Stainless steel central tube type optical unit manufacturing process optical fiber attenuation control method

Abstract

The invention discloses a stainless steel central tube type optical unit manufacturing process optical fiber attenuation control method and belongs to the technical field of submarine optical cables. Comprising optical unit structure design and optical unit production process attenuation control. Before the optical unit is produced, the pipe diameter, the optical fiber type and the optical fiber core number of the optical unit are determined, and the theoretical maximum excess length of the optical unit is calculated according to a formula; the attenuation control device for the optical unit production process comprises a needle tube, a laser, a drawing forming unit, a pressure sensor, a wheel tractor and an extrusion wheel set which are arranged in sequence. An optical fiber and fiber paste are guided into a steel pipe welded by a laser through a needle tube, the steel pipe passes through a drawing forming unit and a pressure sensor and then is wound on a wheel tractor, the wheel tractor stretches the steel pipe through large tension to generate elastic deformation, the steel pipe releases stretching tension after passing through the wheel tractor, and the steel pipe retracts to generate the excess length of the optical fiber. The excess length of the optical fiber is in a design range, thereby ensuring the stability of the attenuation coefficient of the optical unit and improving the transmission performance of the system.

Description

Technical Field

[0001] The invention relates to an optical fiber attenuation control method for a stainless steel central tube type optical unit process, belonging to the technical field of submarine optical cables. Background Art

[0002] In the submarine optical cable industry, to protect the optical fiber from stress, it is placed in a stainless steel central tube optical unit. The optical fibers are distributed in a spiral pattern within the optical unit, creating a certain excess length. This protects the cable from external forces during manufacturing, installation, and recovery, ensuring stable transmission performance. In long-distance communication systems, the attenuation coefficient is a key transmission characteristic of optical cables. Optical unit production is the first step in the cable manufacturing process and directly affects the attenuation coefficient. Therefore, the ability to stably control the attenuation coefficient of the optical unit is crucial.

[0003] The attenuation coefficient of an optical unit is affected by many factors. The outer diameter of the optical unit, the wall thickness of the optical unit, the number of optical fiber cores, the type of optical fiber, and the excess length of the optical fiber will all significantly affect the attenuation coefficient of the optical unit. The attenuation coefficient of the optical unit fluctuates greatly, which brings uncertainty to the production process. The large attenuation loss affects the transmission performance of the communication system and causes waste in industrial production. In the field of submarine optical cables, the number of optical fiber cores is increasing, and the ultra-large core fiber system is developing rapidly, which brings greater challenges to the stability of the attenuation coefficient of the optical unit. Therefore, based on the existing theories and process technologies, and taking into account the main influencing factors of the attenuation coefficient, the present invention proposes a reliable optical fiber attenuation control method for the optical unit process. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to provide a method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process, which can achieve effective control of optical fiber attenuation in the optical unit manufacturing process.

[0005] The technical solution of the present invention is as follows: a method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process, mainly comprising: an optical unit structure design method, an optical unit production process attenuation control device and a control process.

[0006] 1. The design method of the optical unit structure is as follows:

[0007] Before producing the optical unit, determine the optical unit diameter, optical fiber type, number of optical fiber cores and other parameters according to technical requirements. To ensure that the optical unit attenuation coefficient meets the technical requirements, the maximum excess length y of the optical fiber meets the following formula:

[0008]

[0009] in, is the equivalent diameter of the optical fiber, y(‰) is the excess length of the optical fiber, D is the outer diameter of the optical unit, d is the wall thickness of the stainless steel belt, and d fis the fiber diameter, N is the number of fiber cores, and R is the curvature radius of the fiber.

[0010] Furthermore, according to the fiber type and attenuation requirements, the curvature radius R of the optical fiber is determined as follows:

[0011] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 55mm;

[0012] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 60mm;

[0013] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 70mm;

[0014] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 80mm;

[0015] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 90mm;

[0016] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 100mm;

[0017] The optical unit uses G654 optical fiber, and R is 200mm.

[0018] The theoretical maximum excess length of the optical unit can be calculated according to the above formula. In the optical unit production process, the maximum excess length of the optical fiber is controlled not to exceed the calculated value y, which can ensure the stability of the optical unit attenuation coefficient and meet the optical unit attenuation technical requirements.

[0019] 2. About the attenuation coefficient control device of the optical unit production process

[0020] During the optical unit production process, customer technical requirements, such as the optical unit outer diameter, steel strip wall thickness, and optical fiber core count and type, are already determined. The fiber paste filling ratio is 90%. The excess fiber length during the optical unit manufacturing process determines the stability of the attenuation coefficient. To ensure that the excess fiber length during the optical unit manufacturing process is within the calculated value y, the present invention proposes an excess fiber length control device, namely, an attenuation control device for the optical unit production process.

