Multi-core optical fiber aligning device, multi-core optical fiber ribbon manufacturing device, multi-core optical fiber unit manufacturing device, multi-core optical fiber aligning method, multi-core optical fiber ribbon manufacturing method, multi-core optical fiber unit manufacturing method, multi-core optical fiber ribbon inspection device, and multi-core optical fiber ribbon inspection method

Abstract

An alignment device (4) for a multicore optical fiber (1) comprises: a fiber rotation unit (41) that changes the rotation angle about the axis of the multicore optical fiber (1); a fiber bending unit (42) that bends, in a predetermined direction, the multicore optical fiber (1) the rotation angle of which has been changed; a skew measurement unit (40) that causes light to be incident on a pair of cores (11), (13) of the multicore optical fiber (1), receives light emitted from each of the pair of cores (11), (13), and measures the skew value (S) of each light; and a control unit (49) that controls the fiber rotation unit (41) to adjust the rotation angle of the multicore optical fiber (1) such that the skew value (S) becomes a predetermined value.

Description

[Technical Field]

[0001] The present invention relates to an aligning device for a multi-core optical fiber, an apparatus for manufacturing a multi-core optical fiber ribbon, an apparatus for manufacturing a multi-core optical fiber unit, an aligning method for a multi-core optical fiber, a manufacturing method for a multi-core optical fiber ribbon, a manufacturing method for a multi-core optical fiber unit, an inspection device for a multi-core optical fiber ribbon, and an inspection method for a multi-core optical fiber ribbon. [Background technology]

[0002] It is known that a multi-core optical fiber in which the outer peripheries of multiple cores are surrounded by a single cladding is used to transmit multiple signals by light propagating through each core. When connecting multi-core optical fibers, it is necessary to align the axes of the multi-core optical fibers to be connected in the rotational direction so that the cores of each multi-core optical fiber face each other.

[0003] In Patent Document 1, while light is propagated to a predetermined core, the multi-core optical fiber is bent, and the amount of light leaking from the core is detected, and the multi-core optical fiber is rotated around its axis so that the amount of light becomes approximately constant, thereby aligning the rotational direction of the multi-core optical fiber.

[0004] [Patent Document 1] Patent No. 6046311 [Patent Document 2] Patent No. 6226905 Summary of the Invention

[0005] However, in the alignment method described in Patent Document 1, even if the multi-core optical fiber is rotated around its axis, the change in the amount of leaked light is small, which makes it difficult to detect misalignment in the rotation direction around the axis of the multi-core optical fiber, and therefore difficult to align with high accuracy.

[0006] Therefore, an object of the present invention is to provide a multi-core optical fiber aligning device that can align a multi-core optical fiber in the rotational direction with high accuracy, a multi-core optical fiber ribbon manufacturing device, a multi-core optical fiber unit manufacturing device, a multi-core optical fiber aligning method, a multi-core optical fiber ribbon manufacturing method, a multi-core optical fiber unit manufacturing method, and a multi-core optical fiber ribbon inspection device and multi-core optical fiber ribbon inspection method that can detect misalignment in the rotational direction of a multi-core optical fiber with high accuracy.

[0007] A first aspect of the present invention is an aligning device for a multi-core optical fiber, comprising: a fiber rotating unit that changes a rotation angle about an axis of a multi-core optical fiber; a fiber bending unit that bends the multi-core optical fiber whose rotation angle has been changed in a predetermined direction; a skew measuring unit that measures a skew value of light propagating through a pair of cores of the multi-core optical fiber; and a control unit that controls the fiber rotating unit to adjust the rotation angle of the multi-core optical fiber so that the skew value becomes a predetermined value.

[0008] When a multi-core optical fiber is rotated around its axis while being bent in a predetermined direction, the alignment direction of a pair of cores with respect to the bending direction changes, and the skew value of light propagating through the pair of cores changes. Therefore, by adjusting the rotation angle so that the skew value becomes a predetermined value, the alignment direction of the pair of cores with respect to the bending direction can be set to a predetermined direction. Since the change in the skew value with respect to the rotation angle can be measured more precisely than the change in the leakage light, alignment in the rotation direction can be performed with higher accuracy than the alignment of a multi-core optical fiber described in Patent Document 1.

[0009] A second aspect of the present invention is the multi-core optical fiber aligning device according to the first aspect, wherein the control unit adjusts the rotation angle so that the skew value becomes a maximum value or a minimum value.

[0010] In this case, since the absolute value of the skew value is large, the resolution can be increased and alignment can be performed with higher accuracy than when adjusting to a skew value that is neither maximum nor minimum. Note that when the alignment direction of the pair of cores is along the bending direction, the skew value will be maximum or minimum.

[0011] In the first or second aspect, the pair of cores is preferably a core pair that is farthest from each other among the plurality of cores in the multi-core optical fiber.

[0012] A third aspect of the present invention is a manufacturing device for a multi-core optical fiber ribbon, comprising: a sending unit that sends out one or more multi-core optical fibers; a multi-core optical fiber aligning device according to the first or second aspect that aligns the orientation in the rotation direction of at least one of the multi-core optical fibers sent out from the sending unit; and a ribbonizing unit that ribbonizes a plurality of optical fibers including the multi-core optical fiber aligned by the aligning device.

[0013] According to this multi-core optical fiber ribbon manufacturing apparatus, it is possible to manufacture a multi-core optical fiber ribbon in which the rotation direction of the multi-core optical fibers is aligned with high precision.

[0014] A fourth aspect of the present invention is a manufacturing apparatus for a multi-core optical fiber unit, comprising: the aligning device of the first or second aspect; and a connecting part that connects the multi-core optical fiber aligned by the aligning device to another optical component.

[0015] According to this manufacturing apparatus for a multi-core optical fiber unit, the rotational direction of the multi-core optical fiber is aligned with high accuracy, so that the multi-core optical fiber can be connected to another optical component with the rotational direction properly aligned. Therefore, it is possible to manufacture a multi-core optical fiber unit in which the multi-core optical fiber with the rotational direction properly aligned is connected to another optical component.

[0016] A fifth aspect of the present invention is a method for aligning a multi-core optical fiber, comprising: a fiber rotation step of changing a rotation angle about an axial center of the multi-core optical fiber; a fiber bending step of bending the multi-core optical fiber with the changed rotation angle in a predetermined direction; a skew measurement step of measuring a skew value of light propagating through a pair of cores of the multi-core optical fiber; and in the fiber rotation step, adjusting the rotation angle of the multi-core optical fiber so that the skew value becomes a predetermined value.

[0017] According to this aspect, similarly to the first aspect, the rotational direction of the multi-core optical fiber can be aligned with high precision.

[0018] A sixth aspect of the present invention is the method for aligning a multi-core optical fiber according to the fifth aspect, wherein in the fiber rotating step, the rotation angle is adjusted so that the skew value becomes a maximum value or a minimum value.

[0019] According to this embodiment, similar to the second embodiment, alignment can be achieved with higher accuracy.

[0020] A seventh aspect of the present invention is the aligning method of a multi-core optical fiber according to the fifth or sixth aspect, wherein the pair of cores is a core pair that is farthest from each other among a plurality of cores in the multi-core optical fiber.

[0021] If the arrangement direction of a pair of cores with respect to the bending direction of the multi-core optical fiber is constant, the skew value of light propagating through the most distant core pair will be the largest, and deviation in the rotation angle of the multi-core optical fiber will cause a large change in the skew value. Therefore, according to this aspect, the skew value can be measured with higher accuracy, and the rotational direction alignment of the multi-core optical fiber can be performed with higher accuracy.

[0022] An eighth aspect of the present invention is a method for manufacturing a multi-core optical fiber ribbon, comprising: a sending step of sending out one or more multi-core optical fibers; an aligning step of aligning the orientation in the rotation direction of at least one of the multi-core optical fibers sent out in the sending step by using the multi-core optical fiber aligning method of any one of aspects 5 to 7; and a ribbonizing step of ribbonizing the plurality of multi-core optical fibers aligned in the aligning step.

[0023] According to this embodiment, similarly to the third embodiment, it is possible to manufacture a multi-core optical fiber ribbon in which the rotation direction of the multi-core optical fibers is aligned with high precision.

[0024] A ninth aspect of the present invention is a method for manufacturing a multi-core optical fiber unit, comprising: an aligning step of aligning the orientation of the multi-core optical fiber in a rotational direction by the aligning method for a multi-core optical fiber according to any one of aspects 5 to 7; and a connecting step of connecting the multi-core optical fiber aligned in the aligning step to another optical component.

