Optical fiber cable, optical fiber ribbon core wire, method for laying an optical fiber cable, and optical transmission system

Abstract

An optical fiber cable 1 comprising a multi-core optical fiber 30 including a plurality of cores 32A-32D has arrangement information associated with the multi-core optical fiber 30, wherein the arrangement information is associated with the arrangement of the multiple cores 32A-32D in the cross section of the multicore optical fiber 30.

Description

Technical Field

[0001] The present invention relates to an optical fiber cable provided with a multi-core optical fiber, an optical fiber ribbon core wire provided with a multi-core optical fiber, a laying method of an optical fiber cable provided with a multi-core optical fiber, and an optical transmission system provided with an optical fiber cable provided with a multi-core optical fiber. For designated countries where incorporation by reference is permitted, the contents described in Japanese Patent Application No. 2021-148367 filed in Japan on September 13, 2021 are incorporated herein by reference and made part of the description of this specification.

Background Art

[0002] A multi-core optical fiber including a plurality of cores, a marker, and a common cladding covering the plurality of cores and the marker is known (see, for example, Patent Document 1). In this multi-core optical fiber, in the cross-section of the fiber, a plurality of cores are arranged so as to have symmetry, and a marker is arranged at a position where this symmetry is broken.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, in a multi-core optical fiber, since the symmetry of the core arrangement is lost by the marker, depending on the direction of viewing the cross-section of the optical fiber, the core arrangement (core array) in the cross-section of the optical fiber is different. That is, as the core array of the multi-core optical fiber, there are two mutually opposite core arrays: the core array (normal array) in the cross-section of the optical fiber viewed from one end side, and the core array (reverse array) in the cross-sectional shape of the optical fiber viewed from the other end side.

[0005] Therefore, when laying an optical fiber cable at the laying site or connecting it to another optical fiber cable or device, it is necessary to check the core arrangement of the multi-core optical fiber included in the optical fiber cable. However, it is difficult to grasp the core arrangement from the cross-section of a fine multi-core optical fiber at the laying site, and there is a problem that the laying work and connection work of the optical fiber cable may take a long time.

[0006] The problem to be solved by the present invention is to provide an optical fiber cable, a method of laying an optical fiber cable, and an optical transmission system capable of improving the workability of laying work and connection work.

Means for Solving the Problem

[0007] [1] The optical fiber cable according to the present invention is an optical fiber cable including a multi-core optical fiber including a plurality of cores, wherein the optical fiber cable includes arrangement information associated with the multi-core optical fiber, and the arrangement information is associated with the arrangement of the plurality of cores in the cross-section of the multi-core optical fiber.

[0008] [2] In the above invention, the optical fiber cable includes a plurality of the multi-core optical fibers, and the optical fiber cable includes a plurality of the arrangement information respectively associated with the plurality of multi-core optical fibers, and the arrangement information associated with the multi-core optical fibers having the same core arrangement may have the same content.

[0009] [3] In the above invention, the arrangement information may include first information for specifying the direction of the optical fiber cable and second information indicating the core arrangement based on the direction specified by the first information.

[0010] [4] In the above invention, the first information may be shared by a plurality of the array information, and the second information may be shared by the array information associated with the multi-core optical fiber having the same core array.

[0011] [5] In the above invention, the first information includes the content of a display portion provided on the outer peripheral surface of the optical fiber cable or a component of the optical fiber cable, or the orientation of the display portion, and the second information may include the color of a linear body or a cylindrical body aggregating a plurality of the multi-core optical fibers, a mark provided on the linear body or the cylindrical body, the color of a colored layer included in the multi-core optical fiber, or a mark included in the multi-core optical fiber.

[0012] [6] In the above invention, the optical fiber cable includes an optical connection component connected to an end portion of the multi-core optical fiber, and at least a part of the array information may be provided on the optical connection component.

[0013] [7] In the above invention, the optical fiber cable includes an optical fiber ribbon core wire including the multi-core optical fiber, and at least a part of the array information may be provided on the optical fiber ribbon core wire.

[0014] [8] In the above invention, the optical fiber cable includes a plurality of the multi-core optical fibers, and the plurality of multi-core optical fibers may include a first multi-core optical fiber having a core array as a first array and a second multi-core optical fiber having a core array as a second array opposite to the first array.

[0015] [9] In the above invention, the number of the first multi-core optical fibers included in the optical fiber cable and the number of the second multi-core optical fibers included in the optical fiber cable may be the same.

[0016]

[10] In the above invention, the optical fiber cable includes an assembly including a plurality of optical fibers assembled together, the optical fibers include the multi-core optical fiber, and the core arrays of all the multi-core optical fibers included in the assembly may be the same.

[0017]

[11] In the above invention, the optical fiber cable includes a plurality of the assemblies, the plurality of assemblies include a first assembly and a second assembly, the core array of all the multi-core optical fibers included in the first assembly is a first array, and the core array of all the multi-core optical fibers included in the second assembly may be a second array opposite to the first array.

[0018]

[12] The optical fiber ribbon core wire according to the present invention is an optical fiber ribbon core wire including a multi-core optical fiber including a plurality of cores, the optical fiber ribbon core wire includes arrangement information associated with the multi-core optical fiber, and the arrangement information is associated with the arrangement of the plurality of cores in the cross section of the multi-core optical fiber.

[0019]

[13] In the above invention, the optical fiber ribbon core wire includes a plurality of the multi-core optical fibers, the optical fiber ribbon core wire includes a plurality of the arrangement information respectively associated with the plurality of multi-core optical fibers, and the arrangement information associated with the multi-core optical fibers having the same core array may have the same content.

[0020]

[14] In the above invention, the arrangement information may include first information for specifying the direction of the optical fiber ribbon core wire and second information indicating the core array based on the direction specified by the first information.

[0021]

[15] In the above invention, the first information may be shared by a plurality of the arrangement information.

[0022]

[16] In the above invention, the first information may include the content of a display portion provided on the outer surface of the optical fiber ribbon core wire or the orientation of the display portion, and the second information may include the color of a colored layer included in the multi-core optical fiber or a mark included in the multi-core optical fiber.

[0023]

[17] In the above invention, the optical fiber ribbon core wire may include a plurality of the multi-core optical fibers, and the core arrays of all the multi-core optical fibers may be the same.

[0024]

[18] In the above invention, the first information and the second information may be the same information.

[0025]

[19] In the above invention, the optical fiber ribbon core wire may include a plurality of the multi-core optical fibers, and the plurality of multi-core optical fibers may include a first multi-core optical fiber having a core array that is a first array and a second multi-core optical fiber having a core array that is a second array reverse to the first array.

[0026]

[20] A method for laying an optical fiber cable according to the present invention is a method for laying an optical fiber cable including a multi-core optical fiber including a plurality of cores, the optical fiber cable including arrangement information associated with the multi-core optical fiber, the arrangement information being associated with the arrangement of the plurality of cores in a cross section of the multi-core optical fiber, and the laying method being a method for laying an optical fiber cable including a reference step of referring to the arrangement information.

[0027]

[21] In the above invention, the arrangement information may include first information for specifying the orientation of the optical fiber cable and second information indicating the core arrangement based on the first information, and the reference step may include distinguishing the core arrangement of the multi-core optical fiber based on the arrangement information.

[0028]

[22] In the above invention, the reference step may include distinguishing the core array of the multi-core optical fiber based on the array information by using association information associating the core array with the array information.

[0029]

[23] In the above invention, the laying method may include a laying step of laying the optical fiber cable and a connecting step of connecting the optical fiber cable to a connected body.

[0030]

[24] In the above invention, the reference step may be executed before the laying step.

[0031]

[25] An optical transmission system according to the present invention is an optical transmission system including an optical fiber cable having a plurality of multi-core optical fibers each including a plurality of cores, wherein the plurality of multi-core optical fibers include a first multi-core optical fiber in which a core array, which is an array of the plurality of cores in a cross section of the multi-core optical fiber, is a first array, and a second multi-core optical fiber in which the core array is a second array opposite to the first array, and the optical transmission system includes a first optical transmission path for upstream including the first multi-core optical fiber and a second optical transmission path for downstream including the second multi-core optical fiber.

[0032]

[26] In the above invention, the core arrays of all the multi-core optical fibers included in the first optical transmission path may be the first array, and the core arrays of all the multi-core optical fibers included in the second optical transmission path may be a second array opposite to the first array.

Effect of the Invention

[0033] According to the present invention, the optical fiber cable has array information associated with the core array of the multi-core optical fiber. Thereby, the core array of the multi-core optical fiber can be easily distinguished, so that the workability of the laying work and the connection work of the optical fiber cable can be improved.

[0034] Further, according to the present invention, the first optical transmission path for upstream includes a first multi-core optical fiber having a first array, and the second optical transmission path for downstream includes a second multi-core optical fiber having a second array. In this way, by properly using the multi-core optical fibers for upstream / downstream according to the core array, it is possible to improve the workability of the laying work and connection work of the optical fiber cable.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0036] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[0037] First, with reference to FIGS. 1(a) and 1(b), the configuration of the multi-core optical fiber 30 in this embodiment will be described.

[0038] FIGS. 1(a) and 1(b) are cross-sectional views showing the multi-core optical fiber 30 in this embodiment, and show a cross-section perpendicular to the axial direction of the multi-core optical fiber 30. FIG. 1(a) is a cross-sectional view when the multi-core optical fiber 30 is viewed from one end side, and FIG. 1(b) is a cross-sectional view when the multi-core optical fiber 30 is viewed from the other end side.

[0039] The multi-core optical fiber (optical fiber coloring wire) 30 in this embodiment includes, as shown in FIGS. 1(a) and 1(b), an optical fiber bare wire (bare fiber) 31, a coating layer 35, an identification mark 36, and a coloring layer 37. Note that the multi-core optical fibers in the second to fifth embodiments described later also have basically the same configuration as the multi-core optical fiber 30 in this first embodiment, except for the configurations detailed in each embodiment.