[0021] The device includes a needle tube, a laser, a drawing and forming unit, a pressure sensor, a pulley, and an extrusion wheel assembly, which are arranged in sequence. The extrusion wheel assembly includes a fixed plate, an upper wheel assembly, a lower wheel assembly, a dial indicator, and upper and lower wheel spacing adjustment assemblies. The upper wheel assembly is installed between the fixed plate and the lower wheel assembly, and the upper and lower wheel spacing adjustment assemblies are used to adjust the distance between the upper and lower wheel assemblies. The dial indicator is installed on the fixed plate to detect the displacement of the upper wheel assembly.

[0022] Furthermore, the diameter of the wheel pulley is 1m, the upper wheel group includes an upper base and 4 small guide wheels installed on the upper base, and the lower wheel group includes a lower base and 5 small guide wheels installed on the lower base; the distance between adjacent small guide wheels in the same row is 6cm, the diameter of the small guide wheel is 5cm, and the small guide wheels in the upper and lower rows are staggered.

[0023] Furthermore, the upper and lower wheelbase adjustment components include: a pair of guide sleeves, a pair of polished rods, a threaded column, and a spring; a pair of polished rods are symmetrically and fixedly installed between the fixed plate and the lower wheel group; a pair of guide sleeves are arranged at both ends of the upper base of the upper wheel group, and are respectively mounted on the pair of polished rods; the threaded column is respectively rotatably assembled with the fixed plate and the lower base of the lower wheel group, and is threadedly connected with the upper base of the upper wheel group; the top of the threaded column extends out of the fixed plate, and the spring is mounted on the threaded column and compressed between the upper and lower bases.

[0024] Rotating the threaded column drives the upper base of the upper wheel assembly up and down along a pair of polished rods, thereby changing the distance between the upper and lower wheel assemblies and achieving different extrusion effects. A micrometer is mounted on a fixed plate to monitor the displacement of the upper wheel assembly in real time and feed the data back to the control system, which can further accurately determine the extrusion condition of the extrusion wheel assembly. During the extrusion process, the spring acts as a buffer and elastic support. When the steel pipe passes through the extrusion wheel assembly, it may generate a certain impact force. The spring can absorb this impact force and prevent the wheel assembly from being damaged by excessive impact. At the same time, the spring can also ensure that the contact pressure between the wheel assemblies is within a certain range, ensuring the stability of the extrusion process.

[0025] 3. About the attenuation coefficient control process of optical unit production process

[0026] The optical fiber and fiber paste are introduced into the steel pipe welded by the laser through the needle tube. The steel pipe is formed into a certain outer diameter through the drawing forming unit. The steel pipe is wrapped around the pulley after passing through the pressure sensor. The pulley pulls the steel pipe with high tension to produce elastic deformation. After the steel pipe passes through the pulley, the tensile tension is released and the steel pipe retracts to produce excess length of the optical fiber.

[0027] The more times the steel pipe is wrapped around the pulley, the greater the friction between the steel pipe and the pulley, the greater the force and deformation of the steel pipe, and thus the greater the excess length.

[0028] When a larger excess length of the optical unit is required, the steel tube is pulled into the optical unit extrusion wheel assembly. The upper and lower rows of guide wheels are evenly spaced, and the spacing (wheelbase) between the upper and lower rows is adjustable. As the steel tube passes through the extrusion wheel assembly, the upper and lower rows of small guide wheels apply pressure to the steel tube horizontally and vertically, respectively. This relieves stress on the steel tube and bends the optical fiber to a certain extent, thereby increasing the excess length of the optical fiber. The greater the pressure applied by the extrusion wheel assembly, the greater the excess length of the optical unit.

[0029] The excess fiber length is controlled by the pulley and extrusion wheel group, and the excess fiber length is within the design range, ensuring the stability of the optical unit attenuation coefficient and improving the system transmission performance.

[0030] The optical fiber attenuation control method for the stainless steel central tube optical unit process of the present invention mainly includes an optical unit structure design method and an optical unit production process attenuation control process, provides a theoretical method for attenuation control of optical fibers of different types and different core counts in cabling, and gives the key process points and implementation methods for attenuation control in the optical unit production process to guide actual production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a control flow chart of the attenuation coefficient control device for the optical unit production process of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the extrusion wheel assembly of the present invention;

[0033] Figure 3 This is a schematic structural diagram of the extrusion wheel assembly of the present invention (excluding the dial indicator and the three small guide wheels);

[0034] In the figure: needle tube 1, laser 2, drawing unit 3, pressure sensor 4, pulley 5, extrusion wheel group 6, stainless steel tube 7, fixing plate 8, micrometer 9, upper base 10, small guide wheel 11, lower base 12, guide sleeve 13, polished rod 14, threaded column 15, spring 16. DETAILED DESCRIPTION