[0025] According to this embodiment, similarly to the fourth embodiment, it is possible to manufacture a multi-core optical fiber unit in which a multi-core optical fiber whose rotation direction is properly aligned is connected to another optical component.

[0026] A tenth aspect of the present invention is an inspection device for a multi-core optical fiber ribbon, comprising: a fiber bending unit that bends a multi-core optical fiber ribbon having one or more multi-core optical fibers by bending the multi-core optical fiber; a skew measuring unit that measures a skew value of light propagating through a pair of cores in at least one of the multi-core optical fibers; and a determining unit that determines whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range.

[0027] According to this aspect, by detecting that the skew value is outside a predetermined range in the part bent at the fiber bending portion, misalignment of the multi-core optical fiber can be detected with high accuracy. Furthermore, when detecting a section where the alignment of the multi-core optical fiber in the rotation direction is misaligned, the section can be detected with high accuracy by sequentially feeding the multi-core optical fiber ribbon to the fiber bending portion.

[0028] In aspect 10, the pair of cores is preferably arranged perpendicular to the arrangement direction of the plurality of multi-core optical fibers.

[0029] An eleventh aspect of the present invention is a method for inspecting a multi-core optical fiber ribbon, comprising: a fiber bending step of bending a multi-core optical fiber ribbon having one or more multi-core optical fibers by bending the multi-core optical fiber; a skew measuring step of measuring a skew value of light propagating through a pair of cores in at least one of the multi-core optical fibers; and a determination step of determining whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range.

[0030] According to this aspect, similarly to the tenth aspect, misalignment of the multi-core optical fiber can be detected with high accuracy.

[0031] A twelfth aspect of the present invention is an inspection method for a multi-core optical fiber ribbon according to the eleventh aspect, characterized in that the multi-core optical fiber ribbon comprises a plurality of parallel optical fibers including the multi-core optical fiber, and the pair of cores are aligned perpendicular to the alignment direction of the optical fibers.

[0032] A multi-core optical fiber ribbon is usually bent in a direction perpendicular to the arrangement direction of the optical fibers. When the arrangement direction of a pair of cores is along the bending direction, the skew value is maximum or minimum. Therefore, according to this embodiment, since the absolute value of the skew value is large, the resolution of the skew value can be increased and misalignment can be detected with higher accuracy.

[0033] As described above, according to the present invention, there are provided a multi-core optical fiber aligning device capable of aligning a multi-core optical fiber in the rotational direction with high accuracy, a multi-core optical fiber ribbon manufacturing device, a multi-core optical fiber unit manufacturing device, a multi-core optical fiber aligning method, a multi-core optical fiber ribbon manufacturing method, a multi-core optical fiber unit manufacturing method, and a multi-core optical fiber ribbon inspection device and multi-core optical fiber ribbon inspection method capable of detecting misalignment in the rotational direction of a multi-core optical fiber with high accuracy. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a diagram showing an example of a cross-sectional view of a multi-core optical fiber. [Figure 2] FIG. 2 is a diagram illustrating a state in which the multi-core optical fiber of FIG. 1 is bent. [Figure 3] FIG. 3 is a diagram showing the relationship between the bending radius and the skew value per unit length of light propagating through a pair of cores in the multi-core optical fiber of FIGS. [Figure 4] 10 is a diagram showing the relationship between the angle between the arrangement direction of a pair of cores and the bending direction of the multi-core optical fiber, and the skew value per unit length. FIG. [Figure 5] 1 is a diagram showing an example of a multi-core optical fiber ribbon according to a first embodiment of the present invention. [Figure 6] FIG. 1 is a diagram showing a manufacturing apparatus for a multi-core optical fiber ribbon. [Figure 7] FIG. 10 is a diagram showing the state of a fiber rotation unit. [Figure 8] 1 is a flowchart showing a method for manufacturing a multi-core optical fiber ribbon. [Figure 9] FIG. 6 is a diagram showing an example of a multi-core optical fiber unit according to a second embodiment of the present invention. [Figure 10] 10 is a diagram showing a manufacturing apparatus for the multi-core optical fiber unit of FIG. 9. FIG. [Figure 11] 10 is a flowchart showing a method for manufacturing a multi-core optical fiber unit. [Figure 12] FIG. 10 is a diagram showing an inspection device for a multi-core optical fiber ribbon according to a third embodiment of the present invention. [Figure 13] 1 is a flowchart showing a method for inspecting a multi-core optical fiber ribbon. [Figure 14] 10A and 10B are diagrams showing modified examples of multi-core optical fiber ribbons. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, preferred embodiments of a multi-core optical fiber aligning apparatus, a multi-core optical fiber ribbon manufacturing apparatus, a multi-core optical fiber unit manufacturing apparatus, a multi-core optical fiber aligning method, a multi-core optical fiber ribbon manufacturing method, a multi-core optical fiber unit manufacturing method, a multi-core optical fiber ribbon inspection apparatus, and a multi-core optical fiber ribbon inspection method according to the present invention will be described in detail with reference to the drawings. The embodiments exemplified below are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can be modified and improved from the embodiments without departing from the spirit and scope of the present invention. Note that, for ease of understanding, the scales shown in the drawings may differ from those used in the following description.

[0036] (First embodiment) First, the skew of a multi-core optical fiber will be described. Fig. 1 is a diagram showing an example of a cross section of a multi-core optical fiber. As shown in Fig. 1, the multi-core optical fiber 1 in this description includes a plurality of cores 10 to 16, a cladding 18 tightly surrounding the outer circumferential surfaces of each of the cores 10 to 16, and a protective layer 19 covering the outer circumferential surface of the cladding 18. The refractive index of each of the cores 10 to 16 is higher than the refractive index of the cladding 18. Each of the cores 10 to 16 and the cladding 18 are made of glass to which a dopant is added as necessary. The protective layer 19 is made of resin, and may be made of a plurality of layers with different hardnesses.

[0037] In this description, the total number of cores is seven, with one core 10 arranged along the central axis of the cladding 18, and multiple cores 11 to 16 arranged at equal intervals around this single core 10. No twist is applied to the multi-core optical fiber 1, and the multiple cores 10 to 16 are linear when the cladding 18 is linear.

[0038] Fig. 2 is a diagram showing how the multi-core optical fiber 1 of Fig. 1 is bent. The protective layer 19 is omitted in Fig. 2. Here, the x-axis represents a predetermined radial direction from the center of the cladding 18, the y-axis represents a radial direction perpendicular to the x-axis, and θ represents the angle between the direction in which the multi-core optical fiber 1 is bent and the x-axis. In the examples of Figs. 1 and 2, the line passing through the cores 10, 11, and 14 is the x-axis, with the core 11 on the outside of the bend and the core 14 on the inside of the bend. If the x-axis, y-axis, and angle θ are defined in this way, when the multi-core optical fiber 1 is bent as shown in Fig. 2, the angle θ is 180°.

[0039] When a pair of cores among the cores 10 to 16 of the multi-core optical fiber 1 is designated as core m and core n, the skew value S, which is the group delay difference between light propagating through core m and light propagating through core n, is expressed by the following formula, where i is m or n, as shown in detail in Patent Document 2. TIFF0007778248000001.tif57170 where L is the length of the optical fiber, c is the speed of light in a vacuum, and N 1m is the group refractive index of the core m, and N 1n is the group refractive index of core n, and R b is the bending radius of the multi-core optical fiber, B1 is the photoelastic coefficient for the ordinary ray in each core, B2 is the photoelastic coefficient for the extraordinary ray in each core, and x m ,y m is the coordinate position of the core m relative to the center of the cladding 18, and x n ,y n is the coordinate position of the core n relative to the center of the cladding 18, E is the Young's modulus of the core, and ν is the Poisson's ratio of the core.

[0040] This skew value S can be found for all combinations of pairs of cores in the cores 10 to 16 of the multi-core optical fiber 1. Fig. 3 is a diagram showing the relationship between the bending radius of the multi-core optical fiber 1 of Figs. 1 and 2 and the skew value S per unit length of light propagating through a pair of cores. Fig. 3 shows the skew value S between the core 11 and the core 14 of the multi-core optical fiber 1, the skew value S between the core 11 and the core 13, and the skew value S between the core 11 and the core 12. In creating Fig. 3, the bending direction was set to the x-axis direction, i.e., θ=180°. In addition, the group refractive index N of the pair of cores is 1m , N 1n were set to the same value. In other words, the skew value S was set to zero when the multi-core optical fiber 1 was in a straight state. As can be seen from Figure 3, the skew value S increases as the bending radius decreases, and the skew value S increases rapidly in areas with small bending radii.