[0040] The optical fiber bare wire 31 includes four cores 32A to 32D, a marker (tracer) 33, and a cladding 34. This optical fiber bare wire 31 has a circular cross-sectional shape as a whole.

[0041] Each of the cores 32A to 32D has a circular cross-sectional shape and extends along the axial direction of the multi-core optical fiber 30. Similarly, the marker 33 also has a circular cross-sectional shape and extends along the axial direction of the multi-core optical fiber 30. In this embodiment, the diameters of the cores 32A to 32D are the same, but it is not particularly limited thereto, and the diameters of the cores 32A to 32D may be different from each other. The cladding 34 is a common cladding that surrounds all the cores 32A to 32D and the marker 33.

[0042] The cores 32A to 32D, the marker 33, and the cladding 34 are made of a material mainly composed of quartz glass, and impurities are added as necessary to adjust their refractive indices. The refractive indices of the cores 32A to 32D are higher than that of the cladding 34. The refractive index of the marker 33 is also higher than that of the cladding 34. In this embodiment, the refractive indices of the cores 32A to 32D are the same, but it is not particularly limited thereto, and the refractive indices of the cores 32A to 32D may be different from each other.

[0043] The four cores 32A to 32D are respectively arranged at the vertices of a virtual square VS that shares the optical fiber bare wire 31 and the central CP, and have symmetry in the fiber cross section. On the other hand, the marker 33 is arranged in the vicinity of a specific core (core 32A in this embodiment), and is provided at a position that breaks the above-mentioned symmetry.

[0044] The four cores 32A to 32D are individually identified by having core numbers assigned thereto based on this marker 33. For example, core 32A is the "first" core, core 32B is the "second" core, core 32C is the "third" core, and core 32D is the "fourth" core. As will be described later, this core number is used for connection management of each core when connecting the optical fiber cable 1 including the multi-core optical fiber 30 to a counterpart connected body (such as a counterpart optical fiber cable or optical connection component).

[0045] In this embodiment, since numbers are individually assigned to the cores 32A to 32D as described above, there are two types of core arrangements (hereinafter also simply referred to as "core arrangements") in the cross section of the multi-core optical fiber 30: the "normal arrangement" shown in Fig. 1(a) and the "reverse arrangement" shown in Fig. 1(b).

[0046] Note that FIG. 1(a) is a cross-sectional view of the multi-core optical fiber 30 when the optical fiber cable 1 including the multi-core optical fiber 30 is viewed from the first end (one end) 101 side. That is, FIG. 1(a) is a cross-sectional view of the multi-core optical fiber 30 when the optical fiber cable 1 is viewed along the arrow A in FIG. 4 (described later). On the other hand, FIG. 1(b) is a cross-sectional view of the multi-core optical fiber 30 when the optical fiber cable 1 is viewed from the second end (the other end) 102 side. That is, FIG. 1(b) is a cross-sectional view of the multi-core optical fiber 30 when the optical fiber cable 1 is viewed along the arrow B in FIG. 4.

[0047] Specifically, in the "normal arrangement" shown in FIG. 1(a), the first core 32A located near the marker 33 is located on the left side in the figure, the second core 32B is located on the upper side in the figure, the third core 32C is located on the right side in the figure, and the fourth core 32D is located on the lower side in the figure. The first to fourth cores 32A to 32D are arranged in a clockwise direction in the figure. On the other hand, in the "reverse arrangement" shown in FIG. 1(b), compared with FIG. 1(a), the marker 33 moves to the right side in the figure, the first core 32A located near the marker 33 is located on the right side in the figure, the second core 32B is located on the upper side in the figure, the third core 32C is located on the left side in the figure, and the fourth core 32D is located on the lower side in the figure. The first to fourth cores 32A to 32D are arranged in a counterclockwise direction in the figure. That is, the "normal arrangement" shown in FIG. 1(a) and the "reverse arrangement" shown in FIG. 1(b) are in a mirror image relationship.

[0048] As described above, in the present embodiment, since individual numbers are assigned to the cores 32A to 32D, the core arrangement when the multi-core optical fiber 30 is viewed from the first end 101 side is different from the core arrangement when viewed from the second end 102 side, and these core arrangements are reversed with respect to each other.

[0049] Note that the "core arrangement" of the multi-core optical fiber in the present embodiment means the order of the arrangement of the numbered cores (cores individually identified based on the marker 33) in the cross-section of the fiber when the positions and relative positional relationships of the unnumbered cores (cores not individually identified) in the cross-section of the fiber are known, and does not indicate the positions and relative positional relationships of the unnumbered cores in the fiber cross-section. In other words, the "core arrangement" of the multi-core optical fiber in the present embodiment means the arrangement (relative positional relationship) of a plurality of cores 32A to 32D that are individually identified relative to one specific core 32A selected from among the plurality of cores 32A to 32D. In the present embodiment, this specific core 32A is identified based on the marker 33.

[0050] Note that the number of cores included in the multi-core optical fiber 30 is not particularly limited as described above. Also, the arrangement of the unnumbered cores in the cross-section of the multi-core optical fiber 30 is not particularly limited as described above. For example, the arrangement of the unnumbered cores may not have symmetry. In this case, since the cores can be individually identified, the marker 33 may be omitted.

[0051] Also, the marker for individually identifying the plurality of cores 32A to 32D is not particularly limited as long as it is arranged so as to break the symmetry of the arrangement of the unnumbered cores in the cross-section of the multi-core optical fiber 30. Instead of the above marker 33 embedded in the cladding 34, for example, a marker composed of a colored portion or the like may be provided on the outer peripheral surface of the coating layer 35 or the colored layer 37.

[0052] The coating layer 35 covers the outer periphery of the above-described optical fiber bare wire 31 over the entire circumference. The coating layer 35 in the present embodiment has a two-layer structure composed of a primary layer 351 and a secondary layer 352. The secondary layer 352 is located outside the primary layer 351. The primary layer 351 and the secondary layer 352 are formed by applying a resin material to the outer peripheral surface of the cladding 34 of the optical fiber bare wire 31 and curing it. Examples of the resin material constituting such primary layer 351 and secondary layer 352 include ultraviolet curable resin materials and thermosetting resin materials. Note that the number of layers constituting the coating layer 35 is not limited to the above two layers, and the coating layer 35 may have a single-layer structure or may be constituted by three or more layers.

[0053] The identification mark 36 is formed on the coating layer 35. This mark 36 is formed by printing ink on the coating layer 35 and curing it. Specific printing methods for printing this mark 36 include, for example, intaglio roll printing method and inkjet method. Examples of the material constituting this mark 36 include ultraviolet curable resin materials and thermosetting resin materials. This mark 36 has a predetermined width in the axial direction of the multi-core optical fiber 30 (see FIG. 2 described later), and is formed over the entire circumference of the coating layer 35, having a ring shape. Note that the mark 36 may be formed only on a part of the circumferential direction of the coating layer 35.

[0054] The coloring layer 37 covers the outer periphery of the coating layer 35 over the entire circumference while covering the mark 36. This coloring layer 37 is formed by applying a resin material to the surface of the coating layer 35 and curing it. Examples of the resin material constituting such coloring layer 37 include ultraviolet curable resin materials and thermosetting resin materials. This coloring layer 37 has a color different from the color of the above mark 36 and also has a color different from other multi-core optical fibers 30 constituting the same optical fiber ribbon core wire 20 (described later).

[0055] Note that the positional relationship among the coating layer 35, the mark 36, and the coloring layer 37 is not particularly limited to the above. For example, the mark 36 may be disposed on the coloring layer 37, or the mark 36 may be disposed under the coating layer 35. Alternatively, since the coating layer 35 is colored, the coloring layer 37 may be omitted.

[0056] Also, the multi-core optical fiber 30 may not include the coloring layer 37. In this case, if necessary, other components of the multi-core optical fiber 30 may have the function of the coloring layer 37. Similarly, the multi-core optical fiber 30 may not include the mark 36. In this case, if necessary, other components of the multi-core optical fiber 30 may have the function of the mark 36.

[0057] Next, the configuration of the optical fiber ribbon core wire 20 using the multi-core optical fiber 30 described above will be described with reference to FIG. 2.

[0058] FIG. 2 is a perspective view showing the optical fiber ribbon core wire 20 in the present embodiment.

[0059] The optical fiber ribbon core wire 20 in the present embodiment is a so-called intermittent fixed type ribbon core wire. As shown in FIG. 2, this optical fiber ribbon core wire 20 includes a plurality (12 in this embodiment) of multi-core optical fibers 30 and a first connecting portion 21. The optical fiber ribbon core wire 20 in the present embodiment corresponds to an example of the "aggregate" in the present invention. Note that the optical fiber ribbon core wires in the second to fifth embodiments also have basically the same configuration as the optical fiber ribbon core wire 20 in the first embodiment, except for the configurations described in detail in each embodiment.

[0060] The plurality of multi-core optical fibers 30 each have the configuration described above with reference to FIGS. 1(a) and 1(b). In the present embodiment, all the multi-core optical fibers 30 constituting the same optical fiber ribbon core wire 20 have the same core array (the above-mentioned "positive array" or "reverse array").

[0061] In addition to the multi-core optical fiber 30, a single-core optical fiber having a single core may be included in the optical fibers constituting the optical fiber ribbon core wire. That is, as the plurality of optical fibers included in the optical fiber ribbon core wire, the multi-core optical fiber 30 and the single-core optical fiber may be mixed. For example, the optical fiber ribbon core wire may include one multi-core optical fiber 30, and the remaining optical fibers included in the optical fiber ribbon core wire may be single-core optical fibers.

