, an excitation source 2 for chemically depositing reactants within the quartz tube 6, and a suction structure 8 located at the outlet end of the quartz tube 6.
  • This structure constitutes the main structure for preparing the mandrel, but is not the entirety of the structure.
  • Auxiliary structures include a rotating chuck assembly 4, comprising an infeed end rotating chuck assembly 41 and an outlet end rotating chuck assembly 42.
  • the quartz tube 6 is mounted between these two chuck assemblies.
  • a corresponding motion structure 7 is also provided at the bottom of the excitation source 2.
  • the excitation source 2 is used to move along the axis of the quartz tube 6.
  • the exhaust structure 8 is used for the discharge of reaction tail gas and the pressure control at the outlet of the quartz tube.
  • a heat preservation furnace 5 is also provided outside the excitation source 2 and the quartz tube 6 to reduce heat loss and improve the reaction effect. All of the above structures are conventional structures.
  • the preparation equipment 100 is a vapor deposition equipment used in the production process of the master rod. It is an existing equipment. The specific structure of the production equipment will not be explained in detail here. The following description is also based on the main reaction structure.
  • the final mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6 is determined.
  • the axial variation parameter of the discharge pressure needs to be iteratively optimized through multiple master rods to obtain the correspondence between the discharge pressure and the position of the excitation source under specific deposition conditions, so as to obtain stable production data under the current deposition conditions.
  • the preparation equipment 100 to make test master rods multiple times, analyze the test master rods, establish the mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6, and continuously adjust the mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6.
  • the current mapping relationship corresponding to the test master rod is determined as the final mapping relationship.
  • the "multiple times using the preparation equipment 100 to make test master rods, analyzing the test master rods to establish the mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6, and continuously adjusting the mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6" specifically includes the following steps: using the preparation equipment 100 to make an initial test master rod under initial conditions; analyzing the initial test master rod to establish an initial mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6; using the preparation equipment 100 to make a process test master rod based on the initial mapping relationship; analyzing the process test master rod to determine the process mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6.
  • the test rod is typically divided into sections along its axial direction during testing, and a mapping relationship is established between each sub-section and the discharge end pressure.
  • this includes the following steps: fabricating the test rod using preparation equipment 100; cutting the test rod at preset intervals to obtain different cross-sections, wherein the preset interval is generally less than or equal to 20 mm, preferably less than or equal to 10 mm; analyzing and obtaining the cross-sectional parameters of each cross-section; dividing the test rod into multiple sub-sections along its axis based on the multiple cross-sectional parameters; determining the discharge air pressure parameter variation value in each sub-section based on the multiple cross-sectional parameters located in each sub-section; and establishing a mapping relationship between the axial position of the excitation source 2 and the discharge air pressure parameter of the quartz tube 6 based on the discharge air pressure parameter variation value and the axial position distribution of the multiple sub-sections.
  • the method of testing a single master rod is applied to multiple master rods to correct the mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6.
  • the mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6 for the current master rod is obtained using the above method.
  • the next master rod is produced using the current mapping relationship parameter, and the mapping relationship data for the current master rod is obtained again using the above analysis method.
  • the mapping relationship data generated by the previous master rod is corrected using the current mapping relationship data. This process is repeated to continuously correct the previous production data.
  • the mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6 generated by the current master rod is used as the standard production data under the current deposition conditions.
  • the discharge end pressure has a greater impact on the distribution index ⁇ , followed by the relative refractive index, and then the diameter.
  • the axial partitioning of the discharge end pressure is mainly determined by the distribution index ⁇ .
  • the axial partitioning of the discharge end pressure is mainly determined by the relative refractive index.
  • the discharge end pressure is between 5 mbar and 30 mbar.
  • a slightly higher discharge end pressure is preferable, but excessively high pressure leads to low deposition efficiency and dust accumulation causing pipe blockage.
  • the pressure within the sub-region changes continuously.
  • the greater the axial slope of the profile parameters within the sub-region the greater the axial slope of the discharge end pressure.
  • the discharge end pressure can remain stable.
  • the total fluctuation range of the discharge air pressure parameter of the quartz tube 6 within each sub-region is generally controlled to be within 30%.
  • the parameters of the two end sub-regions fluctuate significantly, and the corresponding discharge end pressure adjustment range is also larger. Sufficient length is required to avoid drastic changes in discharge end pressure.
  • the length of the main bar is generally 500mm to 2500mm. Therefore, the length of the two end sub-regions is 0.05 to 0.3 times the length of the main bar.
  • the master rod can be divided into three regions along its axis for doping compensation. Further subdivisions can be made if some intermediate parameters exhibit significant axial fluctuations.
  • the actual axial position of the excitation source 2 can be obtained according to the corresponding mapping relationship, and the actual discharge gas pressure parameter of the quartz tube 6 can be determined by querying the mapping relationship based on the actual position.
  • the mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6 is as follows:
  • the test parameters of the test master rod serve as the primary adjustment reference. After all parameters of the test master rod pass the tests, the parameters of the drawn optical fiber are used as an auxiliary adjustment reference. Specifically, this includes the following steps: drawing the test master rod that meets the qualification conditions to form an optical fiber; analyzing the cross-sectional parameters of the optical fiber; and obtaining the position of the cross-sectional parameters of the optical fiber on the master rod based on the location of the optical fiber and the total length of the drawn test master rod.
  • the cross-sectional parameters of the drawn optical fiber, the location of the optical fiber, and the total length of the drawn master rod can be converted into the axial position of the cross-sectional parameters on the master rod. If the total length of the drawn master rod is 200 km, and the test optical fiber is at the 100 km mark, the measured cross-sectional parameters are located at 50% of the axial length of the master rod. The final mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameters of the quartz tube 6 is corrected using the cross-sectional parameters of the optical fiber.
  • the axial variation parameter of the discharge end pressure needs to be iteratively optimized using multiple test master rods to obtain the response relationship between the discharge end pressure and the profile parameters under specific deposition conditions.
  • the axial variation of the profile parameters of the test master rod can be partitioned and fitted into a smooth curve, and the corresponding axial variation curve of the discharge end pressure can be directly calculated according to the above response relationship.
  • continuous axial variation of the discharge end pressure for continuous compensation is desirable, errors are unavoidable in parameter control during actual production.
  • a control method where the discharge end pressure remains constant within a certain region is simpler and more stable. Therefore, there is at least one sub-region in the partition where the discharge end pressure remains constant, and the length of the sub-region is L2, where L2 ⁇ 0.2Lt, and Lt is the total length of the test master rod.
  • ⁇ affects NA (numerical aperture of the fiber), and since the required range for NA is relatively large, ⁇ is considered as a zoning indicator next. Core diameter is considered last as the zoning criterion.
  • a 1580mm core rod is selected as the mother rod for testing. Specifically, test points are taken at 20mm intervals on the mother rod, and the cross-sections at these test points are tested using a profile testing device to measure the profile parameters of each cross-section (including the relative refractive index and diameter of each layer; for graded-index fibers, the distribution index ⁇ is also included).
  • the axial position in the device is divided into four sub-regions. Specifically, the lengths of the two sub-regions corresponding to the feed end and the output end are set to 240mm and 440mm respectively. The lengths of the two intermediate sub-regions, from the feed end to the output end, are 260mm and 640mm respectively.
  • the pressure values at the corresponding extraction structure 8 within multiple sub-regions are adjusted between 10 mbar and 25 mbar to establish a mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6. This mapping relationship is then used as the production control parameters under the current deposition conditions. Production is then carried out using these control parameters.
  • the quartz tube 6 is fixed on the rotating chuck assembly 4 of the preparation equipment 100.
  • Reactive gas is introduced into the quartz tube 6 through the flow control device 5, and the excitation source 2 (resonant cavity/flame torch) is activated and reciprocates along the axial direction of the quartz tube 6 (during this process, the operating parameters of the excitation source 2 remain constant), causing the reactive gas to react and deposit on the inner wall of the quartz tube 6.
  • the pressure values at the extraction structure 8 at the outlet end of the quartz tube 6 at different positions of the excitation source 2 along the axial direction of the quartz tube 6 are recorded. Through the above process, another intermediate master rod is produced. Next, testing is conducted using the current master bar.
  • the relevant cross-sectional test parameters for the current master bar can be obtained.
  • the axial position of the master bar in the equipment can be divided into four regions based on its parameter changes, each region being approximately linearly variable.
  • Sub-region 1 near the feed inlet and sub-region near the discharge end are affected by factors such as temperature changes, pressure fluctuations, mechanical vibrations, and speed fluctuations, exhibiting significant slopes and parameter fluctuations.