[0041] 4 is a diagram showing the relationship between the angle θ between the arrangement direction of a pair of cores and the bending direction of the multi-core optical fiber 1, and the skew value S per unit length. In FIG. 4, the multi-core optical fiber 1 is bent at a predetermined bending radius R b4 shows the skew value S of light propagating through two of the cores 10, 11, and 14 when the core is bent at θ=90° or 270°, i.e., when bending in the y-axis direction, the skew value S is 0, and when θ=0° or 180°, i.e., when bending in the x-axis direction, the skew value S is maximized or minimized. In other words, the absolute value of the skew value S when the pair of cores is aligned along the bending direction is larger than the skew value S when the pair of cores is aligned not along the bending direction. In addition, the absolute value of the skew value S between core 11 and core 14 is larger than the absolute value of the skew value S between core 11 and core 10 and the absolute value of the skew value S between core 14 and core 10. In other words, when the alignment direction of the pair of cores with respect to the bending direction is constant, the absolute value of the skew value S is larger when the inter-core distance between the pair of cores is larger. This is because, when a multi-core optical fiber is bent, if a pair of cores are aligned along the bending direction or if the inter-core distance between the pair of cores is large, the difference in curvature radius between the core located on the inner side of the bend and the core located on the outer side becomes larger than in other cases, and the difference in transmission path length and the difference in effective group index between the pair of cores due to bending become larger. For example, when the multi-core optical fiber 1 is bent as shown in Fig. 2, the skew value S between core 12 and core 15 becomes the skew value S between core 11 and core 14 at θ=-60° (θ=300°).

[0042] Next, the multi-core optical fiber ribbon will be described.

[0043] Fig. 5 is a diagram showing an example of a multi-core optical fiber ribbon according to this embodiment. In the example of Fig. 5, a multi-core optical fiber ribbon 2 according to this embodiment includes a plurality of multi-core optical fibers 1 and a ribbon coating 21. In this example, the multi-core optical fiber ribbon 2 includes four multi-core optical fibers 1.

[0044] The multi-core optical fibers 1 are arranged in parallel to each other. Moreover, in the example of Fig. 5, unlike the multi-core optical fiber 1 of Fig. 1, the multi-core optical fiber 1 has four cores 11 to 14, and the cores 11 to 14 are arranged at the vertices of a square centered at the center of the cladding 18. Moreover, in this example, a pair of cores 11, 13 are arranged along a direction perpendicular to the arrangement direction of the plurality of multi-core optical fibers 1. The pair of cores 11, 13, together with the cores 12, 14, are the most distant core pair among the core pairs in the multi-core optical fiber 1. The pair of cores 12, 14 are arranged along the arrangement direction of the plurality of multi-core optical fibers 1.

[0045] The ribbon coating 21 coats the outer circumferential surface of the multi-core optical fiber 1, integrating each multi-core optical fiber 1. The ribbon coating 21 has a flat shape with its main surface aligned along the arrangement direction of the multiple multi-core optical fibers 1. Therefore, the multi-core optical fiber ribbon 2 has a flat string-like shape. In this example, the cross section perpendicular to the longitudinal direction has a roughly oval track shape. The ribbon coating 21 is made of resin. The resin of the ribbon coating 21 may be the same type of resin as that of the protective layer 19, or a different type of resin.

[0046] Next, the manufacture of the multi-core optical fiber ribbon 2 will be described.

[0047] Fig. 6 is a diagram showing a manufacturing apparatus 3 for the multi-core optical fiber ribbon 2. As shown in Fig. 6, the manufacturing apparatus 3 for the multi-core optical fiber ribbon 2 of this embodiment mainly includes a feeding section 31, a winding section 32, an aligning device 4, and a ribbonizing section 33.

[0048] The delivery unit 31 is made up of, for example, a reel around which one ends of the multiple multi-core optical fibers 1 are wound in parallel. The delivery unit 31 can deliver the multiple multi-core optical fibers 1 by rotating. The delivery unit 31 is configured, for example, with multiple reels arranged in parallel. One end of each multi-core optical fiber 1 is optically individually connected to the same number of multi-core optical fibers 31F as the number of multi-core optical fibers 1 by optical rotary joints incorporated in the delivery unit 31. The optical rotary joint is a joint component between optical fibers that can maintain the optical connection between the multi-core optical fibers 1 and the multi-core optical fibers 31F even when the delivery unit 31 rotates. The delivery unit 31 may be made up of multiple reels arranged in parallel.

[0049] The aligning device 4 is a device that aligns the orientation in the rotation direction of the axial center of the multi-core optical fiber 1 sent out from the sending unit 31. Details of the aligning device 4 will be described later.

[0050] The ribbonizing unit 33 ribbonizes the multiple multi-core optical fibers 1 aligned by the aligning device 4. The ribbonizing unit 33 is composed of, for example, a die that applies uncured resin to become the ribbon coating 21 onto the outer circumferential surface of each multi-core optical fiber 1, and a curing unit that cures the resin applied to the multi-core optical fibers 1 that have passed through the die. The resins applied to the multiple multi-core optical fibers 1 are integrated when they are fed out of the die, and the multiple multi-core optical fibers 1 are ribbonized into a multi-core optical fiber ribbon 2 shown in Fig. 5. Examples of the resin that becomes the ribbon coating 21 include an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin.

[0051] The take-up unit 32 is made of, for example, a reel, and can take up the multi-core optical fiber ribbon 2 by rotating. The other end of each multi-core optical fiber 1 in the multi-core optical fiber ribbon 2 is optically connected individually to the same number of multi-core optical fibers 32F as the number of multi-core optical fibers 1, by optical rotary joints incorporated in the take-up unit 32. Therefore, even when the take-up unit 32 rotates, the optical connection between the multi-core optical fibers 1 and the multi-core optical fibers 32F can be maintained.

[0052] The aligning device 4 mainly comprises a fiber rotation unit 41, a fiber bending unit 42, a skew measurement unit 40, and a control unit 49. The skew measurement unit 40 in this example mainly comprises a network analyzer 43, channel selectors 44 and 47, a fan-in device 45, a fan-out device 46, and a calculation unit 48.

[0053] The fiber rotator 41 changes the rotation angle of the axis of the multi-core optical fiber 1. FIG. 7 is a diagram showing an example of the fiber rotator 41. As shown in FIG. 7, the fiber rotator 41 mainly includes a pulley 41P, a pulley shaft 41A, and a driver 41D. The pulley 41P is a disk-shaped member with a V-groove on its side. The multi-core optical fiber 1 delivered from the delivery unit 31 is sandwiched in the V-groove. A through-hole is formed in the center of the pulley 41P along the thickness direction, and the pulley shaft 41A is inserted into the through-hole. Therefore, the pulley 41P can rotate around the pulley shaft 41A. One end of the pulley shaft 41A is connected to the driver 41D. The driver 41D includes, for example, a stepping motor or the like, and can change the longitudinal angle of the pulley shaft 41A as shown by the dashed line in FIG. 7. Due to this change in angle of the pulley shaft 41A, the angle of the pulley 41P changes as shown by the dashed line, and the rotation angle of the axis center of the multi-core optical fiber 1 sandwiched in the groove of the pulley 41P changes as shown by the dotted line.

[0054] 7 shows a configuration for changing the rotation angle of one multi-core optical fiber 1, the fiber rotation unit 41 has the same number of configurations as the number of multi-core optical fibers 1, and can individually change the rotation angles of multiple multi-core optical fibers 1. The groove of the pulley 41P is not limited to a V-groove. For example, it is preferable that the bottom of the groove is formed into a curved surface and that the radius of curvature of the bottom is a U-groove, which is approximately the same as the radius of the multi-core optical fiber 1, from the viewpoint of increasing the contact area between the multi-core optical fiber 1 and the pulley 41P and making it easier to rotate the multi-core optical fiber 1 about its axis.

