An ultra-low-loss optical fiber drawing preparation device

Abstract

The application provides an ultra-low-loss optical fiber drawing preparation device, a drawing furnace is used for melting a preform rod and drawing into an optical fiber, a gas guide ring is arranged in the drawing furnace, the gas guide ring is used for guiding airflow into the drawing furnace, a heat conduction center pipe is arranged outside the gas guide ring, a heat conduction heater is arranged outside the heat conduction center pipe, the heat conduction center pipe is used for transmitting heat of the heat conduction heater to the gas guide ring, the heat conduction heater, the heat conduction center pipe and the gas guide ring are matched with each other to reduce eddy current entering the drawing furnace and temperature fluctuation in the drawing furnace, the problems of unstable airflow and temperature fluctuation in the traditional device are solved, accurate guidance and heating of the airflow entering the drawing furnace are realized, the eddy current generated by cold and hot intersection is reduced, the temperature uniformity in the drawing furnace is further improved, the influence of temperature fluctuation on the quality of the optical fiber is reduced, the problems of core diameter fluctuation and Mie scattering loss are effectively reduced, and the strength and low-loss attenuation performance of the optical fiber are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical fiber drawing, and particularly relates to an ultra-low-loss optical fiber drawing preparation device. BACKGROUND

[0002] As a key physical medium for long-distance transmission of optical signals, ultra-low-loss optical fiber has extremely stringent requirements on optical and mechanical properties. Its manufacturing process is not only precise and complex, but also requires more advanced equipment and processes compared to conventional optical fibers, and even higher requirements in some aspects. However, the traditional optical fiber drawing preparation has exposed a series of obvious shortcomings when facing the manufacturing needs of ultra-low-loss optical fiber, which seriously restricts the further development of ultra-low-loss optical fiber in terms of attenuation reduction and strength improvement.

[0003] Specifically, the existing optical fiber drawing preparation method is not up to the task when facing the dual requirements of high-end product 200kPsi on optical fiber strength and low-loss attenuation performance. The most prominent problem is that the airflow management and temperature control in the drawing furnace have always been a problem restricting the improvement of optical fiber quality.

[0004] Firstly, the airflow condition in the drawing furnace has an important influence on the preparation quality of optical fiber. If the airflow is unstable or there is vortex, it will not only cause defects on the surface of the optical fiber, but also affect the uniformity and transmission performance of the optical fiber. When these normal temperature gases flow downward, they will meet some upward flowing hot air, thus forming a clear cold and hot intersection area in the drawing furnace. In this area, the cold and hot air flow interweave and collide, forming a complex vortex structure. These vortices not only exacerbate the non-uniformity of the temperature field in the drawing furnace, causing the diameter of the bare fiber to fluctuate, but also have a serious erosion effect on the graphite parts, causing the surface to appear powdering phenomenon. Once the graphite powder attached to the surface of the optical fiber, it will have an adverse effect on the strength of the optical fiber. More seriously, the temperature field non-uniformity caused by vortex will further cause the core diameter fluctuation and Mie scattering loss problem, thereby seriously reducing the transmission performance of the ultra-low-loss optical fiber.

[0005] Secondly, the temperature fluctuation in the drawing furnace is also a key factor affecting the quality of optical fiber. Temperature fluctuation will cause the melting rate and drawing rate of the optical fiber to change, thereby affecting the uniformity and consistency of the optical fiber. During the drawing process, a stable temperature environment needs to be maintained to ensure that the preform can be uniformly melted and smoothly drawn into optical fiber. However, due to the complexity of the internal structure of the drawing furnace and the interference of the external environment, temperature fluctuation is often difficult to completely avoid, which will adversely affect the preparation efficiency and yield of the optical fiber.

[0006] The disclosure of the foregoing Background Art is given solely for the purpose of aiding in the understanding of the inventive concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present patent application, nor necessarily give technical teaching; in the absence of explicit evidence showing that the above-mentioned content has been disclosed before the filing date of the present patent application, the above-mentioned background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0007] In order to solve the technical problems of unstable air flow and temperature fluctuation existing in the traditional device, the present application provides an ultra-low loss optical fiber drawing preparation device, which solves the technical problems of unstable air flow and temperature fluctuation existing in the traditional device, not only realizes the accurate guidance and heating of the air flow entering the drawing furnace, thereby reducing the vortex generated by the cold and hot intersection, but also improves the temperature uniformity in the drawing furnace, reduces the influence of temperature fluctuation on the quality of optical fiber, effectively reduces the problems of core diameter fluctuation and Mie scattering loss, and ensures the strength and low loss attenuation performance of optical fiber.

[0008] In order to achieve the above-mentioned purpose, the technical solutions of the present application are as follows:

[0009] The present application provides an ultra-low loss optical fiber drawing preparation device, comprising: a drawing furnace, the drawing furnace is used for melting a preform rod and drawing into an optical fiber, a gas guide ring is arranged in the drawing furnace, the gas guide ring is used for guiding the air flow entering the drawing furnace, a heat conduction center tube is arranged outside the gas guide ring, a heat conduction heater is arranged outside the heat conduction center tube, the heat conduction center tube is used for transmitting the heat of the heat conduction heater to the gas guide ring, and the heat conduction heater, the heat conduction center tube and the gas guide ring cooperate with each other to reduce the vortex entering the drawing furnace and the temperature fluctuation in the drawing furnace.