  • the intermediate state of the master bar is stable, with fluctuations generally controllable within ⁇ 1%, and ideally within ⁇ 0.5%.
  • sub-region 2 exhibits smaller parameter slopes and fluctuations. In this case, it can be merged with the intermediate sub-region, sometimes requiring only three sub-regions.
  • the comparative example uses a constant discharge end pressure, while the embodiment adjusts the discharge end pressure according to the axial position to achieve compensation and control of the refractive index deviation, significantly reducing the deviation of the profile parameters at both ends, and producing a core rod with a profile close to the ideal profile in a long axial region.
  • the slope of change at the left and right ends is significantly reduced, which increases the effective rod length and improves the yield of qualified optical fibers.
  • the pressure change at the discharge end in the corresponding sub-region is adjusted, and the above test process is repeated.
  • a curve showing the relationship between the test parameter changes between each sub-region and the pressure changes at the discharge end is established, and the final mapping relationship between the optimal excitation source 2 position and the discharge end pressure under the current deposition conditions is continuously optimized.
  • the test master rod that passes the final test is drawn into an optical fiber.
  • the cross-sectional parameters of the drawn optical fiber, the position of the optical fiber, and the total length of the drawn master rod can be converted into the axial position of the cross-sectional parameters on the core rod. Based on the production ratio of qualified optical fibers, the optical fiber test results, and their positions, the axial change trend of the discharge end pressure is further fine-tuned.
  • the deviation of ⁇ 0 between the two intermediate sub-regions can be controlled to be below 0.7.
  • the final mapping relationship is used as a control parameter to produce according to the current deposition conditions, thereby improving the axial parameter quality of the master rod.
  • the deposition conditions can be changed according to different needs, and the corresponding mapping relationship parameters can be obtained in the above manner.
  • production control can be directly performed using another corresponding mapping relationship to obtain a master rod that finally meets the production requirements.
  • the change of the ⁇ parameter is the main influencing parameter of the actual partition.
  • the specific reasons can be explained in 8. It can be seen that the total length of the mother bar is the distance between the inflection points at both ends of the reciprocating motion, and the effective bar length is the length of each profile parameter that meets the production control range requirements. Its total length is definitely greater than the effective bar length.
  • the excitation source itself has a certain length and the deposition is not uniform, with less deposition on both sides, a flared end forms at both ends after repeated deposition. This results in the length of the mandrel at both ends failing to meet geometric specifications. Therefore, although the total deposition length is relatively long, the actual length of the qualified mandrel obtained is not actually long.
  • the flared end of the quartz tube 6 has a relatively long flared end after deposition. This flared portion will be cut or melted off after compaction.
  • the core diameter ( ⁇ ) is the primary zoning criterion.
  • the numerical aperture (NA) affects the fiber's numerical aperture (NA), and since the required range for NA is relatively large, ⁇ is considered as a secondary zoning criterion. Finally, the core diameter is considered as the zoning criterion.
  • step-index core rods such as single-mode fiber
  • core diameter is more important, followed by core diameter as a zoning criterion.
  • a 1200mm core rod is selected for testing. Specifically, test points are taken at 10mm intervals on the core rod, and the cross-section at each test point is measured using a profile testing device to obtain the profile parameters of each section (including the relative refractive index and diameter of each layer; if it is a graded refractive index, its distribution index ⁇ is also included).
  • the axial position of the core rod in the device is divided into four sub-regions. Specifically, the core diameter is then divided into four sub-regions.
  • the lengths of the two sub-regions at the feed end and the discharge end should be set to 210mm and 230mm respectively, the length of one intermediate sub-region near the feed end should be set to 430mm, and the length of the other intermediate sub-region should be 330mm.
  • the pressure values at the corresponding locations within the multiple sub-regions corresponding to the suction structure 8 should be adjusted between 8mbar and 23mbar to establish a mapping relationship between the axial position of the excitation source 2 and the discharge gas pressure parameter of the quartz tube 6. This mapping relationship should then be used as the production control parameter under the current deposition conditions. Then, production is carried out using the above control parameters.
  • the quartz tube 6 is fixed on the rotating chuck assembly 4 of the preparation equipment 100.
  • Reactive gas is introduced into the quartz tube 6 through the flow control device 5, and the excitation source 2 (resonant cavity/flame torch) is activated and reciprocates along the axis of the quartz tube 6 (during this process, the operating parameters of the excitation source 2 are constant).
  • This causes the reactive gas to react and deposit on the inner wall of the quartz tube 6.
  • the pressure value of the suction structure 8 at the discharge end of the quartz tube 6 is recorded at different positions of the excitation source 2 along the axis of the quartz tube 6.
  • Another intermediate master rod is produced.
  • the current master rod is then tested, with test parameters referring to the above content.
  • the pressure change at the discharge end in the corresponding sub-region is adjusted.
  • the above test process is repeated, and a curve showing the relationship between the test parameter changes between each sub-region and the pressure changes between the discharge ends is established.
  • the curve is analyzed to obtain the corresponding ⁇ 0 deviation.
  • the final qualified test master rod is drawn into an optical fiber.
  • the cross-sectional parameters of the drawn optical fiber, the position of the optical fiber, and the total length of the drawn master rod can be converted into the axial position of the corresponding cross-sectional parameters on the core rod.
  • the optical fiber test results, and their positions the axial variation trend of the discharge end pressure is further fine-tuned.
  • the final mapping relationship between the optimal position of the excitation source 2 and the discharge end pressure corresponding to the current deposition conditions is determined.
  • the deviation of ⁇ 0 between the two intermediate sub-regions can be controlled between 0.6 and 0.8.
  • the final mapping relationship is used as a control parameter to produce according to the current deposition conditions, thereby improving the axial parameter quality of the master rod.
  • the deposition conditions can be changed according to different needs.
  • the corresponding mapping relationship parameters are obtained in the above manner, so that under one production condition, production control can be directly performed using another corresponding mapping relationship to obtain a core rod that finally meets the production requirements.
  • a 900mm diameter mother rod is selected for testing. Specifically, test points are taken at 10mm intervals on the test mother rod, and the cross-section at the test point is tested using a cross-section testing device to measure the cross-sectional parameters of each cross-section (including the relative refractive index and diameter of each layer; if it is a graded refractive index, its distribution index ⁇ is also included). Based on the changes in the cross-sectional parameters of the test mother rod, the axial position of the test mother rod in the device is divided into five sub-regions.
  • the lengths of the two sub-regions corresponding to the feed end and the discharge end are set to 180mm and 160mm respectively, the length of the middle sub-region near the feed end is set to 120mm, and the lengths of the other two middle sub-regions are 360mm and 80mm.
  • the pressure values at the corresponding extraction structure 8 within multiple sub-regions are adjusted between 9 mbar and 20 mbar to establish a mapping relationship between the axial position of the excitation source 2 and the outlet gas pressure parameter of the quartz tube 6. This mapping relationship is then used as the production control parameters under the current deposition conditions. Production is then carried out using these control parameters.
  • the quartz tube 6 is fixed on the rotating chuck 4 of the preparation equipment 100.
  • Reactive gas is introduced into the quartz tube 6 through the flow control device 5, and the excitation source 2 (resonant cavity/flame torch) is activated and reciprocates along the axial direction of the quartz tube 6 (during this process, the operating parameters of the excitation source 2 remain constant), causing the reactive gas to react and deposit on the inner wall of the quartz tube 6.
  • the pressure values at the extraction structure 8 at the outlet end of the quartz tube 6 at different positions of the excitation source 2 along the axial direction of the quartz tube 6 are recorded.
  • Another intermediate master rod is produced.
  • the current master rod is then tested again, with test parameters referring to the above content. Based on the obtained test parameters, the pressure change at the discharge end in the corresponding sub-region is adjusted.
  • the above test process is repeated, and a curve showing the relationship between the test parameter changes and the pressure changes at the discharge end between each sub-region is established.
  • the curve is analyzed to determine the ⁇ 0 deviation in each sub-region.
  • the final qualified test master rod is drawn into an optical fiber.
  • the cross-sectional parameters of the drawn optical fiber, the position of the optical fiber, and the total length of the drawn master rod can be converted into the axial position of the cross-sectional parameters on the core rod.
  • the axial change trend of the discharge end pressure is further fine-tuned to determine the final mapping relationship between the optimal position of the excitation source 2 and the discharge end pressure under the current deposition conditions.
  • the ⁇ 0 deviation of the two intermediate sub-regions can be controlled between 0.7 and 1.
  • the final mapping relationship is used as a control parameter to produce according to the current deposition conditions in order to improve the axial parameter quality of the master rod.
  • the deposition conditions can be changed according to different needs, and the corresponding mapping relationship parameters can be obtained in the above manner.
  • production control can be directly carried out with another corresponding mapping relationship to obtain a master rod that finally meets the production requirements.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture, Treatment Of Glass Fibers (AREA)