[0055] The fiber bending unit 42 bends the multi-core optical fiber 1 whose rotation angle has been changed in a predetermined direction. The fiber bending unit 42 of this embodiment is composed of a pair of pulleys 42a and 42b. The pulleys 42a and 42b are, for example, configured by stacking pulleys similar to the pulley 41P in the same number as the number of multi-core optical fibers 1. Therefore, the fiber bending unit 42 can bend each multi-core optical fiber 1 under the same conditions. The diameters of the pulleys 42a and 42b may be different from each other. The bending radius of the multi-core optical fiber 1 is preferably 5 mm or more and 30 mm or less. The multiple multi-core optical fibers 1 fed from the fiber rotating unit 41 are bent 360° by the pulleys 42a and 42b in the fiber bending unit 42. Note that each multi-core optical fiber 1 may be wound around the pulleys 42a and 42b multiple times and bent by 360° or more. Furthermore, the radii of the pulleys 42a and 42b may be different from each other, and the multi-core optical fibers 1 may be bent with different radii of curvature.

[0056] In this embodiment, the multi-core optical fiber 1 is wound around the pulleys 42a and 42b such that the arrangement direction of the cores 11 and 13 of the multi-core optical fiber 1 in Fig. 5 is approximately along the radial direction of the pulleys 42a and 42b at the fiber bending portion 42. That is, in this embodiment, the arrangement direction of the cores 11 and 13 of the multi-core optical fiber 1 in Fig. 5 is approximately along the x direction in Fig. 1, and the bending direction of the multi-core optical fiber 1 shown in Fig. 2 is along the x direction. The configuration for winding the multi-core optical fiber 1 around the pulleys 42a and 42b in this manner will be described later.

[0057] The network analyzer 43 is connected to optical fibers 43a and 43b, the number of which is the same as the number of multi-core optical fibers 1 to be aligned. One optical fiber 43a and one optical fiber 43b correspond to one multi-core optical fiber 1. The network analyzer 43 emits light of a predetermined wavelength to each optical fiber 43a, and measures the group delay of each light when the light passes through a predetermined path and enters the optical fiber 43b corresponding to each optical fiber 43a. The network analyzer 43 outputs a signal indicating the measured group delay. In this embodiment, the light emitted from the network analyzer 43 to each optical fiber 43a propagates to either the core 11 or 13 of each multi-core optical fiber 1. Note that the network analyzer 43 may be configured using single-channel network analyzers, each connected to one optical fiber 43a and one optical fiber 43b, the number of which is the same as the number of multi-core optical fibers 1.

[0058] The channel selector 44 is connected to the plurality of optical fibers 43a and the plurality of output optical fibers 44a, 44b. The number of the optical fibers 44a and the optical fibers 44b is the same as the number of the multi-core optical fibers 1, and one optical fiber 44a and one optical fiber 44b are paired, and one pair corresponds to one multi-core optical fiber 1 and one optical fiber 43a. The optical fibers 44a and the optical fibers 44b have the same characteristics and the same length. Light incident from one optical fiber 43a is incident on either the optical fiber 44a or the optical fiber 44b in the pair. The channel selector 44 switches, for each pair, whether the light incident from the optical fiber 43a is output to the optical fiber 44a or the optical fiber 44b. A fan-in device 45 is connected between each of the optical fibers 44a, 44b and the multi-core optical fiber 31F of the optical rotary joint of the sending unit 31. The fan-in device 45 has, for example, a plurality of waveguides and a plurality of optical fibers individually connected to each waveguide. In this embodiment, each optical fiber 44a is optically connected individually to a core 11 of each multi-core optical fiber 1 via the fan-in device 45 and the multi-core optical fiber 31F, and each optical fiber 44b is optically connected individually to a core 13 of each multi-core optical fiber 1 via the fan-in device 45 and the multi-core optical fiber 31F.

[0059] With the above configuration, light incident on each optical fiber 43a from the network analyzer 43 passes through the channel selector 44, the fan-in device 45, and the multi-core optical fiber 31F and is individually incident on either the core 11 or 13 of each multi-core optical fiber 1.

[0060] The channel selector 47 has a configuration similar to that of the channel selector 44. However, instead of the multiple optical fibers 43a, the channel selector 47 is connected with an equal number of output optical fibers 43b, and instead of the multiple pairs of optical fibers 44a, 44b, an equal number of pairs of input optical fibers 47a, 47b. The optical fibers 47a and 47b have the same characteristics and are the same length. Light incident from either the optical fiber 47a or 47b in one pair is incident on one optical fiber 43b. The channel selector 47 switches between the optical fiber 47a or 47b in each pair as the light to be output to the optical fiber 43b. A fan-out device 46 is connected between the multiple multi-core optical fibers 32F of the optical rotary joint of the take-up unit 32 and each of the optical fibers 47a, 47b. The fan-out device 46 has a configuration similar to that of the fan-in device 45, for example. In this embodiment, each optical fiber 47a is individually optically connected to the core 11 of the multi-core optical fiber 1 via the multi-core optical fiber 32F and the fan-out device 46, and each optical fiber 47b is individually optically connected to the multi-core optical fiber 32F and the core 13 via the fan-out device 46.

[0061] With the above configuration, the light emitted from either the core 11 or 13 of each multi-core optical fiber 1 passes through the multi-core optical fiber 32F, the fan-out device 46, and the channel selector 47 and enters the network analyzer 43 individually.

[0062] The network analyzer 43 is electrically connected to the calculation unit 48, and the signal indicating the group delay output by the network analyzer 43 is input to the calculation unit 48. The calculation unit 48 is composed of an arithmetic device having a differential circuit. The calculation unit 48 calculates a skew value S from the signal indicating the group delay of each light input from the network analyzer 43. The skew value S is calculated for each multi-core optical fiber 1. The signal indicating the skew value S calculated by the calculation unit 48 is output to the control unit 49.

[0063] The skew value S of the light propagating through the pair of cores 11, 13 of the multi-core optical fiber 1 is measured by the skew measuring unit 40 configured as described above.

[0064] The control unit 49 is composed of, for example, an integrated circuit such as a microcontroller, an IC (Integrated Circuit), an LSI (Large-scale Integrated Circuit), or an ASIC (Application Specific Integrated Circuit), or an NC (Numerical Control) device. Furthermore, when the control unit 49 is an NC device, it may or may not use a machine learning device. The control unit 49 controls the fiber rotator 41 based on the signal indicating the skew value S output from the calculation unit 48. Specifically, the control unit 49 controls the fiber rotator 41 to adjust the rotation angle of the axis of the multi-core optical fiber 1 so that the skew value S becomes a predetermined value. In this embodiment, the control unit 49 adjusts the rotation angle of the multi-core optical fiber 1 so that the skew value S becomes a maximum value.

[0065] Next, a method for manufacturing the multi-core optical fiber ribbon 2 will be described.

[0066] Fig. 8 is a flowchart showing a manufacturing method of the multi-core optical fiber ribbon 2. As shown in Fig. 8, the manufacturing method of the multi-core optical fiber ribbon 2 of this embodiment includes a feeding step S1, an aligning step S2, and a ribbonizing step S3. The aligning step S2 includes a fiber rotation step S21, a fiber bending step S22, and a skew measurement step S23. The aligning step S2 constitutes an aligning method for aligning the rotation direction of the multi-core optical fiber 1.

[0067] (Sending step S1) This step is a step of feeding out a plurality of multi-core optical fibers 1. Specifically, the take-up unit 32 is rotated by a driving unit (not shown) to wind up the multi-core optical fiber ribbon 2, thereby pulling each multi-core optical fiber 1, and feeding out the plurality of multi-core optical fibers 1 wound around the delivery unit 31. Note that a ribbon take-up machine may be provided before the take-up unit 32, and the multi-core optical fiber ribbon 2 may be pulled by the ribbon take-up machine.

[0068] (Fiber rotation step S21) This step is a step of changing the rotation angle around the axis of the multi-core optical fiber 1. The multiple multi-core optical fibers 1 sent out from the sending unit 31 are sent into the fiber rotator 41. In the fiber rotator 41, as described with reference to Fig. 7 , when the multi-core optical fibers 1 enter the grooves of the pulleys 41P and the tilt of the pulleys 41P changes, the rotation angle around the axis of the multi-core optical fibers 1 changes by the amount of the change in tilt. The tilt of the pulleys 41P is changed as appropriate by an instruction from the control unit 49. Therefore, the rotation angle of the multi-core optical fibers 1 is also changed as appropriate by an instruction from the control unit 49. The multiple multi-core optical fibers 1 whose rotation angles have been changed are sent out from the fiber rotator 41 while the rotation angles are generally maintained.

