Method for manufacturing optical fiber and optical fiber
阅读说明:本技术 光纤的制造方法及光纤 (Method for manufacturing optical fiber and optical fiber ) 是由 久原早织 高崎卓 豊川修平 于 2019-02-19 设计创作,主要内容包括:一种光纤的制造方法,具有:除去一对光纤的要连接侧的端部的纤维被覆层以露出玻璃纤维的步骤;将该玻璃纤维的端面彼此熔融连接的步骤;以及将保护树脂再次被覆在上述玻璃纤维的露出部分的周围以进行保护的步骤,其中,上述纤维被覆层由杨氏模量为0.5MPa以下的内周侧的一次树脂层、以及杨氏模量为800MPa以上的外周侧的二次树脂层构成,上述露出步骤是使包括上述一次树脂层和上述二次树脂层的上述纤维被覆层的被覆残余部的形状成为朝着上述端部侧而变细的锥形形状的步骤,上述再次被覆的步骤是以包括上述被覆残余部的方式被覆上述保护树脂的步骤。(A method of manufacturing an optical fiber, comprising: a step of removing the fiber coating layer of the ends of the pair of optical fibers on the side to be connected to expose the glass fiber; a step of melt-joining the end faces of the glass fibers to each other; and a step of recoating a protective resin around an exposed portion of the glass fiber to protect the exposed portion, wherein the fiber coating layer is formed of a primary resin layer having a young's modulus of 0.5MPa or less on an inner peripheral side and a secondary resin layer having a young's modulus of 800MPa or more on an outer peripheral side, the exposing step is a step of forming a coating residual portion of the fiber coating layer including the primary resin layer and the secondary resin layer into a tapered shape that is tapered toward the end portion side, and the recoating step is a step of recoating the protective resin so as to include the coating residual portion.)
1. A method of manufacturing an optical fiber, comprising:
a step of removing the fiber coating layer of the ends of the pair of optical fibers on the side to be connected to expose the glass fiber;
a step of melt-joining the end faces of the glass fibers to each other; and
a step of coating the periphery of the exposed portion of the glass fiber with a protective resin again,
the fiber coating layer is composed of a primary resin layer having a Young's modulus of 0.5MPa or less on the inner peripheral side and a secondary resin layer having a Young's modulus of 800MPa or more on the outer peripheral side,
the exposing step is a step of making a shape of a coating residual portion of the fiber coating layer including the primary resin layer and the secondary resin layer a tapered shape tapered toward the end portion side,
the step of recoating is a step of coating the protective resin so as to include the coating residue.
2. The method for manufacturing an optical fiber according to claim 1, wherein, prior to the exposing step, there is a step of irradiating ultraviolet rays to the fiber coating layer of the portion to be removed so as to increase the Young's modulus of the primary resin layer,
the exposing step is a step of forming the coating residue of the fiber coating layer into a tapered shape.
3. The method for manufacturing an optical fiber according to claim 1, wherein, prior to the exposing step, there is a step of cooling the fiber of the portion to be removed to increase the Young's modulus of the primary resin layer,
the exposing step is a step of forming the coating residue of the fiber coating layer into a tapered shape.
4. An optical fiber obtained by removing a fiber coating layer from end portions of a pair of optical fibers on a side to be connected, fusion-connecting end surfaces of glass fibers to each other, and providing a protective resin around a fusion-connected portion of the glass fibers,
the fiber coating layer is composed of a secondary resin layer on the outer periphery side and a primary resin layer on the inner periphery side with Young's modulus of 0.15MPa to 0.5MPa,
the shape of the coating residual part of the primary resin layer and the secondary resin layer at the end part of the optical fiber is a tapered shape tapering toward the end part side,
the protective resin is provided so as to include the coating residue portion, and
the length of the taper in the axial direction of the optical fiber is 280 μm or more.
5. The optical fiber according to claim 4, wherein an angle of the taper of the coating residue portion is 10 degrees or less.
Technical Field
The present disclosure relates to a method of manufacturing an optical fiber and an optical fiber.
The present patent application claims priority based on japanese patent application No. 2018-028092, which was filed on 20/2/2018, and cites the entire contents of the descriptions described in the above japanese patent application.