[0062] These plurality of multi-core optical fibers 30 are arranged on the same plane so as to extend substantially parallel to each other. And, adjacent multi-core optical fibers 30 are fixed at the first connecting portion 21 with a predetermined interval in the longitudinal direction of the optical fiber ribbon core wire 20, and the first connecting portions 21 are arranged so as to be shifted from each other in the longitudinal direction of the optical fiber ribbon core wire 20. This first connecting portion 21 is composed of a resin material such as an ultraviolet curable resin material. This connecting portion 21 is formed by intermittently applying an ultraviolet curable resin between adjacent multi-core optical fibers 30 and then irradiating the ultraviolet curable resin with ultraviolet rays to cure it. In addition, after continuously applying and curing an ultraviolet curable resin between adjacent multi-core optical fibers 30, the cured resin may be partially cut to form the connecting portion 21.

[0063] Note that the number of multi-core optical fibers 30 constituting the optical fiber ribbon core wire 20 is not particularly limited as described above. Also, the configuration of the optical fiber ribbon core wire 20 is not particularly limited as described above. For example, the first connecting portion 21 may cover the entire circumference of the multi-core optical fiber 30, or the first connecting portion 21 may cover only a part of the periphery of the multi-core optical fiber 30. Also, the first connecting portion 21 may be provided over the entire region in the longitudinal direction of the optical fiber ribbon core wire 20, not intermittently. Alternatively, instead of the first connecting portion 21, a plurality of multi-core optical fibers 30 may be collectively coated with a resin layer, and the plurality of multi-core optical fibers 30 may be connected by this resin layer.

[0064] As described above, the colors of the colored layers 37 of the plurality of multi-core optical fibers 30 included in the optical fiber ribbon core wire 20 are different from each other. Thereby, it is possible to individually identify the multi-core optical fibers 30 in the optical fiber ribbon core wire 20.

[0065] Also, in this optical fiber ribbon core wire 20, for example, when an optical fiber cable 1 (see FIG. 3) described later is configured using the optical fiber ribbon core wire 20, it is possible to individually identify the optical fiber ribbon core wire 20 by the marks 36 given to the multi-core optical fibers 30.

[0066] In the present embodiment, the optical fiber ribbon core wire 20 can be identified by varying the pattern of the marks 36 along the axial direction of the multi-core optical fiber 30 for each optical fiber ribbon core wire 20. Although not particularly limited, as specific examples of such marks 36, as shown in Table 1 below, six types of patterns in which the number and width of the rings 361 constituting the marks 36 are different can be exemplified. Each rectangular mark in Table 1 indicates a ring 361, and six types of patterns are set by combinations of the width and number of the rings 361.

[0067]

Table 1

[0068] In the present embodiment, as shown in FIG. 2, for all the multi-core optical fibers 30 constituting the same optical fiber ribbon core wire 20, marks 36 are formed at the same positions in the axial direction of the multi-core optical fiber 30. Incidentally, in the example shown in FIG. 2, since the mark 36 of the multi-core optical fiber 30 is composed of two narrow rings 361, it is possible to identify that the number of the optical fiber ribbon core wire 20 is "No. 2" based on Table 1 above.

[0069] Incidentally, since there is a limit to the number of colors of the coloring layer 37 described above, for example, when the optical fiber ribbon core wire 20 includes a larger number of multi-core optical fibers 30, the mark 36 provided on the multi-core optical fiber 30 may be used to identify the multi-core optical fiber 30.

[0070] Next, the configuration of the optical fiber cable 1 using the optical fiber ribbon core wire 20 described above will be described with reference to FIGS. 3 to 5.

[0071] FIG. 3 is a cross-sectional view showing the optical fiber cable 1 in the present embodiment, FIG. 4 is a plan view showing the optical fiber cable 1 in the present embodiment, and FIG. 3 is a cross-sectional view taken along line C-C of FIG. 4. FIG. 5 is a perspective view showing the optical fiber unit 10A in the present embodiment.

[0072] The optical fiber cable 1 in the present embodiment is a so-called slottedless type optical fiber cable. As shown in FIGS. 3 and 4, this optical fiber cable 1 includes optical fiber units 10A to 10D, a holding winding 40, a sheath 50, a tensile strength member 60, and a lip cord 70. The optical fiber units 10A to 10D in the present embodiment correspond to an example of the "aggregate" in the present invention. Incidentally, the optical fiber cables in the second to fourth embodiments also have basically the same configuration as the optical fiber cable 1 in the first embodiment, except for the configurations described in detail in their respective embodiments.

[0073] Note that the configuration of the optical fiber cable 1 is not limited to the slotted type, and for example, it may be a loose tube type or a slotted type. Further, the optical fiber cable 1 of the present embodiment includes a type so-called optical fiber cord. This optical fiber cord has a configuration in which an aggregate of multi-core optical fibers 30 or optical fiber ribbon cores 20 is covered with a jacket via a buffer layer. As the buffer layer, for example, aramid fiber can be exemplified. This buffer layer has a function of relaxing impact and also has a function as a tensile strength body. Therefore, this optical fiber cord does not include the above-mentioned tensile strength body. Further, as the jacket, polyvinyl chloride (PVC) or flame-retardant polyolefin (PO) can be exemplified.

[0074] The optical fiber cable 1 of the present embodiment includes four optical fiber units 10A to 10D. These four optical fiber units 10A to 10D are twisted together. Specific examples of the twisting method of the optical fiber units 10A to 10D include SZ twist and unidirectional twist. Note that the SZ twist is a twisting method in which a plurality of linear bodies are twisted while reversing the twisting direction at predetermined intervals. Further, the unidirectional twist is a twisting method having only one direction as the twisting direction, and is a twisting method in which a plurality of linear bodies are twisted in a spiral shape.

[0075] Since these four optical fiber units 10A to 10D have the same configuration, the configuration of the optical fiber unit 10A will be described in detail below, and the description of the configurations of the other optical fiber units 10B to 10D will be omitted. Note that in FIG. 3, the cross-sectional shapes of the four optical fiber units 10A to 10D are shown as having a fan shape, but the optical fiber units 10A to 10D do not necessarily have a regular cross-sectional shape. Further, a gap may be formed between the optical fiber units 10A to 10D. Further, the optical fiber units 10A to 10D do not necessarily have the same configuration.

[0076] As shown in FIG. 5, the optical fiber unit 10A includes a plurality (six in this embodiment) of optical fiber ribbon cores 20 bundled together and two bundling materials 25 and 26. This optical fiber unit 10A is configured by bundling a plurality of optical fiber ribbon cores 20 with the bundling materials 25 and 26.

[0077] The plurality of optical fiber ribbon cores 20 each have the configuration described above with reference to FIG. 2. In this embodiment, all the multi-core optical fibers 30 that make up all the optical fiber ribbon cores 20 constituting the same optical fiber unit 10A have the same core arrangement (the above-mentioned "positive arrangement" or "reverse arrangement"). That is, all the multi-core optical fibers 30 included in the same optical fiber unit 10A have the same core arrangement. In the optical fiber cables of the second and third embodiments, all the multi-core optical fibers included in the same optical fiber unit may have the same core arrangement.

[0078] In this embodiment, all the multi-core optical fibers 30 included in the optical fiber unit 10A have a core arrangement of "positive arrangement" (see FIG. 1(a)). Similarly, all the multi-core optical fibers 30 included in the optical fiber unit 10C have a core arrangement of "positive arrangement" (see FIG. 1(a)). In contrast, all the multi-core optical fibers 30 included in the optical fiber unit 10B have a core arrangement of "reverse arrangement" (see FIG. 1(b)). Similarly, all the multi-core optical fibers 30 included in the optical fiber unit 10D have a core arrangement of "reverse arrangement" (see FIG. 1(b)). In the optical fiber cables of the second and third embodiments, all the multi-core optical fibers included in one optical fiber unit may have a core arrangement of "positive arrangement", and all the multi-core optical fibers included in other optical fiber units may have a core arrangement of "reverse arrangement".

[0079] Therefore, the optical fiber cable 1 of the present embodiment includes both a multi-core optical fiber 30 having a "positive arrangement" core array and a multi-core optical fiber 30 having a "reverse arrangement" core array. Also, in the optical fiber cable 1 of the present embodiment, the number of multi-core optical fibers 30 having a "positive arrangement" core array is the same as the number of multi-core optical fibers 30 having a "reverse arrangement" core array.

[0080] In addition, in the second to fourth embodiments, the optical fiber cable may include both a multi-core optical fiber having a "positive arrangement" core array and a multi-core optical fiber having a "reverse arrangement" core array. Also, in the optical fiber cable of the second to fourth embodiments, the number of multi-core optical fibers having a "positive arrangement" core array may be the same as the number of multi-core optical fibers having a "reverse arrangement" core array.

[0081] The bundling materials 25 and 26 are filamentous, string-like, or tape-like members capable of bundling a plurality of optical fiber tape cores 20, and are linear bodies extending linearly. In the present embodiment, as shown in FIG. 5, one bundling material 25 (the upper side in the figure) is wound around the upper half portion of the bundle of the optical fiber tape cores 20 in an SZ shape. On the other hand, the other bundling material 26 (the lower side in the figure) is wound around the lower half portion of the bundle of the optical fiber tape cores 20 in an SZ shape. Then, the bundling materials 25 and 26 are joined to each other at the inversion point 251 of the upper bundling material 25 and the inversion point 261 of the lower bundling material 26. Note that the SZ-shaped winding is a winding method in which the bundling material is wound while reversing the winding direction at predetermined intervals, similar to the above-described SZ twist.

