Optical fiber ribbon, optical fiber ribbon with connector, optical fiber cable, and optical fiber

Abstract

An optical fiber ribbon (1) is provided with: an optical fiber (10) having a plurality of cores (12) in a cladding (13), a spiral section (11A) in which the positions of the plurality of cores (12) in the longitudinal direction (X) of the cladding (13) change helically, a non-spiral section (11B) in which the positions of the plurality of cores (12) in the longitudinal direction (X) do not change helically, and a coating layer (L) that covers the cladding (13); and a fixing part (30) for fixing the coating layers (L) such that the plurality of optical fibers (10) are arranged in a direction (Y) intersecting the longitudinal direction (X), the coating layers (L) having: a coating region (L1) in which the coating part (20) covering the cladding layer (13) is provided; and a coating removal region (L2) which is provided at a position corresponding to the non-spiral section (11B) and from which the coating section (20) is removed, and which is provided with a first resin (41) that adheres and fixes the cladding (13) and the coating section (20).

Description

Technical Field

[0001] The present invention relates to an optical fiber ribbon, an optical fiber ribbon with a connector, an optical fiber cable, and an optical fiber.

[0002] This application claims priority based on Japanese Patent Application No. 2022-205304 filed in Japan on December 22, 2022, and incorporates its content herein. Background Art

[0003] Conventionally, the development of a so-called multi-core optical fiber in which a plurality of cores are arranged inside a single cladding has become active. When a connector is attached to the front end of such a multi-core optical fiber, a rotational alignment operation for adjusting the rotational angle of the multi-core optical fiber with respect to the connector (the position in the circumferential direction of each core) is generally performed. It is well known that such a rotational alignment operation takes a lot of time.

[0004] Patent Document 1 discloses a technique of attaching a connector to the front end of a spun multi-core fiber, which is a type of multi-core optical fiber, after performing rotational alignment.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-75219

[0006] However, an optical fiber generally has a structure in which the periphery of the cladding is covered with a coating such as resin. In a multi-core optical fiber having such a coating, for example, even if the coating is fixed, after the rotational alignment operation, the multi-core rotates relative to the coating, and there is a possibility that the rotational angle of the multi-core optical fiber deviates. If such relative rotation occurs when attaching a connector to the front end of the multi-core optical fiber, it is necessary to perform rotational alignment on each multi-core optical fiber again. Therefore, there is a possibility that the connector attachment operation requires effort. Summary of the Invention

[0007] The present invention has been made in consideration of such circumstances, and an object thereof is to provide an optical fiber ribbon, an optical fiber ribbon with a connector, an optical fiber cable, and an optical fiber that are easy to attach a connector.

[0008] In order to solve the above problems, the optical fiber ribbon according to Mode 1 of the present invention includes: an optical fiber having a plurality of cores in a cladding, and having a spiral portion in which the positions of the plurality of cores in the longitudinal direction of the cladding change in a spiral shape, a non-spiral portion in which the positions of the plurality of cores in the longitudinal direction do not change in a spiral shape, and a coating layer covering the cladding; and a fixing portion for fixing between the coating layers in such a manner that a plurality of the optical fibers are arranged in a direction intersecting the longitudinal direction. The coating layer has: a coating region provided with a coating portion covering the cladding; and a coating removal region provided at a position corresponding to the non-spiral portion and from which the coating portion is removed. A first resin is provided in the coating removal region, and the first resin adhesively fixes the cladding and the coating portion.

[0009] In addition, Mode 2 of the present invention is completed on the basis of the optical fiber ribbon of Mode 1. The optical fiber has: a plurality of the spiral portions arranged at intervals in the longitudinal direction; and a plurality of the non-spiral portions located between the plurality of spiral portions in the longitudinal direction.

[0010] In addition, Mode 3 of the present invention is completed on the basis of the optical fiber ribbon of Mode 1 or Mode 2. In the non-spiral portion, the plurality of cores are rotationally aligned.

[0011] In addition, Mode 4 of the present invention is completed on the basis of the optical fiber ribbon of any one of Modes 1 to 3. The first resin is provided throughout the coating removal region.

[0012] In addition, Mode 5 of the present invention is completed on the basis of the optical fiber ribbon of any one of Modes 1 to 3. A second resin is provided in the coating removal region. The second resin is arranged at a position different from that of the first resin in the longitudinal direction and covers the cladding. The Young's modulus of the second resin is lower than that of the first resin.