[0010] The present application provides an ultra-low loss optical fiber drawing preparation device, which solves the technical problems of unstable air flow and temperature fluctuation existing in the traditional device, not only realizes the accurate guidance and heating of the air flow entering the drawing furnace, thereby reducing the vortex generated by the cold and hot intersection, but also improves the temperature uniformity in the drawing furnace, reduces the influence of temperature fluctuation on the quality of optical fiber, effectively reduces the problems of core diameter fluctuation and Mie scattering loss, and ensures the strength and low loss attenuation performance of optical fiber.

[0011] As a preferred technical solution, an S-shaped air flow guide groove is arranged in the inner cavity of the gas guide ring.

[0012] As a preferred technical solution, a rod hanging platform is arranged on one end of the drawing furnace, a preform rod is connected to the rod hanging platform, the preform rod passes through one end of the drawing furnace and is arranged in the inner cavity of the gas guide ring, and the other end of the drawing furnace is connected to one end of a distributed annealing furnace.

[0013] As a preferred technical solution, the distributed annealing furnace comprises: a plurality of independent heating sections, each of which is electrically connected with an independent temperature control system, and the inner cavity of the distributed annealing furnace gradually expands its inner diameter from the independent heating section close to the wire drawing furnace to the independent heating section at the middle position, and then gradually shrinks its inner diameter from the independent heating section at the middle position to the independent heating section away from the wire drawing furnace.

[0014] As a preferred technical solution, the other end of the distributed annealing furnace is arranged corresponding to one end of the bare optical fiber diameter measuring instrument, the bare optical fiber diameter measuring instrument is used to monitor the diameter of the bare optical fiber prepared by the distributed annealing furnace in real time, the bare optical fiber diameter measuring instrument is electrically connected with the PID controller, and the PID controller is electrically connected with the hanging rod platform and the wire drawing furnace, so as to control the working state of the hanging rod platform to regulate the rod feeding amount of the preform rod and control the working state of the wire drawing furnace to regulate the stretching speed of the wire drawing furnace, so as to realize automatic tuning of the diameter of the bare optical fiber.

[0015] As a preferred technical solution, the other end of the bare optical fiber diameter measuring instrument is arranged corresponding to one end of the optical fiber coating die seat, the optical fiber coating die seat is used to coat outside the bare optical fiber to form a coating layer, and the optical fiber coating die seat comprises: an inner coating die core and an outer coating die core, and the distance between the inner coating die core and the outer coating die core is reduced to 4-6 mm.

[0016] By comparing the periodic variation of the actual wire drawing coating tension of the optical fiber coating die seat with the set tension value, the variation trend of the wire drawing coating tension is obtained to perform self-coordination of the wire drawing furnace power.

[0017] As a preferred technical solution, the other end of the optical fiber coating die seat is arranged corresponding to one end of the optical fiber curing furnace, the optical fiber curing furnace is used to cure the coating layer of the optical fiber, the other end of the optical fiber curing furnace is arranged corresponding to the optical fiber upper positioning wheel, the optical fiber upper positioning wheel is used to transmit the optical fiber after curing the coating layer to the entrance of the optical fiber stroke cooling assembly, the optical fiber lower positioning wheel is arranged at the outlet of the optical fiber stroke cooling assembly, and the optical fiber lower positioning wheel transmits the cooled optical fiber coating layer to the optical fiber coating layer temperature measuring instrument.

[0018] As a preferred technical solution, the optical fiber stroke cooling assembly comprises: a plurality of elastic guide wheels, a plurality of the elastic guide wheels are arranged in multiple layers in an alternating manner to form heat dissipation channels between every two adjacent layers, each of the elastic guide wheels is connected with a guide wheel driving member, the optical fiber coating layer temperature measuring instrument is used to monitor the surface temperature of the cooled optical fiber coating layer in real time, the optical fiber coating layer temperature measuring instrument is electrically connected with the PID controller, and the PID controller is electrically connected with the guide wheel driving member to control the guide wheel driving member to drive the elastic guide wheels to move so as to regulate the distance of the heat dissipation channels.

[0019] As a preferred technical solution, the optical fiber coating temperature measuring instrument is arranged at one end of the optical fiber coating diameter measuring instrument, the optical fiber coating diameter measuring instrument is used for monitoring the diameter of the optical fiber coating in real time, the optical fiber coating diameter measuring instrument is electrically connected with the PID controller, and the PID controller is electrically connected with the optical fiber coating mold base.

[0020] As a preferred technical solution, the other end of the optical fiber coating diameter measuring instrument is arranged at the optical fiber turning wheel, the optical fiber turning wheel is used for transmitting the coated optical fiber to the optical fiber coating tension wheel, the optical fiber coating tension wheel continues to transmit the coated optical fiber to the optical fiber main traction assembly, the optical fiber main traction assembly comprises a wrapped satellite wheel, and the wrapped satellite wheel is used for realizing high-speed wire drawing of the traction belt driving optical fiber, and finally the optical fiber main traction assembly transmits the coated optical fiber to the optical fiber take-up assembly for take-up.

