Rare earth doped core rod solution soaking device and method

Abstract

The invention provides a rare earth doped core rod solution soaking device and method, the rare earth doped core rod solution soaking device comprises a reaction kettle, a pressure control system, a solution system and a central controller, the reaction kettle is used for accommodating a quartz tube; the pressure control system comprises a vacuum subsystem and a pressure subsystem, and the vacuum subsystem and the pressure subsystem are both connected with the reaction kettle so as to depressurize or depressurize the interior of the reaction kettle; the solution system is connected with the reaction kettle, the solution system is configured to add or recover a doping solution into the reaction kettle, the doping solution comprises a wetting agent, and the wetting agent is used for reducing the surface tension of the doping solution; and the central controller is electrically connected with the vacuum subsystem, the pressure subsystem and the solution system. Through the synergistic effect of a physical pressure circulation system and chemical interface activity improvement, the problem of gas embolism residue is solved, and meanwhile the doping uniformity of the doping solution is improved.

Description

Technical Field

[0001] This application relates to the field of optical fiber manufacturing technology, and in particular to a rare earth doped core rod solution immersion device and method. Background Technology

[0002] In modern optical technologies such as optical communication, fiber lasers, and high-power amplifiers, rare-earth-doped optical fibers are the core materials for achieving high-performance laser output. For example, high-power fiber lasers are widely used in industrial cutting, medical surgery, and scientific research, and their output power, beam quality, and stability directly depend on the performance of rare-earth-doped optical fibers. Rare-earth ions (such as Yb³⁺, Er³⁺, etc.) serve as active media and need to be embedded into the fiber core through a uniform and high-concentration doping process. Currently, porous quartz tubes prepared by MCVD (modified chemical vapor deposition) are the main carriers for rare-earth doping, and their nanoscale porous structure provides the physical space for loading rare-earth ions. Traditional solution immersion processes face two major technical bottlenecks: first, air in the porous structure is difficult to completely escape, forming "air plugs" that lead to uneven doping concentration distribution; second, the surface tension between the solution and the quartz framework is too high, causing slow or even stagnant solution penetration in the micropores, ultimately triggering rare-earth ion clustering effects, which seriously affect the fluorescence lifetime and mode stability of the optical fiber. Furthermore, high-power lasers require extremely high uniformity in fiber doping; even minute concentration fluctuations can lead to instability or power attenuation in laser output. Therefore, developing a rare-earth doping process that can simultaneously address issues such as gas embolism, uneven wetting, and low doping efficiency has become a key technological requirement for improving fiber laser performance.

[0003] In the prior art, the doping time can be effectively reduced and the uniformity of doping can be improved by using a heating component to raise the temperature around the porous tube (e.g., CN118026517A); or, the solute distribution can be made more uniform and the utilization rate of the solution can be improved by rotating the porous tube and the doping solution (e.g., CN211367413U).

[0004] However, increasing the reactor temperature creates gas emboli that are difficult to expel, resulting in uneven radial dopant ion distribution; simply rotating the reactor has limited effect on improving doping uniformity and may also cause powder to fall off. Summary of the Invention

[0005] This application provides a rare earth doped mandrel solution immersion apparatus and method to solve the technical problem of removing air plugs while improving doping uniformity in the prior art.

[0006] In a first aspect, this application provides a rare earth doped mandrel solution immersion apparatus, comprising a reactor, a pressure control system, a solution system, and a central controller. The reactor is used to contain a quartz tube. The pressure control system includes a vacuum subsystem and a pressure subsystem, both of which are connected to the reactor to depressurize or pressurize the interior of the reactor. The solution system is connected to the reactor and is configured to add or recover a doping solution to the reactor. The doping solution includes a wetting agent used to reduce the surface tension of the doping solution. The central controller is electrically connected to the vacuum subsystem, the pressure subsystem, and the solution system.

[0007] The rare earth doped mandrel solution immersion device provided in this application achieves gas-liquid replacement through physical means of vacuum pumping and positive pressure driving. At the same time, it reduces the interfacial tension between the solution and the quartz skeleton by using a wetting agent, thereby achieving efficient and uniform filling of the solution in nanoscale pores. Through the synergistic effect of physical pressure circulation system and chemical interfacial activity improvement, the technical problems of gas embolism residue, doping uniformity and concentration fluctuation are solved.