[0013] In addition, the optical fiber ribbon with a connector according to Mode 6 of the present invention includes: the optical fiber ribbon of any one of Modes 1 to 5; and a connector installed at the front end of the optical fiber ribbon. The first resin is provided at least at the end portion of the coating removal region away from the connector in the longitudinal direction.

[0014] In addition, the optical fiber cable according to Mode 7 of the present invention includes: an optical fiber ribbon with a connector having the optical fiber ribbon of any one of Modes 1 to 5 and a connector installed at the front end of the optical fiber ribbon.

[0015] In order to solve the above problems, the optical fiber according to Mode 8 of the present invention includes: a cladding; a multi-core having a plurality of cores disposed within the cladding, and having a spiral portion in which the positions of the plurality of cores in the longitudinal direction of the cladding change in a spiral shape and a non-spiral portion in which the positions of the plurality of cores in the longitudinal direction do not change in a spiral shape; and a coating layer covering the cladding, and a display portion indicating the position of the non-spiral portion is provided on the coating layer.

[0016] According to the above mode of the present invention, it is possible to provide an optical fiber ribbon, an optical fiber ribbon with a connector, an optical fiber cable, and an optical fiber that suppress the relative rotation of the multi-core after rotational alignment with respect to the coated portion and are easy to install a connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a perspective view showing an optical fiber cable according to a first embodiment of the present invention.

[0018] Figure 2 is a top view showing an optical fiber ribbon with a connector according to a first embodiment of the present invention.

[0019] Figure 3 is along Figure 2 the cross-sectional view taken along line III-III shown.

[0020] Figure 4 is a view showing a multi-core according to a first embodiment of the present invention.

[0021] Figure 5A is a view showing an example of a manufacturing method of an optical fiber ribbon according to a first embodiment of the present invention.

[0022] Figure 5B is showing following Figure 5A the state.

[0023] Figure 5C is showing following Figure 5B the state.

[0024] Figure 6A is a view showing an example of a method of replacing a connector in an optical fiber ribbon with a connector according to a first embodiment of the present invention.

[0025] Figure 6B is showing following Figure 6A the state.

[0026] Figure 6C is showing following Figure 6B the state.

[0027] Figure 7 is a top view showing an optical fiber ribbon according to a second embodiment of the present invention. Detailed Implementation Modes

[0028] (First Implementation Mode)

[0029] Hereinafter, based on the accompanying drawings, the optical fiber ribbon, the optical fiber ribbon with a connector, the optical fiber cable, and the optical fiber related to the first implementation mode will be described.

[0030] As Figure 1 shown, the optical fiber cable C related to the present implementation mode includes at least one optical fiber ribbon 100 with a connector. The optical fiber ribbon 100 with a connector is housed in a cylindrical outer sheath 200. The outer sheath 200 is formed of, for example, resin. The outer sheath 200 protects the optical fiber ribbon 100 with a connector. In addition, the number of optical fiber ribbons 100 with a connector housed in the outer sheath 200 can be appropriately changed.

[0031] As Figure 2 shown, each optical fiber ribbon 100 with a connector includes an optical fiber ribbon 1 and a connector (ferrule) 2 mounted at the front end of the optical fiber ribbon 1. The connector 2 has a connection end face 2a. The connection end face 2a is a face that docks with other connectors or the like when the connector 2 is connected to other connectors or the like.

[0032] The optical fiber ribbon 1 includes a plurality of spun multi-core optical fibers (optical fibers) 10. In the optical fiber ribbon 1, the plurality of spun multi-core optical fibers 10 are arranged and configured in a direction intersecting (e.g., orthogonal) to the length direction of the spun multi-core optical fibers 10. Thereby, the optical fiber ribbon 1 has a strip-shaped (ribbon-shaped) shape. The number of spun multi-core optical fibers 10 included in the optical fiber ribbon 1 can be appropriately changed.

[0033] As Figure 3 shown, the spun multi-core optical fiber 10 has a multi-core 11, a cladding 13, and a coating layer L. The multi-core 11 has a plurality of cores 12. The cladding 13 covers the multi-core 11 (the plurality of cores 12). The core 12 and the cladding 13 are formed of, for example, quartz glass. The refractive index of each core 12 is less than the refractive index of the cladding 13. Thereby, the spun multi-core optical fiber 10 can confine light inside the core 12. Hereinafter, the multi-core 11 (the plurality of cores 12) and the cladding 13 may be collectively referred to as the waveguide portion W.