Abstract

本申请公开了一种管内法光纤预制棒的制备方法，包括以下制备步骤：提供制备设备，其中，制备设备包括转动安装的石英管，激发反应物在石英管内进行化学沉积的激发源，以及处在石英管的出气端的抽气结构；在预设的沉积条件下，确定激发源处在轴向上的位置和石英管的出料气压参数之间的终映射关系；获取激发源处在轴向上的实际位置，根据实际位置查询映射关系以确定石英管的实际出料气压参数；根据所述石英管的实际出料气压参数控制所述抽气结构动作。

Description

管内法光纤预制棒的制备方法
相关申请
本申请要求于2024年7月2日申请地、申请号为202410879027.6的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光纤制造技术领域，特别涉及一种管内法光纤预制棒的制备方法。
背景技术
生产光纤预制棒母棒可采用管内法的PCVD(Plasma Chemical Vapor Deposition)或MCVD(Modified Chemical Vapor Deposition)或管外法的VAD(Vertical Axial Deposition)和OVD(Outside Vapor Deposition)工艺制备。
其中管内法通过一定的途径在高纯石英管内通入如SiCl4、O2、GeCl4等高纯度反应物，利用微波源谐振腔或火焰喷灯激发而进行化学反应和气相沉积，形成石英玻璃沉积层。光纤母棒制备反应式如下：
SiCl4+O2＝SiO2+2Cl2
GeCl4+O2＝GeO2+2Cl2
在气相沉积法工艺制备母棒时，通过在SiO2中掺入掺杂剂(如：Ge、P、F、B、Al、Ti、Zr等)来调节光纤的折射率分布。通过高温炉熔缩，将沉积后的石英管制备成一根实心母棒。然后，母棒经腐蚀、清洗、干燥后与其相匹配的套管组合成光纤预制棒，通过拉丝设备将该预制棒拉制成光纤。
光纤预制棒的轴向参数波动会直接影响光纤的性能一致性，因此，提高预制棒的轴向参数均匀性至关重要。在管内法制备母棒的过程中，高纯度反应物在石英管内进行化学反应和气相沉积。由于混合气体在管内从进料端向出料端流动，管内各点的组分、温度、压力、密度和能量分布不均，导致母棒的折射率剖面在轴向上存在一定偏差，进而影响预制棒的轴向参数一致性，增加废纤率。本申请提出一种管内法光纤预制棒的制备方法用于解决以上问题。
发明内容
本申请的主要目的是提出一种管内法光纤预制棒的制备方法，旨在解决传统的母棒沉积过程中，管内各点的组分、温度、压力、密度和能量分布不均，导致母棒的折射率剖面在轴向上存在一定偏差，进而影响预制棒的轴向参数一致性，增加废纤率的问题。
为实现上述目的，本申请提出的管内法光纤预制棒的制备方法，包括以下制备步骤：
提供制备设备，其中，所述制备设备包括转动安装的石英管，激发反应物在所述石英管内进行化学沉积的激发源，以及处在所述石英管的出气端的抽气结构；
在预设的沉积条件下，确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的终映射关系；
获取所述激发源处在轴向上的实际位置，根据所述实际位置查询所述映射关系以确定所述石英管的实际出料气压参数；
根据所述石英管的实际出料气压参数控制所述抽气结构动作。
在一实施例中，确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的终映射关系，包括：
多次利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，并不断调整所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系；
在所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系。
在一实施例中，所述多次利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，并不断调整所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，包括：
利用制备设备以初始条件制作初始测试母棒；
分析所述初始测试母棒，以建立激发源处在轴向上的位置和所述石英管的出料气压参数之间的初始映射关系；
利用制备设备以所述初始映射关系制作过程测试母棒；
分析所述过程测试母棒，以确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的过程映射关系；
重复所述利用制备设备以前一次的所述过程映射关系再次制作过程测试母棒，直至所述过程测试母棒满足合格条件。
在一实施例中，所述在所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系之后，还包括：
对满足合格条件的所述测试母棒进行拉丝，以形成光纤；
对光纤的剖面参数进行分析，根据光纤所在位置与所述测试母棒的拉丝总长，获得所述光纤的剖面参数对应在所述母棒上的位置；
通过所述光纤的剖面参数修正所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的最终映射关系。
在一实施例中，利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，包括：
利用制备设备制作测试母棒；
根据预设间隔剖切所述测试母棒，以获得不同的剖切截面；
分析获取各所述剖切截面的剖面参数；
根据多个所述剖面参数将所述测试母棒沿其轴线分为多个子区；
根据处在各所述子区上的多个所述剖面参数确定各所述子区上的出料气压参数变化值；
根据所述出料气压参数变化值和所述多个子区在轴向上的位置分布建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系。
在一实施例中，所述预设间隔为D，且D≦20mm。
在一实施例中，多个所述子区的数量为正整数，且大于或等于3；和/或，
所述石英管用以沉积所述测试母棒的总长度为Lt，多个所述子区包括靠近所述测试母棒的进料端和出料端的端部子区，所述端部子区的长度为L1，且0.05Lt≦L1≦0.3Lt；和/或，
所述石英管用以沉积所述测试母棒的总长度为Lt，且Lt≧500mm。
在一实施例中，所述石英管的出料气压参数介于8mbar～25mbar。
在一实施例中，所述石英管的出料气压参数在各个所述子区内总的波动幅度在30％以内。
在一实施例中，所述石英管用以沉积所述测试母棒的总长度为Lt；
多个所述子区中至少有一个所述子区的石英管的出料端压力的轴向变化参数保持不变，该所述子区的长度L2，L2≧0.2Lt。
在一实施例中，所述石英管的出料气压参数随所述制备设备中的微波谐振腔或火焰喷灯的轴向位移在各个所述子区内连续渐变。
在一实施例中，所述剖面参数包括所述测试母棒各层的相对折射率差、直径和分布指数α中的至少一个。
本申请的技术方案通过对母棒进行测试分区，能够将各个所述剖面参数对应形成的位置看做是激发源的作用位置，然后得到所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，通过多个测试母棒测试迭代，去优化在当前沉积条件下的所述激发源位置与所述出料端压力参数之间的映射关系，以最终的映射关系，用作实际生产的控制参数。这种方式，因为是根据实际生产数据不断的进行迭代优化，所以最终形成的映射关系可靠性高，能够很好的提高芯棒生产之后的轴向参数的一致性。尤其是在传统的制备参数下，所述芯棒两端部的部分棒长轴向参数的一致性较差，通常这部分的棒长占据了总棒长的大部分，本方案中的生产方式能够制备出在较长的轴向区域内都接近理想剖面的芯棒，尤其是左右两端的变化斜率显著降低，提高了有效棒长，提高了合格光纤的产出比，具有较好的实际应用价值。
附图说明
为了更清楚地说明本申请实施例或相关技术中的技术方案，下面将对实施例或相关技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图示出的结构获得其他的附图。
图1为本申请提供的管内法光纤预制棒的制备方法的工艺流程图；
图2为图1中“确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的终映射关系”的具体工艺流程图；
图3为图2中公布的部分工艺的具体工艺流程图；
图4为图2中“所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系”之后的部分工艺流程图；
图5为图2中“利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系”的具体流程示意图；