[0069] (Fiber bending step S22) In this step, the multi-core optical fiber 1 whose rotation angle has been changed is bent in a predetermined direction. The multi-core optical fiber 1 sent out from the fiber rotation unit 41 is sent into the fiber bending unit 42. In the fiber bending unit 42, the multi-core optical fiber 1 is bent by the pulleys 42a and 42b as described above. Therefore, a skew occurs in the light propagating through the pair of cores 11 and 13 of the multi-core optical fiber 1. As described with reference to FIG. 4 , the skew value S changes depending on the relationship between the arrangement direction of the pair of cores 11 and 13 and the bending direction of the multi-core optical fiber 1. In this embodiment, the multi-core optical fiber 1 is bent by the pulleys 42a and 42b so that the bending direction of the multi-core optical fiber 1 coincides with the arrangement direction of the cores 11 and 13. That is, the fiber rotation unit 41 changes the rotation angle of the multi-core optical fiber 1 so that the multi-core optical fiber 1 is bent by the pulleys 42a and 42b in this manner. 4 is approximately 0° and the skew value S is approximately maximum. Note that, as described above, it is preferable to wind each multi-core optical fiber 1 around the pulleys 42a and 42b multiple times, since this increases the skew value S. Each multi-core optical fiber 1 is bent at the fiber bending unit 42 and then fed out from the fiber bending unit 42.

[0070] (Skew measurement step S23) In this step, light is input to a pair of cores 11 and 13 of the multi-core optical fiber 1, and each of the light beams output from the pair of cores 11 and 13 is received to measure the skew value S of each light beam. The network analyzer 43 inputs light of a predetermined wavelength into each optical fiber 43a. The channel selector 44, for example, first sets a channel so that the light from the optical fiber 43a propagates through the optical fiber 44a. Therefore, the light output from the network analyzer 43 is input to the cores 11 of each multi-core optical fiber 1 via the channel selector 44, the fan-in device 45, etc. The light propagating through the cores 11 is subject to group delay. The light output from each core 11 of each multi-core optical fiber 1 is input to the network analyzer 43 via the fan-out device 46 and the channel selector 47. The network analyzer 43 measures the group delay of each light beam, and outputs a signal including the group delay of each light beam to the calculation unit 48. Next, the channel selector 44 sets a channel so that the light from the optical fiber 43a propagates through each optical fiber 44b. Therefore, each light beam is incident on the core 13 of the corresponding multi-core optical fiber 1. A group delay occurs in the light beam propagating through the core 13, and the group delay of each light beam incident on the network analyzer 43 is measured, and a signal including the group delay of each light beam is output to the calculation unit 48. The group delay varies depending on the curvature radius of the core through which the light beam propagates. Therefore, in the fiber bending unit 42, the group delay of the light beam propagating through the core 11 differs from that of the light beam propagating through the core 13 due to the curvature radius of the cores 11 and 13 determined by the pulleys 42a and 42b. The calculation unit 48 calculates the skew value S based on the two group delays propagating through the cores 11 and 13. In this way, the skew value S of each multi-core optical fiber 1 is measured for each multi-core optical fiber 1. A signal including the calculated skew value S is output to the control unit 49.

[0071] The control unit 49 controls the fiber rotator 41 based on the signal including the skew value S input from the calculation unit 48 so that the skew value S becomes a predetermined value. That is, in the fiber rotation step S21, the rotation angle of the multi-core optical fiber 1 is adjusted so that the skew value S becomes a predetermined value. In this embodiment, the fiber rotator 41 is controlled so that the skew value S becomes a maximum. When the skew value S becomes smaller, the control unit 49 controls the driver 41D of the fiber rotator 41 to change the rotation angle of the multi-core optical fiber 1, for example, so that the alignment direction of the cores 11 and 13 moves toward +θ. At this time, when the skew value S becomes even smaller, the control unit 49 changes the rotation angle of the multi-core optical fiber 1 so that the alignment direction of the cores 11 and 13 moves toward −θ. Therefore, in this embodiment, the multi-core optical fiber 1 is bent by the pulleys 42a and 42b so that the bending direction of the multi-core optical fiber 1 is aligned with the alignment direction of the cores 11 and 13 as described above. In this way, the rotation direction of the axial center of each multi-core optical fiber 1 is aligned.

[0072] (Ribbonization step S3) This step is a step of ribbonizing the multiple multi-core optical fibers 1 aligned in the aligning step S2. In the aligning step S2, the rotational direction of each multi-core optical fiber 1 is aligned, and the multi-core optical fibers 1 are fed from the fiber bending unit 42 to the ribbonizing unit 33. In the ribbonizing unit 33, the outer circumferential surface of each multi-core optical fiber 1 is coated with uncured resin that becomes the ribbon coating 21, and the resin is cured, thereby ribbonizing the multiple multi-core optical fibers 1. In this way, the multi-core optical fiber ribbon 2 shown in Fig. 5 is manufactured.

[0073] The multi-core optical fiber ribbon 2 is wound around a winding unit 32 .

[0074] As described above, in the aligning device 4 for a multi-core optical fiber 1 and the aligning method for a multi-core optical fiber 1 of the present embodiment, the rotation angle about the axis of the multi-core optical fiber 1 is changed, the multi-core optical fiber 1 with the changed rotation angle is bent in a predetermined direction, the skew value S of light propagating through a pair of cores 11, 13 of the multi-core optical fiber 1 is measured, and when rotating the multi-core optical fiber 1, the rotation angle of the multi-core optical fiber 1 is adjusted so that the skew value S becomes the predetermined value. By adjusting the rotation angle so that the skew value S becomes the predetermined value, it is possible to align the pair of cores in the bending direction in a predetermined direction. Since the change in the skew value S with respect to the rotation angle can be measured more precisely than the change in the leakage light, the aligning device 4 for a multi-core optical fiber 1 and the aligning method for a multi-core optical fiber 1 of the present embodiment can perform alignment in the rotation direction with high accuracy.

[0075] Furthermore, in the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1 of the present embodiment, the rotation angle is adjusted so that the skew value S becomes the maximum value. Note that the rotation angle may be adjusted so that the skew value S becomes the minimum value. In these cases, the absolute value of the skew value S is larger, the resolution of the skew value S can be increased, and alignment can be performed with higher accuracy than when the rotation angle is adjusted so that the skew value S becomes a predetermined value between the maximum and minimum values. Furthermore, when the alignment direction of the pair of cores 11 and 13 is along the bending direction, the skew value S becomes maximum or minimum. Therefore, the alignment direction of the pair of cores 11 and 13 is along the bending direction, making it easy to grasp the alignment direction of the pair of cores 11 and 13 and making the aligned multi-core optical fiber 1 easier to handle. Note that, unlike the present embodiment, in the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1, the rotation angle may be adjusted so that the skew value S becomes a predetermined value other than the maximum value. In this case, the arrangement direction of the cores 11, 13 is along a direction other than a direction perpendicular to the arrangement direction of the multi-core optical fibers 1 in the multi-core optical fiber ribbon 2. For example, the rotation angle may be adjusted so that the skew value S becomes zero. In this case, the arrangement direction of the cores 11, 13 is along the arrangement direction of the multi-core optical fibers 1. Alternatively, the rotation angle may be adjusted so that the arrangement direction of the cores 11, 13 has a skew value S that forms, for example, 45° with respect to the arrangement direction of the multi-core optical fibers 1.

[0076] Furthermore, in the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1 according to the present embodiment, the pair of cores 11 and 13 for which the skew value S is measured is the core pair that is most distant from each other among the multiple cores 11 to 14 in the multi-core optical fiber 1. Therefore, a deviation in the rotation angle of the multi-core optical fiber 1 causes a large change in the skew value S. Therefore, the skew value S can be measured with higher accuracy, and alignment can be performed with higher accuracy. Note that the core pair for which the skew value S is measured does not have to be the core pair that is most distant from each other. For example, the skew value S of light propagating through the cores 11 and 12 may be measured. In this case, if the rotation angle is adjusted so that the skew value S becomes a maximum value, the cores 11 and 12 will be aligned in a direction perpendicular to the arrangement direction of the multi-core optical fiber 1, and the cores 11 and 13 will be aligned in a direction that forms an angle of 45° with the direction perpendicular to the arrangement direction of the multi-core optical fiber 1.