[0008] As an optional implementation, the vacuum subsystem includes a first vacuum pump, a vacuum pipeline, and a vacuum valve. The first vacuum pump is connected to the interior of the reactor through the vacuum pipeline, and the vacuum valve is located in the vacuum pipeline for opening or closing the vacuum pipeline.

[0009] The pressure subsystem includes a gas source, a pressure regulating valve, and a pressurization pipeline. The gas source is connected to the inside of the reactor through the pressurization pipeline. The pressure regulating valve is located in the pressurization pipeline and is used to regulate the internal gas pressure of the reactor.

[0010] The pressure control system also includes a first pressure sensor, which is used to monitor the internal gas pressure of the reactor.

[0011] This setup, through the integration of vacuum extraction, pressure injection, and real-time monitoring, enables precise, automatic, and bidirectional control of the gas pressure inside the reactor, ensuring efficient, uniform, and depth-controllable penetration of the doping solution into the micropores of the quartz tube.

[0012] As an optional implementation, the solution system includes a second vacuum pump, a solution bottle, a filling valve, a solution pipeline, and a second pressure sensor. The solution bottle is connected to the interior of the reactor via the solution pipeline. The second vacuum pump is connected to the solution bottle and is used to adjust the pressure difference across the solution bottle to control the backflow of the doped solution. The filling valve is located in the solution pipeline and is used to open or close the solution pipeline. The second pressure sensor is used to monitor the pressure inside the solution bottle.

[0013] This setup, by precisely controlling the pressure difference between the solution bottle and the reactor, enables the uniform injection or discharge of the doping solution into the reactor, thereby improving the uniformity of rare earth doping and process efficiency.

[0014] As an optional implementation, the solvent of the doping solution is an alcohol; the rare earth element in the doping solution includes at least one of Y, Ce, Nd, Yb, Tm, Er, La, Bi, Ho, Pm, Sm, and Lu, and the non-rare earth element in the doping solution includes at least one of Al, P, and Ge.

[0015] This configuration improves the emission wavelength, amplification capability, and laser performance of active optical fibers through rare earth elements, while providing a uniform, stable, and efficient host environment for rare earth ions to emit light through non-rare earth elements, and constructing an optical waveguide.

[0016] As an alternative implementation, the wetting agent includes perfluoropolyether derivatives and / or perfluoroalkyl ethoxylates.

[0017] This configuration, through perfluoropolyether derivatives and / or perfluoroalkyl ethoxylates, reduces the contact angle and surface tension between the doping solution and the porous structure of the quartz tube. This transforms the solution from being difficult to wet into being easy to spread, allowing it to quickly fill the pores of the porous structure and making it easier to obtain highly concentrated doped porous structures.

[0018] As an optional implementation, the mass ratio of the wetting agent to the doping solution is 0.01%-1%.

[0019] This setup improves the wettability and penetration uniformity of the doping solution into the quartz tube, ensuring that the rare earth and co-doped element solutions fill the nanoscale pores more evenly and deeply.

[0020] As an optional implementation, when the vacuum subsystem depressurizes the quartz tube, the pressure inside the quartz tube is 10 Pa to 1000 Pa; when the pressure subsystem pressurizes the quartz tube, the pressure inside the quartz tube is 120 kPa to 150 kPa.

[0021] With this setup, negative pressure can extract a large amount of air from the pores of the quartz tube, while high pressure can provide an external driving force, ensuring that the doping solution can quickly fill all the pores.

[0022] As an alternative implementation, the reactor includes a shell and a liner, with the liner disposed inside the shell and used to fix the quartz tube.

[0023] This design allows the quartz tube to be secured by the liner, while simultaneously creating a clean chemical environment inside the pressure-bearing housing, providing isolation and protection for the quartz tube.

[0024] As an optional implementation, the liner is made of high-purity perfluoroalkoxy.

[0025] This setup, using high-purity perfluoroalkoxy as a liner to house the quartz tube, leverages its chemical inertness and extremely low metal impurity precipitation characteristics to isolate the container from contamination of the doping solution, ensuring the ultimate purity of the fiber core material.