[0082] By varying the colors of the bundling materials 25 and 26 according to the optical fiber units 10A to 10D, it is possible to identify the optical fiber units 10A to 10D in the optical fiber cable 1. Although not particularly limited, for example, the colors of the bundling materials 25 and 26 of the optical fiber unit 10A are "blue", the colors of the bundling materials 25 and 26 of the optical fiber unit 10B are "orange", the colors of the bundling materials 25 and 26 of the optical fiber unit 10C are "green", and the color of the optical fiber unit 10D is "brown". In addition, by varying the color of one bundling material 25 and the color of the other bundling material 26 in the same optical fiber unit, the number of distinguishable optical fiber units may be increased.

[0083] In addition, the winding method of the bundling materials 25 and 26 is not particularly limited to the above. For example, two bundling materials 25 and 26 may be spirally wound so that the winding directions are opposite to each other. Also, the number of bundling materials is not particularly limited to the above, and the number of bundling materials may be one, or three or more.

[0084] Also, the member for binding a plurality of optical fiber tape cores 20 is not limited to the above-described bundling material. For example, like the above-described optical fiber cable having a loose tube structure, a plurality of optical fiber tape cores 20 may be covered with a cylindrical tube member.

[0085] Also, the configuration of the optical fiber unit is not particularly limited to the above. For example, an optical fiber unit may be configured by twisting a plurality of optical fiber tape cores 20. Alternatively, instead of the optical fiber tape core 20, an optical fiber unit may be configured by bundling or twisting a plurality of multi-core optical fibers 30. Alternatively, a unit intermediate body may be formed by bundling or twisting a plurality of optical fiber tape cores 20 or a plurality of multi-core optical fibers 30, and the optical fiber unit 10 may be configured by bundling or twisting a plurality of the unit intermediate bodies.

[0086] Further, for example, when using the mark 36 or the colored layer 37 as arrangement information as described later, instead of the plurality of optical fiber units 10A to 10D, a single optical fiber unit formed by bundling or twisting a plurality of optical fiber ribbon cores 20 or a plurality of multi-core optical fibers 30 may be accommodated in the sheath 50.

[0087] In addition, the optical fibers constituting the optical fiber unit may include single-core optical fibers in addition to the multi-core optical fibers 30. That is, as the plurality of optical fibers included in the optical fiber unit, multi-core optical fibers 30 and single-core optical fibers may be mixed. For example, the optical fiber unit may include one multi-core optical fiber 30, and the remaining optical fibers included in the optical fiber unit may be single-core optical fibers.

[0088] That is, at least one multi-core optical fiber 30 may be included in the optical fibers constituting the optical fiber unit 10. Alternatively, at least one multi-core optical fiber 30 may be included in the optical fibers included in the optical fiber cable 1. Further, when the optical fiber cable is the slot type described above, at least one multi-core optical fiber 30 may be included in the plurality of optical fibers accommodated in the grooves of the slot rods provided in the slot type cable.

[0089] As shown in FIG. 3, the plurality of optical fiber units 10A to 10D are covered by a retaining wrap 40. In the present embodiment, this retaining wrap 40 is formed by longitudinally winding a retaining tape 41 around the outer periphery of the plurality of optical fiber units 10A to 10D. Specifically, the retaining tape 41 is wound around the outer periphery of the plurality of optical fiber units 10A to 10D in a state where the longitudinal direction of the retaining tape 41 coincides with the axial direction of the optical fiber cable 1 and the width direction of the retaining tape 41 substantially coincides with the circumferential direction of the optical fiber cable 1. Note that the winding method of the retaining tape 41 is not particularly limited to the above, and for example, it may be a lateral winding (helical winding). Note that the optical fiber cable 1 may not include the retaining wrap 40.

[0090] This retaining tape 41 is composed of a non-woven fabric or a film. Specific examples of the non-woven fabric constituting the retaining tape 41 are not particularly limited, and for example, non-woven fabrics made of fibers such as polyester, polyethylene (PE), and polypropylene (PP) can be exemplified. On the other hand, specific examples of the film constituting the retaining tape 41 are not particularly limited, and for example, films made of resins such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene naphthalate (PBT), and nylon can be exemplified.

[0091] When the retaining tape 41 is made of a non-woven fabric, the retaining wrap 40 may function as a water absorption layer for water stoppage into the optical fiber cable 1 by applying a water absorption powder to the non-woven fabric. During flooding, the water absorption powder swells to block the gaps in the optical fiber cable 1, thereby stopping the water inside the optical fiber cable 1.

[0092] Specific examples of such water-absorbing powders are not particularly limited, and examples thereof include, for example, starch-based, cellulose-based, polyacrylic acid-based, polyvinyl alcohol-based, and polyoxyethylene-based materials having high water absorbency, as well as mixtures thereof. Further, as a method for applying the water-absorbing powder to the nonwoven fabric, it may be adhered (coated) on the surface of the nonwoven fabric or interposed between two nonwoven fabrics.

[0093] The sheath (outer covering) 50 is a tubular member that covers the outer circumference of the holding coil 40. The optical fiber units 10A to 10D wrapped by the holding coil 40 are accommodated in the internal space of this sheath 50. When the optical fiber cable 1 does not include the holding coil 40, this sheath 50 covers the outer circumference of the optical fiber units 10A to 10D. Examples of the material constituting this sheath 50 include resin materials such as polyvinyl chloride (PVC), polyethylene (PE), nylon, ethylene fluoride, polypropylene (PP), and polyolefin-based resins, as well as those obtained by mixing a plurality of these resin materials. Additives such as flame retardants and stabilizers may be added to the above resin materials.

[0094] A pair of tensile strength members 60 and a pair of lip cords 70 are embedded in this sheath 50. The tensile strength member 60 is a linear member for suppressing the distortion and bending applied to the multi-core optical fiber 30 due to the shrinkage of the sheath 50. As each tensile strength member 60, for example, a linear body having a circular cross-sectional shape can be used. Each tensile strength member 60 extends along the axial direction of the optical fiber cable 1. The pair of tensile strength members 60 extend substantially parallel to each other with the plurality of optical fiber units 10A to 10D interposed therebetween.

[0095] Examples of the material constituting the tension member 60 include non-metallic materials and metallic materials. Specific examples of non-metallic materials are not particularly limited, and for example, fiber-reinforced plastics (FRP) such as glass fiber-reinforced plastic (GFRP), aramid fiber-reinforced plastic (KFRP) reinforced by Kevlar (registered trademark), and polyethylene fiber-reinforced plastic reinforced by polyethylene fiber can be exemplified. On the other hand, specific examples of metallic materials are not particularly limited, and for example, a metal wire such as a copper wire can be exemplified.

[0096] Note that the tension member 60 does not have to be embedded in the sheath 50. For example, similar to the above-described optical fiber unit 10, the tension member 60 may be accommodated in the internal space of the sheath 50. Alternatively, the optical fiber cable 1 may not include the tension member 60. The number of the tension members 60 is not particularly limited as described above and can be appropriately designed. Also, the arrangement of the tension members 60 is not particularly limited as described above and can be appropriately designed.

[0097] The lip cord 70 is a string-like member (tearing string) for tearing the sheath 50 at an intermediate portion of the optical fiber cable 1 to take out the multi-core optical fiber 30 to the outside. Each lip cord 70 extends along the axial direction of the optical fiber cable 1, and a pair of lip cords 70 are arranged so as to extend substantially parallel to each other with a plurality of optical fiber units 10A to 10D interposed therebetween. In the present embodiment, the direction in which the pair of lip cords 70 face each other is substantially orthogonal to the direction in which the pair of tension members 60 face each other.

[0098] This lip cord 70 is composed of, but not particularly limited to, fibers made of polyester, polyimide, aramid, glass, etc., and aggregates such as twisted yarns formed by twisting a plurality of such fibers. Note that, as the lip cord 70, a material obtained by impregnating the aforementioned twisted yarn with resin may be used. Further, this lip cord 70 only needs to be disposed within the sheath 50, and the entire lip cord 70 may be embedded in the sheath 50, or the lip cord 70 may be partially embedded in the sheath 50 such that a part of the lip cord 70 is exposed from the sheath 50. Further, this lip cord 70 only needs to be disposed in the sheath 50 as necessary, and the optical fiber cable 1 does not necessarily have to include the lip cord 70.

[0099] As shown in FIG. 4, a plurality of display portions 51 are formed on the outer peripheral surface of this sheath 50 by printing or the like. Each display portion 51 includes a character string 52 and a length mark 53. The plurality of display portions 51 are arranged at intervals along the axial direction of the optical fiber cable 1. Although not particularly limited, for example, the display portions 51 are formed at intervals of 1 meter along the axial direction of the optical fiber cable 1.

[0100] The character string 52 is composed of one or a plurality of characters such as English, Japanese, numbers, and symbols. Specific examples of this character string 52 can include, for example, the name of the manufacturing company, the identification number of the manufacturing company, the type of cable, the lot number, and the manufacturing year. The character string 52 is arranged such that an operator can read the character string 52 only from a specific direction. Although not particularly limited, for example, in the example shown in FIG. 4, the character string 52 is arranged in a direction such that an operator located on the lower side in the figure with respect to the optical fiber cable 1 can read the character string 52. Although not particularly limited, the content of this character string 52 is the same for all display portions 51 in the optical fiber cable 1.

[0101] On the one hand, the length mark 53 is a scale value indicating the distance from the first end 101 of the optical fiber cable 1. This length mark 53 increases by one numerical value every one meter away from the first end 101. Therefore, the content of this length mark 53 is different for all display portions 51 in the optical fiber cable 1. Note that this length mark 53 is also arranged in a direction in which an operator can read the length mark 53 only from a specific direction, similar to the above-described character string 52. Although not particularly limited, this length mark 53 is arranged in the same direction as the character string 52.