[0034] The coating layer L covers the cladding 13 (the waveguide portion W). A coating portion 20 covering the multi-core 11 is provided on the coating layer L. The coating portion 20 is formed of, for example, a UV curable resin.

[0035] (Definition of Directions)

[0036] In this specification, the length direction of the spun multi-core optical fiber 10 (the length direction of the cladding 13) is simply referred to as the length direction X. The length direction X is also the same as the central axis O of each spun multi-core optical fiber 10 (also refer to Figure 3)Parallel direction. The direction that intersects (e.g., is orthogonal to) the length direction X and in which a plurality of spun multi-core optical fibers 10 are arranged is called the cross direction Y. The direction that intersects (e.g., is orthogonal to) both the length direction X and the cross direction Y is called the thickness direction Z. The thickness direction Z is also the thickness direction of the optical fiber ribbon 1. The direction from the optical fiber ribbon 1 toward the connector 2 along the length direction X is called the front or the front end side, and is represented by the +X direction. The direction opposite to the +X direction is called the rear or the base end side, and is represented by the -X direction. A cross section perpendicular to the length direction X is called a transverse cross section. Observation from the thickness direction Z is called top view observation. In addition, when the spun multi-core optical fiber 10 is viewed in transverse cross section, the direction orthogonal to the central axis O of the spun multi-core optical fiber 10 is called the radial direction. The direction approaching the central axis O along the radial direction is called the radially inner side, and the direction away from the central axis O is called the radially outer side. When the spun multi-core optical fiber 10 is viewed in transverse cross section, the direction around the central axis O is called the circumferential direction.

[0037] As Figure 2 shown, a plurality of spun multi-core optical fibers 10 are fixed to each other by a plurality of fixing portions 30. The fixing portions 30 fix the claddings L to each other in such a manner that the plurality of spun multi-core optical fibers 10 are arranged in the cross direction Y. In Figure 2 and Figure 3 the example shown, each fixing portion 30 fixes two adjacent spun multi-core optical fibers 10 in the cross direction Y to each other. In addition, the plurality of fixing portions 30 are intermittently arranged in the length direction X and the cross direction Y. As the fixing portion 30, for example, a UV curable resin can also be used.

[0038] In addition, the structure of the fixing portion 30 can be appropriately changed as long as it can fix the adjacent spun multi-core optical fibers 10. For example, a plurality of spun multi-core optical fibers 10 can also be covered by a single fixing portion 30. Or, for example, when the spun multi-core optical fibers 10 can be fixed to each other with sufficient strength by a resin 41 (described later), the optical fiber ribbon 1 may not have the fixing portion 30.

[0039] In the present embodiment, the plurality of cores 12 include one central core 12a and a plurality of (two in the illustrated example) non-central cores 12b. The central core 12a is a core 12 that linearly extends in the length direction X in a manner including the central axis O of the spun multi-core optical fiber 10 (also refer to Figure 4 ). The non-central core 12b is a core 12 other than the central core 12a.

[0040] As Figure 4As shown, the multi-core 11 (woven multi-core optical fiber 10) has a plurality of spiral portions 11A and a plurality of non-spiral portions 11B. The plurality of spiral portions 11A are arranged at intervals in the length direction X. The plurality of non-spiral portions 11B are located between the plurality of spiral portions 11A in the length direction X. That is, the plurality of spiral portions 11A and the plurality of non-spiral portions 11B are alternately arranged in the length direction X. In addition, the multi-core 11 (woven multi-core optical fiber 10) may have only one spiral portion 11A or may have only one non-spiral portion 11B.

[0041] In the spiral portion 11A, a plurality of cores 12 (non-center cores 12b) are wound in a spiral shape. In other words, in the spiral portion 11A, the positions of the plurality of cores 12 (non-center cores 12b) in the length direction X change in a spiral shape. In addition, the term "spiral shape" specifically refers to a shape in which the position in the circumferential direction changes as the position in the length direction X changes. In the present embodiment, the plurality of spiral portions 11A include a plurality of forward spiral portions 11A1 and a plurality of reverse spiral portions 11A2. In the forward spiral portion 11A1 and the reverse spiral portion 11A2, the winding directions of the cores 12 are opposite to each other. In the present embodiment, each non-spiral portion 11B is arranged between the forward spiral portion 11A1 and the reverse spiral portion 11A2.