[0026] Secondly, this application provides a mandrel doping method for use in the above-mentioned rare earth doped mandrel solution immersion apparatus, the method comprising:

[0027] Add an appropriate amount of wetting agent to the pre-prepared doping solution;

[0028] The quartz tube is placed in the reactor, and the vacuum subsystem first evacuates the inside of the reactor;

[0029] After maintaining a vacuum state for a specific time, the vacuum valve of the vacuum subsystem is closed, and the filling valve of the solution system is opened. Under the action of negative pressure, the doped liquid is filled into the interior of the quartz tube.

[0030] The central controller then controls the pressure subsystem to apply positive pressure to the interior of the reactor.

[0031] The pressure regulating valve of the pressure subsystem is closed by the central controller, and the second vacuum pump of the solution system is controlled to make the pressure in the solution bottle of the solution system lower than the pressure inside the reactor.

[0032] After the pressure in the solution bottle is balanced with the pressure inside the reactor, the quartz tube is removed for subsequent drying and sintering.

[0033] This application provides a rare earth doped mandrel solution immersion apparatus and method. The rare earth doped mandrel solution immersion apparatus includes a reaction vessel, a pressure control system, a solution system, and a central controller. The reaction vessel is used to contain a quartz tube. The pressure control system includes a vacuum subsystem and a pressure subsystem, both connected to the reaction vessel to depressurize or pressurize the interior of the reaction vessel. The solution system is connected to the reaction vessel and configured to add or recover a doping solution to the reaction vessel. The doping solution includes a wetting agent used to reduce the surface tension of the doping solution. The central controller is electrically connected to the vacuum subsystem, the pressure subsystem, and the solution system. This application solves the problem of gas embolism residue through the synergistic effect of a physical pressure circulation system and improved chemical interface activity, while simultaneously improving the doping uniformity of the doping solution.

[0034] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the rare earth doped core rod solution immersion device and method provided by this application, other technical features contained in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific embodiments. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of the rare earth doped mandrel solution immersion device provided in the embodiments of this application;

[0037] Figure 2 This is a schematic diagram of a rare earth-doped mandrel immersion method provided in an embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 10-Rare Earth Doped Mandrel Solution Immersion Device;

[0040] 100 - Reactor; 110 - Shell; 120 - Liner; 130 - Quartz tube;

[0041] 200-Pressure control system; 210-Vacuum subsystem; 211-First vacuum pump; 212-Vacuum pipeline; 213-Vacuum valve; 220-Pressure subsystem; 221-Gas source; 222-Pressure regulating valve; 223-Pressure pipeline; 230-First pressure sensor;

[0042] 300 - Solution system; 310 - Second vacuum pump; 320 - Solution bottle; 330 - Filling valve; 340 - Solution pipeline; 350 - Second pressure sensor;

[0043] 400 - Central Controller. Detailed Implementation

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] The terms "first," "second," and "third" (if any) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0047] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or maintenance tool that includes a series of steps or units, not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or maintenance tools.

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] In modern optical technologies such as optical communication, fiber lasers, and high-power amplifiers, rare-earth-doped optical fibers are the core materials for achieving high-performance laser output. For example, high-power fiber lasers are widely used in industrial cutting, medical surgery, and scientific research, and their output power, beam quality, and stability directly depend on the performance of rare-earth-doped optical fibers. Rare-earth ions (such as Yb³⁺, Er³⁺, etc.) serve as active media and need to be embedded into the fiber core through a uniform and high-concentration doping process. Currently, porous quartz tubes prepared by MCVD (modified chemical vapor deposition) are the main carriers for rare-earth doping, and their nanoscale porous structure provides the physical space for loading rare-earth ions. Traditional solution immersion processes face two major technical bottlenecks: first, air in the porous structure is difficult to completely escape, forming "air plugs" that lead to uneven doping concentration distribution; second, the surface tension between the solution and the quartz framework is too high, causing slow or even stagnant solution penetration in the micropores, ultimately triggering rare-earth ion clustering effects, which seriously affect the fluorescence lifetime and mode stability of the optical fiber. Furthermore, high-power lasers require extremely high uniformity in fiber doping; even minute concentration fluctuations can lead to instability or power attenuation in laser output. Therefore, developing a rare-earth doping process that can simultaneously address issues such as gas embolism, uneven wetting, and low doping efficiency has become a key technological requirement for improving fiber laser performance.