[0077] Furthermore, the manufacturing apparatus 3 for a multi-core optical fiber ribbon 2 and the manufacturing method for a multi-core optical fiber ribbon 2 of the present embodiment feeds out a plurality of multi-core optical fibers 1, aligns the orientations of the fed multi-core optical fibers 1 in the rotation direction by the above-mentioned alignment, and ribbonizes the aligned plurality of multi-core optical fibers 1. According to such manufacturing apparatus 3 and manufacturing method for a multi-core optical fiber ribbon 2, it is possible to manufacture a multi-core optical fiber ribbon 2 in which the rotation direction of each multi-core optical fiber 1 is aligned with high accuracy.

[0078] In this embodiment, the rotational direction alignment of the multiple multi-core optical fibers 1 included in the multi-core optical fiber ribbon 2 is performed. However, it is also possible that the rotational direction alignment of some of the multi-core optical fibers 1 included in the multi-core optical fiber ribbon 2 is performed, and the rotational direction alignment of other multi-core optical fibers 1 is not performed. In this case, only the multi-core optical fibers 1 to be aligned are fed from the feed-out unit 31 to the ribbonizing unit 33 via the aligning device 4, and the other multi-core optical fibers 1 not to be aligned are fed from the feed-out unit 31 to the ribbonizing unit 33 without passing through the aligning device 4. In this case, it is sufficient that the fiber rotating unit 41, the fiber bending unit 42, and the skew measuring unit 40 have a configuration that can align the multi-core optical fibers 1 to be aligned.

[0079] (Second embodiment) Next, a second embodiment of the present invention will be described in detail with reference to Figures 9 to 11. Note that components that are the same as or equivalent to those in the first embodiment will be given the same reference numerals and will not be described again unless otherwise specified.

[0080] Fig. 9 is a diagram showing a multi-core optical fiber unit 100 according to this embodiment. In the example of Fig. 9, the multi-core optical fiber unit 100 includes a multi-core optical fiber 1 and a multi-core optical fiber 101, which is another optical component, and the multi-core optical fiber 1 and the multi-core optical fiber 101 are connected to each other. In this example, the cores 11 to 14 of the multi-core optical fiber 1 are individually connected to the cores 111 to 114 of the multi-core optical fiber 101. Note that Fig. 9 shows the arrangement of each core schematically, and the protective layer 19 is omitted.

[0081] Fig. 10 is a diagram showing a manufacturing apparatus 5 for the multi-core optical fiber unit 100 according to this embodiment. As shown in Fig. 10, the manufacturing apparatus 5 for the multi-core optical fiber unit 100 according to this embodiment mainly includes a feeding section 31, a winding section 32, an aligning device 4, and a splicing section 50.

[0082] The manufacturing apparatus 5 of this embodiment manufactures a multi-core optical fiber unit 100 by individually splicing the cores 11 to 14 of one multi-core optical fiber 1 to the cores 111 to 114 of another multi-core optical fiber 101. Therefore, one multi-core optical fiber 1 is wound around the delivery unit 31, and the take-up unit 32 takes up one multi-core optical fiber 1. Therefore, the aligning device 4 aligns one multi-core optical fiber 1 in the rotational direction.

[0083] The splicing unit 50 splices the multi-core optical fiber 1 aligned by the aligning device 4 to another multi-core optical fiber 101. The splicing unit 50 of this embodiment has a pulley 51, a fiber rotating, fixing, and moving unit 52, a fiber cutting unit 53, and a welding unit 54. The pulley 51 has, for example, the same configuration as the pulley 41P. The fiber cutting unit 53 has, for example, an optical fiber cutter and can cut the multi-core optical fiber 1. The fiber rotating, fixing, and moving unit 52 has, for example, a configuration that can clamp the outer circumferential surface of the multi-core optical fiber 1 from three directions and can switch between fixing and not fixing the rotation about the axis of the multi-core optical fiber 1. After the multi-core optical fiber 1 is cut by the fiber cutting unit 53 with the rotation of the multi-core optical fiber 1 fixed, the fiber rotating, fixing, and moving unit 52 can move the end of the multi-core optical fiber 1 formed by the cutting to the welding unit 54 as shown by the dashed line.

[0084] An end of the multi-core optical fiber 101 is set in the welded portion 54. As described in Fig. 9, the cores 111 to 114 of the multi-core optical fiber 101 are arranged symmetrically with the cores 11 to 14, and can face the cores 11 to 14 individually.

[0085] The welding part 54 includes, for example, a pair of discharge electrodes facing each other with the end of the multi-core optical fiber 1 and the end of the multi-core optical fiber 101 sandwiched therebetween, and heat is generated by discharge from the discharge electrodes to weld the end of the multi-core optical fiber 1 to the end of the multi-core optical fiber 101. Note that the welding part 54 may be welded by other methods.

[0086] Next, a method for manufacturing the multi-core optical fiber unit 100 will be described.

[0087] Fig. 11 is a flowchart showing a manufacturing method of the multi-core optical fiber unit 100 according to this embodiment. As shown in Fig. 11, the manufacturing method of the multi-core optical fiber unit 100 according to this embodiment includes an aligning step S2 and a splicing step S4. In this embodiment, the aligning step S2 also constitutes an aligning method for aligning the rotational direction of the multi-core optical fiber 1, and includes a fiber rotating step S21, a fiber bending step S22, and a skew measuring step S23. The splicing step S4 is a step of splicing the cores 11 to 14 of the multi-core optical fiber 1 aligned in the aligning step S2 to another waveguide. The splicing step S4 in this embodiment includes a fiber cutting step S41, a fiber moving step S42, and a welding step S43.

[0088] (Alignment step S2) First, similarly to the aligning step S2 in the first embodiment, the rotational direction of the multi-core optical fiber 1 is aligned. However, in this embodiment, only one multi-core optical fiber 1 is aligned.

[0089] (Fiber cutting step S41) This step is a step of cutting the multi-core optical fiber 1. When the portion of the multi-core optical fiber 1 whose rotation direction has been aligned in the alignment step S2 moves to the fiber cutting unit 53 via the pulley 51, the winding unit 32 stops winding the multi-core optical fiber 1, and accordingly the feeding unit 31 stops feeding out the multi-core optical fiber 1. In a state where the movement of the multi-core optical fiber 1 has stopped, the fiber rotation, fixation, and movement unit 52 fixes the rotation of the multi-core optical fiber 1 so that the multi-core optical fiber 1 does not rotate. Thereafter, the fiber cutting unit 53 cuts the multi-core optical fiber 1. The end of the multi-core optical fiber 1 formed by this cutting is in a state where the rotation direction is aligned.

[0090] (Fiber moving step S42) This step is a step of moving the end of the multi-core optical fiber 1 to the fusion splice 54. The fiber rotating / fixing / moving unit 52 moves the end of the multi-core optical fiber 1 while fixing the rotation of the multi-core optical fiber 1 so that the end is positioned at the fusion splice 54. At this time, the fiber rotating / fixing / moving unit 52 rotates, for example, by approximately 90° so as to suppress a change in tension applied to the multi-core optical fiber 1.

[0091] (Welding step S43) This step is a step of welding the multi-core optical fiber 1 and the multi-core optical fiber 101. The cores 11 to 14 of the moved multi-core optical fiber 1 and the cores 111 to 114 of the multi-core optical fiber 101 face each other. In the aligning step S2, after the fiber moving step S42, alignment is performed so that the cores 11 to 14 and the cores 111 to 114 face each other individually. In this step, welding is performed by melting the end of the multi-core optical fiber 1 and the end of the multi-core optical fiber 101 by, for example, electric discharge, and bringing the end into contact with each other. At this time, since the cores 11 to 14 and the cores 111 to 114 face each other individually, the cores 11 to 14 and the cores 111 to 114 are fused to each other. In this way, the multi-core optical fiber 1 and the multi-core optical fiber 101 are connected, and the multi-core optical fiber unit 100 shown in Fig. 9 is manufactured.

[0092] In the manufacturing apparatus 5 for the multi-core optical fiber unit 100 and the method for connecting the multi-core optical fiber unit 100 of the present embodiment, the cores 11 to 14 of the multi-core optical fiber 1 aligned by the aligning apparatus 4 or the above-mentioned aligning method are connected to another optical element. Therefore, since the multi-core optical fiber 1 is connected in a state where the rotational direction of the multi-core optical fiber 1 is aligned with high accuracy, it is possible to manufacture a multi-core optical fiber unit 100 in which the multi-core optical fiber 1 with the rotational direction appropriately aligned is connected to the multi-core optical fiber 101, which is another optical component. Therefore, in the multi-core optical fiber unit 100 of this example, the cores 11 to 14 can be appropriately opposed to the cores 111 to 114, and light leakage at the connection part can be suppressed.