[0035] Example 1

[0036] A method for controlling optical fiber attenuation in a stainless steel central tube optical unit process, including an optical unit structure design method, is as follows:

[0037] Before producing the optical unit, determine the optical unit diameter, optical fiber type, number of optical fiber cores and other parameters according to technical requirements. To ensure that the optical unit attenuation coefficient meets the technical requirements, the maximum excess length y of the optical fiber meets the following formula:

[0038]

[0039] in, is the equivalent diameter of the optical fiber, y(‰) is the excess length of the optical fiber, D is the outer diameter of the optical unit, d is the wall thickness of the stainless steel belt, and d f is the fiber diameter, N is the number of fiber cores, and R is the curvature radius of the fiber.

[0040] According to the fiber type and attenuation requirements, the curvature radius R of the optical fiber is determined as follows:

[0041] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 55mm;

[0042] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 60mm;

[0043] The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 70mm;

[0044] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 80mm;

[0045] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 90mm;

[0046] The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 100mm;

[0047] The optical unit uses G654 optical fiber, and R is 200mm.

[0048] The theoretical maximum excess length of the optical unit can be calculated according to the above formula. In the optical unit production process, the maximum excess length of the optical fiber is controlled not to exceed the calculated value y, which can ensure the stability of the optical unit attenuation coefficient and meet the optical unit attenuation technical requirements.

[0049] Example 2

[0050] Based on Example 1, the optical fiber attenuation control method for the stainless steel central tube optical unit production process further includes an optical unit production process attenuation coefficient control device.

[0051] like Figure 1 As shown, the optical unit production process attenuation control device includes a needle tube 1, a laser 2, a drawing forming unit 3, a pressure sensor 4, a pulley 5 (the diameter of the pulley is 1m), and an extrusion wheel group 6 arranged in sequence.

[0052] like Figure 2 As shown, the extrusion wheel group includes: a fixed plate 8, an upper wheel group, a lower wheel group, a dial indicator 9, and upper and lower wheel spacing adjustment components; the upper wheel group is installed between the fixed plate and the lower wheel group, and the distance between the upper and lower wheel groups is adjusted by the upper and lower wheel spacing adjustment components; the dial indicator is installed on the fixed plate to monitor the displacement of the upper wheel group.

[0053] like Figure 2 、 3 As shown, the upper wheel group includes an upper base 10 and four small guide wheels 11 installed on the upper base, and the lower wheel group includes a lower base 12 and five small guide wheels 11 installed on the lower base; the distance between adjacent small guide wheels in the same row is 6 cm, the diameter of the small guide wheel is 5 cm, and the small guide wheels in the upper and lower rows are staggered.

[0054] like Figure 3 As shown, the upper and lower wheelbase adjustment assembly includes: a pair of guide sleeves 13, a pair of polished rods 14, a threaded post 15, and a spring 16. The pair of polished rods are symmetrically and fixedly mounted between the fixed plate and the lower wheel assembly. A pair of guide sleeves are provided at both ends of the upper base of the upper wheel assembly and are respectively mounted on the pair of polished rods. The threaded post is rotatably assembled with the fixed plate and the lower base of the lower wheel assembly, and is threadedly connected to the upper base of the upper wheel assembly. The top of the threaded post extends outside the fixed plate, and the spring is mounted on the threaded post and compressed between the upper and lower bases. Rotating the threaded post drives the upper wheel assembly up and down, changing the distance between the upper and lower wheel assemblies.

[0055] Example 3

[0056] The control process of the attenuation coefficient control device for the optical unit production process in Example 2 includes:

[0057] The optical fiber and fiber paste are introduced through a needle into a laser-welded steel tube. The tube is then drawn and formed into a specific outer diameter. After passing through a pressure sensor, the tube is wrapped around a pulley. The pulley exerts high tension, stretching the tube and causing elastic deformation. After the pulley releases the tension, the tube retracts, creating excess fiber length. The more turns the tube is wrapped around the pulley, the greater the friction between the tube and the pulley, the greater the deformation, and thus the excess length.

[0058] When a larger excess length is required for the optical unit, the steel tube is pulled into the optical unit extrusion wheel assembly. The upper and lower rows of small guide wheels apply pressure to the steel tube in the horizontal and vertical directions respectively, eliminating stress on the steel tube and causing a certain bend in the optical fiber, thereby increasing the excess length of the optical fiber. The greater the pressure applied by the extrusion wheel assembly, the greater the excess length of the optical unit.