[0050] In the prior art, the doping time can be effectively reduced and the uniformity of doping can be improved by using a heating component to raise the temperature around the porous tube (e.g., CN118026517A); or, the solute distribution can be made more uniform and the utilization rate of the solution can be improved by rotating the porous tube and the doping solution (e.g., CN211367413U).

[0051] However, increasing the reactor temperature creates gas emboli that are difficult to expel, resulting in uneven radial dopant ion distribution; simply rotating the reactor has limited effect on improving doping uniformity and may also cause powder to fall off.

[0052] To address the aforementioned technical problems, this application provides a rare earth doped mandrel solution immersion apparatus and method. The rare earth doped mandrel solution immersion apparatus includes a reaction vessel, a pressure control system, a solution system, and a central controller. The pressure control system includes a vacuum subsystem and a pressure subsystem. Through the adjustment of the central oxygen controller, the vacuum subsystem can evacuate the reaction vessel to remove air plugs in the quartz tube. The solution system can add a doping solution containing a wetting agent to the reaction vessel. The addition of the wetting agent significantly reduces the contact angle between the solution and the quartz skeleton, making it easier for the solution to spread to the pore tips. At the same time, the pressure subsystem can apply positive pressure to the reaction vessel, further pushing the solution to fill the microporous structure of the porous tube through external driving force. Meanwhile, the low interfacial tension characteristics of the wetting agent allow the solution to spontaneously permeate in the micropores, avoiding the formation of secondary bubbles. Thus, through the synergistic effect of the physical pressure circulation system and the chemical interfacial activity improvement, air plug residue can be eliminated, while improving doping efficiency and doping uniformity, without damaging the quartz tube itself.

[0053] Figure 1 This is a schematic diagram of the structure of the rare earth doped mandrel solution immersion device provided in the embodiments of this application; Figure 2 This is a schematic diagram of a rare earth-doped mandrel immersion method provided in an embodiment of this application.

[0054] See Figure 1 and Figure 2 As shown, this application provides a rare earth-doped mandrel solution immersion device 10, including a reaction vessel 100, a pressure control system 200, a solution system 300, and a central controller 400. The reaction vessel 100 is used to contain a quartz tube 130 and provide space for immersing the quartz tube 130 in solution. The quartz tube 130 has a porous structure, and a solution doped with rare earth ions can be immersed in the micropores of the quartz tube 130. Through the rare earth ions, the optical properties of the quartz tube 130 can be improved. The pressure control system 200 includes a vacuum subsystem 210 and a pressure subsystem 220, both of which are connected to the reaction vessel 100. The pressure inside the reactor 100 is reduced or increased; the solution system 300 is connected to the reactor 100 and is configured to add a doping solution to the reactor 100 to soak the quartz tube 130, or to recover the doping solution in the reactor 100 to remove the quartz tube 130; the doping solution includes a wetting agent used to reduce the surface tension of the doping solution; the central controller 400 is electrically connected to the vacuum subsystem 210, the pressure subsystem 220 and the solution system, and the central controller 400 is equipped with a PLC (programmable logic controller) for programming and automatically controlling the entire pressure process.

[0055] Understandably, by using the physical means of the pressure control system 200 to control the pressure to achieve gas-liquid replacement, and by using a wetting agent to reduce the interfacial tension between the solution and the quartz framework, the solution can be efficiently and uniformly filled into the nanoscale pores. The synergistic effect of this physical pressure circulation system and the improvement of chemical interfacial activity can eliminate gas embolism residue, solve the problem of wetting dead zones, suppress the rare earth ion clustering effect, improve doping efficiency and concentration, and achieve uniform doping.

[0056] The vacuum subsystem 210 includes a first vacuum pump 211, a vacuum line 212, and a vacuum valve 213. The first vacuum pump 211 is connected to the interior of the reactor 100 through the vacuum line 212. The vacuum valve 213 is located in the vacuum line 212 and is used to open or close the vacuum line 212.