[0021] The present application provides an ultra-low loss optical fiber drawing device, which has the following advantages:

[0022] 1) The technical problems of unstable airflow and temperature fluctuation in the traditional device are solved, not only the precise guidance and heating of the airflow entering the drawing furnace are realized, thereby reducing the vortex generated by the cold and hot intersection, but also the temperature uniformity in the drawing furnace is improved, the influence of temperature fluctuation on the quality of optical fiber is reduced, the problems of core diameter fluctuation and Mie scattering loss are effectively reduced, and the strength and low loss attenuation performance of the optical fiber are ensured.

[0023] 2) The gas guide ring is located in the drawing furnace, and its main function is to guide the airflow entering the drawing furnace; the inner cavity of the gas guide ring is preferably provided with an S-shaped airflow guide groove, which can ensure that the flow path of the airflow in the drawing furnace is more stable and the formation of vortex is reduced; the heat conduction center pipe transmits the heat of the heat conduction heater to the gas guide ring, and after the normal temperature gas is heated by the gas guide ring and the heat conduction center pipe, the temperature thereof tends to be consistent with the temperature in the drawing furnace, and meanwhile the distribution of the gas in the drawing furnace is more uniform; in this way, the cold and hot intersection is greatly reduced, thereby reducing the formation of vortex, and the stable stretching of the optical fiber in the drawing process is facilitated, and the quality fluctuation of the optical fiber caused by vortex is reduced.

[0024] The cooperation of the heat conduction heater, the heat conduction center pipe and the gas guide ring not only heats the gas entering the drawing furnace, but also improves the temperature uniformity in the drawing furnace through heat conduction, thereby reducing the problems of core diameter fluctuation and Mie scattering loss caused by temperature fluctuation, and improving the transmission efficiency and performance of the optical fiber.

[0025] 3) The application adopts the change of the inner cavity structure of the distributed annealing furnace, which helps to form a more reasonable temperature gradient, so that the optical fiber can gradually adapt to different temperature environments during the heating process. The inner cavity of the distributed annealing furnace gradually expands its inner diameter from the independent heating section near the drawing furnace to the independent heating section at the middle position. The heating section near the drawing furnace can be set to a higher temperature to ensure that the optical fiber is sufficiently heated and softened in the initial stage. The inner cavity of the distributed annealing furnace then gradually narrows its inner diameter from the independent heating section at the middle position to the independent heating section away from the drawing furnace. As the optical fiber is annealed backward, the temperature gradually decreases, which helps to gradually cool and solidify the optical fiber, reducing internal stress caused by sudden temperature changes.

[0026] The independent temperature control system of each independent heating section can accurately control the temperature of the region, thereby ensuring the uniformity of the temperature during the entire annealing process. This design helps to reduce temperature fluctuations, improve the consistency and quality of optical fiber annealing. Accurate temperature control and stable annealing process help to reduce the generation of thermal stress, optimize the mechanical properties of the optical fiber, and improve the surface quality and optical performance.

[0027] 4) The application uses a bare optical fiber diameter measuring instrument to monitor the bare optical fiber drawn from the distributed annealing furnace in real time. The PID controller receives the bare optical fiber diameter data from the bare optical fiber diameter measuring instrument, compares the real-time monitored optical fiber diameter data with the preset diameter set value, calculates the deviation size, and adjusts the preform rod entering amount of the hanging rod platform into the drawing furnace and the drawing speed of the drawing furnace according to the deviation size. The adjusted control parameters are responded by the hanging rod platform and the drawing furnace, and the hanging rod platform and the drawing furnace adjust their working states according to the received signals, thereby realizing accurate control of the optical fiber diameter. The above control system realizes automatic control of the optical fiber preparation process, reduces manual intervention and error, which helps to improve production efficiency and reduce production cost.

[0028] 5) The application redesigns and adjusts the feeding mode of the mold, thereby greatly reducing the distance between the inner coating mold core and the outer coating mold core to about 5mm, reducing the coating resistance, and reducing the generation of coating bubbles and defects, thereby improving the strength of the optical fiber.

[0029] According to the calculated tension change trend, the control system formulates the adjustment strategy of the drawing furnace power; when the fiber coating mold base sensor monitors that the actual drawing coating tension is higher than the set tension, the PID controller receives the signal that the actual drawing coating tension is higher than the set tension and controls to reduce the drawing furnace power to reduce the stretching force of the optical fiber in the coating process; when the fiber coating mold base sensor monitors that the actual drawing coating tension is lower than the set tension, the PID controller receives the signal that the actual drawing coating tension is lower than the set tension and controls to increase the drawing furnace power to increase the stretching force of the optical fiber in the coating process to reach the preset tension value; the PID controller adjusts the power of the drawing furnace by adjusting the current or voltage of the heating element (such as the induction coil) of the drawing furnace; the adjusted power will directly affect the heating temperature and softening degree of the optical fiber, thereby affecting the stretching force and tension of the optical fiber in the coating process; this automatic control helps to reduce manual intervention, improve production efficiency and product quality.