Background
As for the optical fiber, a long optical fiber as long as several tens of kilometers, such as an undersea cable, is manufactured corresponding to a request from a user. Such long optical fibers are generally formed by fusion-connecting a plurality of optical fibers. In this case, it is required that peeling or cracking does not occur at the interface between the protective resin of the protective connection portion and the initial coating resin. For example,
On the other hand, in an Optical transmission network corresponding to a transmission speed of 100Gbit/s or more, a higher Optical Signal-to-Noise Ratio (OSNR) is required in order to expand the communication capacity of each core of an Optical fiber. As one method of improving the OSNR, it is possible to suppress the nonlinearity of the optical fiber to be low. Therefore, it is necessary to suppress the transmission loss of the optical fiber while increasing the actual effective sectional area Aeff of the optical fiber.
When the nonlinear refractive index of the optical fiber is set to n2 and the actual effective cross-sectional area of the optical fiber is set to Aeff, the nonlinearity of the optical fiber is defined by
Disclosure of Invention
The method for manufacturing an optical fiber according to the present disclosure includes: a step of removing the fiber coating layer of the ends of the pair of optical fibers on the side to be connected to expose the glass fiber; a step of melt-joining the end faces of the glass fibers to each other; and a step of recoating a protective resin around an exposed portion of the glass fiber, wherein the fiber coating layer is composed of a primary resin layer having a young's modulus of 0.5MPa or less on an inner peripheral side and a secondary resin layer having a young's modulus of 800MPa or more on an outer peripheral side, the exposed portion is formed in a tapered shape that tapers toward the end portion side, and a coating residual portion of the fiber coating layer including the primary resin layer and the secondary resin layer is coated with the protective resin so as to include the coating residual portion.
The optical fiber according to the present disclosure is an optical fiber obtained by removing a fiber coating layer at ends of a pair of optical fibers on a side to be connected, fusion-connecting end faces of glass fibers, and providing a protective resin around a fusion-connected portion of the glass fibers, wherein the fiber coating layer is composed of a secondary resin layer on an outer peripheral side and a primary resin layer on an inner peripheral side having a young's modulus of 0.15MPa to 0.5MPa, a shape of a coating residual portion of the primary resin layer and the secondary resin layer at the ends of the optical fibers is a tapered shape tapered toward the ends, the protective resin is provided so as to include the coating residual portion, and a length of the taper in an axial direction of the optical fiber is 280 μm or more.
Brief description of the drawings
Fig. 1A is a sectional view of a connection portion of an optical fiber manufactured according to the present disclosure in an axial direction.
Fig. 1B is a cross-sectional view along a radial direction of an optical fiber manufactured according to the present disclosure at a position other than a connection portion.
FIG. 2 is a view showing a main part of a connection part of the optical fiber of FIG. 1A.
Fig. 3 is a graph showing the specifications of an optical fiber used as a simulated example relating to the connection portion of the optical fiber of the present disclosure.
FIG. 4A is a graph showing the magnitude of the maximum stress acting on the protective resin when the optical fiber of example 1 of the specification shown in FIG. 3 is used and the angle of the taper and the length of the taper are changed, respectively.
FIG. 4B is a graph showing the magnitude of the maximum stress acting on the protective resin when the optical fiber of example 2 of the specification shown in FIG. 3 is used and the angle of the taper and the length of the taper are changed, respectively.
FIG. 5 is a view showing the structure of a connection portion of a conventional optical fiber having a 2-layer coating layer.
Detailed Description
[ problems to be solved by the present disclosure ]
In an undersea cable using an optical fiber having a 2-layer coating layer, cracks may occur in the protective resin of the connection portion. Fig. 5 is a view showing a configuration of a connection portion of a conventional optical fiber having a coating layer of a 2-layer structure, which is obtained by connecting optical fibers having a
In the connection portion of the optical fiber shown in fig. 5, the coating layer is removed in a tapered shape so as to decrease in diameter toward the fusion-spliced
In this manner, in the conventional connection portion, the end portions of the short fibers are melt-connected by removing the coating, and the connection portion is covered again with the
When the young's modulus of the
The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing an optical fiber and an optical fiber, which can prevent cracks from occurring in a protective resin covering a removed portion of a fiber coating layer and an exposed portion of a glass fiber at a connection portion of the optical fiber, have a large communication capacity, and can transmit an optical fiber over a long distance.