[0057] Among them, the first vacuum pump 211 can be an oil-free dry vortex vacuum pump, which achieves vacuuming through vortex motion to avoid oil contamination.

[0058] The pressure subsystem 220 includes a gas source 221, a pressure regulating valve 222, and a pressurization pipeline 223. The gas source 221 is connected to the interior of the reactor 100 through the pressurization pipeline 223. The pressure regulating valve 222 is located in the pressurization pipeline 223 and is used to regulate the internal gas pressure of the reactor 100.

[0059] The gas source 221 is a high-purity inert gas, such as helium or nitrogen, mainly used to change the internal pressure of the reactor 100, but it does not participate in the reaction. The pressure regulating valve 222 can be a digital or mechanical type, allowing for precise adjustment of the gas pressure. A booster pump can also be installed at the gas source 221 to prevent insufficient gas pressure.

[0060] The pressure control system 200 also includes a first pressure sensor 230, which is used to monitor the internal pressure of the reactor 100.

[0061] For example, the vacuum line 212 and the pressurization line 223 are combined into a common line before entering the reactor 100. This common line is connected to the reactor 100. The first pressure sensor 230 is installed on the common line. At most one of the vacuum valve 213 and the pressure regulating valve 222 is in the open state. In this way, the pressure inside the reactor 100 can be monitored in real time through the first pressure sensor 230 when evacuating or pressurizing.

[0062] The first vacuum pump 211, vacuum valve 213, pressure regulating valve 222, and first pressure sensor 230 are all electrically connected to the central controller 400. The central controller 400 obtains the pressure information inside the reactor 100 through the first pressure sensor 230, and adjusts the pressure inside the reactor 100 through the first vacuum pump 211, vacuum valve 213, and pressure regulating valve 222.

[0063] The solution system 300 includes a second vacuum pump 310, a solution bottle 320, a filling valve 330, a solution pipeline 340, and a second pressure sensor 350. The solution bottle 320 is connected to the interior of the reactor 100 through the solution pipeline 340. The second vacuum pump 310 is connected to the solution bottle 320 and is used to adjust the pressure difference across the solution bottle 320 to control the backflow of the doped solution. The filling valve 330 is located in the solution pipeline 340 and is used to open or close the solution pipeline. The second pressure sensor 350 is used to monitor the pressure inside the solution bottle 320.

[0064] The second vacuum pump 310 can also be an oil-free dry vortex vacuum pump to prevent oil contamination. The second vacuum pump 310 is located at the end of the solution bottle 320 away from the reactor 100. The filling valve 330 is located between the second vacuum pump 310 and the solution bottle 320, and the second pressure sensor 350 is located between the second vacuum pump 310 and the filling valve 330. When the solution bottle 320 fills the reactor 100, the reactor 100 has already been evacuated by the first vacuum pump 211. At this time, the second vacuum pump 310 is closed, and the filling valve 330 is opened. The doped solution in the solution bottle 320 flows to the reactor 100 under the action of pressure difference, immersing the quartz tube 130 inside the reactor 100. After immersion, because the reactor 100 is under high pressure, the second vacuum pump 310 is opened, causing the doped solution to flow back into the solution bottle 320 under the action of pressure difference.

[0065] The second vacuum pump 310, the filling valve 330, and the second pressure sensor 350 are all electrically connected to the central controller 400. The central controller 400 obtains the pressure information of the solution bottle 320 from the second pressure sensor 350 and calculates the pressure difference between the reactor 100 and the solution bottle 320, thereby controlling the second vacuum pump 310 and the filling valve 330 to start within the corresponding time period.

[0066] It should be noted that the wetting agent can be a fluorocarbon surfactant, which can significantly reduce the contact angle and surface tension between the solution and the porous material of the quartz tube 130. This makes the solution, which is difficult to wet, easy to spread and can quickly fill the pores of the porous material, making it easier to obtain a highly doped porous material. The wetting agent can be added to the prepared doping solution in a certain proportion and then passed into the solution bottle 320.

