An optical fiber preform manufacturing apparatus and system

Abstract

The application provides a kind of optical fiber preform manufacturing equipment and system, it is related to optical fiber preform preparation technical field.The equipment includes gas inlet module and gas outlet module;Gas inlet module is equipped with gas inlet, and gas outlet module is equipped with gas outlet;The opening direction of gas inlet and gas outlet is along the direction of the busbar of the inner wall of reaction tube, so that the gas flow of gas inlet extends along the inner wall of reaction tube to gas outlet;The equipment also includes position adjusting module, for in the process of optical fiber preform deposition, as the deposition layer thickens in the reaction tube, the effective inner diameter of the reaction tube is reduced, the gas inlet and the gas outlet are driven to move along the inner wall of the reaction tube synchronously, so that the gas inlet and the gas outlet always maintain the gas flow path close to the inner wall of the reaction tube until the deposition process is completed.The application concentrates the reaction gas in the pipe wall deposition area, improves the gas molecular concentration of the reaction interface, reduces the invalid flow and waste of gas in the lumen center, and effectively improves the utilization rate of gas raw materials in the process of optical fiber preform manufacturing.

Description

Technical Field

[0001] This invention relates to the field of optical fiber preform preparation technology, and in particular to an optical fiber preform manufacturing equipment and system. Background Technology

[0002] As a core material in modern optical communication networks, the fabrication technology of optical fiber preforms directly affects key performance characteristics such as transmission loss, bandwidth, and reliability. Tubular chemical vapor deposition (CVD) is one of the mainstream processes for fabricating high-end optical fiber preforms, such as plasma chemical vapor deposition (PCVD). In tubular CVD, the process takes place within a sealed quartz reaction tube. Plasma is generated by exciting reactive gases (such as SiCl4 or GeCl4), causing the gaseous raw materials to oxidize and deposit on the inner wall of the tube. This layer-by-layer construction builds the desired glass film structure, which is then condensed at high temperatures to form a solid preform.

[0003] In existing technologies, the reaction gas delivery of tubular PCVD equipment generally adopts a central hole inlet and central hole outlet method. Specifically, at the inlet end of the reaction tube, the gas delivery pipe extends axially into the geometric central axis of the reaction tube; correspondingly, at the outlet end of the reaction tube, the vacuum extraction pipe is also fixed at the central axis position, and the exhaust gas after the reaction is discharged by the negative pressure generated by the vacuum pump.

[0004] While this center-inlet / center-outlet method offers advantages such as simple structure and easy-to-ensure sealing, during actual deposition, vacuum extraction creates an airflow field pointing towards the central axis within the tube. This results in a significant radial gradient in the injected reactive gas: the flow velocity and concentration are highest at the center of the tube, while near the inner wall region where the deposition reaction occurs, the gas velocity and concentration decrease sharply. A large amount of gaseous feedstock fails to react effectively at the tube wall and is extracted from the system as unreacted or intermediate products, limiting the effective reaction efficiency of the reactive gas at the tube wall. Therefore, the existing technology using center-inlet and center-outlet methods suffers from low utilization of reactive gas feedstock. Summary of the Invention

[0005] This invention provides an optical fiber preform manufacturing equipment and system to solve the problem of low utilization rate of reaction gas raw materials in existing methods.

[0006] In a first aspect, embodiments of the present invention provide an optical fiber preform manufacturing apparatus, comprising: an inlet module and an outlet module; a reaction tube is disposed between the inlet module and the outlet module to form a sealed tubular reaction chamber; the inlet module is provided with an inlet, and the outlet module is provided with an outlet; the opening directions of the inlet and outlet are arranged along the generatrix direction of the inner wall of the reaction tube, so that the airflow from the inlet extends along the inner wall of the reaction tube to the outlet; the apparatus further comprises a position adjustment module, used to drive the inlet and outlet to move synchronously with the inner wall of the reaction tube as the deposition layer inside the reaction tube thickens and the effective inner diameter of the reaction tube decreases during the optical fiber preform deposition process, so that the inlet and outlet always maintain an airflow path close to the inner wall of the reaction tube until the deposition process is completed.

[0007] In one possible implementation, the position adjustment module includes a linear motion unit; the linear motion unit is used to drive the air inlet and outlet to move linearly along the radial direction of the reaction tube; the stroke of the linear movement is less than the inner radius of the reaction tube before the optical fiber preform deposition.

[0008] In one possible implementation, it further includes: a first rotation drive module; the first rotation drive module is used to drive the reaction tube to rotate around the central axis during the optical fiber preform deposition process, wherein the positions of the air inlet and air outlet are stationary when the reaction tube rotates.

[0009] In one possible implementation, it further includes: a second rotation drive module; the second rotation drive module is used to drive the air inlet and air outlet to rotate synchronously around the central axis of the reaction tube during the optical fiber preform deposition process, wherein the reaction tube is stationary.

[0010] In one possible implementation, both the air intake module and the air outlet module include a stationary section and a rotating section, wherein the stationary section and the rotating section are rotatably and sealed together; the stationary section is fixedly and sealed together with the reaction tube; and the air inlet and air outlet are located in the rotating section of the corresponding module.

[0011] In one possible implementation, the rotating section includes: a sealing shell, a rotary sealing joint, and a flexible tube; the rotary sealing joint is located outside the sealing shell, with one end connected to an external stationary pipe and the other end fixed to the sealing shell of the rotating section and connected to the flexible tube inside the sealing shell; one end of the flexible tube is connected to the rotary sealing joint, and the other end serves as an air inlet or outlet.

[0012] In one possible implementation, the heating module is further included: a heating module that reciprocates along the axial direction of the reaction tube; wherein, during the deposition of the optical fiber preform, the heating module performs axial reciprocating motion after each time the air inlet and outlet rotate by a preset angle and stop rotating.

[0013] In one possible implementation, it further includes a heating module that reciprocates along the axial direction of the reaction tube; wherein, during the deposition of the optical fiber preform, the rotational motion of the air inlet and outlet is synchronized with the reciprocating motion of the heating module, and the time for the air inlet and outlet to rotate one revolution is not equal to the time for the heating module to reciprocate once along the axial direction of the reaction tube.

[0014] In one possible implementation, the air inlet and / or the air outlet is an arc-shaped flat opening; the concave surface of the arc-shaped flat opening faces the axis of the reaction tube to conform to the inner wall contour of the reaction tube.

[0015] In a second aspect, embodiments of the present invention provide an optical fiber preform manufacturing system, including the optical fiber preform manufacturing equipment as described in any one of the first aspects.