[0102] In this embodiment, the array information associated with the core array of the multi-core optical fiber 30 is constituted by this length mark 53 (first information) and the colors of the bundling materials 25 and 26 described above (second information). That is, first, the direction (reference direction) of the optical fiber cable 1 for distinguishing the core array is specified by the length mark 53. Then, according to the core array of the multi-core optical fiber 30 with this reference direction as a reference, the colors of the bundling materials 25 and 26 of each optical fiber unit 10A to 10B are set. Note that the above "array information" does not include the order of the cores 32A to 32D identified with reference to the marker 33 (that is, the core array) itself. This array information is information other than the core array and means information associated with the core array.

[0103] Note that the optical fiber cables of the second to fourth embodiments also include array information associated with the core array of the multi-core optical fiber. And in the optical fiber cables of the second to fourth embodiments, this array information may include first information for specifying the direction of the optical fiber cable and second information indicating the core array with the direction specified by the first information as a reference.

[0104] More specifically, in the present embodiment, as shown in Table 2 below, the direction in which the numerical value of the length mark 53 formed on the outer peripheral surface of the sheath 50 increases is specified as the reference direction. Here, based on this reference direction, the core arrays of the multi-core optical fibers 30 included in the optical fiber units 10A and 10C are in a "positive array" (see Fig. 1(a)), and the core arrays of the multi-core optical fibers 30 included in the optical fiber units 10B and 10D are in a "reverse array" (see Fig. 1(b)). For the optical fiber units 10A and 10C having the "positive array" core array, the colors of the bundling materials 25 and 26 are set to "blue" and "green". On the contrary, for the optical fiber units 10B and 10D having the "reverse array" core array, the colors of the bundling materials 25 and 26 are set to "orange" and "brown".

[0105] That is, in the present embodiment, the array information associated with the multi-core optical fiber 30 having the same core array has the same content. In the second to fourth embodiments, the optical fiber cable may include a plurality of array information respectively associated with a plurality of multi-core optical fibers, and the array information associated with the multi-core optical fibers having the same core array may have the same content.

[0106]

Table 2

[0107] In the present embodiment, the length mark 53 (first information) for specifying the reference direction of the optical fiber cable 1 is provided on the outer peripheral surface of the sheath 50 of the optical fiber cable 1, and is shared by a plurality of array information respectively associated with the core arrays of all the multi-core optical fibers 30 included in the optical fiber cable 1. In the optical fiber cables of the second to fourth embodiments, the first information may be shared by a plurality of array information respectively associated with the core arrays of all the multi-core optical fibers included in the optical fiber cable.

[0108] On the other hand, the colors of the bundle materials 25 and 26 indicating the core arrays based on this reference orientation are shared by a plurality of array information respectively associated with the core arrays of all the multi-core optical fibers 30 included in the respective optical fiber units 10A to 10D. That is, the colors (second information) of the bundle materials 25 and 26 are shared by a plurality of array information associated with the multi-core optical fibers 30 having the same core array. In the optical fiber cables of the second to fourth embodiments, the second array information may be shared by a plurality of array information associated with the multi-core optical fibers having the same core array.

[0109] Note that, as shown in Table 3 below, the colors of one bundle material 25 and the other bundle material 26 in the same optical fiber unit may be made different. Thereby, the optical fiber unit can be identified by the color of one bundle material 25, and the core array of the optical fiber unit can be distinguished by the color of the other bundle material 26.

[0110] Specifically, in Table 3 below, the optical fiber units (unit numbers: No. 1 to No. 4) can be individually identified by the color of one bundle material 25 (“blue”, “yellow”, “green”, and “red”). Also, the fact that the color of the other bundle material 26 is “white” indicates that the core array of the optical fiber unit is the “normal array”. On the other hand, the fact that the color of the bundle material 26 is “orange” indicates that the core array of the optical fiber unit is the “reverse array”. In this case as well, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0111]

Table 3

[0112] Also, as the second information of the array information of the multi-core optical fiber 30, components other than the colors of the bundling materials 25 and 26 in the optical fiber cable 1 may be used. In this case, it is preferable to use the existing components included in the optical fiber cable 1 as the second information. Also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0113] For example, as shown in Table 4 below, the color of the colored layer 37 of a specific multi-core optical fiber 30 included in the optical fiber ribbon core wire 20 may be used as the second information.

[0114] Table 4 below shows an example of four optical fiber ribbon core wires 20 each constituted by four multi-core optical fibers 30. In this example, the fact that the color of the colored layer 37 of the multi-core optical fiber 30 of the fourth (fiber number: No. 4) of the optical fiber ribbon core wire 20 is "Gray" indicates that the core arrays of all the multi-core optical fibers 30 (fiber numbers: No. 1 to No. 4) included in that optical fiber ribbon core wire 20 are in the "normal arrangement" (see Fig. 1(a)). On the other hand, the fact that the color of the colored layer 37 of the fourth multi-core optical fiber 30 is "Pink" indicates that the core arrays of all the multi-core optical fibers 30 (fiber numbers: No. 1 to No. 4) included in that optical fiber ribbon core wire 20 are in the "reverse arrangement" (see Fig. 1(b)). Also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0115]

Table 4

[0116] Alternatively, although not particularly shown in the table, the above-described mark 36 of the multi-core optical fiber 30 may be used as the second information. For example, for the optical fiber ribbon core wire 20 having the same core array, marks 36 having the same pattern may be provided. Also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0117] Although not particularly limited, for example, with respect to the optical fiber ribbon core wire 20 in which the core arrays of all the multi-core optical fibers 30 are in the "correct array" based on the direction specified by the length mark 53, a mark 36 composed of one narrow ring 361 (see "No. 1" in Table 1 described above) is set. On the other hand, for the optical fiber ribbon core wire 20 in which the core arrays of all the multi-core optical fibers 30 are in the "reverse array", a mark 36 composed of two narrow rings 361 (see "No. 2" in Table 1 described above) is set.

[0118] Alternatively, as shown in FIGS. 6(a) and 6(b), marks 27 may be printed on the bundling materials 25 and 26, and these marks 27 may be used as the second information. FIGS. 6(a) and 6(b) are plan views showing the marks 27 attached to the optical fiber unit provided in the optical fiber cable according to the second embodiment of the present invention, and FIG. 6(b) is a view showing the marks 27 inverted with respect to FIG. 6(a).

[0119] The marks 27 shown in FIGS. 6(a) and 6(b) are diagonal lines inclined with respect to the axial direction of the bundling materials 25 and 26. For example, as shown in FIG. 6(a), when the diagonal lines rise as they go rightward in the figure, this mark 27 indicates that the core arrays of all the multi-core optical fibers 30 included in the optical fiber unit are in a "normal arrangement" (see FIG. 1(a)). On the other hand, as shown in FIG. 6(b), when the diagonal lines descend as they go rightward in the figure, this mark 27 indicates that the core arrays of all the multi-core optical fibers 30 included in the optical fiber unit are in a "reverse arrangement" (see FIG. 1(b)). In this case as well, similar to the example in Table 2 described above, the length mark 53 is used as the first information of the array information.

[0120] In addition, as the second information of the array information of the multi-core optical fiber 30, other components included in the optical fiber unit may be used. For example, when the optical fiber cable is of the above-described loose tube type, instead of the bundling materials, the mark 27 may be formed on the outer peripheral surface of the tubular member 28 that covers a plurality of optical fiber ribbon cores. Alternatively, although not particularly shown, the color of the tubular member 28 may be used as the second information. In this case as well, similar to the example in Table 2 described above, the length mark 53 is used as the first information of the array information.

[0121] Incidentally, in the case of the bundling materials 25 and 26, the linear bodies shown in FIG. 6(a) or FIG. 6(b) are wound around the outer peripheries of a plurality of mutually bundled optical fiber ribbon cores 20 (see FIG. 5). On the other hand, in the case of the tubular member 28, a plurality of mutually bundled optical fiber ribbon cores 20 are inserted into the inside of the tubular body shown in FIG. 6(a) or FIG. 6(b).

[0122] Alternatively, as shown in FIG. 7, an optical connector 80 may be connected to the terminal of each multi-core optical fiber 30 of the optical fiber cable 1, and the connector number 81 attached to each optical connector 80 may be used as the second information. FIG. 7 is a plan view showing the optical fiber cable 1 with the optical connector 80 in the third embodiment of the present invention. Note that the number of multi-core optical fibers 30 included in the optical fiber cable 1 is not particularly limited to the example shown in FIG. 7.

[0123] In the example shown in FIG. 7, connector numbers 81 from "1" to "4" are attached to eight optical connectors 80 respectively. The optical connectors 80 having the same connector number 81 are connected to both ends of the same multi-core optical fiber 30. And in the example shown in this FIG. 7, the optical connectors 80 with connector numbers 81 being "1" and "3" indicate that the core arrangement of the multi-core optical fiber 30 is in a "normal arrangement" (see FIG. 1(a)). On the contrary, the optical connectors 80 with connector numbers 81 being "2" and "4" indicate that the core arrangement of the multi-core optical fiber 30 is in a "reverse arrangement" (see FIG. 1(b)). Note that also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0124] Note that in the example shown in FIG. 7 above, the numbers of all the optical connectors 80 are made different, but it is not particularly limited thereto. The same number may be attached to the optical connectors 80 connected to the multi-core optical fiber 30 having the same core arrangement.

[0125] Also, in the example shown in FIG. 7 above, the number 81 attached to the optical connector 80 is used as the second information, but it is not particularly limited thereto. For example, the color of the optical connector 80 may be used as the second information. Note that also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0126] Also, the orientations of the connector numbers 81 of the four optical connectors 80 on the first end 101 side of the optical fiber cable 1 and the orientations of the connector numbers 81 of the four optical connectors 80 on the opposite second end 102 side may be aligned in the same direction. In this case, since the direction (reference direction) of the optical fiber cable 1 for distinguishing the core array can be specified by the orientation of this connector number 81, the length mark 53 may not be used as the first information.