[0030] 6) The main function of the optical fiber curing furnace is to heat and cure the coating on the optical fiber, and the upper and lower positioning wheels of the optical fiber are responsible for transmitting the optical fiber from the optical fiber curing furnace to the optical fiber stroke cooling assembly, and then transmitting the cooled optical fiber to the optical fiber coating temperature measuring instrument; these positioning wheels ensure that the optical fiber maintains a stable path during transmission, preventing the optical fiber from being damaged or deviating from the predetermined path during transmission;

[0031] At the same time, the fully cooled coated optical fiber has high robustness when entering the optical fiber main traction assembly and the optical fiber take-up assembly, is not prone to flattening, and the geometric roundness is well maintained, improving the roundness of the coated optical fiber;

[0032] The optical fiber coating temperature measuring instrument is used to monitor the surface temperature of the cooled optical fiber coating in real time, and the temperature data is fed back to the PID controller, and the PID controller controls the guide wheel driving member to drive the elastic guide wheel to move to regulate the spacing of the heat dissipation channel, and the PID controller controls the guide wheel driving member to drive the multiple layers of alternately arranged elastic guide wheels to move to form heat dissipation channels with larger or smaller spacing, allowing more or less air to flow in the heat dissipation channels, thereby effectively taking away the heat of the optical fiber, realizing rapid cooling of the optical fiber, and stably controlling the temperature of the optical fiber coating surface at the outlet of the optical fiber stroke cooling assembly within a reasonable range, thereby realizing control of the thermal stress of the cured optical fiber coating, improving the uniformity of the optical fiber coating stress, and being beneficial to further reducing the attenuation of the optical fiber.

[0033] 7) The fiber coating diameter diameter gauge continuously emits a light beam and receives reflected light, calculates the diameter data of the fiber coating by measuring the intensity and waveform changes of the reflected light signal, and the data is fed back to the PID controller in real time, and the PID controller compares the diameter data with the preset diameter standard value, if the actual diameter of the fiber coating deviates from the standard value of the fiber coating, the PID controller will start the adjustment program, through PID operation, the PID controller calculates the temperature and pressure value parameters that need to be adjusted, then it sends these parameter adjustment instructions to the fiber coating mold base, the fiber coating mold base adjusts the temperature and pressure during coating according to the control instructions of the PID controller; by accurately controlling these parameters, the fiber coating mold base can gradually reduce the deviation between the actual diameter of the fiber coating and the standard value of the fiber coating, realize the automatic tuning of the coating diameter, and the automatic adjustment ensures the uniformity of the fiber coating, the diameter of the fiber coating will be stably maintained within the standard range, without manual operation, the quality and production efficiency of the fiber product are improved.

[0034] 8) The fiber main traction assembly of the present application can realize high-speed fiber drawing by canceling the belt and adopting the wrapping satellite wheel, the wrapping satellite wheel will not slip during operation, and the length metering reliability is maintained, this method reduces the coating non-circularity of the fiber and improves the coating additional attenuation of the fiber. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 A structural schematic diagram of an ultra-low-loss fiber drawing preparation device is provided.

[0036] Figure 2 A partial structural schematic diagram of an ultra-low-loss fiber drawing preparation device is provided.

[0037] Figure 3 A structural schematic diagram of a gas guide ring in an ultra-low-loss fiber drawing preparation device is provided.

[0038] Wherein: 1-hanging rod platform; 2-preform rod; 3-laser furnace gas inlet position; 4-heat conduction heater; 5-heat conduction center pipe; 6-gas guide ring; 7-laser furnace; 8-distributed annealing furnace; 81-independent heating section; 82-independent heating section at the middle position; 9-bare fiber diameter gauge; 10-fiber coating mold base; 11-fiber curing furnace; 12-fiber upper positioning wheel; 13-fiber stroke cooling assembly; 131-elastic guide wheel; 132-heat dissipation channel; 14-fiber lower positioning wheel; 15-fiber coating temperature gauge; 16-fiber coating diameter diameter gauge; 17-fiber turning wheel; 18-fiber coating tension wheel; 19-wrapping satellite wheel; 20-fiber main traction upper positioning wheel; 21-fiber take-up positioning wheel; 22-fiber take-up reel. DETAILED DESCRIPTION

[0039] The preferred embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0040] As Figures 1-3 shown, the present application provides an ultra-low loss optical fiber drawing preparation device, comprising: a drawing furnace 7 for melting a preform rod 2 and drawing into an optical fiber, a gas guide ring 6 is arranged in the drawing furnace 7, the gas guide ring 6 is used to guide the airflow into the drawing furnace, a heat-conducting central tube 5 is arranged outside the gas guide ring 6, a heat-conducting heater 4 is arranged outside the heat-conducting central tube 5, the heat-conducting central tube 5 is used to transfer the heat of the heat-conducting heater 4 to the gas guide ring 6, the heat-conducting heater 4, the heat-conducting central tube 5 and the gas guide ring 6 cooperate with each other to reduce the eddy current entering the drawing furnace 7 and the temperature fluctuation in the drawing furnace 7.

[0041] The present application provides an ultra-low loss optical fiber drawing preparation device, which solves the technical problems of unstable airflow and temperature fluctuation in traditional devices, not only realizes accurate guidance and heating of the airflow entering the drawing furnace, thereby reducing the eddy current generated by the intersection of cold and hot air, but also improves the temperature uniformity in the drawing furnace, reduces the influence of temperature fluctuation on the quality of optical fiber, effectively reduces the problems of core diameter fluctuation and Mie scattering loss, and ensures the strength and low loss attenuation performance of the optical fiber.