[0093] Furthermore, in the present embodiment, the splicing unit 50 includes the pulley 51, the fiber rotating / fixing / moving unit 52, the fiber cutting unit 53, and the welding unit 54. However, these are not essential as long as they can connect the cores 11 to 14 of the multi-core optical fiber 1 aligned by the aligning device 4 to other optical components. For example, although the present embodiment shows an example of connection by welding, connection by crimping may also be performed. In this case, the splicing unit 50 includes a crimping unit instead of the welding unit 54, and the splicing step S4 includes a crimping step instead of the welding step S43. Then, after the end of the multi-core optical fiber 1 is moved in the fiber moving step S42 as in the above embodiment, the crimping step is performed, and in the crimping step, the crimping unit crimps the end of the multi-core optical fiber 1 to the end of the multi-core optical fiber 101.

[0094] In addition, in the present embodiment, the multi-core optical fiber 101 has been described as an example of an optical component. However, the optical component does not have to be the multi-core optical fiber 101 as long as it is connected to the multi-core optical fiber 1. The optical component may be, for example, a waveguide substrate, a fan-in-fan-out device, or a multi-core optical connector. Furthermore, the optical component may be optically connected to only some of the cores 11 to 14 of the multi-core optical fiber 1.

[0095] Furthermore, the optical component may be, for example, a ferrule, which is connected to the multi-core optical fiber 1 and is not optically coupled to the cores 11 to 14. For example, when the optical component is a ferrule, the connection unit 50 has an insertion unit instead of the welding unit 54, and the connection step S4 has an insertion step instead of the welding step S43. Then, after the end of the multi-core optical fiber 1 is moved in the fiber moving step S42 as in the above embodiment, the insertion step is performed, and in the insertion step, the insertion unit moves the multi-core optical fiber 1 and the ferrule relatively so that the end of the multi-core optical fiber 1 is inserted into the ferrule, thereby connecting the multi-core optical fiber 1 and the ferrule. Therefore, a multi-core optical fiber unit is manufactured in which the multi-core optical fiber 1 and the ferrule are connected together in a state in which the alignment of the multi-core optical fiber 1 in the rotational direction is highly accurate. When this ferrule is housed in a housing of an optical fiber connector, the optical fiber connector becomes a multi-core optical fiber unit.

[0096] In addition, in the present embodiment, an example in which one multi-core optical fiber 1 is connected to an optical component has been described. However, a plurality of multi-core optical fibers 1 may be connected to an optical component by performing alignment in the rotational direction of the multi-core optical fibers 1. The alignment of the multi-core optical fibers 1 can be performed by the aligning device 4 in the first embodiment, for example.

[0097] (Third embodiment) Next, a third embodiment of the present invention will be described in detail with reference to Figures 12 and 13. Note that components that are the same as or equivalent to those in the first embodiment will be given the same reference numerals and will not be described again unless otherwise specified.

[0098] Fig. 12 is a diagram showing an inspection device 6 for a multi-core optical fiber ribbon 2 according to this embodiment. As shown in Fig. 12, the inspection device 6 for a multi-core optical fiber ribbon 2 according to this embodiment mainly includes a sending unit 31, a fiber bending unit 42, a winding unit 32, a network analyzer 43, channel selectors 44 and 47, a fan-in device 45, a fan-out device 46, a calculation unit 48, and a determination unit 60.

[0099] The multi-core optical fiber ribbon 2 is wound around the delivery section 31 of this embodiment. One end of each multi-core optical fiber 1 of the multi-core optical fiber ribbon 2 is optically and individually connected to the same number of multi-core optical fibers 31F as the multi-core optical fibers 1, in the same manner as in the first embodiment. The pulleys 42a, 42b in the fiber bending section 42 of this embodiment have groove widths that are larger than the width of the multi-core optical fibers 1 of the multi-core optical fiber ribbon 2 in the arranging direction of the multi-core optical fibers 1, and the bottoms of the grooves are formed flat. Therefore, the multi-core optical fiber ribbon 2 can be bent in a direction perpendicular to the arranging direction of the multi-core optical fibers 1.

[0100] The calculation unit 48 of the present embodiment outputs the calculated skew value S to the determination unit 60. The determination unit 60 has the same configuration as, for example, the control unit 49, and determines whether the skew value S is outside the predetermined range. In the present embodiment, for example, the arrangement direction of the cores 11 and 13 of the multi-core optical fiber 1 is perpendicular to the arrangement direction of the multi-core optical fibers 1 in the multi-core optical fiber ribbon 2 as shown in Fig. 5 , and the skew value of the light propagating through the cores 11 and 13 of each multi-core optical fiber 1 is measured in the same manner as in the first embodiment. In this case, the predetermined range is, for example, from the maximum value of the skew value S to a value 1% lower than the maximum value. When the skew value S of any of the multi-core optical fibers 1 is outside the predetermined range, the determination unit 60 outputs which multi-core optical fiber 1 has a longitudinal position at which the skew value S is outside the predetermined range.

[0101] Next, a method for inspecting the multi-core optical fiber ribbon 2 will be described.

[0102] Fig. 13 is a flowchart showing the inspection method for the multi-core optical fiber ribbon 2 according to this embodiment. As shown in Fig. 13, the inspection method for the multi-core optical fiber ribbon 2 according to this embodiment includes a sending step S1, a fiber bending step S22, a skew measuring step S23, and a determination step S5.

[0103] (Sending step S1) In this step, the multi-core optical fiber ribbon 2 including a plurality of multi-core optical fibers 1 is sent out from the sending unit 31.

[0104] (Fiber bending step S22) In this step, each multi-core optical fiber 1 is bent by bending the multi-core optical fiber ribbon 2. The multi-core optical fiber ribbon 2 sent out from the sending unit 31 is sent to the fiber bending unit 42 and bent in a predetermined direction by the respective pulleys 42a and 42b. At this time, in this embodiment, the fiber bending unit 42 bends the multi-core optical fiber ribbon 2 in its thickness direction. This direction is perpendicular to the arrangement direction of the multi-core optical fibers 1, and is the arrangement direction of the cores 11 and 13.

[0105] (Skew measurement step S23) This step is a step of making light incident on a pair of cores 11, 13 in each multi-core optical fiber 1, and receiving each light emitted from the pair of cores 11, 13 in each multi-core optical fiber 1, and measuring the skew value S of each light for each multi-core optical fiber 1. In this embodiment, the skew value S is measured in the same manner as in the first embodiment.

[0106] (Decision step S5) This step is a step for determining whether the skew value S in at least one multi-core optical fiber 1 is outside a predetermined range. When the skew value S is input from the calculation unit 48, the determination unit 60 determines whether the skew value S is outside the predetermined range, and, for example, does not output any particular signal if the skew value S is within the predetermined range, and outputs a signal indicating the multi-core optical fiber 1 whose skew value S is outside the predetermined range and a signal indicating the longitudinal position of the multi-core optical fiber 1 where the skew value S is outside the predetermined range.

[0107] In the inspection device 6 for the multi-core optical fiber ribbon 2 and the inspection method for the multi-core optical fiber ribbon 2 of the present embodiment, misalignment of the multi-core optical fiber 1 is detected by using the skew value S being outside a predetermined range in the portion bent at the fiber bending portion 42, and therefore, misalignment of the multi-core optical fiber 1 can be detected with high accuracy.

[0108] Furthermore, in this embodiment, since the multi-core optical fiber ribbons 2 are sequentially fed to the fiber bending unit 42, misalignment of the multi-core optical fibers 1 can be detected along the longitudinal direction. Therefore, it is possible to detect with high accuracy a section where the alignment of the multi-core optical fibers 1 is misaligned in the rotational direction. Note that feeding the multi-core optical fiber ribbons 2 to the fiber bending unit 42 is not an essential configuration. For example, in the case of a multi-core optical fiber ribbon 2 in which the rotational direction of the multi-core optical fibers 1 hardly changes in the longitudinal direction, the multi-core optical fibers 1 in the multi-core optical fiber ribbon 2 are bent at the fiber bending unit 42 and the skew value S is measured, thereby making it possible to identify the multi-core optical fibers 1 that have misalignment in the rotational direction.