[0127] Moreover, the components connected to the terminals of the optical fiber cable 1 are not limited to the optical connectors 80 as long as they are optical connection components. For example, a FIFO (Fan - in / Fan - out) device may be connected to the terminals of each multi - core optical fiber 30 of the optical fiber cable 1. This FIFO device is a device that connects each core of the multi - core optical fiber to a single - core optical fiber. Specific examples of such FIFO devices include, for example, fiber bundle type, fusion stretching type, free - space optical type, and planar optical waveguide type, etc. A number may be assigned to this FIFO device and this number may be used as the second information. In this case as well, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0128] Note that in the above example, any one of the color of the bundling materials 25, 26 (or the color of the tube member 28), the color of the coloring layer 37, the pattern of the mark 36, the mark 27 of the bundling materials 25, 26 (or the mark 27 of the tube member 28), the connector number 81 of the optical connector 80 (or the number of the FIFO device), or the color of the optical connector 80 (or the color of the FIFO device) is used alone as the second information, but it is not particularly limited to this. A combination consisting of two or more of these elements may be used as the second information.

[0129] Further, the display unit 51 of the sheath 50 may include only one of the character string 52 or the length mark 53. Further, instead of the length mark 53, the orientation of the character string 52 may be used as the first information of the array information. Alternatively, the orientation of the length mark 53 may be used as the first information of the array information. In the second to fourth embodiments, the orientation of the character string or the length mark of the display unit may be used as the first information of the array information.

[0130] Further, the display unit 51 of the sheath 50 may include a pattern that is not point-symmetrical in the axial direction of the optical fiber cable 1 in a plan view (hereinafter also simply referred to as a "non-point-symmetrical pattern"), and this non-point-symmetrical pattern may be used as the first information of the array information. Specific examples of such non-point-symmetrical patterns include, for example, geometric shapes such as figures, the arrangement of shapes (relative positional relationship), and the arrangement of colors (relative positional relationship). In the second to fourth embodiments, a pattern (non-point-symmetrical pattern) of the display unit that is not point-symmetrical in the axial direction of the optical fiber cable may be used as the first information of the array information.

[0131] As an example of the shape constituting the non-point-symmetrical pattern, for example, an arrow extending along the axial direction of the optical fiber cable 1 can be exemplified. Further, as an example of the arrangement of the shapes constituting the non-point-symmetrical pattern, for example, a pair of straight lines extending parallel to each other along the axial direction of the optical fiber cable 1 and having different thicknesses can be exemplified. Further, as an example of the arrangement of the colors constituting the non-point-symmetrical pattern, for example, a pair of straight lines extending parallel to each other along the axial direction of the optical fiber cable 1 and having different colors can be exemplified.

[0132] Alternatively, although not particularly shown, as the above-described non-axisymmetric pattern, a dot array or a dot group formed by arranging a plurality of dots may be used. For example, as the display unit 51, a pair of dot arrays extending in parallel along the axial direction of the optical fiber cable 1 may be formed on the outer peripheral surface of the sheath 50, and this pair of dot arrays is composed of dots of different colors. Alternatively, as the display unit 51, a plurality of dot groups arranged along the axial direction of the optical fiber cable 1 with different intervals may be formed on the outer peripheral surface of the sheath 50. Alternatively, as the display unit 51, dot groups composed of different numbers of dots may be arranged along the axial direction of the optical fiber cable 1 on the outer peripheral surface of the sheath 50.

[0133] In addition, when the core arrays of all the multi-core optical fibers 30 included in the optical fiber cable 1 are the same, by using the above-described non-axisymmetric pattern as arrangement information, the reference direction of the optical fiber cable 1 can be specified, and the core array based on the specified direction can also be specified. Therefore, this non-axisymmetric pattern can function as both the first and second pieces of information of the arrangement information. That is, in this case, only the above-described non-axisymmetric pattern needs to be used as the arrangement information, and an element for indicating only the second arrangement information becomes unnecessary.

[0134] Alternatively, the display unit 51 may be formed on a component other than the sheath 50 in the optical fiber cable 1, and the display unit 51 may be used as the first piece of information. Here, the component other than the sheath 50 in the optical fiber cable 1 is a member that extends along the entire longitudinal direction in the optical fiber cable 1. Specific examples of such components include, for example, the holding tape 41, the optical fiber tape core wire 20, and the tension member 60. Although not particularly limited, for example, a display unit 51 including the character string 52 and the length mark 53 may be formed on the outer surface of the optical fiber tape core wire 20, and this length mark 53 may be used as the first piece of information for specifying the reference direction of the optical fiber cable 1. In addition, in the second to fourth embodiments, the display unit formed on a component other than the sheath of the optical fiber cable may be used as the first piece of information of the arrangement information.

[0135] The optical fiber cable 1 described above is laid by an operator, for example, underground, overhead, or indoors. Note that the optical fiber cables of the second to fourth embodiments can also be laid by the following similar method.

[0136] For example, when laying the optical fiber cable 1 in the underground pipeline to connect to an optical fiber cable already installed in the underground pipeline, the operator refers to the arrangement information of the multi-core optical fibers 30 provided in the optical fiber cable 1 (the above-mentioned length marks 53 and the colors of the bundling materials 25, 26) to distinguish the core arrangements of the respective multi-core optical fibers 30.

[0137] Specifically, first, the operator checks the direction in which the numerical value of the length mark 53 formed on the outer peripheral surface of the optical fiber cable 1 increases. Thereby, the direction of the optical fiber cable 1 (the above-mentioned reference direction) for distinguishing the core arrangement is specified. For example, in the example shown in FIG. 4, since the numerical value of the length mark 53 increases from the left side to the right side in the figure, the direction from the first end portion 101 to the second end portion 102 is specified as the above-mentioned reference direction.

[0138] Next, the operator checks the colors of the bundling materials 25, 26 of the optical fiber units 10A to 10D, respectively. Thereby, the core arrangements of the respective optical fiber units 10A to 10D according to the above-mentioned reference direction are specified. For example, in the example shown in Table 2 above, the core arrangement of the optical fiber unit 10A in which the colors of the bundling materials 25, 26 are "blue" is specified as "positive arrangement", and the core arrangement of the optical fiber unit 10C in which the colors of the bundling materials 25, 26 are "green" is also specified as "positive arrangement". In contrast, the core arrangement of the optical fiber unit 10B in which the colors of the bundling materials 25, 26 are "orange" is specified as "reverse arrangement", and the core arrangement of the optical fiber unit 10D in which the colors of the bundling materials 25, 26 are "brown" is also specified as "reverse arrangement".

[0139] Then, after the operator confirms that the core arrays of the respective optical fibers 10A to 10D are the same as the pre-set core array (that is, the orientation of the optical fiber cable 1 is appropriate), the optical fiber cable 1 is introduced into the underground pipeline. In this way, by checking the core arrays of the optical fibers 10A to 10D before introducing them into the underground pipeline, it is possible to prevent the situation where it is found that the core array of the optical fiber cable 1 is incorrect after laying, and the laying work has to be redone.

[0140] In addition, when the operator has the correspondence information as shown in Table 2 above at the laying site and distinguishes the core array of the multi-core optical fiber 30 based on the length mark 53 and the colors of the bundling materials 25 and 26, the operator may check while referring to the correspondence information.

[0141] This correspondence information is information that associates array information with a core array. For example, when the color of the colored layer 37 of the multi-core optical fiber 30 is used as the second information, the correspondence information is information that associates the color of the colored layer 37 with the core array, and has the content as shown in Table 4 above. Also, when the mark 36 of the multi-core optical fiber 30 is used as the second information, the correspondence information is information that associates the pattern of the mark 36 with the core array. Also, when the connector number 81 of the optical connector 80 is used as the second information, the correspondence information is information that associates the connector number 81 with the core array. Note that the correspondence information may include information related to the first information. Such correspondence information may be printed on a paper medium, or may be displayed on a portable terminal such as a tablet.

[0142] In addition, the above optical fiber cable 1 is connected to a counterpart optical fiber cable, for example, in a closure or an optical termination box installed at the laying site. Specifically, the multi-core optical fiber 30 included in this optical fiber cable 1 is fusion-connected to the optical fiber included in the counterpart optical fiber cable, or optically connected via a mechanical splice element or an optical connector. At this time, in the present embodiment, an operator refers to the arrangement information of the multi-core optical fiber 30 (the above-mentioned length marks 53 and the colors of the bundling materials 25 and 26), and for example, after confirming that the core arrangement of the multi-core optical fiber 30 of the optical fiber cable 1 is the same as the pre-set core arrangement, the multi-core optical fiber 30 is connected to the optical fiber of the counterpart.

[0143] Note that, as a specific example of the above optical connector, although not particularly limited, an optical connector including a ferrule and a sleeve, an optical connector including a free-space optical system including a lens, or an optical connector including an optical waveguide can be exemplified.

[0144] Alternatively, the above optical fiber cable 1 may be connected to a counterpart optical component such as a planar lightwave circuit (PLC) or a silicon waveguide chip. Specifically, the multi-core optical fiber 30 included in this optical fiber cable 1 is optically connected to the optical waveguide included in the counterpart optical component via an optical fiber array. At this time, in the present embodiment, an operator refers to the arrangement information of the multi-core optical fiber 30 (the above-mentioned length marks 53 and the colors of the bundling materials 25 and 26), and for example, after confirming that the core arrangement of the multi-core optical fiber 30 of the optical fiber cable 1 is the same as the pre-set core arrangement, the multi-core optical fiber 30 is connected to the optical waveguide of the counterpart.

[0145] As an example of the optical fiber array, there can be mentioned one in which optical fibers are positioned in a plurality of grooves formed in the substrate so as to extend to the end of the substrate, and the end faces of the optical fibers are arranged at the end of the substrate. Examples of the cross-sectional shape of the above grooves include a V shape or a U shape. Further, as means for positioning the optical fibers, the above substrate may be provided with means other than the grooves.