[0042] Preferably, as Figure 3 shown, the inner cavity of the gas guide ring 6 is provided with an S-shaped airflow guide groove, the design of the S-shaped airflow guide groove enables the airflow entering the drawing furnace 7 to flow along a relatively smooth and continuous path, which avoids the formation of sharp turns or collisions of the airflow in the furnace, thereby reducing the eddy current generated when cold and hot airflows intersect, and improving the temperature uniformity in the drawing furnace; at the same time, through the guidance of the S-shaped airflow guide groove, the pressure distribution of the airflow in the furnace becomes more uniform, maintaining a stable drawing environment and improving product quality.

[0043] Preferably, as Figures 1-2 shown, the material of the heat-conducting central tube 5 is preferably graphite, and the material of the heat-conducting heater 4 is preferably graphite; graphite has good thermal conductivity and high thermal conductivity coefficient, which can quickly transfer heat, making graphite the preferred material for the heat-conducting central tube 5, as it can ensure that the heat is quickly and uniformly distributed in the heat-conducting central tube 5, thereby improving the thermal efficiency of the entire system; graphite has good electrical conductivity and resistance, when electrified, graphite will generate heat and quickly transfer to the heated object, making graphite the ideal material for the heat-conducting heater 4, as it can quickly transfer heat to the target object, improving the heating efficiency.

[0044] Preferably, as Figures 1-2As shown, the one end of the drawing furnace 7 is provided with a hanging rod platform 1, the hanging rod platform 1 is connected with a preform rod 2, the preform rod 2 passes through the one end of the drawing furnace 7 and is arranged in the inner cavity of the gas guide ring 6, and the other end of the drawing furnace 7 is connected with the one end of the distributed annealing furnace 8. The structure is simple, and the operation is convenient.

[0045] Preferably, as shown in the drawings, Figure 1 As shown, the distributed annealing furnace 8 comprises a plurality of independent heating sections 81, each of which is electrically connected with an independent temperature control system, the inner cavity of the distributed annealing furnace 8 gradually expands its inner diameter from the independent heating section 81 close to the drawing furnace 7 to the independent heating section 82 at the middle position, and then gradually reduces its inner diameter from the independent heating section 82 at the middle position to the independent heating section 81 away from the drawing furnace 7.

[0046] The traditional annealing process has the following disadvantages: the temperature control precision and uniformity in the annealing process are insufficient, and the performance of the optical fiber is adversely affected;

[0047] The change of the inner cavity structure of the distributed annealing furnace 8 helps to form a more reasonable temperature gradient, so that the optical fiber can gradually adapt to different temperature environments during the heating process. The inner cavity of the distributed annealing furnace 8 gradually expands its inner diameter from the independent heating section 81 close to the drawing furnace 7 to the independent heating section 82 at the middle position. The heating section close to the drawing furnace can be set to a higher temperature to ensure that the optical fiber is sufficiently heated and softened in the initial stage. The inner cavity of the distributed annealing furnace 8 gradually reduces its inner diameter from the independent heating section 82 at the middle position to the independent heating section 81 away from the drawing furnace 7. As the optical fiber is annealed backward, the temperature gradually decreases, which helps to gradually cool and solidify the optical fiber and reduces the internal stress caused by sudden temperature changes.

[0048] The independent temperature control system provided in each independent heating section 81 can accurately control the temperature in the region, thereby ensuring the uniformity of the temperature in the entire annealing process. This design helps to reduce temperature fluctuations and improve the consistency and quality of the optical fiber annealing. Accurate temperature control and stable annealing process help to reduce the generation of thermal stress, so that the mechanical properties of the optical fiber are optimized, and the surface quality and optical performance are improved.

[0049] Preferably, as shown in the drawings, Figure 1 As shown, the other end of the distributed annealing furnace 8 is arranged corresponding to the one end of the bare optical fiber diameter measuring instrument 9, the bare optical fiber diameter measuring instrument 9 is used for real-time monitoring of the diameter of the bare optical fiber prepared by the distributed annealing furnace 8, the bare optical fiber diameter measuring instrument 9 is electrically connected with a P ID controller, the P ID controller is electrically connected with the hanging rod platform 1 and the drawing furnace 7, the working state of the hanging rod platform 1 is controlled to regulate the preform rod 2 feeding amount, and the working state of the drawing furnace 7 is controlled to regulate the drawing speed of the drawing furnace 7, so as to realize automatic tuning of the diameter of the bare optical fiber.

[0050] This application utilizes a bare fiber diameter gauge 9 to monitor the bare fiber drawn from the distributed annealing furnace 8 in real time. The PID controller receives the bare fiber diameter data from the bare fiber diameter gauge 9, compares the real-time monitored fiber diameter data with the preset diameter setting value, calculates the deviation, and adjusts parameters such as the feed amount of the preform 2 entering the drawing furnace 7 from the rod platform 1 and the drawing speed of the drawing furnace 7 according to the deviation. The adjusted control parameters are responded to by the rod platform 1 and the drawing furnace 7. The rod platform 1 and the drawing furnace 7 adjust their working state according to the received signals, thereby achieving precise control of the fiber diameter. The above control system realizes the automated control of the fiber preparation process, reduces manual intervention and error generation, which helps to improve production efficiency and reduce production costs.

