Optical fiber ribbon core, method for manufacturing optical fiber ribbon core, and apparatus for manufacturing optical fiber ribbon core

Abstract

To provide optical fiber ribbon cores that can stabilize optical connections. [Solution] The optical fiber ribbon cable comprises a plurality of multicore fibers arranged in parallel, each containing a plurality of cores and a cladding surrounding the plurality of cores, and a covering member covering at least a portion of the plurality of multicore fibers. Each of the plurality of multicore fibers has bending anisotropy. In each of the plurality of multicore fibers, the arrangement of the plurality of cores is determined to be in a predetermined position with respect to the direction in which bending is easier based on bending anisotropy. The arrangement of the plurality of cores in the plurality of multicore fibers is aligned with each other.

Description

Technical Field

[0005]

[0001] The present disclosure relates to an optical fiber ribbon core wire, a method for manufacturing the optical fiber ribbon core wire, and a manufacturing apparatus for the optical fiber ribbon core wire.

Background Art

[0002] Patent Document 1 discloses an optical fiber ribbon core wire in which a plurality of multi-core fibers are adhered to each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the optical fiber ribbon core wire described in Patent Document 1, in order to adjust the positions of the plurality of cores of each optical fiber in the rotational direction, light is introduced into the cores, and rotational alignment is performed based on the amount of leakage at that time. However, it is difficult to adjust the core position with the leaked light while running at high speed, and the core positions in the optical fiber ribbon core wire may shift between the optical fibers. When the core positions shift, the optical connection becomes unstable when connecting an optical fiber ribbon core wire including a plurality of multi-core fibers to other members. Also, although it is possible to perform rotational alignment individually for each optical fiber during fusion, when the number of optical fibers and the number of cores increase, it takes a considerable amount of time, so it is desired to be able to perform batch fusion in the state of the optical fiber ribbon core wire.

[0005] An object of the present disclosure is to provide an optical fiber ribbon core wire that can perform batch fusion of an optical fiber ribbon core wire using multi-core fibers while suppressing an increase in loss during connection, a manufacturing method for the optical fiber ribbon core wire, and a manufacturing apparatus.

Means for Solving the Problems

[0006] An optical fiber ribbon cable according to one embodiment of the present disclosure comprises a plurality of multicore fibers arranged in parallel, each including a plurality of cores and a cladding surrounding the plurality of cores, and a covering member covering at least a portion of the plurality of multicore fibers. Each of the plurality of multicore fibers has bending anisotropy. In each of the plurality of multicore fibers, the arrangement of the plurality of cores is determined to be in a predetermined position with respect to the direction of ease of bending based on bending anisotropy. The arrangement of the plurality of cores in the plurality of multicore fibers is aligned with each other. [Effects of the Invention]

[0007] According to this disclosure, optical fiber ribbon cores can be fused together in one go while suppressing the increase in loss during connection. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing an optical fiber ribbon core according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view showing a multicore fiber used in the optical fiber ribbon shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram illustrating the manufacturing method and manufacturing apparatus for the optical fiber ribbon shown in Figure 1. [Figure 4] Figure 4 is a schematic cross-sectional view of a roller component used in the manufacturing method shown in Figure 3. [Figure 5] Figure 5 is a cross-sectional view showing a first modified example of a multicore fiber used in the optical fiber ribbon shown in Figure 1. [Figure 6] Figure 6 is a cross-sectional view showing a second modified example of the multicore fiber used in the optical fiber ribbon shown in Figure 1. [Figure 7] Figure 7 is a cross-sectional view showing a third modified example of the multicore fiber used in the optical fiber ribbon shown in Figure 1. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and explained. [1] An optical fiber ribbon cable according to one embodiment comprises a plurality of multicore fibers arranged in parallel, each containing a plurality of cores and a cladding surrounding the plurality of cores, and a covering member covering at least a portion of the plurality of multicore fibers. Each of the plurality of multicore fibers has bending anisotropy. In each of the plurality of multicore fibers, the arrangement of the plurality of cores is determined to be in a predetermined position with respect to the direction in which bending is easier based on bending anisotropy. The arrangement of the plurality of cores in the plurality of multicore fibers is aligned with each other.