图6为应用于图1中管内法光纤预制棒的制备方法的制备设备结构示意图；
图7为对应于图1中管内法光纤预制棒的制备方法的实施例二中，所述母棒的剖面参数与出料端压力之间的关系图；
图8为图1中所述母棒的有效棒长与所述母棒的总长之间的关系图；
图9为对应于图1中管内法光纤预制棒的制备方法的实施例一中，所述母棒的剖面参数与出料端压力之间的关系图；
图10为对应于图1中管内法光纤预制棒的制备方法的实施例一中，子区内压力变化对应Δ0的变化关系图；
图11为对应于图1中管内法光纤预制棒的制备方法的实施例一中，出料端压力的波动对沉积速率的影响关系图；
图12为对应于图1中管内法光纤预制棒的制备方法的实施例三中，所述母棒的剖面参数与出料端压力之间的关系图。
附图标号说明：
100、制备设备；2、激发源；3、保温炉；4、旋转夹头组件；41、进料夹头组件；42、出料夹头组件；5、流量控
制装置；6、石英管；7、运动结构；8、抽气结构。
本申请目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请的一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有作出创造性劳动的前提下所获得的所有其他实施例，都属于本申请保护的范围。
需要说明，若本申请实施例中有涉及方向性指示(诸如上、下、左、右、前、后……)，则该方向性指示仅用于解释在某一特定姿态下各部件之间的相对位置关系、运动情况等，如果该特定姿态发生改变时，则该方向性指示也相应地随之改变。
另外，若本申请实施例中有涉及“第一”、“第二”等的描述，则该“第一”、“第二”等的描述仅用于描述目的，而不能理解为指示或暗示其相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。另外，若全文中出现的“和/或”或者“及/或”，其含义包括三个并列的方案，以“A和/或B”为例，包括A方案、或B方案、或A和B同时满足的方案。另外，各个实施例之间的技术方案可以相互结合，但是必须是 以本领域普通技术人员能够实现为基础，当技术方案的结合出现相互矛盾或无法实现时应当认为这种技术方案的结合不存在，也不在本申请要求的保护范围之内。
生产光纤预制棒母棒可采用管内法的PCVD(Plasma Chemical Vapor Deposition)或MCVD(Modified Chemical Vapor Deposition)或管外法的VAD(Vertical Axial Deposition)和OVD(Outside Vapor Deposition)工艺制备。
其中管内法通过一定的途径在高纯石英管6内通入如SiCl4、O2、GeCl4等高纯度反应物，利用微波源谐振腔或火焰喷灯激发而进行化学反应和气相沉积，形成石英玻璃沉积层。光纤母棒制备反应式如下：
SiCl4+O2＝SiO2+2Cl2
GeCl4+O2＝GeO2+2Cl2
在气相沉积法工艺制备母棒时，通过在SiO2中掺入掺杂剂(如：Ge、P、F、B、Al、Ti、Zr等)来调节光纤的折射率分布。通过高温炉熔缩，将沉积后的石英管6制备成一根实心母棒。然后，母棒经腐蚀、清洗、干燥后与其相匹配的套管组合成光纤预制棒，通过拉丝设备将该预制棒拉制成光纤。
光纤预制棒的轴向参数波动会直接影响光纤的性能一致性，因此，提高预制棒的轴向参数均匀性至关重要。在管内法制备母棒的过程中，高纯度反应物在石英管6内进行化学反应和气相沉积。由于混合气体在管内从进料端向出料端流动，管内各点的组分、温度、压力、密度和能量分布不均，导致母棒的折射率剖面在轴向上存在一定偏差，进而影响预制棒的轴向参数一致性，增加废纤率。本申请提出一种管内法光纤预制棒的制备方法用于解决以上问题。
本申请提出一种管内法光纤预制棒的制备方法用于解决以上问题。
为方便介绍本申请内容，定义部分术语：
流量计(Mass Flow Controller，MFC)：质量流量控制器，为母棒制备提供精确反应物(如GeCl4、C2F6等)流量自动控制的气体稳流装置。
剖面参数：光纤预制棒的剖面折射率可分为多层，每层的半径为外边缘到轴心的距离，每层相对折射率为相对包层的折射率，通常也是相对纯二氧化硅的折射率。剖面的几何参数包括各层的直径、圆度、同心度等，光学参数包括相对折射率和分布指数。
渐变折射率光纤的芯层折射率剖面需设计成芯层中心至边缘连续逐渐降低的折射率分布，通常称其为“α剖面”。即满足如下幂指数函数的折射率分布：
其中，n1：表示光纤轴心的折射率；
r：表示离开光纤轴心的距离；
a：表示光纤芯半径；
α：表示分布指数；
Δ0：表示纤芯中心相对包层的折射率。
相对折射率，即Δi：
其中，ni：表示距离纤芯中心i位置的折射率；
n0：表示光纤芯层的最小折射率，通常也是光纤包层的折射率。
芯棒：含有芯层和部分包层的预制件。
芯棒的总长度为往复运动两端拐点的间距。
芯棒的有效棒长为其中各个剖面参数满足生产控制范围要求的长度。
母棒：用于测试剖面参数轴向分布的参考芯棒。
如图1所示为母棒PCVD生产设备和反应物供给示意图。反应气体通过控制阀进入制备设备100中(该装置为恒温控制装置)，某一气体反应物(如GeCl4)经质量流量控制器进行平稳的流量控制，其余反应物同理，由各自的质量流量控制器进行控制。各气体反应物在管道内混合并通过进料端旋转夹头组件4装置和延长管进入保温炉3和高纯石英管6内被进一步加热，后在往复高速运行的激发源2(谐振腔/火焰喷灯)内反应生成玻璃沉积层在高纯石英管6内壁，反应尾气从出料端延长管和出料端旋转夹头组件4装置被抽出，沉积完成后的母棒经熔缩后制备成光纤预制件。MCVD(改良化学气相沉积)生产设备则是将图中的高频谐振腔替换成火焰喷灯，且无需保温炉3。
本申请提供了一种管内法光纤预制棒的制备方法，提高芯棒的轴向一致性的方法，可以大大提高母棒的有效棒长和合格光纤的产出比例。
实际的生产过程中，母棒的参数轴向分布受高频设备、运动系统、高温分布等影响，存在一定的轴向波动性。由于谐振腔或者火焰喷灯来回移动，两端存在加减速过程及移动速度波动，沉积的保温炉3内轴向温度分布曲线变化，进料端反应气体的升温过程，母棒靠近进料端(IS)的区域参数偏离理想情况，且波动剧烈。另一方面，出料端的抽气导致的气流波动、沉积过程中出料端管道内粉尘逐渐堆积等，母棒靠近出料端(OS)区域的母棒参数波动更为显著。
发明人发现，在激发源2(谐振腔/火焰喷灯)沿轴向位置运动时，出料端处的压力可以影响气体的流动和分布、等离子体的形状等，直接影响混合气体的反应效率，从而影响母棒折射率剖面。通过精确调整出料端的压力，可以实现对剖面各层直径、折射率或者分布指数α的轴向精确管控，提升母棒的轴向一致性。
出料端压力对剖面参数的影响受其沉积条件影响，沉积条件包括火焰喷灯的开度、谐振腔的功率、谐振腔/火焰喷灯的移动速度、管内混合气体的总流量及组分比例、出料端压力、总沉积时间等。比如，在某个特定沉积条件下，出料端压力增大1mbar，分布指数α增大0.008。在另一个特定沉积条件下，出料端压力增大2mbar，相对折射率增大了3％，直 径相对初始条件减小0.7％。
所以本方案中，基于以上实际发现，通过探讨在某一特定的生产工况下，所述激发源2于所述石英管6轴线方向上的位置与出料端压力的映射关系，来确定在此工况下的出料端压力的生产参数。在实际的应用过程中，如果将不同工况下的所述激发源2与所述出料端压力之间的映射关系都进行确定，那么在生产的时候，就可以直接把对应当前生产工况的映射关系参数拿来直接进行使用控制，以得到在当前生产工况下的轴向一致性较好的母棒质量。
本申请提供一种管内法光纤预制棒的制备方法，包括以下步骤：
提供制备设备100，其中，所述制备设备100包括转动安装的石英管6，激发反应物在所述石英管6内进行化学沉积的激发源2，以及处在所述石英管6的出气端的抽气结构8，以上结构为制备芯棒的主要结构，并不是全部结构，其辅助结构还包括旋转夹头组件4，所述旋转夹头组件包括进料端旋转夹头组件41及出料端夹头组件42，所述石英管6安装于以上两个夹头组件之间，所述激发源2底部也设有相应的运动结构7，用以带动所述激发源2沿所述石英管6的轴线方向运动，所述抽气结构8用于反应尾气的排放及石英管出料端的压力控制，在所述激发源2与所述石英管6外侧还设有保温炉5，以减少热量的损失，提升反应效果，以上结构都为常规结构，所述制备设备100为母棒生产过程中使用的气相沉积设备，为现有的使用设备，此处不再对生产设备的具体结构作具体的解释说明，以下说明书中的内容也是根据主要的反应结构进行说明补充。