[0051] Preferably, such as Figure 1 As shown, the other end of the bare optical fiber diameter measuring instrument 9 is correspondingly set to one end of the optical fiber coating mold base 10. The optical fiber coating mold base 10 is used to coat the bare optical fiber to form a coating. The optical fiber coating mold base 10 includes an inner coating mold core and an outer coating mold core. The distance between the inner coating mold core and the outer coating mold core is reduced to 4-6 mm.

[0052] By calculating and comparing the periodic changes in the actual fiber coating tension of the fiber coating mold base with the set tension value, the trend of the fiber coating tension change is obtained, and the power of the fiber drawing furnace is self-coordinated.

[0053] In the design of traditional coating molds, optical fibers need to be coated with two layers of coating at once, one inner and one outer. Generally, the fiber first passes through the inner coating core and then enters the outer coating core through a channel of about 20mm, resulting in a long travel distance. This invention redesigns and adjusts the feeding method of the mold, thereby greatly reducing the distance between the inner and outer coating cores to about 5mm, reducing coating resistance, reducing the generation of coating bubbles and defects, and improving the strength of the optical fiber.

[0054] By calculating and comparing the periodic change of the actual drawing and coating tension of the fiber coating mold base 10 with the set tension value, the trend of the drawing and coating tension change is obtained to achieve self-coordination of the power of the drawing furnace 7.

[0055] According to the calculated tension change trend, the control system formulates the adjustment strategy of the power of the drawing furnace 7; when the fiber coating mold base sensor monitors that the actual drawing coating tension is higher than the set tension, the PID controller receives the signal that the actual drawing coating tension is higher than the set tension and controls to reduce the power of the drawing furnace, so as to reduce the stretching force of the optical fiber in the coating process; when the fiber coating mold base sensor monitors that the actual drawing coating tension is lower than the set tension, the PID controller receives the signal that the actual drawing coating tension is lower than the set tension and controls to increase the power of the drawing furnace, so as to increase the stretching force of the optical fiber in the coating process to reach the preset tension value; the PID controller adjusts the power of the drawing furnace 7 by regulating the current or voltage of the heating element (such as an induction coil) of the drawing furnace 7; the adjusted power will directly affect the heating temperature and softening degree of the optical fiber, thereby affecting the stretching force and tension of the optical fiber in the coating process. This automatic control helps to reduce manual intervention, improve production efficiency and product quality.

[0056] Preferably, as shown in Figure 1 The other end of the fiber coating mold base 10 corresponds to one end of the fiber curing furnace 11, which is used for curing the coating of the optical fiber. The other end of the fiber curing furnace 11 corresponds to the fiber upper positioning wheel 12, which is used for transmitting the optical fiber with cured coating to the inlet of the fiber stroke cooling assembly 13. The fiber lower positioning wheel 14 is arranged at the outlet of the fiber stroke cooling assembly 13, and the fiber lower positioning wheel 14 transmits the cooled optical fiber coating to the fiber coating temperature measuring instrument 15.

[0057] The main function of the fiber curing furnace is to heat and cure the coating on the optical fiber. The fiber upper positioning wheel 12 and the fiber lower positioning wheel 14 jointly transmit the optical fiber from the fiber curing furnace 11 to the fiber stroke cooling assembly 13, and then transmit the cooled optical fiber to the fiber coating temperature measuring instrument 15. These positioning wheels ensure that the optical fiber maintains a stable path during transmission, preventing the optical fiber from being damaged or deviating from the predetermined path during transmission.

[0058] At the same time, the fully cooled coated optical fiber has high robustness and is not prone to flattening when entering the fiber main traction assembly and the fiber take-up assembly, and the geometric roundness is well maintained, improving the roundness of the coated optical fiber.

[0059] Preferably, as shown in Figure 1As shown, the optical fiber stroke cooling assembly 13 comprises a plurality of elastic guide wheels 131, the plurality of elastic guide wheels 131 are arranged in multiple layers alternately to form heat dissipation channels 132 between each two adjacent layers, each of the elastic guide wheels 131 is connected with a guide wheel driving member (not shown), the optical fiber coating temperature measuring instrument 15 is electrically connected with a PID controller, the PID controller is electrically connected with the guide wheel driving member (not shown), and the guide wheel driving member (not shown) is controlled to drive the elastic guide wheels 131 to move to regulate the spacing of the heat dissipation channels 132 between each two adjacent layers;

[0060] After the optical fiber leaves the optical fiber curing furnace, the surface temperature of the optical fiber is usually high, and simple natural cooling or forced cooling by adding a helium pipe with water is usually adopted. However, the cost is higher after adding helium, and the effect of simple self-cooling is poor, and it is unable to ensure the risk of deformation, fracture of the optical fiber caused by the high temperature of the coating, and increase of attenuation, deterioration of strength and other performances caused by the stress of the coating;

[0061] The optical fiber coating temperature measuring instrument 15 is adopted to monitor the surface temperature of the optical fiber coating after cooling in real time, and the temperature data is fed back to the PID controller. According to the feedback temperature data, the guide wheel driving member (not shown) is controlled to drive the elastic guide wheels 131 to move to regulate the spacing of the heat dissipation channels 132. The PID controller controls the guide wheel driving member (not shown) to drive the elastic guide wheels 131 arranged in multiple layers alternately to move to form heat dissipation channels 132 with large spacing or small spacing, so that more or less air flows in the heat dissipation channels 132, thereby effectively taking away the heat of the optical fiber, realizing rapid cooling of the optical fiber, and stably controlling the temperature of the optical fiber coating surface at the outlet of the optical fiber stroke cooling assembly 13 in a reasonable range, thereby realizing control of the thermal stress of the optical fiber coating after curing, improving the uniformity of the stress of the optical fiber coating, and being beneficial to further reduction of the attenuation of the optical fiber, and reducing the production cost.