[0146] As described above, in the present embodiment, the optical fiber cable 1 has arrangement information associated with the core arrangement of the multi-core optical fiber 30. At the laying site, by referring to this arrangement information, the operator can easily distinguish the core arrangement of the multi-core optical fiber 30, so that the workability of the laying work and connection work of the optical fiber cable 1 can be improved.

[0147] Further, in the present embodiment, as the arrangement information associated with the core arrangement of the multi-core optical fiber 30, the length marks 53 existing in the existing optical fiber unit and the colors of the bundle materials 25 and 26 are used. Thus, since the existing components of the optical fiber cable 1 are used as the arrangement information, an increase in the cost of the optical fiber cable 1 due to the provision of the arrangement information can be suppressed.

[0148] Further, in the present embodiment, since the core arrangements of all the multi-core optical fibers 30 included in each of the optical fiber units 10A to 10D are the same, the management of the core arrangement in the optical fiber cable 1 is facilitated.

[0149] In addition, in the present embodiment, the same optical fiber cable 1 includes both a multi-core optical fiber 30 having a "positive arrangement" core array and a multi-core optical fiber 30 having a "reverse arrangement" core array. Therefore, for example, compared with the case of installing an optical fiber cable including only a multi-core optical fiber having a "positive arrangement" core array and an optical fiber cable including only a multi-core optical fiber having a "reverse arrangement" core array in a conduit, the occupied area of the optical fiber cable 1 can be reduced.

[0150] And the optical transmission system including the above optical fiber cable 1 connects between an upstream side (for example, a communication facility center of a communication carrier, etc.) and a downstream side (for example, a user base, etc.). Note that the optical transmission system may include the optical fiber cables of the second to fourth embodiments. This optical transmission system includes a first transmission path for upstream (upload) and a second optical transmission path for downstream (download). In addition to the above optical fiber cable 1, these first and second transmission paths also include other optical fiber cables connected to the optical fiber cable 1 and optical components such as optical connectors connected to the optical fiber cable 1. In the present embodiment, "upstream (upload)" means communication from the downstream side to the upstream side, and "downstream (download)" means communication from the upstream side to the downstream side.

[0151] In the present embodiment, optical fiber units 10A and 10C having a "positive arrangement" core array are included in the first optical transmission path for upstream. The core arrays of all the multi-core optical fibers 30 included in this first optical transmission path are in a "positive arrangement". On the other hand, optical fiber units 10B and 10D having a "reverse arrangement" core array are included in the second optical transmission path for downstream. The core arrays of all the multi-core optical fibers 30 included in this second optical transmission path are in a "reverse arrangement".

[0152] Thus, in this embodiment, the first optical transmission path for upstream includes optical fiber units 10A and 10C having a positive arrangement, and the second optical transmission path for downstream includes optical fiber units 10B and 10D having a second arrangement. In this way, by properly using the multi-core optical fiber 30 for upstream / downstream according to the core arrangement, it is possible to improve the workability of the laying work and connection work of the optical fiber cable 1.

[0153] Note that the embodiments described above are described for facilitating the understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[0154] The number of optical fiber units included in the optical fiber cable 1 is not particularly limited to the above. For example, the optical fiber cable 1 may include 1 to 3 optical fiber units. Alternatively, the optical fiber cable 1 may include 5 or more optical fiber units.

[0155] Also, in the above-described embodiment, the multi-core optical fiber 30 included in the optical fiber units 10A and 10C has a core arrangement of "positive arrangement", while the multi-core optical fiber 30 included in the optical fiber units 10B and 10D has a core arrangement of "reverse arrangement". That is, in the above-described optical fiber cable 1, the "positive arrangement" multi-core optical fiber 30 and the "reverse arrangement" multi-core optical fiber 30 are mixed, but it is not particularly limited. The core arrangement of all the multi-core optical fibers 30 included in the optical fiber cable 1 may be "positive arrangement", or the core arrangement of all the multi-core optical fibers may be "reverse arrangement". That is, all the multi-core optical fibers 30 included in the optical fiber cable 1 may have the same core arrangement.

[0156] In the optical fiber cable 1 of the above-described embodiment, the number of multi-core optical fibers 30 having a "positive arrangement" core arrangement is the same as the number of multi-core optical fibers 30 having a "reverse arrangement" core arrangement. However, it is not particularly limited thereto. The number of multi-core optical fibers having a "positive arrangement" core arrangement included in the optical fiber cable and the number of multi-core optical fibers having a "reverse arrangement" core arrangement included in the optical fiber cable may be different.

[0157] In the above-described embodiment, the core arrangements of all the multi-core optical fibers 30 included in the same optical fiber unit are the same. However, it is not particularly limited thereto. For example, an optical fiber unit may be configured using a sub-unit 15 as shown in FIG. 8. FIG. 8 is a perspective view showing the sub-unit 15 included in the optical fiber cable according to the fourth embodiment of the present invention.

[0158] The sub-unit 15 shown in FIG. 8 includes two optical fiber ribbon core wires 20A and 20B. Although not particularly limited, in this fourth embodiment, the optical fiber unit is configured by bundling a plurality of sub-units 15 bundled together with bundling materials 25 and 26. Both the optical fiber ribbon core wires 20A and 20B have the same configuration as the above-described optical fiber ribbon core wire 20. These two optical fiber ribbon core wires 20A and 20B are connected at the second connection portion 22.

[0159] In the example shown in FIG. 8, the core arrangement of all the multi-core optical fibers 30 included in one optical fiber ribbon core wire 20A is "positive arrangement" (see FIG. 1(a)), while the core arrangement of all the multi-core optical fibers 30 included in the other optical fiber ribbon core wire 20B is "reverse arrangement" (see FIG. 1(b)), and the core arrangement of one optical fiber ribbon core wire 20A is opposite to the core arrangement of the other optical fiber ribbon core wire 20B.

[0160] In the example shown in FIG. 8, the pattern of the mark 36 of the multi-core optical fiber 30 is used as the second information. Specifically, the mark 235 composed of two rings 361 indicates that the core array of one optical fiber ribbon core wire 20A is in the "normal arrangement". On the other hand, the mark 235 composed of three rings 361 indicates that the core array of the other optical fiber ribbon core wire 20A is in the "reverse arrangement".

[0161] Such a subunit 15 may be used to form an optical fiber unit. In this case, in one optical fiber unit, the multi-core optical fiber 30 with the "normal arrangement" and the multi-core optical fiber 30 with the "reverse arrangement" are mixed. By using such a subunit 15 to form an optical fiber unit, the management of the core array in the optical fiber cable becomes easy.

[0162] In addition, in this fourth embodiment, instead of the pattern of the mark 36, the color of the coloring layer 37, the connector number 81 of the optical connector 80 (or the number of the FIFO device), or the color of the optical connector 80 (or the color of the FIFO device) may be used as the second information. Alternatively, a combination consisting of two or more elements among the pattern of the mark 36, the color of the coloring layer 37, the connector number 81 of the optical connector 80 (or the number of the FIFO device), or the color of the optical connector 80 (or the color of the FIFO device) may be used as the second information.

[0163] Also, in the above-described embodiment, all the multi-core optical fibers 30 constituting the same optical fiber ribbon core wire 20 have the same core array, but it is not particularly limited thereto. Although not particularly shown, in the fifth embodiment of the present invention, the same (one) optical fiber ribbon core wire 20 includes a multi-core optical fiber 30 having a "normal arrangement" core array and a multi-core optical fiber 30 having a "reverse arrangement" core array.

[0164] In addition to the multi-core optical fiber 30, a single-core optical fiber having a single core may be included in the optical fibers constituting the optical fiber ribbon core wire 20. That is, as the plurality of optical fibers included in the optical fiber ribbon core wire, the multi-core optical fiber 30 and the single-core optical fiber may be mixed.

[0165] In this fifth embodiment, a display portion 51 including a character string 52 and a length mark 53 is formed on the outer surface of the optical fiber ribbon core wire 20 (see FIG. 4), and this length mark 53 is used as the first information of the array information. Further, in this fifth embodiment, the color of the colored layer 37 of each multi-core optical fiber 30 included in the optical fiber ribbon core wire 20 is used as the second information of the array information. In this fifth embodiment, the length mark 53 (first information) for specifying the reference direction of the optical fiber ribbon core wire 20 is provided on the outer surface of the optical fiber ribbon core wire 20 and is shared by a plurality of array information respectively associated with the core arrays of all the multi-core optical fibers 30 included in the optical fiber ribbon core wire 20.

[0166] Although not particularly limited, for example, when the same optical fiber ribbon core wire 20 includes six multi-core optical fibers 30 with a core array of "positive array" and the remaining six multi-core optical fibers 30 with a core array of "reverse array", the color of the colored layer 37 of the six multi-core optical fibers 30 with a core array of "positive array" is set to "Gray". On the other hand, the color of the colored layer 37 of the remaining six multi-core optical fibers 30 with a core array of "reverse array" is set to "Pink". In this case, by specifying the direction in which the numerical value of the length mark 53 increases as the reference direction and then checking the color of the colored layer 37 of each multi-core optical fiber 30, the core array of the individual multi-core optical fiber 30 can be specified.

[0167] Note that, as the second information of the array information of the multi-core optical fiber 30, components other than the color of the colored layer 37 in the optical fiber ribbon core wire 20 may be used. In this case, it is preferable to use the existing components included in the optical fiber ribbon core wire 20 as the second information. For example, the mark 36 of each multi-core optical fiber 30 included in the optical fiber ribbon core wire 20 may be used as the second information. In this case, for a plurality of multi-core optical fibers 30 included in one optical fiber ribbon core wire 20, marks 36 corresponding to the core arrays of the individual multi-core optical fibers 30 are individually attached. Note that also in this case, similar to the example of Table 2 described above, the length mark 53 is used as the first information of the array information.