[0010] In the optical fiber ribbon cable described in [1] above, each of the multiple multicore fibers has bending anisotropy, and the arrangement of the multiple cores in each of the multiple multicore fibers is determined to be in a predetermined position relative to the direction in which bending is easiest based on bending anisotropy. Furthermore, the arrangement of the multiple cores in the multiple multicore fibers is aligned with each other. Therefore, with this optical fiber ribbon cable, simultaneous fusion splicing can be performed while suppressing the increase in loss during connection. Note that "aligned core arrangement" here means that the deviation of the core arrangement between each multicore fiber is within 3° from each other.

[0011] [2] In the optical fiber ribbon cable described in [1] above, each of the multiple multicore fibers may include at least one void provided within the cladding and extending along the multiple cores, and bending anisotropy may be provided by the void. In this case, bending anisotropy can be easily provided for each multicore fiber.

[0012] [3] In the optical fiber ribbon cable described in [1] above, each of the multiple multicore fibers may include a pair of voids provided within the cladding and extending along the multiple cores, and the pair of voids may provide bending anisotropy. The multiple cores may be arranged between the pair of voids. In this case, bending anisotropy can be easily provided for each multicore fiber. In addition, the arrangement of the cores can be easily determined.

[0013] [4] In the optical fiber ribbon cable described in [1] above, each of the multiple multicore fibers may include at least one low-rigidity glass portion extending along the multiple cores, the low-rigidity glass portion may have lower rigidity than the cladding glass, and the low-rigidity glass portion may provide bending anisotropy. In this case, bending anisotropy can be easily provided for each multicore fiber.

[0014] [5] A method for manufacturing an optical fiber ribbon core according to one embodiment comprises the steps of: preparing a plurality of multicore fibers, each containing a plurality of cores and a cladding surrounding the plurality of cores, and arranged in parallel; conveying each of the plurality of multicore fibers to an apparatus for applying a coating resin, after changing the direction of each of the plurality of multicore fibers so as to be bent by 90° or more using a roller member; and curing the applied coating resin. Each of the plurality of multicore fibers has bending anisotropy. In each of the plurality of multicore fibers, the arrangement of the plurality of cores is determined to be in a predetermined position with respect to the direction in which bending is easier based on bending anisotropy.

[0015] In the method for manufacturing an optical fiber ribbon core wire according to [5] above, each multi-core fiber has bending anisotropy, and the arrangement of a plurality of cores is determined to be at a predetermined position with respect to the direction in which bending is easy based on the bending anisotropy. Each of such multi-core fibers is conveyed to an apparatus for applying a coating resin by changing the direction so as to bend it by 90° or more by a roller member. When such a multi-core fiber having bending anisotropy is bent by 90° or more by a roller member, the optical fibers tend to align in the direction in which bending is easy. Therefore, according to this manufacturing method, it is possible to easily align the arrangements of a plurality of cores in a plurality of multi-core fibers by the above-described bending, and to easily manufacture an optical fiber ribbon core wire that can be collectively fused while suppressing an increase in loss during connection.

[0016] [6] The manufacturing apparatus used in the method for manufacturing an optical fiber ribbon core wire according to [5] above includes a roller member that conveys each of a plurality of multi-core fibers to an apparatus for applying a coating resin by changing the direction so as to bend it by 90° or more. In this case, the above-described manufacturing method can be surely performed.

[0017] [Details of Embodiments of the Present Disclosure] Specific examples of an optical fiber ribbon core wire, a method for manufacturing an optical fiber ribbon core wire, and a manufacturing apparatus for an optical fiber ribbon core wire according to an embodiment of the present disclosure will be described below with reference to the drawings. In the following description, the same reference numerals will be used for the same elements or elements having the same function, and redundant descriptions will be omitted. The present invention is not limited to these examples, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0018] Referring to FIG. 1, the optical fiber ribbon core wire according to the present embodiment will be described. FIG. 1 is a cross-sectional view showing an optical fiber ribbon core wire according to an embodiment. As shown in FIG. 1, the optical fiber ribbon core wire 1 includes a plurality of optical fibers 10 arranged in parallel with each other in the lateral direction. The plurality of optical fibers 10 are coated with a taping resin 20 (coating member) and are connected to each other. Such an optical fiber ribbon core wire 1 extends in a direction orthogonal to FIG. 1.