[0042] In the non-spiral portion 11B, the plurality of cores 12 are not wound in a spiral shape. In other words, in the non-spiral portion 11B, the positions of the plurality of cores 12 in the length direction X do not change in a spiral shape. That is, in the non-spiral portion 11B, the positions of the respective cores 12 in the circumferential direction are substantially constant over the length direction X. In Figure 4 In the non-spiral portion 11B shown, the positions of the cores 12 in the radial direction (distance from the central axis O) change over the length direction X. However, the positions of the cores 12 in the radial direction may also be substantially constant over the length direction X. In other words, in the non-spiral portion 11B, each core 12 may also extend linearly in the length direction X. In addition, the term "substantially constant" also includes cases where it can be regarded as constant if manufacturing errors are excluded.

[0043] In the present embodiment, in each of the plurality of non-spiral portions 11B, the plurality of cores 12 (multi-core 11) are rotationally centered. Here, "the plurality of cores 12 (multi-core 11) are rotationally centered" means that the positions of the respective cores 12 in the circumferential direction (the rotation angle of the multi-core 11 around the central axis O) are adjusted within a specified range. For example, in the non-spiral portion 11B, the positions of the plurality of cores 12 (non-center cores 12b) of the multi-core 11 in the circumferential direction are substantially the same among all the woven multi-core optical fibers 10. In addition, the term "substantially the same" also includes cases where it can be regarded as the same if manufacturing errors are excluded.

[0044] As Figure 2As shown, the coating layer L according to this embodiment has a plurality of coating regions L1 and a plurality of coating removal regions L2. The coating region L1 is a region where the coating portion 20 is provided. The coating removal region L2 is a region where the coating portion 20 is not provided. In other words, the coating removal region L2 is a region where the coating portion 20 has been removed. The plurality of coating regions L1 and the plurality of coating removal regions L2 are alternately arranged in the length direction X.

[0045] The coating removal region L2 is provided at a position corresponding to the above-mentioned non-helical portion 11B. Specifically, the range where the coating removal region L2 exists coincides with the range where the non-helical portion 11B exists in the length direction X. In other words, when viewed from above, the coating removal region L2 overlaps with the non-helical portion 11B. For example, the center of the coating removal region L2 in the length direction X and the center of the non-helical portion 11B in the length direction X may be located at substantially the same position. Hereinafter, the end portion of the two end portions of the coating removal region L2 in the length direction X that is close to the connector 2 is referred to as the front end portion L2a, and the end portion that is far from the connector 2 is referred to as the rear end portion L2b.

[0046] As Figure 2 shown, a resin (first resin) 41 is provided in the coating removal region L2. In this embodiment, the resin 41 is provided from the front end portion L2a to the rear end portion L2b of the coating removal region L2. That is, the resin 41 according to this embodiment is provided throughout the coating removal region L2. In addition, the resin 41 adhesively fixes the cladding 13 (waveguide portion W) and the coating portion 20. From the viewpoint of sufficiently improving the fixing strength between the waveguide portion W and the coating portion 20, it is preferable that the Young's modulus of the resin 41 is high to a certain extent. The Young's modulus of the resin 41 is preferably 500 MPa or more, for example. In addition, in order to reliably adhesively fix the cladding 13 and the coating portion 20 with the resin 41, the region of the resin 41 may be extended to include not only the entire region of the coating removal region L2 but also a part of the coating region L1.

[0047] Next, an example of the manufacturing method of the optical fiber ribbon 1 configured as described above will be described.

[0048] As Figure 5A shown, when manufacturing the optical fiber ribbon 1 according to this embodiment, first, an optical fiber ribbon 1' having a plurality of spun multi-core optical fibers 10' is prepared. At this time, the above-mentioned coating removal region L2 is not provided in the optical fiber ribbon 1'. That is, the cladding 13 is covered with the coating portion 20 in the entire length direction X. In other words, the coating region L1 is provided throughout the entire length direction X of the cladding 13 (coating layer L).