[0016] This invention provides an optical fiber preform manufacturing device. By setting the opening directions of the inlet and outlet along the generatrix direction of the inner wall of the reaction tube, the reactive gas, after being injected through the inlet, flows along the inner wall of the reaction tube and extends to the outlet where it is extracted. This changes the gas distribution state of "high concentration at the center and low concentration at the tube wall" in the traditional center-inlet method. Simultaneously, through a position adjustment module, the inlet and outlet move radially towards the central axis of the reaction tube during the deposition process as the deposition layer thickens and the effective inner diameter of the reaction tube decreases. This ensures that the airflow path always stays close to the dynamically changing tube wall reaction interface, guaranteeing that the reactive gas can be directly and continuously delivered to the deposition reaction surface throughout the entire deposition cycle.

[0017] The embodiments of the present invention concentrate the reactive gas in the deposition area of ​​the tube wall, thereby increasing the gas molecule concentration at the reaction interface, reducing the ineffective flow and waste of gas in the center of the tube, and effectively improving the utilization rate of gas raw materials in the optical fiber preform manufacturing process. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an optical fiber preform manufacturing equipment provided in an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached diagram: 1. Air intake module; 11. Air inlet; 2. Air outlet module; 21. Air outlet; 3. Reaction tube; 4. Position adjustment module; 5. Heating module. Detailed Implementation

[0020] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0021] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0022] The implementation of the present invention will be described in detail below with reference to the accompanying drawings: Tubular chemical vapor deposition (CVD) equipment is used to introduce gaseous reactants into a high-purity quartz glass tube. Through heating or plasma excitation, the gas undergoes oxidation or decomposition reactions on the inner wall of the tube, depositing quartz or doped quartz layers layer by layer, ultimately producing optical fiber preforms. Tubular CVD equipment can be widely used in the production of multimode optical fiber preforms for data centers, single-mode optical fiber core preforms, stress preforms for polarization-maintaining optical fibers, and radiation-resistant optical fiber preforms.

[0023] Tubular chemical vapor deposition equipment mainly includes PCVD (plasma chemical vapor deposition) and MCVD (modified chemical vapor deposition).

[0024] The reaction method of MCVD is a thermochemical reaction. The heat source is an oxyhydrogen flame that moves back and forth along the tube axis outside the tube. The tube wall is heated by high temperature, and the raw material gas is passed through the tube. The gas is oxidized and deposited on the tube wall at high temperature.

[0025] The reaction mechanism of PCVD is a plasma-induced reaction, with the heat source being an external microwave resonant cavity. The microwave resonant cavity generates microwaves, which directly excite the gas inside the tube to form plasma, which can be deposited on the tube wall at low temperatures.

[0026] In existing tubular chemical vapor deposition (CVD) equipment, the gas delivery method typically uses a central hole for both the inlet and outlet of the reaction tube. The gas flow distribution characteristics of this method are: the highest velocity and concentration in the center, with the concentration gradually decreasing radially outwards. This results in low utilization of the feedstock in the central region of the reaction tube, leading to feedstock waste.

[0027] Specifically, because the extraction port is located in the center of the tube and has a small diameter, a gas flow field pointing towards the central axis is formed inside the tube under vacuum negative pressure. This results in a significant gradient in the flow trajectory and concentration distribution of the reactant gas injected from the center along the tube diameter: the gas velocity is fastest and the concentration is highest near the central axis of the tube; while as the radial position moves outward closer to the inner wall surface where the actual deposition reaction occurs, the gas velocity and concentration decrease sharply.

[0028] This distribution pattern contradicts the energy supply method of CVD processes. For example, the energy for the PCVD reaction originates from the microwave radiation field generated by the external microwave resonant cavity. This microwave energy first acts on the quartz reaction tube wall, and then is conducted and permeates into the internal cavity space through the tube wall. Therefore, the region with the highest energy density, most conducive to exciting gas molecules to undergo deposition reactions, is precisely a thin layer of space close to the inner wall. From the reaction mechanism perspective, the resonant cavity of the PCVD system provides reaction energy through microwave radiation, and the effective distance of the microwave radiation field directly determines the sufficiency and efficiency of the reaction. Microwaves first act on the surface of the reaction tube and then propagate radially towards the center. Therefore, if the reactant gas can be brought closer to the inner wall of the reaction tube, the sufficiency of the reaction can be significantly improved, further optimizing the deposition efficiency.

[0029] This demonstrates that in existing technologies, high-concentration reactant gases are concentrated in the lower-energy center of the tube, while the area near the tube wall, where energy is highest, only receives lower concentrations of reactant gases. This mismatch—where high-concentration gases are far from the high-energy region, and the high-energy region lacks high-concentration gases—results in a large amount of valuable raw materials failing to be effectively activated and deposited, and instead being discharged from the system as unreacted or intermediate products through the central exhaust port. Although the macroscopic deposition efficiency of existing processes can reach a high level by optimizing parameters such as gas flow rate and pressure, the inefficient utilization of gas in the central region remains a major technical bottleneck leading to hidden waste of raw materials and hindering further cost reduction.

[0030] Therefore, there is an urgent need in the field to change the initial distribution and transport path of the reactant gas in the tube, so that it can be concentrated to the maximum extent in the area near the tube wall where the microwave energy is strongest, thereby significantly improving the utilization efficiency of the gas raw materials and reducing production costs.

[0031] The embodiments of the present invention address the problem of low utilization rate of reactant gas raw materials in existing methods by concentrating the reactant gas in the deposition area on the pipe wall.

[0032] Figure 1 This is a schematic diagram of an optical fiber preform manufacturing apparatus provided in an embodiment of the present invention. (Refer to...) Figure 1 The optical fiber preform manufacturing equipment includes: an inlet module 1 and an outlet module 2; a reaction tube 3 is arranged between the inlet module 1 and the outlet module 2 to form a sealed tubular reaction chamber; the inlet module is provided with an inlet 11 and the outlet module is provided with an outlet 21; the opening direction of the inlet and outlet is arranged along the generatrix direction of the inner wall of the reaction tube, so that the airflow from the inlet extends along the inner wall of the reaction tube to the outlet; the equipment also includes a position adjustment module 4, which is used to drive the inlet and outlet to move synchronously with the inner wall of the reaction tube as the deposition layer inside the reaction tube thickens and the effective inner diameter of the reaction tube shrinks during the optical fiber preform deposition process, so that the inlet 11 and outlet 21 always maintain an airflow path close to the inner wall of the reaction tube until the deposition process is completed.