[0067] For example, the wetting agent can be one of a perfluoropolyether (PEPE) derivative or a perfluoroalkyl ethoxylate, or a mixture of a perfluoropolyether derivative and a perfluoroalkyl ethoxylate in a certain proportion. The nonionic wetting agent can completely decompose into gaseous products (such as CO2 and H2O) at high temperatures, leaving no carbon impurities in the quartz tube 130, thus ensuring the optical quality of the quartz tube 130.

[0068] As one possible approach, the mass ratio of the wetting agent to the doping solution is 0.01%-1%. At this concentration, the wetting agent can improve the wettability and penetration uniformity of the doping solution into the quartz tube 130, ensuring that the rare earth and co-doped element solutions are more uniformly and deeply filled into the nanoscale pores. This results in a glass core layer with highly uniform rare earth ion distribution and precisely controllable concentration after subsequent sintering. If the wetting agent concentration is below 0.01%, the surface tension of the solution is not sufficiently reduced; if the concentration is above 1%, the excess wetting agent is difficult to completely decompose and volatilize during the subsequent high-temperature sintering stage.

[0069] In some embodiments, the solution system 300 may also be equipped with a dynamic concentration adjustment module for the wetting agent. This module may include a concentration sensor and a micropump, both electrically connected to a central controller 400. Based on the concentration signal from the concentration sensor, the central controller 400 can control the micropump to dynamically adjust the amount of wetting agent added, ensuring wetting capability while avoiding increased solution viscosity or residue due to excessively high wetting agent concentration. The dynamic concentration adjustment module further eliminates the localized concentration fluctuations that may occur with traditional one-time wetting agent addition, thereby improving the doping uniformity at pore tips and in complex structural regions.

[0070] It should be noted that the solvent of the doping solution is an alcohol, such as methanol or ethanol; the rare earth elements in the doping solution include any one of Y, Ce, Nd, Yb, Tm, Er, La, Bi, Ho, Pm, Sm, and Lu, or any combination of these elements; the non-rare earth elements in the doping solution include any one of Al, P, and Ge, or any combination of these elements. Among these, rare earth elements are functional dopants that impart active amplification capability to the optical fiber, while Al, P, and Ge are functional dopants; they do not emit light directly but create an environment conducive to the efficient production of rare earth ions.

[0071] It should be noted that when the vacuum subsystem 210 reduces or evacuates the quartz tube 130, the pressure inside the quartz tube 130 is 10Pa-1000Pa. Under this negative pressure environment, a large amount of air in the pores of the quartz tube 130 will be extracted. When the pressure subsystem 220 pressurizes the quartz tube 130, the pressure inside the quartz tube 130 is 120kPa-150kPa. Under this high pressure environment, the gas pressure provides a strong external driving force, which, combined with the wetting agent, can ensure that the doping solution can quickly fill all the pores.

[0072] It should be noted that the reactor 100 includes a shell 110 and a liner 120. The liner 120 is disposed inside the shell 110. The shell 110 can be made of stainless steel, and the liner 120 can be made of an inert material, such as high-purity PFA (perfluoroalkoxy). On the one hand, the liner 120 can fix and house the quartz tube 130. On the other hand, the liner 120 separates a clean chemical environment inside the shell 110, providing isolation and protection for the quartz tube 130. This physically isolates the metal shell 110 from potential contamination, ensuring the cleanliness of the process.

[0073] This application also provides a mandrel doping method for the above-mentioned rare earth doped mandrel solution immersion apparatus 10, the method comprising:

[0074] S100. Add an appropriate amount of wetting agent to the pre-prepared doping solution.

[0075] S200. Place the quartz tube 130 in the reactor 100. The vacuum subsystem 210 first evacuates the inside of the reactor 100.

[0076] S300 After maintaining the vacuum state for a specific time, close the vacuum valve 213 of the vacuum subsystem 210 and open the filling valve 330 of the solution system 300. Under the action of negative pressure, the doped liquid is filled into the interior of the quartz tube 130.

[0077] S400, the central controller 400, and the pressure subsystem 220 control the application of positive pressure to the interior of the reactor 100.