[0109] In this embodiment, the predetermined range may be from the minimum value of the skew value S to a value 1% higher than the minimum value. Furthermore, the pair of cores for measuring the skew value S do not have to be aligned in the thickness direction of the multi-core optical fiber ribbon 2. However, it is preferable that the pair of cores are aligned in the thickness direction of the multi-core optical fiber ribbon 2, because this increases the skew value S and enables misalignment of the multi-core optical fiber 1 in the rotational direction to be detected with higher accuracy.

[0110] In this embodiment, misalignment of a plurality of multi-core optical fibers 1 included in the multi-core optical fiber ribbon 2 is detected. However, it is also possible that misalignment of some of the multi-core optical fibers 1 included in the multi-core optical fiber ribbon 2 is detected, and misalignment of other multi-core optical fibers 1 is not detected. In this case, only the multi-core optical fibers 1 for which misalignment detection is to be performed may be connected to the skew measuring unit 40. In this case, the skew measuring unit 40 may have a configuration capable of measuring the skew value of the multi-core optical fiber 1 for which misalignment detection is to be performed.

[0111] Although the present invention has been described above using the embodiments as examples, the present invention is not limited to these.

[0112] For example, the number and arrangement of cores in the multi-core optical fiber 1 may be different from those in the above embodiment. The cores of the multi-core optical fiber 1 may be arranged linearly, annularly, or in a lattice pattern.

[0113] Furthermore, the configuration of the multi-core optical fiber ribbon 2 may be different from that shown in Fig. 5. For example, the number of multi-core optical fibers 1 constituting the multi-core optical fiber ribbon 2 can be changed as appropriate. Furthermore, all of the optical fibers constituting the multi-core optical fiber ribbon 2 do not need to be multi-core optical fibers 1, and the multi-core optical fiber ribbon 2 only needs to include at least one multi-core optical fiber 1. Therefore, for example, the multi-core optical fiber ribbon 2 may have one or more multi-core optical fibers 1 and one or more single-core optical fibers. In this case, the aligning device 4 performs alignment of at least one multi-core optical fiber 1 in the rotational direction.

[0114] Fig. 14 is a diagram showing a modified example of the multi-core optical fiber ribbon 2. As shown in Fig. 14, a multi-core optical fiber ribbon 2 may be formed by fixing a plurality of adjacent multi-core optical fibers 1 to each other with a fixing resin 22. Although Fig. 14 shows a case in which there are two multi-core optical fibers 1, there may be three or more multi-core optical fibers 1. Furthermore, the fixing resin 22 may be provided piecemeal along the longitudinal direction of the multi-core optical fiber 1. When such a fixing resin 22 is used, the multi-core optical fiber 1 is more likely to be displaced in the rotational direction than the multi-core optical fiber ribbon 2 shown in Fig. 5. Therefore, in the third embodiment, it is preferable to increase the tension when inspecting the multi-core optical fiber ribbon 2. Furthermore, in this modified example as well, the multi-core optical fiber ribbon 2 may include one or more multi-core optical fibers 1 and one or more single-core optical fibers.

[0115] In the first and third embodiments, the plurality of optical fibers 43a and 43b are connected to the network analyzer 43, but one optical fiber 43a and one optical fiber 43b may be connected to the network analyzer 43. In this case, the channel selector 44 switches the optical path so that light propagates in turn through the plurality of multi-core optical fibers 1, and the channel selector 47 switches the optical path so that light incident from one of the plurality of optical fibers 47a and 47b is output to the optical fiber 43b.

[0116] The aligning device 4 may also include a memory having a table showing the relationship between the angle θ formed between the alignment direction of a pair of cores and the bending direction, and the skew value S. In this case, the control unit 49 may refer to the memory, calculate the skew value S from the measured skew value S and the table, and adjust the rotation angle of the multi-core optical fiber 1 in the fiber rotation unit 41.

[0117] The delivery unit and the winding unit do not need to use reels. For example, the multi-core optical fiber 1 may be pulled out from a folded or twisted state within a range where it will not be damaged, and may be pulled out in the same state instead of being wound.

[0118] Furthermore, the skew measuring section 40 may have other configurations as long as it can measure the skew value S of the light propagating through a pair of cores of the multi-core optical fiber 1.

[0119] As described above, according to the present invention, there are provided a multi-core optical fiber aligning device capable of aligning a multi-core optical fiber in the rotational direction with high accuracy, a multi-core optical fiber ribbon manufacturing device, a multi-core optical fiber splicing device, a multi-core optical fiber aligning method, a multi-core optical fiber ribbon manufacturing method, and a multi-core optical fiber splicing method, as well as a multi-core optical fiber ribbon inspection device and multi-core optical fiber ribbon inspection method capable of detecting misalignment in the rotational direction of a multi-core optical fiber with high accuracy, which can be used in fields such as optical communications.

Claims

1. a fiber rotation unit that changes the rotation angle of the multi-core optical fiber around its axis; a fiber bending unit that bends the multi-core optical fiber whose rotation angle has been changed in a predetermined direction; a skew measurement unit that measures a skew value of light propagating through a pair of cores of the multi-core optical fiber; a control unit that controls the fiber rotation unit to adjust the rotation angle of the multi-core optical fiber so that the skew value becomes a predetermined value; Equipped with 1. A multi-core optical fiber alignment device according to claim 1, wherein:

2. The control unit adjusts the rotation angle so that the skew value becomes a maximum value or a minimum value.

2. The multi-core optical fiber alignment device according to claim 1 .

3. a sending unit for sending out one or more multi-core optical fibers; the multi-core optical fiber aligning device according to claim 1 or 2, which aligns the orientation in a rotation direction of at least one of the multi-core optical fibers sent out from the sending unit; a ribbonizing unit that ribbonizes a plurality of optical fibers including the multi-core optical fiber aligned by the aligning device; A manufacturing apparatus for a multi-core optical fiber ribbon, comprising:

4. The aligning device according to claim 1 or 2; a connecting portion for connecting the multi-core optical fiber aligned by the aligning device to another optical component; Equipped with 1. A manufacturing apparatus for a multi-core optical fiber unit.

5. a fiber rotation step of changing a rotation angle of the multi-core optical fiber about its axis; a fiber bending step of bending the multi-core optical fiber whose rotation angle has been changed in a predetermined direction; a skew measurement step of measuring a skew value of light propagating through a pair of cores of the multi-core optical fiber; In the fiber rotation step, the rotation angle of the multi-core optical fiber is adjusted so that the skew value becomes a predetermined value. A method for aligning a multi-core optical fiber.

6. In the fiber rotation step, the rotation angle is adjusted so that the skew value becomes a maximum value or a minimum value.

6. The method for aligning a multi-core optical fiber according to claim 5.

7. The pair of cores is the core pair that is farthest from each other among the multiple cores in the multi-core optical fiber.

6. The method for aligning a multi-core optical fiber according to claim 5.

8. a launching step of launching one or more multi-core optical fibers; an aligning step of aligning the orientation of at least one of the multi-core optical fibers in the rotation direction delivered in the delivering step by the method for aligning a multi-core optical fiber according to any one of claims 5 to 7; a ribbonizing step of ribbonizing the plurality of multi-core optical fibers aligned in the aligning step; Equipped with A method for manufacturing a multi-core optical fiber ribbon.

9. an aligning step of aligning the orientation of the multi-core optical fiber in a rotation direction by the aligning method for a multi-core optical fiber according to any one of claims 5 to 7; a connecting step of connecting the multi-core optical fiber aligned in the aligning step to another optical component; Equipped with 1. A method for manufacturing a multi-core optical fiber unit, comprising:

10. a fiber bending unit that bends a multi-core optical fiber ribbon having one or more multi-core optical fibers by bending the multi-core optical fiber; a skew measurement unit that measures a skew value of light propagating through a pair of cores in at least one of the multi-core optical fibers; a determination unit that determines whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range; Equipped with 1. A multi-core optical fiber ribbon inspection device.

11. a fiber bending step of bending a multi-core optical fiber ribbon having one or more multi-core optical fibers, thereby bending the multi-core optical fiber; a skew measuring step of measuring a skew value of light propagating through a pair of cores in at least one of the multi-core optical fibers; a determining step of determining whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range; Equipped with A method for inspecting a multi-core optical fiber ribbon.

12. the multi-core optical fiber ribbon comprises a plurality of optical fibers including the multi-core optical fiber arranged in parallel, The pair of cores are aligned perpendicular to the alignment direction of the optical fibers.

12. The method for inspecting a multi-core optical fiber ribbon according to claim 11.

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