[0033] Reference Figure 1 The core improvement of this optical fiber preform manufacturing equipment lies in its specially designed air inlet and outlet modules.

[0034] These two modules are positioned opposite each other, with the reaction tube serving as the basis for the deposition reaction between them. Once the reaction tube is in place, the inlet module, outlet module, and reaction tube together form a sealed tubular reaction chamber, providing a closed environment for chemical vapor deposition processes (e.g., PCVD).

[0035] The improvement in this embodiment is primarily reflected in the initial configuration of the gas passage. The inlet module has an inlet, and the outlet module has an outlet. The opening directions of the inlet and outlet are set along the generatrix of the inner wall of the reaction tube, i.e., they are set to coincide with the generatrix of the inner wall of the reaction tube. This means that the initial jet direction of the reaction gas ejected from the inlet is not directed towards the center of the tube cavity, but rather parallel to and closely adhering to the surface of the inner wall of the reaction tube. It should be noted that the coincidence described herein does not refer to an absolute, tolerance-free geometric coincidence. Those skilled in the art will understand that due to manufacturing and assembly tolerances, minor deviations that do not affect the primary function of "guiding the airflow along the inner wall of the reaction tube" are permissible. For example, there may be an angle of no more than 5 degrees between the opening direction and the generatrix; deviations within this angle range should still be considered as the coincidence described in this application.

[0036] This design allows the airflow to extend along the inner wall surface of the reaction tube and ultimately be extracted by the outlet, which is also located close to the inner wall. Through the directional design of the hardware structure, the mainstream of the reactive gas is forcibly guided to the area where it is most needed, such as the vicinity of the tube wall where the microwave energy field is strongest and where deposition actually occurs. This avoids the initial waste caused by gas enrichment in an ineffective central area, as is common in traditional center-inlet methods, from the very beginning of deposition.

[0037] Furthermore, this embodiment introduces a position adjustment module to address the dynamic changes during the deposition process. During the fiber preform deposition, as the deposition layer thickens on the inner wall of the reaction tube, the effective inner diameter of the reaction tube continuously shrinks, meaning the actual reaction "working surface" moves towards the center of the tube. The position adjustment module drives the inlet and outlet to move synchronously and coaxially radially, allowing them to "follow" this inwardly moving inner wall of the reaction tube in real time. Essentially, this achieves dynamic tracking and locking of the airflow path inlet and outlet relative to the reaction interface. Through this mechanism, regardless of the stage of deposition (early, middle, or late), the inlet and outlet always remain close to the latest inner wall of the reaction tube, thus maintaining a stable airflow path that remains firmly attached to the reaction interface until the entire deposition process is complete.

[0038] For example, the specific implementation of the position adjustment module may include a precision linear guide, a lead screw and slider mechanism, or a radial moving platform driven by a servo motor. The air inlet and outlet can be mounted on independent moving units and coordinated by a central controller to ensure the synchronicity and collinearity of their movements.

[0039] In summary, this embodiment combines "initially close to the inner wall lateral flow" with "synchronous tracking as the inner diameter decreases," ensuring that the reactant gas is directly transported to the deposition reaction interface from two dimensions: initial spatial distribution and maintenance over time, thereby improving the utilization rate of gaseous raw materials.

[0040] In some embodiments, the optical fiber preform manufacturing equipment includes: an inlet module and an outlet module; a reaction tube is disposed between the inlet module and the outlet module to form a sealed tubular reaction chamber.

[0041] For example, the reaction tube, also known as the liner, can be a quartz glass tube. For instance, the inner diameter of the reaction tube can be 28 to 32 centimeters.

[0042] There is a reserved installation space between the air intake module and the air outlet module to accommodate the reaction tube, which can be detachably installed. When the three are assembled, they together form a sealed tubular reaction chamber.

[0043] It should be noted that the reaction tube is not an inherent component of the optical fiber preform manufacturing equipment of this invention; its essence is the carrier and forming substrate for the deposition reaction. Specifically, the function of the reaction tube is to provide an adhesion surface for the deposition of reactive gases: during the deposition process, the reactive gases undergo oxidation, decomposition, and other reactions on the inner wall of the reaction tube, forming a quartz deposition layer layer by layer; after the deposition reaction is completed, the reaction tube itself will fuse with the deposition layer on the inner wall to form the main structure of the optical fiber preform, that is, the reaction tube ultimately becomes part of the optical fiber preform.

[0044] In some embodiments, the air intake module is provided with an air inlet, and the air outlet module is provided with an air outlet; the opening directions of the air inlet and the air outlet are arranged along the generatrix direction of the inner wall of the reaction tube, so that the airflow from the air inlet extends along the inner wall of the reaction tube to the air outlet.

[0045] For example, the air intake module is provided with an air intake pipe; the air intake pipe is used to deliver the reaction gas into the reaction tube; the air inlet of the air intake pipe that delivers the reaction gas into the reaction tube is the air intake port of the air intake module.

[0046] For example, the gas outlet module is provided with an exhaust pipe; the exhaust pipe is used to draw in the reaction tail gas in the reaction tube; the gas outlet of the exhaust pipe that draws in the reaction tail gas in the reaction tube is the gas outlet of the gas outlet module.

[0047] The reaction tube used for optical fiber preforms is geometrically a cylinder. If you cut the cylinder straight along its length and flatten it, straight lines parallel to the central axis of the tube will appear on the inner wall. These straight lines are called generatrices. The direction of the generatrices on the inner wall of the reaction tube is the direction of the straight lines along the length of the tube, parallel to the central axis of the tube, and attached to the tube wall.

[0048] It should be noted that the opening direction of the inlet refers to the initial flow direction of the reactant gas when it is ejected from the inlet; similarly, the opening direction of the outlet refers to the flow direction of the reactant gas and reaction products when they enter the outlet.

[0049] For example, the opening direction of the air inlet coincides with the generatrix direction of the inner wall of the reaction tube; the opening direction of the air outlet coincides with the generatrix direction of the inner wall of the reaction tube; the opening direction of the air inlet and the opening direction of the air outlet coincide with the same generatrix direction.

[0050] For example, the air inlet of the air inlet module is located on the inner wall of the air inlet end face of the reaction tube, and the air outlet of the air outlet module is located on the inner wall of the air outlet end face of the reaction tube. The air inlet points towards the inside of the reaction tube along the inner wall of the air inlet end; the air outlet points towards the inside of the reaction tube along the inner wall of the air outlet end.