在预设的沉积条件下，确定激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的终映射关系；所述出料端压力的轴向变化参数需要经过多根母棒的迭代优化，才可以得到特定沉积条件下所述出料端压力与所述激发源之间位置的对应关系，以得到在当前沉积条件下的稳定生产数据，所以具体的，在预设的沉积条件下、例如特定的沉积气体，特定的气体供给参数以及特定的所述激振源的工作参数下，需要多次利用所述制备设备100制作测试母棒，分析所述测试母棒，以建立所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，并不断调整所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系；在所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系。
以上过程中，在一定的沉积条件下，为了保证得出的所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系的准确性，我们一般需要结合在当前沉积条件下生产的多个母棒测试参数对得出的中间映射关系进行不断的修正，所以所述“所述多次利用所述制备设备100制作测试母棒，分析所述测试母棒，以建立所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，并不断调整所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系”具体的包括以下步骤：利用制备设备100以初始条件制作初始测试母棒；分析所述初始测试母棒，以建立激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的初始映射关系；利用制备设备100以所述初始映射关系制作过程测试母棒；分析所述过程测试母棒，以确定激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的过程映射关系。
其中，为了测试过程中的便利性并且更加直观的反映沿所述母棒轴向方向上参数一致性与所述出料端压力之间的映射关系，在对所述测试母棒进行测试的时候，我们通常会沿所述测试母棒的轴线方向将所述测试母棒进行分区，并建立各个子区与所述出料端压力之间的映射关系。具体包括以下步骤：利用制备设备100制作测试母棒；根据预设间隔剖切所述测试母棒，以获得不同的剖切截面，其中预设间隔一般小于等于20mm，以小于等于10mm为佳；分析获取各所述剖切截面的剖面参数；根据多个所述剖面参数将所述测试母棒沿其轴线分为多个子区；根据处在各所述子区上的多个所述剖面参数确定各所述子区上的出料气压参数变化值；根据所述出料气压参数变化值和所述多个子区在轴向上的位置分布建立所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系。
将以上对单个母棒进行测试的方式应用到多个测试母棒中，从而对得出的所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系进行修正。简单的来讲就是，对单个所述测试母棒进行分区之后通过以上方式，得到对应当前所述测试母棒的所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，然后通过当前映射关系参数，生产下一个所述测试母棒，并通过以上分析方式再次得到对应当前所述测试母棒的映射关系数据，通过当前映射关系数据对上一个所述母棒产生的映射关系数据进行修正，以这种方式不断的对前一生产数据进行修正，在生产的测试母棒的各层的相对折射率差、直径和分布指数α符合生产需求的时候，以当前测试母棒产生的所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系为当前沉积条件下的标准生产数据。
在实际生产过程中，所述出料端压力对分布指数α的影响较大，其次是相对折射率，再次是直径。对渐变折射率光纤，尤其是多模光纤，出料端压力的轴向分区以分布指数α为主。而对于阶跃折射率剖面，出料端压力的轴向分区以相对折射率为主。
出料端压力介于5mbar～30mbar之间。出料端压力，现状是高一些好，但是太高会导致沉积效率太低，粉尘堆积导致堵管。通过设置激发源2移动至各端点时对应的出料端压力，子区内的压力连续变化。子区内剖面参数轴向变化斜率越大，出料端压力轴向变化斜率也越大。当子区内剖面参数变化不大，仅是＜0.5％以内的微小扰动时，可以保持出料端压力稳定不变，在生产的过程中一般控制所述石英管6的出料气压参数在各个所述子区内总的波动幅度在30％以内。
两端子区的参数波动较大，其对应的出料端压力调整范围也更大，需要足够的长度避免出料端压力的剧烈变化，母棒长度一般为500mm～2500mm。因此两端子区的长度为母棒长度的0.05～0.3倍。
一般而言，两端由于运动折返或进料出料等原因，其参数波动较大，中间区域受实际设备和工艺参数，其参数变化趋势存在差异。因此，可以将母棒轴向分为3个区域进行掺杂补偿。部分中间参数轴向波动显著的情况下，可以进一步细分。
在确定最终的所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系之后，在实际的生产过程中，可根据相应的映射关系，获取所述激发源2处在轴向上的实际位置，根据所述实际位置查询所述映射关系以确定所述石英管6的实际出料气压参数。
从而可以在生产过程中，根据所述石英管6的实际出料气压参数控制所述抽气结构8动作。使生产过程中的激发源2位置与所述出料端的实际压力进行对应，从而提高生产之后的母棒的轴向参数的一致性。
另外需要补充的是，上述的激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系以对应的所述 测试母棒的测试参数为主要调整参照，在所述测试母棒的各项参数测试合格之后，还需要以拉丝之后的光纤参数作为辅助调整参照，具体的包括以下步骤：对满足合格条件的所述测试母棒进行拉丝，以形成光纤；对光纤的剖面参数进行分析，根据光纤所在位置与所述测试母棒的拉丝总长，获得所述光纤的剖面参数对应在所述母棒上的位置，例如所述测试母棒拉丝后的光纤剖面参数、光纤所处位置与母棒拉丝总长度可换算成剖面参数对应在母棒的轴向位置。如母棒拉丝总长为200km，测试光纤在第100km处，即测得的所述剖面参数位于母棒轴向长度的50％处；通过所述光纤的剖面参数修正所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的最终映射关系。
以上过程制备过程中，由于出料端压力的轴向变化参数需要经过多根所述测试母棒的迭代优化，可以得到特定沉积条件下出料端压力对剖面参数的响应关系。在此条件下，可以将所述测试母棒剖面参数的轴向变化分区拟合成平滑曲线，按上述的响应关系直接计算出对应的出料端压力轴向变化曲线。出料端压力沿轴向连续变化以连续补偿固然是好的，但实际生产中参数控制不可避免的存在误差，出料端压力在一定区域内保持不变的控制方式是更简单且稳定的。因此，分区中至少有一个出料端压力保持不变的子区，子区的长度为L2，存在L2≧0.2Lt，Lt为所述测试母棒总长。
实施例一：
对渐变折射率多模光纤而言，带宽是最重要的，因此芯层的α是主要的分区依据。Δ影响NA(光纤的数值孔径)，NA的要求范围较大，其次考虑Δ作为分区指标。最后才考虑芯径作为分区依据。参照图8到图11，选取一个1580mm的芯棒作为母棒进行测试，具体的，在所述测试母棒上间隔20mm取一个测试点，然后通过剖面测试设备对所述测试点处的剖面进行测试，以测得各个所述剖面的剖面参数(包括各层的相对折射率、直径，如果是渐变折射率，还包括其分布指数α)，根据测试母棒的剖面参数变化，将所述测试母棒在设备中的轴向位置分为四个子区，具体的，将对应于进料端及出料端的两个子区长度分别设为240mm和440mm，二个中间子区的长度，由进料端向出料端依次为：260mm、640mm。并根据对应位置处的测试参数，在10mbar-25mbar之间调节多个所述子区内对应在所述抽气结构8处的压力值，使其形成一个所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，然后通过以上所述映射关系，作为当前沉积条件下的生产控制参数。然后以以上控制参数进行生产，具体的，将石英管6固定在所述制备设备100的旋转夹头组件4上，通过流量控制装置5向所述石英管6内部通入反应气体，并启动激发源2(谐振腔/火焰喷灯)工作并沿所述石英管6的轴线方向往复运动(此过程中，所述激发源2的工作参数一定)，促使所述反应气体产生反应并在所述石英管6内壁上产生沉积，并记录所述激发源2于所述石英管6轴线方向上的不同位置处时，对应在所述石英管6出料端处的抽气结构8的压力值。通过以上流程，再次生产一个所述中间母棒。再以当前所述母棒进行测试，测试参数参考上述内容，可得到对应当前母棒的相关剖面测试参数。具体的如图9所示，其中，母棒在设备中的轴向位置可根据其参数变化情况分为4个区域，每个区域近似看作是线性变化的。靠近进料口的子区1和靠近出料端的子区受到如温度变化、压力波动、机械振动、速度波动等因素的影响，呈现出较大的变化斜率和参数波动。母棒中间状态稳定，波动幅度一般可以控制在±1％以内，更优的可以控制在±0.5％以内。部分工艺条件合适的情况下，如图7错误！未找到引用源。所示，子区2的参数变化斜率和波动较小，此时可以将之与中间子区合并，有时仅需要分为3个子区。对比例采用的是恒定的出料端压力，而实施例中通过根据轴向位置调整出料端压力，可以实现对折射率偏差的补偿调控，显著降低两端剖面参数的偏离，制备出在较长的轴向区域内都接近理想剖面的芯棒，尤其是左右两端的变化斜率显著降低，提高了有效棒长，提高了合格光纤的产出比。