[0049] On the covering portion 20 (covering layer L) of the spun multi-core optical fiber 10', a display portion 21 indicating the position of the non-helical portion 11B is provided. In the present embodiment, the display portion 21 is a mark marked on the covering portion 20. The position of the display portion 21 corresponds to the position of the non-helical portion 11B. Specifically, the range where the display portion 21 exists coincides with the range where the non-helical portion 11B exists in the length direction X. In other words, when viewed from above, the display portion 21 overlaps with the non-helical portion 11B. For example, the center of the display portion 21 in the length direction X and the center of the non-helical portion 11B in the length direction X may also be located at substantially the same position. Alternatively, the display portion 21 may be provided at the position where the cores 12 are closest to each other in the non-helical portion 11B ( Figure 4 the position P shown).

[0050] Next, around the display portion 21, the covering portion 20 is removed (refer to Figure 5B ). The portion where the covering portion 20 is removed in this process is the above-mentioned covering removal region L2. Here, since the position of the display portion 21 corresponds to the position of the non-helical portion 11B, the position of the covering removal region L2 corresponds to the position of the non-helical portion 11B as described above.

[0051] Next, in the covering removal region L2, the non-helical portion 11B is rotationally aligned. Specifically, in the covering removal region L2, the waveguide portion W is held and rotated around the central axis O of the spun multi-core optical fiber 10. As a result, the waveguide portion W rotates relative to the covering portion 20 in the covering removal region L2 and its vicinity. In addition, when rotationally aligning the non-helical portion 11B, for example, the positions of the respective cores 12 may be confirmed by irradiating light from the side of the non-helical portion 11B.

[0052] After rotational alignment, the resin 41 is filled into the covering removal region L2 (refer to Figure 5C ). Using the adhesive force of the resin 41, the waveguide portion W is fixed to the covering portion 20 in a state where the non-helical portion 11B is rotationally aligned. Thus, the manufacturing of the optical fiber ribbon 1 is completed. When manufacturing (assembling) the optical fiber ribbon 100 with a connector, for example, the optical fiber ribbon 1 is cut in the covering removal region L2. Then, the resin 41 is removed to expose the waveguide portion W, and the exposed waveguide portion W is inserted into the connector 2. Thus, the optical fiber ribbon 100 with a connector in which the multi-core 11 is rotationally aligned at the connection end face 2a is manufactured. The front end of the waveguide portion W may also be polished as needed.

[0053] Next, the operation of the optical fiber ribbon 1 configured as described above will be described.

[0054] In the past, the development of so-called multi-core optical fibers in which multiple cores are arranged inside a cladding has become active. When a connector is installed at the front end of the multi-core optical fiber, the multi-core optical fiber is usually rotated to align the center. However, in a multi-core optical fiber having a structure in which the cladding is covered by a coating, for example, even if the coating is fixed, after the rotation alignment operation, the multiple cores rotate relative to the coating, and there is a possibility that the rotation angle of the multi-core optical fiber will deviate.

[0055] To address this problem, the optical fiber ribbon 1 according to the present embodiment has a coating removal area L2 where the coating 20 is removed. In addition, a resin 41 is provided in the coating removal area L2, and the resin 41 bonds and fixes the cladding 13 and the coating 20. The adhesive force of the resin 41 suppresses the relative rotation of the waveguide W (multi-core 11) with respect to the coating 20.

[0056] Moreover, in this embodiment, in a state where the non-helical portion 11B is rotationally aligned, a plurality of spun-braided multi-core optical fibers 10 are fixed in a ribbon shape by the fixing portion 30 and the resin 41. Thus, it is possible to easily manufacture an optical fiber ribbon 100 with a connector in which the multi-core 11 is rotationally aligned at the connection end face 2a. In addition, for example, the replacement of the connector 2 can also be easily performed by the method described below.

[0057] like Figure 6A As shown, when replacing the connector 2, first, the optical fiber ribbon 1 is cut in the coating removal area L2. At this time, in order to be able to easily cut the optical fiber ribbon 1, it is preferred that the Young's modulus of the resin 41 is low to a certain extent. The Young's modulus of the resin 41 is preferably, for example, 1000 MPa or less. That is, together with the conditions related to the above-mentioned adhesive fixing force, the Young's modulus of the resin 41 involved in this embodiment is preferably in the range of 500 MPa to 1000 MPa or less. In addition, in the example shown in the figure, in a plurality of coating removal areas L2 (also refer to Figure 2 ) the optical fiber ribbon 1 is cut in the coating removal area L2 closest to the connector 2, but the optical fiber ribbon 1 may be cut in other coating removal areas L2.