[0051] Another example is that the air inlet is a certain distance from the air inlet end of the reaction tube, and the air outlet is a certain distance from the air outlet end of the reaction tube. That is, the air inlet and air outlet can also be located outside the reaction tube.

[0052] In some embodiments, the device further includes a position adjustment module, which drives the air inlet and outlet to move synchronously with the inner wall of the reaction tube as the deposition layer inside the reaction tube thickens and the effective inner diameter of the reaction tube shrinks during the deposition of the optical fiber preform, so that the air inlet and outlet always maintain an airflow path close to the inner wall of the reaction tube until the deposition process is completed.

[0053] It should be noted that "following the inner wall movement" means that the position adjustment module does not fix the inlet and outlet in their initial positions. Instead, it dynamically adjusts their positions based on the real-time changing inner wall surface of the deposition layer and the latest inner wall position after deposition. As the deposition layer thickens inward, the inlet and outlet, driven by the position adjustment module, gradually move radially towards the central axis of the reaction tube, maintaining synchronous movement to ensure they are always at a radial height matching the current inner wall position. Through this dynamic position adjustment, the inlet and outlet remain close to the current inner wall of the deposition layer throughout the entire deposition cycle, ensuring the airflow path always extends along the latest inner wall surface. This allows the reactive gas to be continuously and directly delivered to the interface where the deposition reaction occurs, preventing the airflow from deviating from the reaction area due to changes in the inner wall position. This ensures that gas utilization efficiency and deposition uniformity remain stable throughout the entire deposition process, from start to finish.

[0054] This invention provides an optical fiber preform manufacturing device. By setting the opening directions of the inlet and outlet along the generatrix direction of the inner wall of the reaction tube, the reactive gas, after being injected through the inlet, flows along the inner wall of the reaction tube and extends to the outlet where it is extracted. This changes the gas distribution state of "high concentration at the center and low concentration at the tube wall" in the traditional center-inlet method. Simultaneously, through a position adjustment module, the inlet and outlet move radially towards the central axis of the reaction tube during the deposition process as the deposition layer thickens and the effective inner diameter of the reaction tube decreases. This ensures that the airflow path always stays close to the dynamically changing tube wall reaction interface, guaranteeing that the reactive gas can be directly and continuously delivered to the deposition reaction surface throughout the entire deposition cycle.

[0055] The embodiments of the present invention concentrate the reactive gas in the deposition area of ​​the tube wall, shorten the distance between the transported reactive gas and the reaction interface, increase the gas molecule concentration at the reaction interface, reduce the ineffective flow and waste of gas in the center of the tube, and effectively improve the utilization rate of gas raw materials in the optical fiber preform manufacturing process.

[0056] The following explains how the position adjustment module is implemented.

[0057] In one possible implementation, the position adjustment module includes a linear motion unit; the linear motion unit is used to drive the air inlet and outlet to move linearly along the radial direction of the reaction tube; the stroke of the linear movement is less than the inner radius of the reaction tube before the optical fiber preform deposition.

[0058] The linear motion unit provides the driving force for the dynamic adjustment of the air inlet and outlet, and is the specific execution structure for realizing the movement following the inner wall. In the specific structure, since the two ends of the reaction tube are far apart, a linear motion unit can be set for the air inlet and the air outlet respectively, and the two linear motion units are driven synchronously.

[0059] The linear motion unit drives the air inlet and outlet to move linearly along the radial direction of the reaction tube. Here, radial direction refers to the direction perpendicular to the central axis of the reaction tube, pointing towards or away from the tube center; it is also the direction in which the deposited layer thickens inward and the inner wall position changes. Using radial linear movement allows the air inlet and outlet to precisely match the displacement direction of the inner wall, ensuring that the airflow path always matches the constantly changing inner wall.

[0060] Meanwhile, this implementation limits the linear movement stroke to less than the inner radius of the reaction tube before fiber preform deposition. This avoids problems such as structural interference and collisions caused by excessive movement of the inlet and outlet beyond the effective internal space of the reaction tube, while also fully covering the actual displacement range of the inner wall throughout the deposition process.

[0061] The above describes a dynamic moving pipe port. The following describes a multi-pipe switching position adjustment method.

[0062] In one possible implementation, the position adjustment module can be configured with multiple radially arranged gas delivery pipes, each of which can be independently controlled to open and close, and the outlet end of each pipe corresponds to different radial positions of the reaction tube (arranged in layers from the position close to the inner wall of the initial reaction tube towards the central axis of the reaction tube).

[0063] Each gas pipeline has one end connected to an external gas source / vacuum system via an independent valve, and the other end converges to a rotary sealing joint to accommodate the rotational movement requirements of the inlet / outlet. During the optical fiber preform deposition process, as the deposition layer thickens and the effective inner diameter of the reaction tube shrinks, the position adjustment module gradually closes the gas pipelines at the corresponding outer radial position (away from the central axis) and simultaneously opens the gas pipelines at the corresponding inner radial position (close to the central axis) through valve switching. This ensures that the outlet of the currently connected gas pipeline remains close to the inner wall surface of the newly formed deposition layer, thereby maintaining the airflow path along the inner wall of the reaction tube.

[0064] This embodiment uses a multi-pipe stepped arrangement to replace the physical linear movement of a single pipe, breaking down the continuous radial position adjustment into multiple preset radial levels, each corresponding to the inner wall position of a deposition stage. Without moving the pipe body itself, the effective airflow channel can be switched simply by opening and closing the valve, ensuring that the outlet of the guided pipe always conforms to the current inner wall, achieving a dynamic following effect.

[0065] This embodiment avoids complex linear motion mechanisms and can still maintain good sealing and airflow stability under rotational conditions (in conjunction with a rotary sealing joint), while reducing mechanical wear and control complexity. It is especially suitable for scenarios where the air inlet / outlet rotates synchronously in this solution.

[0066] In one possible implementation, it further includes: a first rotation drive module; the first rotation drive module is used to drive the reaction tube to rotate around the central axis during the optical fiber preform deposition process, wherein the positions of the air inlet and air outlet are stationary when the reaction tube rotates.