然后根据得到的相应测试参数对对应子区内的所述出料端的压力变化进行调整，重复以上测试过程，并建立相应的各个子区之间的测试参数变化与所述出料端之间压力的变化关系曲线，并不断的优化当前沉积条件的最佳的所述激发源2位置与所述出料端压力的最终映射关系。对最终测试合格的所述测试母棒进行拉丝，以形成光纤，测试所述测试母棒拉丝后的光纤剖面参数、光纤所处位置与母棒拉丝总长度可换算成剖面参数对应在芯棒的轴向位置，根据合格光纤的产出比例、光纤测试结果及其所处位置，进一步对出料端压力的轴向变化趋势进行微调。
得到在当前沉积沉积条件下的更优的所述激发源2位置与所述出料端压力的最终映射关系参数，且最中生产形成的芯棒的测试参数与出料端压力之间的关系如图9所示，其中，子区1、2和4的α显著提高，变化斜率明显降低。有利于提高高端多模光纤的产出比例。
本实施例中，两个中间子区的所述△0偏离量可控制在0.7以下。在具体的生产流程中，以所述最终映射关系作为控制参数，以对应当前沉积条件进行生产，以提高所述母棒的轴向参数质量，另外可根据不同的需求，更改沉积条件，以以上方式得到对应的映射关系参数，从而在一个生产条件下，可以直接以另一个对应的映射关系进行生产控制，以获得最终符合生产要求的芯棒。
其中，具体的剖面测试参数中，主要以α参数的变化为实际分区的主要影响参数，具体的原因可参照8进行说明，可以看出母棒的总长度为往复运动两端拐点的间距，有效棒长为其中各个剖面参数满足生产控制范围要求的长度，其总长度肯定是大于有效棒长的。
另外，由于激发源本身存在一定的长度，且沉积不是均匀性的，两侧的沉积量较少，因此在反复沉积后两端会形成喇叭口，所以导致所述芯棒两端部的部分棒长无法满足几何指标。因此沉积的总长度虽然较长，但是实际获得的合格芯棒长度其实并不长。沉积后石英管6内出料端的喇叭口较长。喇叭口的部分在熔实后就会被切割或者熔断。
对渐变折射率多模光纤而言，带宽是最重要的，因此芯层的α是主要的分区依据。Δ影响NA(光纤的数值孔径)，NA的要求范围较大，其次考虑Δ作为分区指标。最后才考虑芯径作为分区依据。
另一方面，如图10所示，子区1和子区2的出料端压力降低，其Δ0也同步降低，子区2和子区3的Δ0分布更为平稳。子区4的压力提高，Δ0提高。
实际上，如图11所示，在上述沉积条件下，压力的波动对沉积速率的影响较小，因此改进前后芯径基本无明显变化。
实施例二：
对于阶跃折射率的芯棒，如单模光纤，折射率的控制更重要，其次才考虑才考虑芯径作为分区依据。参照图7内容，选取一个1200mm的母棒进行测试，具体的，在所述测试母棒上间隔10mm取一个测试点，然后通过剖面测试设备对所述测试点处的剖面进行测试，以测得各个所述剖面的剖面参数(包括各层的相对折射率、直径，如果是渐变折射率，还包括其分布指数α)，根据测试母棒的剖面参数变化，将所述测试母棒在设备中的轴向位置分为四个子区，具体的，将对 应于进料端及出料端的两个子区长度分别设为210mm和230mm，靠近所述进料端的一个所述中间子区的长度设为430mm，另外一个中间子区长度为330mm。并根据对应位置处的测试参数，在8mbar-23mbar之间调节多个所述子区内对应在所述抽气结构8处的压力值，使其形成一个所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，然后通过以上所述映射关系，作为当前沉积条件下的生产控制参数。然后以上控制参数进行生产，具体的，将石英管6固定在所述制备设备100的旋转夹头组件4上，通过流量控制装置5向所述石英管6内部通入反应气体，并启动激发源2(谐振腔/火焰喷灯)工作并沿所述石英管6的轴线方向往复运动(此过程中，所述激发源2的工作参数一定)，促使所述反应气体产生反应并在所述石英管6内壁上产生沉积，并记录所述激发源2于所述石英管6轴线方向上的不同位置处时，对应在所述石英管6出料端处的抽气结构8的压力值。通过以上流程，再次生产一个所述中间母棒。再以当前所述母棒进行测试，测试参数参考上述内容，根据得到的相应测试参数对对应子区内的所述出料端的压力变化进行调整，重复以上测试过程，并建立相应的各个子区之间的测试参数变化与所述出料端之间压力的变化关系曲线，对曲线进行分析，得到对应的△0偏离量。对最终测试合格的所述测试母棒进行拉丝，以形成光纤，测试所述测试母棒拉丝后的光纤剖面参数、光纤所处位置与母棒拉丝总长度可换算成剖面参数对应在芯棒的轴向位置，根据合格光纤的产出比例、光纤测试结果及其所处位置，进一步对出料端压力的轴向变化趋势进行微调。确定对应当前沉积条件的最佳的所述激发源2位置与所述出料端压力的最终映射关系，本实施例中，两个中间子区的所述△0偏离量可控制在0.6到0.8。在具体的生产流程中，以所述最终映射关系作为控制参数，以对应当前沉积条件进行生产，以提高所述母棒的轴向参数质量，另外可根据不同的需求，更改沉积条件，以以上方式得到对应的映射关系参数，从而在一个生产条件下，可以直接以另一个对应的映射关系进行生产控制，以获得最终符合生产要求的芯棒。
实施例三：
如图12所示，选取一个900mm的母棒进行测试，具体的，在所述测试母棒上间隔10mm取一个测试点，然后通过剖面测试设备对所述测试点处的剖面进行测试，以测得各个所述剖面的剖面参数(包括各层的相对折射率、直径，如果是渐变折射率，还包括其分布指数α)，根据测试母棒的剖面参数变化，将所述测试母棒在设备中的轴向位置分为五个子区，具体的，将对应于进料端及出料端的两个子区长度分别设为180mm和160mm，靠近所述进料端的一个所述中间子区的长度设为120mm，另外两个中间子区长度为360mm和80mm。并根据对应位置处的测试参数，在9mbar-20mbar之间调节多个所述子区内对应在所述抽气结构8处的压力值，使其形成一个所述激发源2处在轴向上的位置和所述石英管6的出料气压参数之间的映射关系，然后通过以上所述映射关系，作为当前沉积条件下的生产控制参数。然后以以上控制参数进行生产，具体的，将石英管6固定在所述制备设备100的旋转夹头4上，通过流量控制装置5向所述石英管6内部通入反应气体，并启动激发源2(谐振腔/火焰喷灯)工作并沿所述石英管6的轴线方向往复运动(此过程中，所述激发源2的工作参数一定)，促使所述反应气体产生反应并在所述石英管6内壁上产生沉积，并记录所述激发源2于所述石英管6轴线方向上的不同位置处时，对应在所述石英管6出料端处的抽气结构8的压力值。通过以上流程，再次生产一个所述中间母棒。再以当前所述母棒进行测试，测试参数参考上述内容，根据得到的相应测试参数对对应子区内的所述出料端的压力变化进行调整，重复以上测试过程，并建立相应的各个子区之间的测试参数变化与所述出料端之间压力的变化关系曲线，对曲线进行分析，确定各个所述子区内的所述△0偏离量。对最终测试合格的所述测试母棒进行拉丝，以形成光纤，测试所述测试母棒拉丝后的光纤剖面参数、光纤所处位置与母棒拉丝总长度可换算成剖面参数对应在芯棒的轴向位置，根据合格光纤的产出比例、光纤测试结果及其所处位置，进一步对出料端压力的轴向变化趋势进行微调确定对应当前沉积条件的最佳的所述激发源2位置与所述出料端压力的最终映射关系，本实施例中，两个中间子区的所述△0偏离量可控制在0.7到1。在具体的生产流程中，以所述最终映射关系作为控制参数，以对应当前沉积条件进行生产，以提高所述母棒的轴向参数质量，另外可根据不同的需求，更改沉积条件，以以上方式得到对应的映射关系参数，从而在一个生产条件下，可以直接以另一个对应的映射关系进行生产控制，以获得最终符合生产要求的芯棒。
以上所述仅为本申请的示例性的实施方式，并非因此限制本申请的专利范围，凡是在本申请的技术构思下，利用本申请说明书及附图内容所作的等效结构变换，或直接/间接运用在其他相关的技术领域均包括在本申请的专利保护范围内。