[0058] In addition, when replacing connector 2, prepare Figure 6B The replacement part 100A is shown in FIG. The replacement part 100A includes a replacement connector 2A and a replacement optical fiber ribbon 1A. The structure of the replacement connector 2A may be the same as that of the connector 2. A cover removal area L2 is provided at the rear end of the replacement optical fiber ribbon 1A. As with the optical fiber ribbon 1, a resin 41 and a non-helical portion 11B that has been rotationally aligned in advance are provided in the cover removal area L2.

[0059] Moreover, if Figure 6CAs shown, the resin 41 is removed from both the coating removal area L2 of the optical fiber ribbon 1 and the coating removal area L2 of the replacement optical fiber ribbon 1A. As a result, the front end portions of the waveguide portions W included in the optical fiber ribbon 1 and the rear end portions of the waveguide portions W included in the replacement optical fiber ribbon 1A are exposed. Then, the front ends of the plurality of waveguide portions W included in the optical fiber ribbon 1 are fusion-connected to the rear ends of the plurality of waveguide portions W included in the replacement optical fiber ribbon 1A, whereby the optical fiber ribbon 1 and the replacement member 100A are connected. At this time, in the coating removal area L2, the non-helical portion 11B is pre-rotated and aligned, and the spun multi-core optical fibers 10 are fixed to each other in a ribbon shape, so that the plurality of waveguide portions W can be easily connected together. In addition, when performing the fusion connection, the ends of the waveguide portions W can be polished as needed. Finally, the resin 41 is filled again into the coating removal area L2, thereby completing the replacement operation of the connector 2.

[0060] As described above, the optical fiber ribbon 1 according to the present embodiment includes: a spun multi-core optical fiber (optical fiber) 10 having a plurality of cores 12 in a cladding 13, and having a helical portion 11A in which the positions of the plurality of cores 12 in the length direction X of the cladding 13 change in a spiral shape, a non-helical portion 11B in which the positions of the plurality of cores 12 in the length direction X do not change in a spiral shape, and a coating layer L covering the cladding 13; and a fixing portion 30 for fixing the coating layers L so that the plurality of spun multi-core optical fibers 10 are arranged in a direction (crossing direction Y) crossing the length direction X. The coating layer L has: a coating area L1 provided with a coating portion 20 covering the cladding 13; and a coating removal area L2 provided at a position corresponding to the non-helical portion 11B and from which the coating portion 20 is removed. A resin 41 (first resin) is provided in the coating removal area L2, and the resin 41 adhesively fixes the cladding 13 and the coating portion 20.

[0061] According to this structure, the relative rotation of the cladding 13 and the multi-core 11 with respect to the coating portion 20 is suppressed by the adhesive force of the resin 41. Moreover, the plurality of spun multi-core optical fibers 10 are fixed in a ribbon shape by the fixing portion 30 and the resin 41, so that the connector 2 can be easily attached to the optical fiber ribbon 1.

[0062] In addition, the spun multi-core optical fiber 10 has: a plurality of helical portions 11A arranged at intervals in the length direction X; and a plurality of non-helical portions 11B located between the plurality of helical portions 11A in the length direction X. With this structure, an operator can arbitrarily select a portion for attaching the connector 2 from the plurality of non-helical portions 11B.

[0063] Further, in the non-helical portion 11B, the plurality of cores 12 (multi-core 11) are rotationally aligned. Assuming that the helical portion 11A is rotationally aligned instead of the non-helical portion 11B, when the connector 2 is installed in the helical portion 11A, the position of the core 12 exposed at the front end of the waveguide portion W changes circumferentially according to the amount of the ground waveguide portion W. By performing the rotational alignment in the non-helical portion 11B instead of the helical portion 11A, it is possible to suppress the circumferential position shift of the core 12 regardless of the grinding amount of the waveguide portion W. Thus, the connector 2 can be more easily installed on the optical fiber ribbon 1.