[0067] It should be noted that in the tubular deposition process for optical fiber preforms, the heating module (such as a microwave resonant cavity or an oxyhydrogen flame) reciprocates along the axial direction of the reaction tube to complete layer-by-layer deposition. If the reaction tube remains stationary, the contact time between different circumferential positions on the tube wall and the gas flow and energy field will vary, easily leading to uneven thickness and refractive index distribution deviations in the circumferential direction of the deposited layer, ultimately affecting the optical performance and mechanical stability of the optical fiber. Rotating the reaction tube, through uniform circumferential rotation, ensures that every circumferential position on the tube wall passes evenly through the heating area and the wall-mounted gas flow path, expanding the original one-dimensional axial deposition into a two-dimensional uniform deposition process of axial reciprocating and circumferential rotation, eliminating circumferential deposition differences and ensuring the consistency of the preform in the circumferential direction.

[0068] When the first rotary drive module drives the reaction tube to rotate around its central axis, the inlet, outlet, and corresponding gas delivery / extraction pipelines remain stationary and do not rotate synchronously with the reaction tube. The stationary inlet and outlet ensure that their opening directions always coincide with the generatrix direction of the inner wall of the reaction tube, guaranteeing that the gas flow path along the wall is not disturbed by rotation, and that the reactant gas is continuously and accurately delivered to the deposition interface on the tube wall. The gas delivery / extraction pipelines do not need to rotate with the tube, avoiding risks such as pipeline entanglement and rotary seal failure, simplifying the gas delivery system structure, and improving the long-term operational stability of the equipment.

[0069] The following describes the specific implementation of the first rotation drive module.

[0070] In one possible implementation, both the air intake module and the air outlet module include a stationary section and a rotating section, wherein the stationary section and the rotating section are rotatably and sealed together; the rotating section is fixedly and sealed together with the reaction tube; and the air inlet and air outlet are located in the stationary section of the corresponding module.

[0071] For example, along the gas conveying direction, it sequentially includes a stationary section of the inlet module, a rotating section of the inlet module, a reaction tube, a rotating section of the outlet module, and a stationary section of the outlet module.

[0072] Both the inlet and outlet modules consist of a stationary section and a rotating section, which are rotatably sealed together by a rotary sealing structure. The rotating section is fixedly sealed to the reaction tube, meaning that the reaction tube, the rotating section, and the output end of the first rotary drive module form a rigid linkage. When the first rotary drive module is working, it synchronously drives the reaction tube and the rotating section to rotate around the central axis of the reaction tube. The stationary section remains fixedly connected to the equipment frame and external gas supply / extraction pipelines, and does not rotate with the reaction tube. The inlet and outlet are respectively located on the stationary section of the corresponding module to ensure that the pipe positions are always stationary.

[0073] The rotating section serves as a transitional carrier between the reaction tube and the module body. It rotates synchronously with the reaction tube to ensure the overall sealing integrity of the tubular reaction chamber and prevent leakage caused by the rotation of the reaction tube. The stationary section serves as a fixed reference for gas delivery and pipe positioning, ensuring that the inlet and outlet always maintain their initial installation posture and that the opening direction continuously coincides with the generatrix direction of the inner wall of the reaction tube. This prevents the pipe from disturbing the airflow path along the wall as the pipe rotates, ensuring that the reactant gas is always delivered to the deposition interface on the pipe wall. The rotary sealing connection forms a dynamic sealing barrier between the two sections, allowing relative rotation between the rotating and stationary sections while effectively blocking the exchange of reactant gas inside the pipe with the external environment, maintaining the pressure stability and gas purity of the reaction chamber.

[0074] In one possible implementation, it further includes: a second rotation drive module; the second rotation drive module is used to drive the air inlet and air outlet to rotate synchronously around the central axis of the reaction tube during the optical fiber preform deposition process, wherein the reaction tube is stationary.

[0075] This rotation scheme is particularly suitable for the following demanding production scenarios: Production of large / long preforms: When the reaction tube length exceeds 1.5 meters, the "skipping rope effect" of traditional tube rotation is particularly prominent, while this scheme can avoid the risk of deformation. The maximum operating temperature of the PCVD process is approximately 1200℃, lower than the melting point of pure quartz reaction tubes (1530℃). Within this temperature range, the reaction tube can maintain good rigidity and strength and is not prone to deformation. Although the front and rear chucks of existing PCVD systems can achieve synchronous rotation, in some high-temperature demand scenarios, the temperature of the reaction tube may approach the softening threshold. At the same time, due to the large length of the reaction tube, the "skipping rope effect" is prone to occur during rotation, which exacerbates the deformation of the reaction tube under inertia, causing the middle part of the tube to bend, thereby increasing the risk of rubbing against the inside of the reaction resonant cavity, affecting the stability of equipment operation and product quality.

[0076] It should be noted that traditional processes typically drive the entire reaction tube to rotate to achieve circumferential uniformity. However, when long quartz tubes rotate at high temperatures and high speeds, they are prone to a "skipping rope effect" (swinging deformation), posing a safety risk of rubbing against the heating module. Furthermore, in the tubular deposition process for optical fiber preforms, the skipping rope effect refers to the lateral bending and periodic swinging of long, high-purity quartz reaction tubes at high temperatures and high speeds due to their own gravity, centrifugal force, and high-temperature softening properties, resembling the swinging of a skipping rope. Quartz reaction tubes are slender hollow cylinders (often exceeding 1.5 meters in length with extremely thin walls). While possessing a certain rigidity at room temperature, the elastic modulus of quartz decreases significantly in the high-temperature environment required for deposition, becoming softer and more easily bent. When the reaction tube rotates at high speed, its own gravity and centrifugal force work together to amplify the initially minute bending deformation, forming a periodic lateral swing. The tube swings left and right like a skipping rope, with the amplitude of the swing increasing with rotational speed, tube length, and temperature.

[0077] In this implementation, the quartz reaction tube remains stationary throughout the deposition process, eliminating centrifugal force and the swaying and deformation caused by rotation, thus fundamentally preventing the "skipping rope effect." This implementation instead drives only the lightweight inlet / outlet to rotate, while the reaction tube remains stationary, eliminating the mechanical instability caused by the rotation of a long tube and significantly improving the safety of equipment operation.

[0078] In one possible implementation, both the air intake module and the air outlet module include a stationary section and a rotating section, wherein the stationary section and the rotating section are rotatably and sealed together; the stationary section is fixedly and sealed together with the reaction tube; and the air inlet and air outlet are located in the rotating section of the corresponding module.

[0079] To accommodate the working mode where the reaction tube is stationary and the inlet and outlet rotate, both the inlet and outlet modules adopt a split structure combining stationary and rotating sections. The specific structural relationship, working logic, and design essence are explained below: For example, along the gas conveying direction, it sequentially includes an intake module rotating section, an intake module stationary section, a reaction tube, an outlet module stationary section, and an outlet module rotating section.