Claims (12)

  1. 一种管内法光纤预制棒的制备方法，其中，所述管内法光纤预制棒的制备方法包括以下制备步骤：
    提供制备设备，其中，所述制备设备包括转动安装的石英管，激发反应物在所述石英管内进行化学沉积的激发源，以及处在所述石英管的出气端的抽气结构；
    在预设的沉积条件下，确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的终映射关系；
    获取所述激发源处在轴向上的实际位置，根据所述实际位置查询所述映射关系以确定所述石英管的实际出料气压参数；
    根据所述石英管的实际出料气压参数控制所述抽气结构动作。
  2. 如权利要求1所述的管内法光纤预制棒的制备方法，其中，确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的终映射关系，包括：
    多次利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，并不断调整所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系；
    在所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系。
  3. 如权利要求2所述的管内法光纤预制棒的制备方法，其中，所述多次利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，并不断调整所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，包括：
    利用制备设备以初始条件制作初始测试母棒；
    分析所述初始测试母棒，以建立激发源处在轴向上的位置和所述石英管的出料气压参数之间的初始映射关系；
    利用制备设备以所述初始映射关系制作过程测试母棒；
    分析所述过程测试母棒，以确定激发源处在轴向上的位置和所述石英管的出料气压参数之间的过程映射关系；
    重复所述利用制备设备以前一次的所述过程映射关系再次制作过程测试母棒，直至所述过程测试母棒满足合格条件。
  4. 如权利要求2所述的管内法光纤预制棒的制备方法，其中，所述在所述测试母棒满足合格条件时，确定所述测试母棒对应的当前映射关系为终映射关系之后，还包括：
    对满足合格条件的所述测试母棒进行拉丝，以形成光纤；
    对光纤的剖面参数进行分析，根据光纤所在位置与所述测试母棒的拉丝总长，获得所述光纤的剖面参数对应在所述母棒上的位置；
    通过所述光纤的剖面参数修正所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的最终映射关系。
  5. 如权利要求2所述的管内法光纤预制棒的制备方法，其中，利用所述制备设备制作测试母棒，分析所述测试母棒，以建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系，包括：
    利用制备设备制作测试母棒；
    根据预设间隔剖切所述测试母棒，以获得不同的剖切截面；
    分析获取各所述剖切截面的剖面参数；
    根据多个所述剖面参数将所述测试母棒沿其轴线分为多个子区；
    根据处在各所述子区上的多个所述剖面参数确定各所述子区上的出料气压参数变化值；
    根据所述出料气压参数变化值和所述多个子区在轴向上的位置分布建立所述激发源处在轴向上的位置和所述石英管的出料气压参数之间的映射关系。
  6. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，所述预设间隔为D，且D≦20mm。
  7. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，多个所述子区的数量为正整数，且大于或等于3；和/或，
    所述石英管用以沉积所述测试母棒的总长度为Lt，多个所述子区包括靠近所述测试母棒的进料端和出料端的端部子区，所述端部子区的长度为L1，且0.05Lt≦L1≦0.3Lt；和/或，
    所述石英管用以沉积所述测试母棒的总长度为Lt，且Lt≧500mm。
  8. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，所述石英管的出料气压参数介于8mbar～25mbar。
  9. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，所述石英管的出料气压参数在各个所述子区内总的波动幅度在30％以内。
  10. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，所述石英管用以沉积所述测试母棒的总长度为Lt；
    多个所述子区中至少有一个所述子区的石英管的出料端压力的轴向变化参数保持不变，该所述子区的长度L2，L2≧0.2Lt。
  11. 如权利要求5所述的管内法光纤预制棒的制备方法，其中，所述石英管的出料气压参数随所述制备设备中的微波谐振腔或火焰喷灯的轴向位移在各个所述子区内连续渐变。
  12. 如权利要求1所述的管内法光纤预制棒的制备方法，其中，所述剖面参数包括所述测试母棒各层的相对折射率差、直径和分布指数α中的至少一个。
PCT/CN2024/120104 2024-07-02 2024-09-20 管内法光纤预制棒的制备方法 Pending WO2026007240A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202410879027.6A CN118908558A (zh) 2024-07-02 2024-07-02 管内法光纤预制棒的制备方法
CN202410879027.6 2024-07-02