[0064] Further, the resin 41 is provided over the entire coating removal region L2. According to this structure, for example, compared with the case where the resin 41 is provided only at the end portions L2a and L2b of the coating removal region L2, the cladding 13 (waveguide portion W) and the coating portion 20 can be fixed more firmly. In addition, the cladding 13 (waveguide portion W) can be protected by the resin 41.

[0065] Further, the optical fiber cable C according to the present embodiment includes the connector-equipped optical fiber ribbon 100 having the above-described optical fiber ribbon 1 and the connector 2 mounted at the front end of the optical fiber ribbon 1. With this structure, the relative rotation of the multi-core 11 with respect to the coating portion 20 is suppressed in each optical fiber ribbon 1, and the optical fiber cable C capable of easily installing the connector 2 can be realized.

[0066] Further, the braided multi-core optical fiber 10' according to the present embodiment includes: a cladding 13; a multi-core 11 having a plurality of cores 12 disposed within the cladding 13 and having a helical portion 11A in which the positions of the plurality of cores 12 in the length direction X of the cladding 13 change in a helical shape and a non-helical portion 11B in which the positions of the plurality of cores 12 in the length direction X do not change in a helical shape; and a coating portion 20 (coating layer L) covering the cladding 13, and a display portion 21 indicating the position of the non-helical portion 11B is provided in the coating portion 20 (coating layer L).

[0067] According to such a braided multi-core optical fiber 10', the above-described optical fiber ribbon 1, the connector-equipped optical fiber ribbon 100, and the optical fiber cable C can be easily manufactured.

[0068] (Second Embodiment)

[0069] Next, the second embodiment will be described. However, the basic structure is the same as that of the first embodiment. Therefore, the same reference numerals are given to the same structures and their description is omitted, and only the differences will be described.

[0070] As Figure 7As shown, in the optical fiber ribbon 3 according to the present embodiment, two types of resins 41A and 42A are provided in the coating removal region L2. Both the resins 41A and 42A cover the cladding 13. The first resin 41A is provided at least at the rear end portion L2b of the coating removal region L2. The second resin 42A is arranged at a position different from that of the first resin 41A in the length direction X. In the present embodiment, the second resin 42A is provided in all portions of the coating removal region L2 other than the portion (rear end portion L2b) where the first resin 41A is provided. The Young's modulus of the second resin 42A is lower than that of the first resin 41A.

[0071] Similar to the resin 41 in the first embodiment, the first resin 41A bonds and fixes the cladding 13 (waveguide portion W) and the coating portion 20. From the viewpoint of fixing strength, the Young's modulus of the first resin 41A is preferably as high as a certain level, similar to the resin 41 in the first embodiment. The Young's modulus of the first resin 41A is preferably, for example, 500 MPa or more.

[0072] On the other hand, in the present embodiment, a second resin 42A having a Young's modulus lower than that of the first resin 41A is provided in the coating removal region L2. Therefore, even if the Young's modulus of the first resin 41A is extremely high, the optical fiber ribbon 3 can be cut at the portion where the second resin 42A is provided. Therefore, the Young's modulus of the first resin 41A in the present embodiment can also be, for example, 1000 MPa or more. Moreover, the Young's modulus of the second resin 42A is preferably as low as a certain level. The Young's modulus of the second resin 42A is preferably, for example, 10 MPa or more and 100 MPa or less.

[0073] As described above, in the optical fiber ribbon 3 according to the present embodiment, the second resin 42A is provided in the coating removal region L2. The second resin 42A is arranged at a position different from that of the first resin 41A in the length direction X and covers the cladding 13, and the Young's modulus of the second resin 42A is lower than that of the first resin 41A. According to this structure, it is possible to reduce the force required for cutting the optical fiber ribbon 3 while ensuring the fixing strength between the cladding 13 and the coating portion 20.

[0074] In addition, the first resin 41A is provided at least at the end portion (rear end portion L2b) of the two end portions in the length direction X of the coating removal region L2 that is far from the connector 2. According to this structure, for example, as Figure 6A shown, even after cutting the optical fiber ribbon 3, the waveguide portion W (cladding 13) can be continuously bonded and fixed to the coating portion 20 by the first resin 41A.