[0078] S500: The pressure regulating valve of the pressure subsystem 220 is closed by the central controller 400, and the second vacuum pump 310 of the solution system 300 is controlled so that the pressure in the solution bottle 320 of the solution system 300 is less than the pressure inside the reactor 100.

[0079] S600. After the pressure in the solution bottle 320 is balanced with the pressure inside the reactor 100, the quartz tube 130 is removed for subsequent drying and sintering.

[0080] The beneficial effects of this application will be illustrated below through three embodiments.

[0081] Example 1: Using the traditional atmospheric pressure immersion doping method.

[0082] A porous core rod was vertically immersed in an open PFA container filled with the aforementioned doping solution and allowed to stand for 60 minutes at ambient pressure and room temperature. The final EPMA test results showed a Yb³⁺ concentration of 2000 ppm. The concentration fluctuation ((Cmax-Cmin) / Caverage×100%) was ±48%, and the average fluorescence lifetime of the core rod was measured to be 850 μs under 980 nm pumping.

[0083] Example 2: Pressure immersion doping.

[0084] A porous mandrel was placed in the pressure immersion apparatus of this invention. After closing the vessel lid, the following program was automatically executed by the PLC: vacuum was drawn to 100 Pa and held for 10 minutes. After introducing the doping solution, the positive pressure was controlled at 120 kPa and held for 20 minutes. The final EPMA test results showed that the concentration of Yb³⁺ was 2200 ppm, the concentration fluctuation ((Cmax-Cmin) / Caverage×100%) was ±30%, and the average fluorescence lifetime increased to 900 μs. 3+ The significant increase in doping concentration, lifetime, and uniformity indicates a weakening of the Yb³⁺ clustering effect.

[0085] Example 3: Pressure control combined with wetting agent immersion and doping

[0086] In the doping solution, 0.05 wt% of α-(perfluoro-1,1-dimethyl-2-hydroxyethyl)-ω-hydro-perfluoropolyether was added, and the soaking process was exactly the same as in Example 2. The EPMA test results of the resulting mandrel showed that the concentration of Yb³⁺ was 2500 ppm, the concentration fluctuation ((Cmax-Cmin) / Caverage×100%) was ±15%, and the average fluorescence lifetime was improved to 950 μs. The Yb³⁺ doping concentration was significantly improved, and it showed the best optical performance.

[0087] Referring to Table 1, the immersion apparatus and method provided by the present invention (Example 3) is significantly superior to the traditional atmospheric pressure immersion method in terms of the uniformity of rare earth ion distribution. At the same time, it can obtain a higher doping concentration in a shorter doping time. It also solves the problem of doped ion clusters caused by gas embolism and uneven wetting in the traditional process, providing a reliable core material guarantee for the preparation of high-performance high-power fiber lasers.

[0088] Table 1

[0089]

[0090] This application provides a rare earth doped mandrel solution immersion apparatus 10 and method. The rare earth doped mandrel solution immersion apparatus 10 includes a reaction vessel 100, a pressure control system 200, a solution system 300, and a central controller 400. The reaction vessel 100 is used to contain a quartz tube 130. The pressure control system 200 includes a vacuum subsystem 210 and a pressure subsystem 220, both of which are connected to the reaction vessel 100 to depressurize or pressurize the interior of the reaction vessel 100. The solution system 300 is connected to the reaction vessel 100 and is configured to add or recover a doping solution to the reaction vessel 100. The doping solution includes a wetting agent used to reduce the surface tension of the doping solution. The central controller 400 is electrically connected to the vacuum subsystem 210, the pressure subsystem 220, and the solution system. This application solves the problem of gas embolism residue through the synergistic effect of a physical pressure circulation system and improved chemical interface activity, while also improving the doping uniformity of the doping solution.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A rare earth-doped mandrel solution immersion device, characterized in that, include: A reaction vessel (100) for containing a quartz tube (130); A pressure control system (200) includes a vacuum subsystem (210) and a pressure subsystem (220), both of which are connected to the reactor (100) to depressurize or pressurize the interior of the reactor (100). A solution system (300) connected to the reactor (100) is configured to add or recover a doping solution to the reactor (100), the doping solution comprising a wetting agent for reducing the surface tension of the doping solution; A central controller (400) is electrically connected to the vacuum subsystem (210), the pressure subsystem (220), and the solution system (300).