[ Effect of the present disclosure ]
According to the present disclosure, it is possible to provide a method for manufacturing an optical fiber and an optical fiber, which can prevent cracks from occurring in a protective resin covering a removed portion of a coating layer and an exposed portion of a glass fiber at a connection portion of the optical fiber, have a large communication capacity, and can transmit the optical fiber over a long distance.
[ description of embodiments of the present disclosure ]
First, embodiments of the present disclosure are listed and explained.
(1) The method for manufacturing an optical fiber according to the present disclosure includes: a step of removing the fiber coating layer of the ends of the pair of optical fibers on the side to be connected to expose the glass fiber; a step of melt-joining the end faces of the glass fibers to each other; and recoating a protective resin around an exposed portion of the glass fiber, wherein the fiber coating layer is composed of a primary resin layer having a young's modulus of 0.5MPa or less on an inner peripheral side and a secondary resin layer having a young's modulus of 800MPa or more on an outer peripheral side, the exposed portion is formed by forming a coating residual portion of the fiber coating layer including the primary resin layer and the secondary resin layer into a tapered shape that is tapered toward the end portion side, and the recoating step is formed by coating the protective resin so as to include the coating residual portion.
According to this aspect, even when a soft resin is used for the primary resin layer of the fiber coating layer, since the coating remaining portion (the vicinity of the boundary) of the primary resin layer and the secondary resin layer from which the coating layer has been removed is formed in a tapered shape, it is possible to reduce the stress applied to the protective resin at the boundary between the primary resin layer and the secondary resin layer. Therefore, an optical fiber that can prevent the occurrence of cracks in the protective resin covering the removed portion of the coating layer and the exposed portion of the glass fiber at the connection portion of the optical fiber, has a large communication capacity, and can transmit over a long distance can be obtained.
In addition, (2) the method for manufacturing an optical fiber according to the present disclosure includes, in the method for manufacturing an optical fiber according to the above (1), a step of irradiating ultraviolet rays to the fiber coating layer of the portion to be removed to increase the young's modulus of the primary resin layer before the exposing step, and the exposing step is a step of forming the coating residual portion of the fiber coating layer into a tapered shape.
According to this aspect, even if a soft resin is used for the primary resin layer of the fiber coating layer, the fiber coating layer can be cured before removing the fiber coating layer, and thus the coating residual portion of the fiber coating layer can be easily processed into a tapered shape. Therefore, when the fiber coating layer is removed using a tool such as a grinding wheel or a razor, the shape deviation due to the difference in skill is less likely to occur, and the quality of the manufactured optical cable can be maintained.
Further, (3) according to the method for manufacturing an optical fiber of the present disclosure, in the method for manufacturing an optical fiber of the above (1), a step of cooling the fiber of the portion to be removed to increase the young's modulus of the primary resin layer is provided before the exposing step, and the exposing step is a step of forming the coating residual portion of the fiber coating layer into a tapered shape.
According to this aspect, even if a soft resin is used for the primary resin layer of the fiber coating layer, the fiber coating layer can be cured before removing the fiber coating layer, and thus the coating residual portion of the fiber coating layer can be easily processed into a tapered shape. Therefore, when the fiber coating layer is removed using a tool such as a grinding wheel or a razor, the shape deviation due to the difference in skill is less likely to occur, and the quality of the manufactured optical cable can be maintained.
(4) An optical fiber according to the present disclosure is an optical fiber obtained by removing a fiber coating layer at ends of a pair of optical fibers on sides to be connected, fusion-connecting end faces of glass fibers, and providing a protective resin around a fusion-connected portion of the glass fibers, wherein the fiber coating layer is composed of a secondary resin layer on an outer peripheral side and a primary resin layer on an inner peripheral side having a young's modulus of 0.15MPa to 0.5MPa, a shape of a coating residual portion of the primary resin layer and the secondary resin layer at the ends of the optical fibers is a tapered shape tapered toward the ends, the protective resin is provided so as to include the coating residual portion, and a length of the taper in an axial direction of the optical fiber is 280 μm or more.