[0075] Furthermore, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

[0076] For example, in the above embodiment, although it is described that the multiple cores 12 (multi-cores 11) are rotationally aligned in each of the multiple non-helical portions 11B, there may be multiple non-helical portions 11B in which the cores 12 are not rotationally aligned. In at least one non-helical portion 11B, the multiple cores 12 are rotationally aligned, and the coating removal area L2 is provided at a position corresponding to the non-helical portion 11B, so that the same effects as those of the above embodiment can be achieved.

[0077] In addition, in the above-mentioned embodiment, any one of the resins 41, 41A, 42A is provided in the entire coating removal area L2, but the resins 41, 41A, 42A may not be provided in a part of the coating removal area L2, so that the cladding 13 (waveguide portion W) is exposed. In this case, the resins 41, 41A for bonding and fixing the cladding 13 (waveguide portion W) and the coating 20 are also provided in the coating removal area L2, so that the relative rotation of the multi-core 11 (waveguide portion W) can be suppressed. In this case, it is preferred that the resins 41, 41A are provided at least in the rear end portion L2b of the coating removal area L2. This is because: even after the coating removal is performed Figure 6A Even after the optical fiber ribbons 1 and 3 are cut as shown, the waveguide portion W (cladding 13) can continue to be bonded and fixed to the coating portion 20 by the resins 41 and 41A.

[0078] In addition, the components of the above-described embodiment may be appropriately replaced with known components without departing from the gist of the present invention, and the above-described embodiment and modified examples may be appropriately combined.

[0079] Description of Reference Numerals

[0080] C…optical fiber cable; 100…optical fiber ribbon with connector; 1, 3…optical fiber ribbon; 2…connector; 10, 10′…spun-braided multi-core optical fiber (optical fiber); 11…multi-core; 11A…helical portion; 11B…non-helical portion; 12…core; 13…cladding; 20…coating portion; 21…display portion; 41, 41A…first resin; 42A…second resin; L…coating layer; L1…coating area; L2…coating removal area; L2a…front end portion; L2b…rear end portion; X…length direction; Y…cross direction.

Claims

1. An optical fiber ribbon, characterized in that, Comprising: An optical fiber having a plurality of cores within a cladding, and having a helical portion in which the positions of the plurality of cores in the longitudinal direction of the cladding change in a spiral shape, a non-helical portion in which the positions of the plurality of cores in the longitudinal direction do not change in a spiral shape, and a coating layer covering the cladding; and A fixing portion for fixing between the coating layers in such a manner that a plurality of the optical fibers are arranged in a direction crossing the longitudinal direction, The coating layer has: a coated area provided with a coated portion covering the cladding; and a coating-removed area provided at a position corresponding to the non-helical portion and from which the coated portion is removed, A first resin is provided in the coating-removed area, and the first resin adhesively fixes the cladding and the coated portion.

2. The optical fiber ribbon according to claim 1, wherein The optical fiber has: a plurality of the helical portions arranged at intervals in the longitudinal direction; and a plurality of the non-helical portions located between the plurality of helical portions in the longitudinal direction.

3. The optical fiber ribbon according to claim 1 or 2, wherein In the non-helical portion, the plurality of cores are rotationally aligned.

4. The optical fiber ribbon according to any one of claims 1 to 3, wherein The first resin is provided throughout the coating-removed area.

5. The optical fiber ribbon according to any one of claims 1 to 3, wherein A second resin is provided in the coating-removed area, and the second resin is arranged at a position different from that of the first resin in the longitudinal direction and covers the cladding, The Young's modulus of the second resin is lower than that of the first resin.

6. An optical fiber ribbon with a connector, characterized in that, Comprising: The optical fiber ribbon according to any one of claims 1 to 5; and A connector mounted at the front end of the optical fiber ribbon, The first resin is provided at least at an end portion of the coating-removed area in the longitudinal direction that is far from the connector.

7. An optical fiber cable, characterized in that, Comprising: An optical fiber ribbon with a connector, having the optical fiber ribbon according to any one of claims 1 to 5 and a connector mounted at the front end of the optical fiber ribbon.

8. An optical fiber, characterized in that, Comprising: A cladding; A multi-core having a plurality of cores arranged within the cladding, and having a helical portion in which the positions of the plurality of cores in the longitudinal direction of the cladding change in a spiral shape and a non-helical portion in which the positions of the plurality of cores in the longitudinal direction do not change in a spiral shape; and A coating layer covering the cladding, A display portion indicating the position of the non-helical portion is provided in the coating layer.

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