2. The rare earth doped mandrel solution immersion device according to claim 1, characterized in that, The vacuum subsystem (210) includes a first vacuum pump (211), a vacuum pipeline (212), and a vacuum valve (213). The first vacuum pump (211) is connected to the interior of the reactor (100) through the vacuum pipeline (212). The vacuum valve (213) is located in the vacuum pipeline (212) and is used to open or close the vacuum pipeline (212). The pressure subsystem (220) includes a gas source (221), a pressure regulating valve (222), and a pressurization pipeline (223). The gas source (221) is connected to the interior of the reactor (100) through the pressurization pipeline (223). The pressure regulating valve (222) is located on the pressurization pipeline (223) and is used to regulate the internal gas pressure of the reactor (100). The pressure control system (200) also includes a first pressure sensor (230) for monitoring the internal pressure of the reactor (100).

3. The rare earth doped mandrel solution immersion device according to claim 1, characterized in that, The solution system (300) includes a second vacuum pump (310), a solution bottle (320), a filling valve (330), a solution pipeline (340), and a second pressure sensor (350). The solution bottle (320) is connected to the interior of the reaction vessel (100) through the solution pipeline (340). The second vacuum pump (310) is connected to the solution bottle (320) and is used to adjust the pressure difference between the two ends of the solution bottle (320) to control the backflow of the doped solution. The filling valve (330) is located in the solution pipeline (340) and is used to open or close the solution pipeline. The second pressure sensor (350) is used to monitor the pressure inside the solution bottle (320).

4. The rare earth doped mandrel solution immersion device according to claim 1, characterized in that, The solvent of the doping solution is an alcohol; the rare earth element in the doping solution includes at least one of Y, Ce, Nd, Yb, Tm, Er, La, Bi, Ho, Pm, Sm, and Lu; and the non-rare earth element in the doping solution includes at least one of Al, P, and Ge.

5. The rare earth doped mandrel solution immersion device according to claim 4, characterized in that, The wetting agent includes perfluoropolyether derivatives and / or perfluoroalkyl ethoxylates.

6. The rare earth doped mandrel solution immersion device according to claim 5, characterized in that, The mass ratio of the wetting agent to the mass of the doped solution is 0.01%-1%.

7. The rare earth doped mandrel solution immersion device according to claim 2, characterized in that, When the vacuum subsystem (210) depressurizes the quartz tube (130), the pressure inside the quartz tube (130) is 10Pa-1000Pa; when the pressure subsystem (220) pressurizes the quartz tube (130), the pressure inside the quartz tube (130) is 120kPa-150kPa.

8. The rare earth doped mandrel solution immersion device according to claim 1, characterized in that, The reactor (100) includes a shell (110) and a liner (120), the liner (120) being disposed inside the shell (110) and used to fix the quartz tube (130).

9. The rare earth doped mandrel solution immersion apparatus according to claim 8, characterized in that, The liner (120) is made of high-purity perfluoroalkoxy.

10. A method for immersing a rare earth-doped mandrel in a solution, characterized in that, The method is used in the rare earth doped mandrel solution immersion apparatus (10) as described in any one of claims 1-9, the method comprising: Add an appropriate amount of wetting agent to the pre-prepared doping solution; The quartz tube (130) is placed in the reactor (100), and the vacuum subsystem (210) first evacuates the inside of the reactor (100); After maintaining the vacuum state for a specific time, the vacuum valve (213) of the vacuum subsystem (210) is closed, and the filling valve (330) of the solution system (300) is opened. Under the action of negative pressure, the doped liquid is filled into the pores of the quartz tube (130). The central controller (400) then controls the pressure subsystem (220) to apply positive pressure to the interior of the reactor (100); The central controller (400) closes the pressure regulating valve (222) of the pressure subsystem (220) and controls the second vacuum pump (310) of the solution system (300) to operate so that the pressure in the solution bottle (320) of the solution system (300) is less than the pressure inside the reactor (100); After the pressure in the solution bottle (320) is balanced with the pressure inside the reactor (100), the quartz tube (130) is taken out for subsequent drying and sintering.

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