[0019] FIG. 2 is a cross-sectional view showing each optical fiber 10 included in the optical fiber ribbon core wire 1 shown in FIG. 1. As shown in FIGS. 1 and 2, each optical fiber 10 is a multi-core fiber and includes a plurality of cores 11, a cladding 12 covering so as to surround the plurality of cores 11, a resin coating layer 13 contacting the cladding 12 and surrounding the cladding 12, and a colored layer 14 provided on the outer periphery of the resin coating layer 13. In the example shown in FIG. 2, the optical fiber 10 includes 4 cores 11, but the number of cores 11 is not limited thereto. The number of cores 11 included in each optical fiber 10 may be 2 or more, may be 6, or may be 10. The optical fiber 10 is protected from the external environment (e.g., side pressure, etc.) by the resin coating layer 13.

[0020] The core 11 and the cladding 12 are formed of, for example, silica glass. The Young's modulus of the glass material forming the core 11 and the cladding 12 is, for example, 74 GPa. The cladding 12 has a refractive index lower than that of the core 11. Incidentally, the outer diameter of the cladding 12, that is, the glass fiber portion of the optical fiber 10 is, for example, 125 μm.

[0021] The resin coating layer 13 includes a primary resin layer and a secondary resin layer surrounding the primary resin layer. The primary resin layer is formed by curing an ultraviolet-curable resin composition containing a photopolymerizable compound, a photopolymerization initiator, and a silane coupling agent with ultraviolet light. As the photopolymerizable compound, for example, urethane (meth)acrylate or epoxy (meth)acrylate can be used. The primary resin layer has a lower elastic modulus (Young's modulus) than the secondary resin layer and is softer than the secondary resin layer. For example, the Young's modulus of the primary resin layer at 23°C is 0.1 MPa to 5 MPa. This provides the optical fiber 10 with lateral pressure resistance, and suppresses the increase in transmission loss in the optical fiber 10 even when lateral pressure is applied.

[0022] The secondary resin layer is formed by curing a resin composition containing urethane (meth)acrylate, monomer, and photopolymerization initiator with ultraviolet light. For example, the Young's modulus of the secondary resin layer at 23°C is between 1200 MPa and 2800 MPa. The thickness of each layer of the primary and secondary resin layers is, for example, between 5 μm and 50 μm.

[0023] The colored layer 14 is, for example, a layer colored with ink. This allows each optical fiber 10 to be identified. Alternatively, instead of providing the colored layer 14 on the optical fiber 10, the secondary resin layer of the resin coating layer 13 may be a colored resin layer. In this case, the material forming the secondary resin layer may contain a pigment.

[0024] In the optical fiber 10 according to this embodiment, as shown in Figures 1 and 2, a pair of voids 15 are provided within the cladding 12 of each optical fiber 10. The voids 15 are hollow portions that do not contain glass material and extend along the core 11. Between the pair of voids 15, a plurality of cores 11 are arranged in cross-section. The cross-sectional area of ​​the voids 15 may be larger than the cross-sectional area of ​​each core 11, or larger than the sum of the cross-sectional areas of a plurality of cores 11 (for example, four cores 11). Such voids 15 may have a circular cross-section, or a rectangular or polygonal cross-section. The diameter or maximum width of the voids 15 may be 15 μm or more and 40 μm or less, or 20 μm or more and 35 μm or less, and as an example, 30 μm.

[0025] Furthermore, the voids 15 are formed to be separated from the adjacent cores 11. The distance from the adjacent cores 11 to the voids 15 may be, for example, 5 μm or more, or 10 μm or more, and is 15 μm.