According to this aspect, even if a soft resin is used for the primary resin layer of the fiber coating layer, since the coating remaining portion (the vicinity of the boundary) of the primary resin layer and the secondary resin layer from which the coating layer has been removed is formed into a tapered shape having a predetermined length, it is possible to reduce the stress applied to the protective resin at the boundary between the primary resin layer and the secondary resin layer. Therefore, an optical fiber that can prevent the occurrence of cracks in the protective resin covering the removed portion of the coating layer and the exposed portion of the glass fiber at the connection portion of the optical fiber, has a large communication capacity, and can transmit over a long distance can be obtained.
Further, according to the optical fiber of the present disclosure, in the optical fiber of the above (4), an angle of the taper of the coating residual portion is 10 degrees or less.
According to this aspect, it is possible to more reliably prevent the occurrence of cracks in the protective resin covering the removed portion of the coating layer and the exposed portion of the glass fiber at the connection portion of the optical fiber.
[ details of embodiments of the present disclosure ]
Hereinafter, a method for manufacturing an optical fiber and a specific example of the optical fiber according to the present disclosure will be described with reference to the drawings. It should be noted that the present invention is not limited to the following examples, but is represented by the scope of the claims, and is intended to include all changes within the meaning and scope equivalent to the scope of the claims. In addition, as long as a plurality of embodiments can be combined, the present invention includes any combination of the embodiments. In the following description, the same reference numerals are used for the same components in different drawings, and the description thereof may be omitted.
Fig. 1A is a sectional view of a connection portion of an optical fiber manufactured according to the present disclosure in an axial direction, and fig. 1B is a sectional view of an optical fiber manufactured according to the present disclosure in a radial direction at a position other than the connection portion. Fig. 2 is a view showing a main part of the connection portion of the optical fiber of fig. 1. An optical fiber manufactured according to the present disclosure is formed by fusion-splicing a plurality of short
The
In the fusion-splicing of the
In the present embodiment, the
The resin constituting the
H- (I-polypropylene glycol)A)2-I-H
H- (I-polypropylene glycol)B)2-I-H
H- (I-polypropylene glycol)C)2-I-H
Further, examples of the low polymer having a single terminal reactive group include (for example)
H- (I-polypropylene glycol)A)2-I-X
H- (I-polypropylene glycol)B)2-I-X
H- (I-polypropylene glycol)C)2-I-X
H represents a residue of hydroxyethyl acrylate, I represents a residue of isophorone diisocyanate, X represents methanol, polypropylene glycolA-CRespectively represent the residues of the following polypropylene glycols. Namely, polypropylene glycolARepresents a residue of ACCLAIM 4200 (molecular weight: 4000; unsaturation degree: 0.003meq/g), polypropylene glycolBRepresents XS-3020C (molecular weight: 3000; unsaturation: 0.03meq/g), polypropylene glycolCRepresents the residue of EXCENOL 3020 (molecular weight: 3000; unsaturation: 0.09 meq/g). The urethane oligomer is prepared from H- (I-propylene glycol)2-I-H.
The both-terminal reactive oligomer and the single-terminal reactive oligomer are not limited to the above-mentioned materials. In addition to the above, polypropylene glycols or copolymers of polypropylene glycol/ethylene glycol having a molecular weight of 1000 to 13000, preferably 2000 to 8000, and an unsaturation degree of less than 0.01meq/g, preferably 0.0001 to 0.009meq/g, are also possible, for example. Further, if necessary, a urethane compound having at least one (meth) acrylate group derived from a mixture thereof with at least one other polyol may be contained.
Examples of the resin constituting the
Examples of the polyol compound include polytetramethylene glycol and polypropylene glycol. Examples of the polyisocyanate compound include 2, 4-tolylene diisocyanate and isophorone diisocyanate. Examples of the hydroxyl group-containing acrylate compound include 2-hydroxyethyl acrylate, 2-hydroxybutyl acrylate, 1, 6-hexanediol monoacrylate, tripropylene glycol diacrylate and the like.