Publications (1)

Publication Number Publication Date
WO2026007240A1 true WO2026007240A1 (zh) 2026-01-08

Family

ID=93311273

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/120104 Pending WO2026007240A1 (zh) 2024-07-02 2024-09-20 管内法光纤预制棒的制备方法

Country Status (2)

Country Link
CN (1) CN118908558A (zh)
WO (1) WO2026007240A1 (zh)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1778744A (zh) * 2004-11-24 2006-05-31 三星电子株式会社 用于石英管的自动压力控制装置
CN106746591A (zh) * 2016-12-26 2017-05-31 长飞光纤光缆股份有限公司 一种pcvd沉积制作光纤预制棒芯棒的方法
CN112408775A (zh) * 2020-11-13 2021-02-26 烽火通信科技股份有限公司 一种光纤预制棒制造设备
CN113292240A (zh) * 2021-06-17 2021-08-24 长飞光纤光缆股份有限公司 一种渐变折射率剖面光纤预制棒芯层的沉积方法
US20220066113A1 (en) * 2020-08-25 2022-03-03 Northeastern University Gas pressure maintaining and adjusting device, and microstructure optical fiber and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1778744A (zh) * 2004-11-24 2006-05-31 三星电子株式会社 用于石英管的自动压力控制装置
CN106746591A (zh) * 2016-12-26 2017-05-31 长飞光纤光缆股份有限公司 一种pcvd沉积制作光纤预制棒芯棒的方法
US20220066113A1 (en) * 2020-08-25 2022-03-03 Northeastern University Gas pressure maintaining and adjusting device, and microstructure optical fiber and preparation method thereof
CN112408775A (zh) * 2020-11-13 2021-02-26 烽火通信科技股份有限公司 一种光纤预制棒制造设备
CN113292240A (zh) * 2021-06-17 2021-08-24 长飞光纤光缆股份有限公司 一种渐变折射率剖面光纤预制棒芯层的沉积方法

Also Published As

Publication number Publication date
CN118908558A (zh) 2024-11-08

Similar Documents

Publication Publication Date Title
CN101746949B (zh) 用于制备光学预制件的方法和装置
EP0061901A1 (en) Optical waveguide fiber, and methods of forming an optical waveguide fiber, and an optical waveguide preform
CN102757179B (zh) 一种大规格光纤预制棒的制备方法
CN106746591A (zh) 一种pcvd沉积制作光纤预制棒芯棒的方法
US7946133B2 (en) Methods for modifying ovality of optical fiber preforms
CN113292240B (zh) 一种渐变折射率剖面光纤预制棒芯层的沉积方法
RU2235071C2 (ru) Способ изготовления заготовки оптического волокна
CN120058229A (zh) 一种光纤预制棒、光纤的制备方法及高带宽多模光纤
EP2551248A2 (en) Methods for manufacturing low water peak optical waveguide
EP4253335A1 (en) A pcvd deposition process for manufacturing a primary preform as well as a method for forming optical fibres from such a preform
CN1194916C (zh) 一种高沉积速率pcvd工艺制作光纤芯棒的方法
CN117369041A (zh) 一种硼锗共掺型保偏光敏光纤及其制备方法
WO2026007240A1 (zh) 管内法光纤预制棒的制备方法
EP2784034B1 (en) Process for making large core multimode optical fibers
US5145509A (en) Method of manufacturing optical fibres
JP3576873B2 (ja) 光ファイバ母材の製造方法
CN109206006B (zh) 喷灯及芯棒的制造方法
DK2796420T3 (en) PCVD method for producing a primary optical fiber preform
CN203866200U (zh) 一种基于基管外径维持与修正控制制造光纤预制芯棒的装置
CN102276145A (zh) 一种光波导轴向均匀的光纤预制棒制作方法
CN111676468B (zh) 一种光纤预制件、多模光纤及其制备方法
US8826698B2 (en) Method for manufacturing a primary preform for optical fibres, primary preform, final preform and optical fibre
CN109608031B (zh) 一种pcvd工艺制备光纤预制棒的方法
JP3975709B2 (ja) 光ファイバ母材の製造方法
CN118908560A (zh) 管内法光纤预制棒的制备方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24946109

Country of ref document: EP

Kind code of ref document: A1