[0026] Such voids 15 are low-rigidity regions with lower rigidity than the cladding 12 formed from the glass material, and provide anisotropy to the bending rigidity of the optical fiber 10. In other words, the optical fiber 10 is provided with bending anisotropy, and the direction in which it is easier to bend is determined based on this bending anisotropy. Now, with reference to Figures 3 and 4, a method for fabricating an optical fiber ribbon core 1 from a plurality of optical fibers 10 having such bending anisotropy will be described.

[0027] Figure 3 is a schematic diagram illustrating the manufacturing method and manufacturing apparatus for the optical fiber ribbon core 1. Figure 4 is a schematic cross-sectional view of a roller member used in the manufacturing method shown in Figure 3. As shown in Figures 3 and 4, in the manufacturing method for the optical fiber ribbon core 1, first, a plurality of optical fibers 10 are prepared as described above. Each optical fiber 10 is prepared wound on a roll 101. Next, each optical fiber 10 is pulled out from the roll 101 and transported toward the die 102 of the manufacturing apparatus 100. The die 102 is a device for applying a coating resin to the optical fiber 10. The coating resin applied here corresponds to the tape resin 20 of the optical fiber ribbon core 1.

[0028] The optical fiber 10, drawn from the roll 101, is directed by the roller member 110 to change its direction of transport by 90° or more (for example, 120°) while being transported toward the die 102. During this bending, the groove 111 of the roller member 110 aligns the rotational direction of the transported optical fiber 10 around its central axis. The diameter of the roller member 110 is, for example, about 60 mm. Specifically, when the optical fiber 10 is transported in a way that bends it with the roller member 110, the parts with low bending rigidity (voids 15) move towards the inside of the roller member 110. This is because the direction in which it is easier to bend is defined starting from the parts with low bending rigidity, and this occurs similarly in the transport of all optical fibers 10. In other words, because there are voids 15 without glass on both the inside and outside, the bending strain energy of the optical fiber 10 as a whole is reduced, and the roller member 110 bends so that the voids 15 are located on both the inside and outside of the bend. Therefore, when multiple optical fibers 10 are transported by the roller member 110 in the same way, the portions of the voids 15 will align with each other in the multiple optical fibers 10 (see Figure 4). Furthermore, in the optical fiber 10 according to this embodiment, the arrangement of the multiple cores 11 is predetermined to be in a specific position relative to the voids 15 in the region that determines the direction in which bending is easier based on such bending anisotropy, i.e., the low-rigidity region. As a result, bending by the roller member 110 causes the arrangement of the multiple cores 11 in the multiple optical fibers 10 to align with each other.

[0029] Next, when the cores 11 of each optical fiber 10 are aligned by bending with the roller member 110, the multiple optical fibers 10 enter the die 102 and are coated with a coating resin. After that, the coated coating resin is cured by UV irradiation from the UV lamp 103, which is a curing device. As a result, the multiple optical fibers 10 are connected to each other and integrated by the coating resin (tape resin). Thus, an optical fiber ribbon core 1 is manufactured in which the arrangement of the multiple cores 11 in the multiple optical fibers 10 is aligned to each other. Note that the tape resin 20 formed by the coating resin may have planes 21 and 22 formed on both the upper and lower surfaces, as shown in Figure 1. Alternatively, recesses may be provided between each optical fiber 10, and planes 21 and 22 may be formed above and below, or on either side of, each optical fiber 10. The planes 21 and 22 extend in the direction in which the multiple optical fibers 10 are arranged in parallel. In the optical fiber ribbon core 1, the voids 15 may be located between the multiple cores 11 and the planes 21 and 22. In this case, the arrangement of the voids 15 and cores can be easily inspected from the outside.