As the monomer, there may be mentioned an N-vinyl monomer having a cyclic structure, for example, N-vinylcaprolactam. When these monomers are contained, the curing speed is improved, and therefore, it is preferable. Other than these, monofunctional monomers such as isobornyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, phenoxyethyl acrylate, and polypropylene glycol monoacrylate; or a polyfunctional monomer such as polyethylene glycol diacrylate, polypropylene glycol diacrylate or bisphenol A/ethylene oxide adduct glycol diacrylate.
In the present embodiment, the coating residual portion of the
In the present embodiment, since the
Further, in order to increase the hardness of the portion from which the
Next, the simulation result of the maximum value of the internal stress acting on the
Fig. 3 is a graph showing the specifications of an optical fiber used as a simulated example of the connection portion of the optical fiber of the present disclosure. Fig. 4A and 4B are diagrams showing the magnitude of the maximum stress acting on the protective resin when the optical fiber of the gauge shown in fig. 3 is used and the angle of the taper and the length of the taper are changed, respectively.
In the simulation, two kinds of optical fibers of examples 1 and 2 were subjected. The optical fibers of examples 1 and 2 have different Young's moduli of the primary resin layer and the secondary resin layer, and have the same specifications. Specifically, the outer diameters of the glass fibers of both were 125 μm, the outer diameters of the primary resin layers were 200 μm, the outer diameters of the secondary resin layers were 245 μm, the outer diameters of the protective resins provided at the connection portions were 260 μm, and the Young's moduli of the glass fibers were 74500 MPa. However, the young's modulus of the primary resin layer was 0.15MPa in the optical fiber of example 1, and 0.45MPa in the optical fiber of example 2.
In the simulation, for the optical fibers of examples 1 and 2, the change in the maximum value of the internal stress of the
Fig. 4A and 4B are graphs showing the results of the optical fibers of examples 1 and 2, respectively, and are obtained by plotting the axial length L of the taper as the horizontal axis and the maximum value of the internal stress of the protective resin as the vertical axis, the case where the angle θ of the taper is 10 degrees is plotted in the graph as a circle, and the case where the angle θ of the taper is 5 degrees is plotted in the graph as a square.
In the optical fibers of example 1 and example 2, regardless of whether the taper angle θ is 10 degrees or 5 degrees, the maximum value of the internal stress tends to decrease as the axial length L of the taper increases, and the maximum value of the internal stress changes more greatly with respect to the change in the axial length L of the taper in the case where the taper angle is 5 degrees, which is smaller. It is also understood that, in example 1 in which a softer resin is used for the
Next, in order to determine the relationship between the magnitude of the maximum value of the internal stress acting on the protective resin and the occurrence of the crack X, an experiment was performed using an actual optical fiber, and as a result, it was found that the crack occurs when the maximum value of the internal stress acting on the protective resin exceeds 15 MPa.
Therefore, when the characteristics of the shape of the taper T having the maximum value of the internal stress of 15MPa or less are found from the simulation results, it can be confirmed that the maximum value of the internal stress is 15MPa or less when the axial length L of the taper is 280 μm or more at a taper angle that is generally used. In the case where a taper having an axial length L of 280 μm or more is formed, the taper T is formed to include the boundary a between the
The larger the young's modulus of the primary resin layer is, the smaller the maximum value of the internal stress of the protective resin is, and thus the generation of cracks can be prevented. However, when the young's modulus of the primary resin layer is increased, as described above, the loss when wound on a bobbin becomes large. Therefore, considering the loss at the time of winding on the bobbin, the young's modulus of the primary resin layer is desirably 0.5MPa or less. Further, although the case where the young's modulus of the primary resin layer is 0.45MPa is shown in example 2, even if the young's modulus is 0.5MPa or less, the maximum value of the internal stress of the protective resin can be made to be 15MPa or less as the maximum value by setting the axial length L of the taper to 280 μm. When the young's modulus of the secondary resin layer is 800MPa or more, the maximum value of the internal stress of the protective resin is less affected, and the maximum value of the internal stress of the protective resin can be set to 15MPa or less by setting the axial length of the taper to 280 μm.
Description of the symbols
1. fiber; 2 · melt junction; 10. glass fiber; 11. core; 12. cladding; 20. fiber coating; 21. primary resin layer; 22. a secondary resin layer; 30. protective resin.
- 上一篇:一种医用注射器针头装配设备
- 下一篇:光分插复用器及光信号处理方法