[0080] In this embodiment, both the inlet and outlet modules include a stationary section and a rotating section; the stationary and rotating sections are connected by a rotary sealing structure. The stationary section is fixedly and sealed to the reaction tube. Because the reaction tube remains stationary during the deposition process, the stationary section also remains fixed, serving as the foundation for the entire module's installation and maintaining the airtight integrity of the tubular reaction chamber, preventing leakage of reaction gas or the entry of external impurities.

[0081] The rotating section and the stationary section can rotate relative to each other, and the air inlet and outlet are respectively located on the rotating sections of the air inlet module and the air outlet module. Driven by the second rotation drive module, the rotating section can drive the air inlet and outlet to rotate synchronously around the central axis of the reaction tube, while the stationary section and the reaction tube remain stationary.

[0082] The essence of this structure is to decouple the functions of sealing and fixing the reaction chamber from the rotational movement of the nozzle: the stationary section is dedicated to sealing the chamber and rigidly fixing it to the reaction tube, providing a stable and sealed environment for the deposition reaction; the rotating section is dedicated to driving the nozzle to rotate, achieving circumferential uniformity of the deposition layer through rotational scanning, and further enhancing the gas flow adhesion effect by utilizing the centrifugal force generated by the rotation. The rotational sealing structure between the two sections ensures the free rotation of the rotating section relative to the stationary section, while forming a reliable sealing barrier at the junction of the dynamic and static sections, maintaining the stability of the internal pressure and gas atmosphere of the reaction chamber.

[0083] This method eliminates the need to drive the reaction tube to rotate, thus avoiding the rope-jumping effect, mechanical deformation, and safety hazards caused by the high-temperature rotation of long quartz reaction tubes. It achieves circumferential uniform deposition while significantly improving the safety of equipment operation.

[0084] The following describes the specific structure of the rotating segment.

[0085] In one possible implementation, the rotating section includes: a sealing shell, a rotary sealing joint, and a flexible tube; the rotary sealing joint is located outside the sealing shell, with one end connected to an external stationary pipe and the other end fixed to the sealing shell of the rotating section and connected to the flexible tube inside the sealing shell; one end of the flexible tube is connected to the rotary sealing joint, and the other end serves as an air inlet or outlet.

[0086] It should be noted that the rotating section, as the core component responsible for the rotation function in the air intake and exhaust modules, is mainly composed of three parts: a sealed outer shell, a rotary sealing joint, and a flexible tube. The components work together to achieve both the rotational movement of the pipe opening and ensure the closed-loop delivery of the reaction gas.

[0087] The sealed outer shell, serving as the main load-bearing structure of the rotating section, is an entirely sealed shell. Internally, it accommodates the flexible tube; externally, it secures the rotary sealing joint. It also forms a closed gas transition space to prevent leakage of reactant gases during rotation, and simultaneously acts as a carrier for transmitting the rotational driving force. The second rotational drive module can directly drive the sealed outer shell to rotate around the central axis of the reaction tube, thereby causing the entire rotating section and the pipe inlet to rotate synchronously.

[0088] The rotary sealing joint, located outside the sealing shell, is a connecting component that links the external stationary pipeline to the rotating section. Its two ends perform different functions: one end is fixedly connected to an external stationary gas supply or extraction pipeline to ensure stable input of external gas or stable discharge of gas after the reaction; the other end is fixed to the sealing shell and connected to a flexible tube inside the sealing shell. Its purpose is to solve the problem of gas connectivity and dynamic sealing between the stationary pipeline and the rotating component. It allows the sealing shell to rotate the flexible tube and its opening while forming a reliable sealing barrier at the rotational connection to prevent leakage of reactive gas, ensure continuous gas delivery, and prevent external impurities from entering the reaction chamber.

[0089] The flexible tube is located inside the sealed outer shell, with one end connected to the rotary sealing joint and the other end directly serving as an air inlet or outlet, extending into the interior of the reaction tube. The core advantage of the flexible tube is its flexible deformation capability. When the position adjustment module drives the air inlet and outlet to move radially along the reaction tube to follow the changes in the inner wall of the deposition layer, the flexible tube can adapt to the radial displacement through its own deformation. It will not break or twist due to the movement of the tube opening, nor will it affect the overall rotational movement of the rotating section. At the same time, the flexible tube can flexibly adjust the tube opening orientation to ensure that the opening direction of the air inlet and outlet always coincides with the generatrix direction of the inner wall of the reaction tube, maintaining the stability of the wall-attached airflow path.

[0090] The working logic of the entire rotating section is as follows: the reaction gas (or the waste gas to be extracted) transported by the external static pipeline enters the flexible tube inside the sealing shell through the rotary sealing joint, and is then transported to the reaction tube (or discharge equipment) through the pipe opening at the end of the flexible tube; at the same time, the second rotation drive module drives the sealing shell to rotate, and the sealing shell drives the flexible tube and the pipe opening to rotate synchronously around the central axis of the reaction tube, realizing the rotational scanning of the pipe opening and ensuring the circumferential uniformity of the deposition layer; when the position adjustment module needs to adjust the radial position of the pipe opening, the flexible tube flexibly deforms to adapt to the displacement, ensuring that the pipe opening is always close to the inner wall.

[0091] The sealed outer shell supports rotation and sealing, the rotary sealing joint solves the sealing and connection between dynamic and static elements, and the flexible tube adapts to position adjustment and maintain the attitude of the pipe opening. The three work together to achieve the design goal of rotating the pipe opening and keeping the pipeline stationary, avoiding problems such as pipe entanglement and sealing failure in traditional rotation methods. In addition, the position adjustment module enables dynamic adaptation of the airflow path, providing structural protection for uniform deposition and efficient utilization of gas raw materials.

[0092] The above describes the rotational motion mode. The following explains how the rotational motion coordinates with the reciprocating motion of the heating module. Based on the realization of the rotating pipe and the stationary reaction tube, the rotational motion of the air inlet and outlet, and the reciprocating motion of the heating module along the axial direction of the reaction tube, can work together in two ways: time-sharing coordination and synchronous coordination. Both modes aim to achieve full axial coverage and circumferential uniformity of the deposition layer, adapting to different process requirements.

[0093] In one possible implementation, it further includes a heating module 5 that reciprocates along the axial direction of the reaction tube; wherein, during the deposition of the optical fiber preform, the heating module 5 reciprocates axially after each time the air inlet and outlet rotate by a preset angle and stop rotating.