[0030] As described above, in the optical fiber ribbon cable 1 according to this embodiment, each of the multiple optical fibers 10 has bending anisotropy, and the arrangement of the multiple cores 11 in each of the multiple optical fibers 10 is determined to be in a predetermined position relative to the direction in which bending is easiest based on bending anisotropy. Furthermore, the arrangement of the multiple cores 11 in the multiple optical fibers 10 is aligned with each other. Therefore, with the optical fiber ribbon cable 1, simultaneous fusion splicing can be performed while suppressing the increase in loss during connection. Note that the arrangement of the cores 11 being aligned here means that the misalignment of the arrangement of the cores 11 between each optical fiber 10 is within 3°. In this case, rotational alignment becomes easier, and the mechanism of the fusion splicer can be simplified. In addition, in the optical fiber ribbon cable 1, the misalignment of the arrangement of the cores 11 between the optical fibers 10 may be within 0.3°. If the misalignment is within 0.3°, the optical fiber 10 can be fused to the corresponding optical fiber without rotational alignment.

[0031] In the optical fiber ribbon cable 1 according to this embodiment, each of the multiple optical fibers 10 includes a pair of voids 15 extending along the multiple cores 11, and the pair of voids 15 provides bending anisotropy. This makes it easy to provide bending anisotropy to each optical fiber 10. Furthermore, the multiple cores 11 are arranged between the pair of voids 15. This makes it easy to position the cores 11 in predetermined locations.

[0032] Next, modified examples of the optical fiber 10 used in the optical fiber ribbon cable 1 will be described with reference to Figures 5 to 7. Even when using the optical fibers 10A to 10C according to the following modified examples, it is possible to manufacture an optical fiber ribbon cable 1 that can be fused together in one go while suppressing the increase in loss during connection.

[0033] [First variation] Referring to Figure 5, the optical fiber 10A according to the first modification will be described. As shown in Figure 5, the optical fiber 10A, like the optical fiber 10, includes a plurality of cores 11, a cladding 12, a resin coating layer 13, and a colored layer 14. Unlike the optical fiber 10, the optical fiber 10A has four voids 15. Each void 15 extends along the core 11. In the optical fiber 10A according to the first modification, the plurality of cores 11 are arranged between the two upper voids 15 and the two lower voids 15. The size of the voids 15 is the same as in the optical fiber 10. However, the voids 15 may be arranged to be closer to the cores 11 than in the case of the optical fiber 10. For example, the distance between a void 15 and an adjacent core 11 may be 5 μm or more, or 15 μm or less, and as an example, 9.5 μm.

[0034] [Second variation] Referring to Figure 6, the optical fiber 10B according to the second modified example will be described. As shown in Figure 6, the optical fiber 10B, like the optical fiber 10, includes a plurality of cores 11, a cladding 12, a resin coating layer 13, and a colored layer 14. Unlike the optical fiber 10, the optical fiber 10B is provided with a pair of low-rigidity glass portions 16. The low-rigidity glass portions 16 extend along the cores 11. The low-rigidity glass portions 16 are formed from a glass material having a Young's modulus lower than that of the glass material of the cladding 12. For example, the low-rigidity glass portions 16 are formed from borosilicate glass, although this is not limited to the above. The Young's modulus of the glass material used for the low-rigidity glass portions 16 may be, for example, 50 GPa or more and less than 70 GPa, or 60 GPa or more and 65 GPa or less, and as an example, 64 GPa. Assuming the Young's modulus of the glass used in the cladding 12 is 74 GPa, the Young's modulus of the material used in the low-rigidity glass portion 16 may be 5 GPa or more lower than the Young's modulus of the material used in the cladding 12, and may also be 10 GPa or more lower. The size, cross-sectional shape, and distance from the core 11 of the low-rigidity glass portion 16 are the same as in the case of the void 15. When the optical fiber 10 with such a structure is bent by the roller member 110 as shown in Figures 3 and 4, the compression and tensile strains are smaller when the low-rigidity glass portion 16 is on the inside and outside of the bend, thus reducing the overall bending strain energy of the optical fiber 10. As a result, the roller member 110 bends so that the low-rigidity glass portion 16 is located on the inside and outside of the bend, and the arrangement of the cores 11 is aligned. When the optical fiber 10B is an optical fiber ribbon core 1, the low-rigidity glass portion 16 is located between the multiple cores 11 and the planes 21 and 22 of the tape resin 20.