[0059] Example 4

[0060] Based on Example 2 or 3, a project is to produce an optical unit with 24-core G652 optical fibers and an outer diameter D of 3.0 mm. The technical requirement is that the 1550 nm optical fiber attenuation is ≤ 0.22 dB / km. In order to control the optical fiber attenuation in the optical unit process to meet the technical requirements, the optical unit structure is first designed. The wall thickness d of the steel belt in the factory is 0.25 mm. According to the optical fiber type and attenuation requirement, R is taken as 55 mm. Substituting it into the formula, the maximum excess length of the optical fiber can be calculated to be 4.8‰. In order to ensure that the optical fiber is effectively protected from tension during the process and laying of the optical cable, the range of the excess length of the optical fiber can be 2.0-4.8‰, which can ensure that the attenuation of the optical unit is within the technical requirements.

[0061] During the optical unit production stage, after the steel pipe is drawn into a 3.0mm diameter, it is wrapped around the pulley for 8 turns with the pulley tension set to 120kg. When the steel pipe passes through the optical unit extrusion wheel group, the pressure is set to 30kg. The optical fiber excess length of the optical unit process is strictly controlled within the range of 2.0-4.8‰ to ensure that the 1550nm optical fiber attenuation of the optical unit is ≤0.22dB / km.

Claims

1. A method for controlling optical fiber attenuation in a stainless steel central tube optical unit process, characterized in that: Including optical unit structure design method: Before producing the optical unit, determine the optical unit diameter, optical fiber type, and number of optical fiber cores based on technical requirements. To ensure that the optical unit attenuation coefficient meets technical requirements, the maximum excess length y of the optical fiber satisfies the following formula: in, is the equivalent diameter of the optical fiber, y(‰) is the excess length of the optical fiber, D is the outer diameter of the optical unit, d is the wall thickness of the stainless steel belt, and d f is the fiber diameter, N is the number of fiber cores, and R is the curvature radius of the fiber.

2. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 1, wherein: According to the fiber type and attenuation requirements, the curvature radius R of the optical fiber is determined as follows: The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 55mm; The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 60mm; The optical unit uses G652 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 70mm; The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.22dB / km, and R is 80mm; The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.21dB / km, and R is 90mm; The optical unit uses G655 optical fiber, the attenuation requirement at 1550nm is ≤0.20dB / km, and R is 100mm; The optical unit uses G654 optical fiber, and R is 200mm.

3. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 2, wherein: It also includes an optical unit production process attenuation control device, which includes a needle tube, a laser, a drawing and forming unit, a pressure sensor, a pulley, and an extrusion wheel group arranged in sequence.

4. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 3, wherein: The extrusion wheel assembly includes: a fixed plate, an upper wheel assembly, a lower wheel assembly, a dial indicator, and upper and lower wheelbase adjustment components; The upper wheel assembly is installed between the fixed plate and the lower wheel assembly, and the distance between the upper and lower wheel assemblies is adjusted by the upper and lower wheelbase adjustment components; the micrometer is installed on the fixed plate and is used to detect the displacement of the upper wheel assembly.

5. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 4, wherein: The upper wheel assembly includes an upper base and four small guide wheels mounted on the upper base, and the lower wheel assembly includes a lower base and five small guide wheels mounted on the lower base; The distance between adjacent small guide wheels in the same row is 6 cm, the diameter of the small guide wheels is 5 cm, and the small guide wheels in the upper and lower rows are staggered.

6. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 5, wherein: The upper and lower wheelbase adjustment components include: a pair of guide sleeves, a pair of polished rods, a threaded column, and a spring; A pair of polished rods are symmetrically and fixedly installed between the fixed plate and the lower wheel group; a pair of guide sleeves are arranged at both ends of the upper base of the upper wheel group and are respectively sleeved on the pair of polished rods; the threaded column is rotatably assembled with the fixed plate and the lower base of the lower wheel group, and is threadedly connected with the upper base of the upper wheel group; the top of the threaded column extends out of the fixed plate, and the spring is sleeved on the threaded column and compressed between the upper and lower bases.

7. The method for controlling optical fiber attenuation in a stainless steel central tube optical unit manufacturing process according to claim 6, wherein: The diameter of the pulley is 1 m.

8. The control method according to any one of claims 3 to 7, characterized in that: The control process of the optical unit production process attenuation control device includes: The optical fiber and fiber paste are introduced into the laser-welded steel pipe through a needle tube. The steel pipe is formed into a certain outer diameter through a drawing and forming unit. The steel pipe passes through a pressure sensor and is wound on a pulley. The pulley exerts a large tension on the steel pipe to produce elastic deformation. After the pulley releases the tension, the steel pipe retracts to produce excess length of the optical fiber. When the excess length of the optical unit is required to be longer, the steel pipe enters the extrusion wheel group after being pulled by the wheel. The small guide wheels in the upper and lower rows apply pressure to the steel pipe in the horizontal and vertical directions respectively. The steel pipe eliminates stress and the optical fiber produces a certain bend, thereby increasing the excess length of the optical fiber.

Images