[0094] During the deposition of optical fiber preforms, the equipment follows a cyclic process of rotational positioning followed by axial deposition: First, the second rotational drive module drives the air inlet and outlet to rotate around the central axis of the reaction tube by a preset angle, so that the action area of ​​the wall-mounted airflow is switched to a new circumferential sector on the inner wall of the reaction tube; after the air inlet and outlet have rotated into position and completely stopped moving and the position is stable, the heating module completes a complete reciprocating motion along the axial direction of the reaction tube, providing uniform energy supply to the circumferential position and completing the axial deposition of the corresponding area.

[0095] The above-mentioned process of rotating at a preset angle, stationary positioning, and axial reciprocating heating and deposition is repeated until the entire deposition process is completed.

[0096] This combination method completely decouples the circumferential position adjustment from the axial deposition reaction, avoiding interference such as airflow disturbance and energy field fluctuation caused by the simultaneous occurrence of the two movements from the process level: when the air inlet and outlet are stationary, the airflow path along the wall remains constant; at this time, the heating module reciprocates along the axial direction, which can ensure that the energy supply and gas supply at every position along the axial direction of the reaction tube are highly matched, ensuring the uniformity of single-layer deposition.

[0097] The essence of rotating at a preset angle each time is to allow the gas flow along the wall to gradually scan the 360° circumference of the reaction tube. Through multiple rounds of step-by-step deposition, uniform growth with full circumferential and axial coverage is ultimately achieved throughout the entire tube wall. This collaborative mode has simple control logic, stable operation, and minimal motion interference. It can precisely control the thickness and composition distribution of the deposited layer, making it particularly suitable for high-end optical fiber preform fabrication scenarios with stringent requirements for deposition accuracy and uniformity.

[0098] For example, the heating module can be a microwave resonant cavity.

[0099] For example, the preset angle can be 1°. It should be noted that the angle setting needs to take into account the coverage range of the gas jet. If the inlet jet angle is wide and can cover a large angle range, then the preset angle can be appropriately increased to fill the rotation gap by gas diffusion, while still ensuring good time-averaged uniformity.

[0100] In one possible implementation, it further includes a heating module that reciprocates along the axial direction of the reaction tube; wherein, during the deposition of the optical fiber preform, the rotational motion of the air inlet and outlet is synchronized with the reciprocating motion of the heating module, and the time for the air inlet and outlet to rotate one revolution is not equal to the time for the heating module to reciprocate once along the axial direction of the reaction tube.

[0101] In this embodiment, throughout the entire optical fiber preform deposition process, the second rotation drive module drives the air inlet and outlet to rotate continuously and uniformly around the central axis of the reaction tube. At the same time, the heating module continuously reciprocates along the axial direction of the reaction tube. The two movements are carried out in parallel without time interval or pause, and there is no sequential relationship between their execution.

[0102] It should be noted that the time it takes for the air inlet and outlet to rotate one revolution (rotation cycle) is not equal to the time it takes for the heating module to reciprocate once along the axial direction of the reaction tube (reciprocating cycle). This design breaks the repetitive trajectory of the two movements, avoids the formation of fixed deposition superposition areas, and achieves uniform deposition on the inner wall of the reaction tube in all dimensions without dead angles.

[0103] The specific working logic is as follows: Due to the unequal motion cycles of the two, the airflow path along the wall of the inlet and the energy application area of ​​the heating module will not form a fixed superposition trajectory. That is, each point on the pipe wall will not repeatedly receive the same gas supply and energy application time during each heating cycle or pipe rotation, thus effectively avoiding the problems of excessively thick, thin, or unevenly composed local deposits. To further explain, if the motion cycles of the two are equal, the airflow application area and the heating area will always coincide synchronously, forming periodic deposition superposition, and ultimately forming a regular thickness gradient on the pipe wall; however, by setting a period difference, the trajectories of the two motions form asynchronous superposition, which is equivalent to adding randomness (not disorder, but a controllable period difference) to the axial energy supply on the basis of circumferential rotation scanning, so that every position on the inner wall of the reaction tube can obtain uniform gas supply and energy application throughout the entire deposition cycle, achieving a deposition layer without gradients in either the circumferential or axial directions.

[0104] The advantages of the collaborative mode in this embodiment are that it retains the high efficiency of synchronous motion, eliminating the need for pauses and waiting, allowing the deposition process to proceed continuously and significantly improving production efficiency, thus meeting the needs of large-scale industrial production. Furthermore, the design of the cycle difference solves the problem of uneven deposition that may be caused by synchronous motion. At the same time, it works in synergy with the position adjustment module and the wall-mounted airflow design to ensure that the reactant gas always reacts in the tube wall region where the energy is most concentrated, further improving the utilization rate of gas raw materials and the quality of the preformed rod.

[0105] In one possible implementation, the air inlet and / or the air outlet is an arc-shaped flat opening; the concave surface of the arc-shaped flat opening faces the axis of the reaction tube to conform to the inner wall contour of the reaction tube.

[0106] This embodiment further optimizes the shape of the air inlet and outlet. The air inlet and / or outlet adopts an arc-shaped flat opening structure, and the concave surface of the arc-shaped flat opening faces the central axis of the reaction tube, so that the shape of the tube opening fits and matches the arc contour of the inner wall of the reaction tube.

[0107] In this embodiment, the arc-shaped flat opening is not a conventional circular or square straight opening, but a flat arc-shaped opening that extends circumferentially along the reaction tube. Its arc curvature is similar to the curvature of the inner wall of the reaction tube, with the concave surface pointing towards the tube axis and the convex surface close to the tube wall, forming a matching relationship with the inner wall in terms of geometric contour.

[0108] The curved profile perfectly matches the inner wall, allowing the airflow to be confined within a thin layer close to the pipe wall the moment it is ejected from the nozzle; the flat opening shape expands the coverage of the airflow around the pipe wall, allowing the reactant gas to be distributed more evenly on the inner wall surface in a planar form, rather than being concentrated at a certain point. Combined with the rotation of the nozzle or the reaction tube, the uniformity of circumferential deposition can be further improved.

[0109] This invention provides an optical fiber preform manufacturing system, including optical fiber preform manufacturing equipment as described in any of the possible implementations above.

[0110] For example, the optical fiber preform manufacturing system also includes a gas supply module and a vacuum pump. The gas supply module is connected to the gas inlet module. The vacuum pump is connected to the gas outlet module.

[0111] The following two examples illustrate the process of manufacturing optical fiber preforms.