[0168] By configuring an optical fiber cable using such an optical fiber ribbon core wire 20, the core arrays of the multi-core optical fibers 30 can be easily distinguished, so that the ease of managing the core arrays can be improved, and the workability of the laying work and connection work of the optical fiber cable can be improved.

[0169] Note that in this fifth embodiment, instead of the length mark 53, the orientation of the character string 52 may be used as the first information of the array information. Alternatively, the orientation of the length mark 53 may be used as the first information of the array information. Further, the display portion 51 of the sheath 50 may include a pattern (non-point-symmetrical pattern) that is not point-symmetrical in the axial direction of the optical fiber ribbon core wire 20 in a plan view, and this non-point-symmetrical pattern may be used as the first information of the array information.

[0170] Also, the core arrays of all the multi-core optical fibers 30 included in the same (one) optical fiber ribbon core wire 20 may be the same. In this case, by using the above-described non-point-symmetrical pattern as the array information, this non-point-symmetrical pattern can function as both the first and second information of the array information. That is, in this case, only the non-point-symmetrical pattern needs to be used as the array information, and an element for indicating only the second array information becomes unnecessary.

[0171] Also, in the optical transmission system of the above-described embodiment, the core arrays of all the multi-core optical fibers 30 included in the first optical transmission path are in the "normal arrangement", and the core arrays of all the multi-core optical fibers 30 included in the second optical transmission path are in the "reverse arrangement", but it is not particularly limited thereto. The core arrays of all the multi-core optical fibers 30 included in both the first and second optical transmission paths may be in the "normal arrangement", or the core arrays of all the multi-core optical fibers 30 included in both the first and second optical transmission paths may be in the "reverse arrangement".

Explanation of Signs

[0172] 1…Optical fiber cable 101, 102…Ends 10A~10D…Optical fiber units 15…Sub-unit 20, 20B…Optical fiber ribbon core wire 21…First connection part 22…Second connection part 25, 26…Bundle materials 251, 261…Inversion points 27…Mark 30…Multi-core optical fiber 31…Optical fiber bare wire 32A~32D…Cores 33…Marker 34…Cladding 35…Coating layer 351…Primary layer 352…Secondary layer 36…Mark 361…Ring 37…Coloring layer 40…Press winding 41…Press winding tape 50…Sheath 51…Display part 52…Character string 53…Length mark 60…Tensile strength body 70…Lip code 80…Optical connector

Claims

1. An optical fiber cable comprising a multi-core optical fiber including a plurality of cores, wherein the optical fiber cable includes array information associated with the multi-core optical fiber, the array information is associated with a core array which is an array of the plurality of cores in a cross-section of the multi-core optical fiber, the array information includes first information for specifying an orientation of the optical fiber cable, and second information indicating the core array with respect to the orientation specified by the first information. An optical fiber cable.

2. The optical fiber cable according to claim 1, wherein the first information is shared by a plurality of the array information, and the second information is shared by the array information associated with the multi-core optical fibers having the same core array. An optical fiber cable.

3. The optical fiber cable according to claim 1, wherein the first information includes content of a display portion provided on an outer peripheral surface of the optical fiber cable or a component of the optical fiber cable, or an orientation of the display portion, and the second information includes a color of a linear body or a cylindrical body aggregating a plurality of the multi-core optical fibers, a mark provided on the linear body or the cylindrical body, a color of a colored layer included in the multi-core optical fiber, or a mark included in the multi-core optical fiber. An optical fiber cable.

4. The optical fiber cable according to claim 1, wherein the optical fiber cable includes a plurality of the multi-core optical fibers, the plurality of multi-core optical fibers include a first multi-core optical fiber having a core array which is a first array, and a second multi-core optical fiber having a core array which is a second array opposite to the first array. An optical fiber cable.

5. An optical fiber cable comprising a multi-core optical fiber including a plurality of cores, wherein the optical fiber cable includes array information associated with the multi-core optical fiber, the array information is associated with a core array which is an array of the plurality of cores in a cross-section of the multi-core optical fiber, the optical fiber cable includes a plurality of the multi-core optical fibers, the plurality of multi-core optical fibers include a first multi-core optical fiber having a core array which is a first array, An optical fiber cable including a second multi-core optical fiber in which the core array is a second array opposite to the first array. **Claim 6** The optical fiber cable according to claim 4 or 5, wherein the number of the first multi-core optical fibers included in the optical fiber cable is the same as the number of the second multi-core optical fibers included in the optical fiber cable. **Claim 7** The optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber cable includes a plurality of the multi-core optical fibers, wherein the optical fiber cable includes a plurality of pieces of the array information respectively associated with the plurality of multi-core optical fibers, and the array information associated with the multi-core optical fibers having the same core array has the same content. **Claim 8** The optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber cable includes an optical connection component connected to an end of the multi-core optical fiber, and at least a part of the array information is provided on the optical connection component. **Claim 9** The optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber cable includes an optical fiber ribbon core wire including the multi-core optical fiber, and at least a part of the array information is provided on the optical fiber ribbon core wire. **Claim 10** The optical fiber cable according to any one of claims 1 to 5, wherein the optical fiber cable includes an aggregate including a plurality of mutually aggregated optical fibers, the optical fibers include the multi-core optical fibers, and the core arrays of all the multi-core optical fibers included in the aggregate are the same. **Claim 11** The optical fiber cable according to claim 10, wherein the optical fiber cable includes a plurality of the aggregates, the plurality of aggregates include a first aggregate and a second aggregate, the core arrays of all the multi-core optical fibers included in the first aggregate are a first array, and the core arrays of all the multi-core optical fibers included in the second aggregate are a second array opposite to the first array. **Claim 12** An optical fiber ribbon core wire comprising a multi-core optical fiber including a plurality of cores, wherein the optical fiber ribbon core wire includes array information associated with the multi-core optical fiber, the array information is associated with a core array that is an array of the plurality of cores in a cross-section of the multi-core optical fiber, the array information, includes first information for specifying an orientation of the optical fiber ribbon core wire, and second information indicating the core array based on the orientation specified by the first information. An optical fiber ribbon core wire.

13. The optical fiber ribbon core wire according to claim 12, wherein the optical fiber ribbon core wire includes a plurality of the multi-core optical fibers, the plurality of multi-core optical fibers, include a first multi-core optical fiber having the core array as a first array, and a second multi-core optical fiber having the core array as a second array that is opposite to the first array. An optical fiber ribbon core wire.

14. An optical fiber ribbon core wire comprising a multi-core optical fiber including a plurality of cores, wherein the optical fiber ribbon core wire includes array information associated with the multi-core optical fiber, the array information is associated with a core array that is an array of the plurality of cores in a cross-section of the multi-core optical fiber, the optical fiber ribbon core wire includes a plurality of the multi-core optical fibers, the plurality of multi-core optical fibers, include a first multi-core optical fiber having the core array as a first array, and a second multi-core optical fiber having the core array as a second array that is opposite to the first array. An optical fiber ribbon core wire.

15. A method for laying an optical fiber cable, the optical fiber cable comprising a multi-core optical fiber including a plurality of cores, wherein the optical fiber cable includes array information associated with the multi-core optical fiber, the array information is associated with a core array that is an array of the plurality of cores in a cross-section of the multi-core optical fiber, the laying method includes a reference step of referring to the array information, the optical fiber cable includes a plurality of the multi-core optical fibers, the plurality of multi-core optical fibers, include a first multi-core optical fiber having the core array as a first array, and a second multi-core optical fiber having the core array as a second array that is opposite to the first array. A method for laying an optical fiber cable.

16. A method for laying an optical fiber cable according to claim 15, wherein the arrangement information includes first information for specifying the direction of the optical fiber cable, and second information indicating the core arrangement based on the first information, and the reference step includes distinguishing the core arrangement of the multi-core optical fiber based on the arrangement information. A method for laying an optical fiber cable.

17. A method for laying an optical fiber cable including a multi-core optical fiber having a plurality of cores, wherein the optical fiber cable has arrangement information associated with the multi-core optical fiber, the arrangement information is associated with a core arrangement that is an arrangement of the plurality of cores in a cross-section of the multi-core optical fiber, the laying method includes a reference step of referring to the arrangement information, the arrangement information includes first information for specifying the direction of the optical fiber cable, and second information indicating the core arrangement based on the first information, and the reference step includes distinguishing the core arrangement of the multi-core optical fiber based on the arrangement information. A method for laying an optical fiber cable.

18. A method for laying an optical fiber cable including a multi-core optical fiber having a plurality of cores, wherein the optical fiber cable has arrangement information associated with the multi-core optical fiber, the arrangement information is associated with a core arrangement that is an arrangement of the plurality of cores in a cross-section of the multi-core optical fiber, the laying method includes a reference step of referring to the arrangement information, the reference step includes distinguishing the core arrangement of the multi-core optical fiber based on the arrangement information using association information associating the core arrangement with the arrangement information. A method for laying an optical fiber cable.

19. An optical transmission system including an optical fiber cable having a plurality of multi-core optical fibers each including a plurality of cores, wherein the plurality of multi-core optical fibers include a first multi-core optical fiber in which the core arrangement that is the arrangement of the plurality of cores in the cross-section of the multi-core optical fiber is a first arrangement, and a second multi-core optical fiber in which the core arrangement is a second arrangement that is opposite to the first arrangement, and the optical transmission system includes a first optical transmission path for upstream including the first multi-core optical fiber, A second optical transmission path for downstream including the second multi-core optical fiber, and the optical fiber cable includes array information associated with the multi-core optical fiber, the array information is an optical transmission system associated with the core array.

20. The optical transmission system according to claim 19, wherein the array information is first information for specifying the direction of the optical fiber cable, and second information indicating the core array based on the direction specified by the first information. An optical transmission system including

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