[0062] Preferably, as shown in the drawings, Figure 1 As shown, the optical fiber coating temperature measuring instrument 15 is arranged corresponding to one end of an optical fiber coating diameter measuring instrument 16, the optical fiber coating diameter measuring instrument 16 is used to monitor the diameter of the optical fiber coating in real time, the optical fiber coating diameter measuring instrument 16 is electrically connected with a PID controller, and the PID controller is electrically connected with the optical fiber coating die seat 10 to control the working state of the optical fiber coating die seat 10 to adjust the temperature and pressure during coating to realize automatic tuning of the diameter of the optical fiber coating;

[0063] The fiber optic coating diameter measuring instrument 16 continuously emits a light beam and receives reflected light. By measuring the intensity and waveform changes of the reflected light signal, it calculates the diameter data of the fiber optic coating. This data is fed back to the PID controller in real time. After receiving the diameter data, the PID controller compares it with the preset standard diameter value. If there is a deviation between the actual diameter of the fiber optic coating and the standard value, the PID controller will initiate an adjustment program. Through PID calculation, the PID controller calculates the temperature and pressure parameters that need to be adjusted. Then, it sends these parameter adjustment instructions to the fiber optic coating mold 10. The fiber optic coating mold 10 adjusts the temperature and pressure during coating according to the control instructions of the PID controller. By precisely controlling these parameters, the fiber optic coating mold 10 can gradually reduce the deviation between the actual diameter of the fiber optic coating and the standard value, realizing automatic tuning of the coating diameter. Automatic adjustment ensures the uniformity of the fiber optic coating, and the diameter of the fiber optic coating will be stably maintained within the standard range without manual operation, thus improving the quality and production efficiency of fiber optic products.

[0064] Preferably, such as Figure 1 As shown, the main fiber traction assembly includes a wrap-around satellite wheel 19 and a main fiber traction upper positioning wheel 20. The fiber take-up assembly includes a fiber take-up positioning wheel 21 and a fiber take-up reel 22. The other end of the fiber coating diameter measuring instrument 16 is correspondingly set with the fiber steering wheel 17. The fiber steering wheel 17 is used to transmit the coated fiber to the fiber coating tension wheel 18. The fiber coating tension wheel 18 continues to transmit the coated fiber to the wrap-around satellite wheel 19. The wrap-around satellite wheel 19 is used to achieve high-speed fiber drawing. The wrap-around satellite wheel 19 continues to transmit the coated fiber to the main fiber traction upper positioning wheel 20. Finally, the main fiber traction upper positioning wheel 20 transmits the coated fiber to the fiber take-up reel 22 through the fiber take-up positioning wheel 21 for take-up.

[0065] Existing fiber optic main traction methods all use belts to clamp the fiber, which can easily flatten the fiber coating, leading to increased non-circularity. At the same time, the pressure applied to the coating remains inside the coating, which is detrimental to fiber attenuation.

[0066] The fiber optic main traction assembly of this application can achieve high-speed fiber drawing by eliminating the belt and using a wrap-around satellite wheel 19. The wrap-around satellite wheel 19 will not slip during operation, maintaining the reliability of length measurement in meters. This method reduces the non-circularity of the fiber coating and improves the additional attenuation of the fiber coating.

[0067] like Figures 1-3As shown, the present application provides an ultra-low loss optical fiber drawing preparation device, by optimizing each link in the optical fiber drawing preparation production process, including airflow heating design, five-section annealing temperature control, coating mold core spacing optimization, automatic control system, beltless traction design and other key technologies, the mutual cooperation and optimization of each link in the whole production process, not only realizes the minimization of optical fiber attenuation, maximization of strength and uniformity of surface quality, but also ensures the high quality, low loss and high stability of optical fiber, and realizes the breakthrough in production efficiency and optical fiber quality consistency.

[0068] It can be understood that the present application is described by some embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to these features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, modifications can be made to these features and embodiments to adapt to specific conditions and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited by the specific embodiments disclosed herein, and all changes or equivalent replacements falling within the scope of the claims of the present application. In addition, under the guidance of the present application, modifications can be made to these features and embodiments to adapt to specific conditions and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are within the scope of the present application.