[0112] In one possible implementation: (1) Adjust the position of the inlet feed pipe of the PCVD system so that the outlet pipe is aligned with the inlet feed pipe to complete the pre-reaction preparation; (2) Connect and fix the reaction tube, which is connected to the support tube and the tail gas tube, to the inlet and outlet of the PCVD lathe by means of magnetic fluid sealing lock nut; (3) Select the corresponding raw materials (such as SiCl4, GeCl4, BCl3, C2F6, etc.) according to the type of preform. Each raw material is evaporated at the set evaporation temperature of its corresponding evaporator. After evaporation, the materials are introduced into the conveying pipe and the material temperature is kept not lower than 60℃ throughout the process. (4) Inject the mixed gas of SiCl4 and other raw materials (GeCl4, BCl3, C2F6, etc.) into the reaction tube from the feed pipe; (5) The feed pipe and the vacuum pump pipe achieve 360° continuous synchronous rotation. The rotation speed can be adjusted as needed, and the rotation speed must be precisely matched with the single-layer deposition time - the time t1 for one rotation must not be equal to t2 (t2=2L / v, where L is the distance from the gas inlet end to the gas outlet end of the resonant cavity, and v is the moving speed of the resonant cavity), to avoid the formation of superimposed collinear spiral patterns during the deposition process. (6) The PCVD deposition process ends after n layers (n≥1000) are deposited; (7) The reaction tube is collapsed and shrunken by a graphite heating furnace or an oxyhydrogen flame torch to obtain the final optical fiber preform.

[0113] In one possible implementation: (1) Adjust the position of the inlet feed pipe of the PCVD system so that the outlet pipe is aligned with the inlet feed pipe to complete the pre-reaction preparation; (2) Connect and fix the reaction tube, which is connected to the support tube and the tail gas tube, to the inlet and outlet of the PCVD lathe by means of magnetic fluid sealing lock nut; (3) Select the corresponding raw materials (such as SiCl4, GeCl4, BCl3, C2F6, etc.) according to the type of preform. Each raw material is evaporated at the set evaporation temperature of its corresponding evaporator. After evaporation, the materials are introduced into the conveying pipe and the material temperature is kept not lower than 60℃ throughout the process. (4) Inject the mixed gas of SiCl4 and other raw materials (GeCl4, BCl3, C2F6, etc.) into the reaction tube from the feed pipe; (5) After the feed pipe and vacuum pump pipe rotate once at a set angle (n°, the specific angle is determined according to the actual process requirements), the layer deposition process is started - the resonant cavity goes back and forth from the gas inlet end to the gas outlet end once, which is a complete layer deposition. (6) The PCVD deposition process ends after n layers (n≥1000) are deposited; (7) The reaction tube is collapsed and shrunken by a graphite heating furnace or an oxyhydrogen flame torch to obtain the final optical fiber preform.

[0114] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optical fiber preform manufacturing device, characterized in that, include: An air intake module and an air outlet module; a reaction tube is installed between the air intake module and the air outlet module to form a sealed tubular reaction chamber; The air intake module is provided with an air intake port, and the air outlet module is provided with an air outlet port; The opening directions of the air inlet and the air outlet are set along the generatrix direction of the inner wall of the reaction tube, so that the airflow at the air inlet extends along the inner wall of the reaction tube to the air outlet. The device also includes a position adjustment module, which drives the air inlet and outlet to move synchronously with the inner wall of the reaction tube as the deposition layer inside the reaction tube thickens and the effective inner diameter of the reaction tube shrinks during the optical fiber preform deposition process, so that the air inlet and outlet always maintain an airflow path close to the inner wall of the reaction tube until the deposition process is completed.

2. The optical fiber preform manufacturing equipment as described in claim 1, characterized in that, The position adjustment module includes a linear motion unit; The linear motion unit is used to drive the air inlet and outlet to move linearly along the radial direction of the reaction tube; The linear movement distance is less than the inner radius of the reaction tube before the optical fiber preform deposition.

3. The optical fiber preform manufacturing equipment as described in claim 2, characterized in that, Also includes: First rotation drive module; The first rotation drive module is used to drive the reaction tube to rotate around the central axis during the optical fiber preform deposition process, wherein the positions of the air inlet and air outlet remain stationary when the reaction tube rotates.

4. The optical fiber preform manufacturing equipment as described in claim 2, characterized in that, Also includes: Second rotation drive module; The second rotation drive module is used to drive the air inlet and outlet to rotate synchronously around the central axis of the reaction tube during the optical fiber preform deposition process, wherein the reaction tube is stationary.

5. The optical fiber preform manufacturing equipment as described in claim 4, characterized in that, Both the air intake module and the air outlet module include a stationary section and a rotating section, wherein the stationary section and the rotating section are rotatably sealed together. The stationary section is fixedly and sealed to the reaction tube; The air inlet and air outlet are located on the rotating section of the corresponding module.

6. The optical fiber preform manufacturing equipment as described in claim 5, characterized in that, The rotating section includes: a sealed outer shell, a rotary sealing joint, and a flexible tube; The rotary sealing joint is located outside the sealing shell, with one end connected to an external stationary pipe and the other end fixed to the sealing shell of the rotating section and connected to the flexible pipe inside the sealing shell. One end of the flexible tube is connected to a rotary sealing joint, and the other end serves as an air inlet or outlet.

7. The optical fiber preform manufacturing equipment as described in claim 4, characterized in that, Also includes: A heating module that reciprocates along the axial direction of the reaction tube; During the optical fiber preform deposition process, after the air inlet and outlet rotate by a preset angle and stop rotating each time, the heating module performs axial reciprocating motion.

8. The optical fiber preform manufacturing equipment as described in claim 4, characterized in that, Also includes: A heating module that reciprocates along the axial direction of the reaction tube; In the process of optical fiber preform deposition, the rotational motion of the air inlet and outlet is synchronized with the reciprocating motion of the heating module, and the time for the air inlet and outlet to rotate one revolution is not equal to the time for the heating module to reciprocate once along the axial direction of the reaction tube.

9. The optical fiber preform manufacturing equipment as described in claim 1, characterized in that, The air inlet and / or the air outlet are arc-shaped flat openings; the concave surface of the arc-shaped flat opening faces the axis of the reaction tube to conform to the inner wall contour of the reaction tube.

10. A fiber optic preform manufacturing system, characterized in that, Includes the optical fiber preform manufacturing equipment as described in any one of claims 1 to 9.

Images