[0035] [Third variation] Referring to Figure 7, the optical fiber 10C according to the third modified example will be described. As shown in Figure 7, the optical fiber 10C, like the optical fiber 10B, includes a plurality of cores 11, a cladding 12, a resin coating layer 13, and a colored layer 14. Unlike the optical fiber 10B, the optical fiber 10C is provided with four low-rigidity glass sections 16. Each low-rigidity glass section 16 extends along the core 11. In the optical fiber 10C according to the third modified example, a plurality of cores 11 are arranged between the two upper low-rigidity glass sections 16 and the two lower low-rigidity glass sections 16. The size and shape of the low-rigidity glass sections 16 are the same as those of the optical fiber 10B. However, the low-rigidity glass sections 16 may be arranged closer to the core 11 than in the case of the optical fiber 10B. For example, the distance between the low-rigidity glass sections 16 and adjacent cores 11 may be 5 μm or more, or 15 μm or less, and as an example, 10 μm.

[0036] Although the optical fiber ribbon core, method for manufacturing the optical fiber ribbon core, and manufacturing apparatus related to this disclosure have been described in detail above, the present invention is not limited to the above embodiments and can be applied to various embodiments and modifications.

[0037] For example, in the embodiment described above, two or more voids 15 or low-rigidity glass portions 16 were provided in each optical fiber, but the invention is not limited to these. That is, each optical fiber 10, 10B, etc., only needs to have one or more voids 15 or one or more low-rigidity glass portions. By providing one or more low-elasticity regions, bending anisotropy can be provided to the optical fiber. Furthermore, any low-elasticity region other than voids or low-rigidity glass portions may be used as long as it can impart bending anisotropy to the optical fiber 10, etc. [Explanation of Symbols]

[0038] 1… Fiber optic ribbon 10, 10A, 10B, 10C… Optical Fiber 11... Core 12... Clad 13…Resin coating layer 14...Colored layer 15…Vacuum 16…Low-rigidity glass section 20… Tape-type resin 21,22…Plane 100...Manufacturing equipment 101... Roll 102... Dice 103... UV lamp 110... Roller component 111...Groove

Claims

1. Multiple multicore fibers, each containing multiple cores and a cladding surrounding the multiple cores, are arranged in parallel. A covering member that covers at least a portion of the plurality of multicore fibers, Each of the aforementioned multicore fibers has bending anisotropy, In each of the aforementioned multi-core fibers, the arrangement of the plurality of cores is determined to be in a predetermined position with respect to the direction of easy bending based on the bending anisotropy. The arrangement of the multiple cores in the multiple multicore fibers is aligned with each other. Optical fiber ribbon cable.

2. Each of the plurality of multicore fibers includes at least one void provided within the cladding and extending along the plurality of cores, the void providing the bending anisotropy. The optical fiber ribbon core according to claim 1.

3. Each of the plurality of multicore fibers includes a pair of voids provided within the cladding and extending along the plurality of cores, the pair of voids providing the bending anisotropy, and the plurality of cores are arranged between the pair of voids. The optical fiber ribbon core according to claim 1.

4. Each of the plurality of multicore fibers includes at least one low-rigidity glass portion extending along the plurality of cores, the low-rigidity glass portion having lower rigidity than the glass of the cladding, and the low-rigidity glass portion provides the bending anisotropy. The optical fiber ribbon core according to claim 1.

5. A step of preparing multiple multicore fibers, each containing multiple cores and a cladding surrounding the multiple cores, and arranged in parallel; A step of conveying each of the aforementioned multiple multicore fibers to a device for applying a coating resin, by changing their direction so that they are bent by 90° or more using a roller member. The process includes a step of curing the coated resin, Each of the aforementioned multicore fibers has bending anisotropy, In each of the aforementioned multi-core fibers, the arrangement of the multiple cores is determined to be in a predetermined position with respect to the direction of easy bending based on the bending anisotropy. A method for manufacturing optical fiber ribbon cores.

6. A manufacturing apparatus used in the method for manufacturing optical fiber ribbon cores according to claim 5, The device includes a roller member that changes the direction of each of the multiple multicore fibers so as to bend them by 90° or more, and then transports them to a device for applying a coating resin. Manufacturing equipment for optical fiber ribbon cores.

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