Claims

1. An ultra-low-loss optical fiber draw manufacturing apparatus, characterized by, The application relates to a fiber drawing furnace, which comprises the following parts: a fiber drawing furnace for melting a preform rod and drawing the preform rod into an optical fiber, a gas guide ring arranged in the fiber drawing furnace and used for guiding airflow into the fiber drawing furnace, a heat-conducting central tube arranged outside the gas guide ring, a heat-conducting heater arranged outside the heat-conducting central tube, the heat-conducting central tube being used for transmitting heat of the heat-conducting heater to the gas guide ring, the heat-conducting heater, the heat-conducting central tube and the gas guide ring being matched with each other to reduce eddy current entering the fiber drawing furnace and temperature fluctuation in the fiber drawing furnace; an S-shaped airflow guide groove is arranged in the inner cavity of the gas guide ring; a preform rod is connected to a hanging rod platform arranged at one end of the fiber drawing furnace, the preform rod passes through one end of the fiber drawing furnace and is arranged in the inner cavity of the gas guide ring, and the other end of the fiber drawing furnace is connected with one end of a distributed annealing furnace; the distributed annealing furnace comprises a plurality of independent heating sections, each independent heating section is electrically connected with an independent temperature control system, and the inner cavity of the distributed annealing furnace gradually expands its inner diameter from the independent heating section close to the fiber drawing furnace to the independent heating section at the middle position, and then gradually shrinks its inner diameter from the independent heating section at the middle position to the independent heating section far away from the fiber drawing furnace. The other end of the distributed annealing furnace is arranged in correspondence with one end of a bare optical fiber diameter measuring instrument, the bare optical fiber diameter measuring instrument is used for monitoring the diameter of the bare optical fiber prepared by the distributed annealing furnace in real time, the bare optical fiber diameter measuring instrument is electrically connected with a PID controller, and the PID controller is electrically connected with the hanging rod platform and the fiber drawing furnace, so as to control the working state of the hanging rod platform to regulate the preform rod feeding amount and control the working state of the fiber drawing furnace to regulate the drawing speed of the fiber drawing furnace, thereby realizing automatic tuning of the diameter of the bare optical fiber.

2. The ultra-low loss optical fiber draw manufacturing apparatus of claim 1, wherein, The other end of the bare optical fiber diameter measuring instrument is arranged in correspondence with one end of a fiber coating die seat, the fiber coating die seat is used for coating on the bare optical fiber to form a coating layer, the fiber coating die seat comprises an inner coating die core and an outer coating die core, and the spacing between the inner coating die core and the outer coating die core is reduced to 4-6 mm; the actual fiber drawing coating tension periodic change of the fiber coating die seat is compared with a set tension value, so as to obtain the change trend of the fiber drawing coating tension and realize self-coordination of the fiber drawing furnace power.

3. The ultra-low loss optical fiber draw manufacturing apparatus of claim 2, wherein, The other end of the fiber coating die seat is arranged in correspondence with one end of a fiber curing furnace, the fiber curing furnace is used for curing the coating layer of the optical fiber, the other end of the fiber curing furnace is arranged in correspondence with an optical fiber upper positioning wheel, the optical fiber upper positioning wheel is used for transmitting the optical fiber after curing of the coating layer to an entrance of an optical fiber stroke cooling assembly, an optical fiber lower positioning wheel is arranged at an outlet of the optical fiber stroke cooling assembly, and the optical fiber lower positioning wheel transmits the cooled optical fiber coating layer to an optical fiber coating layer temperature measuring instrument.

4. The ultra-low loss optical fiber draw manufacturing apparatus of claim 3, wherein, ​ 5. The ultra-low loss optical fiber draw manufacturing apparatus of claim 4, wherein, The optical fiber stroke cooling assembly comprises a plurality of elastic guide wheels, a plurality of the elastic guide wheels are arranged in multiple layers alternately to form heat dissipation channels between each two adjacent layers, each of the elastic guide wheels is connected with a guide wheel driving member, the optical fiber coating temperature measuring instrument is used for monitoring the surface temperature of the cooled optical fiber coating in real time, the optical fiber coating temperature measuring instrument is electrically connected with a PID controller, the PID controller is electrically connected with the guide wheel driving member, and the guide wheel driving member is controlled to drive the elastic guide wheels to move to regulate the spacing of the heat dissipation channels.

6. The ultra-low loss optical fiber draw manufacturing apparatus of claim 4, wherein, The optical fiber coating temperature measuring instrument is arranged corresponding to one end of an optical fiber coating diameter measuring instrument, the optical fiber coating diameter measuring instrument is used for monitoring the diameter of the optical fiber coating in real time, the optical fiber coating diameter measuring instrument is electrically connected with a PID controller, the PID controller is electrically connected with an optical fiber coating die seat, the working state of the optical fiber coating die seat is controlled to adjust the temperature and pressure during coating to realize automatic tuning of the optical fiber coating diameter.

7. The ultra-low-loss optical fiber draw manufacturing apparatus of claim 6, wherein, The other end of the optical fiber coating diameter measuring instrument is arranged corresponding to an optical fiber turning wheel, the optical fiber turning wheel is used for transmitting the coated optical fiber to an optical fiber coating tension wheel, the optical fiber coating tension wheel continues to transmit the coated optical fiber to an optical fiber main traction assembly, the optical fiber main traction assembly comprises a wrapped satellite wheel, the wrapped satellite wheel is used for realizing high-speed wire drawing of the traction belt, and the optical fiber main traction assembly finally transmits the coated optical fiber to an optical fiber take-up assembly for take-up.

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