WO2024095531A1 - Alignment device for multicore optical fiber, manufacturing device for multicore optical fiber ribbon, manufacturing device for multicore optical fiber unit, alignment method for multicore optical fiber, manufacturing method for multicore optical fiber ribbon, manufacturing method for multicore optical fiber unit, inspection device for multicore optical fiber ribbon, and inspection method for multicore optical fiber ribbon - Google Patents

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

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

The present invention relates to a multi-core optical fiber alignment device, a multi-core optical fiber ribbon manufacturing device, a multi-core optical fiber unit manufacturing device, a multi-core optical fiber alignment method, a multi-core optical fiber ribbon manufacturing method, a multi-core optical fiber unit manufacturing method, a multi-core optical fiber ribbon inspection device, and a multi-core optical fiber ribbon inspection method.

It is known that a multi-core optical fiber, in which the outer circumference of multiple cores is surrounded by a single cladding, can be used to transmit multiple signals by light propagating through each core. When connecting multi-core optical fibers, it is necessary to align the axial center of the multi-core optical fibers to be connected in the rotational direction and align each core of each multi-core optical fiber to face each other.

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

Japanese Patent No. 6046311 Patent No. 6226905

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 leaking light is small. For this reason, it is difficult to detect misalignment in the rotational direction around the axis of the multi-core optical fiber, and it is difficult to perform alignment with high accuracy.

The present invention aims to provide a multi-core optical fiber alignment device capable of aligning the 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 alignment 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 the multi-core optical fiber with high accuracy.

Aspect 1 of the present invention is an alignment device for a multi-core optical fiber, characterized by comprising: a fiber rotation unit that changes the rotation angle of the axis of the multi-core optical fiber; a fiber bending unit that bends the multi-core optical fiber in a predetermined direction after the rotation angle has been changed; a skew measurement unit that measures the skew value of light propagating through a pair of cores of the multi-core optical fiber; and 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.

When the multi-core optical fiber is rotated around its axis while being bent in a predetermined direction, the alignment direction of the pair of cores with respect to the bending direction changes, and the skew value of the 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 leaked light, the alignment in the rotation direction can be performed with higher accuracy than the alignment of the multi-core optical fiber described in Patent Document 1.

Aspect 2 of the present invention is the alignment device for a multi-core optical fiber of aspect 1, characterized in that the control unit adjusts the rotation angle so that the skew value becomes a maximum or minimum value.

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 precision than when adjusting to a skew value that is not the maximum or minimum. Note that when the alignment direction of the pair of cores is along the bending direction, the skew value is maximum or minimum.

In aspect 1 or 2, the pair of cores is preferably the core pair that is farthest from each other among the multiple cores in the multi-core optical fiber.

Aspect 3 of the present invention is a multi-core optical fiber ribbon manufacturing device comprising: a sending section that sends out one or more multi-core optical fibers; an aligning device for multi-core optical fibers according to aspect 1 or 2 that aligns the orientation in the rotational direction of at least one of the multi-core optical fibers sent out from the sending section; and a ribbonizing section that ribbonizes a plurality of optical fibers including the multi-core optical fibers aligned by the aligning device.

This multi-core optical fiber ribbon manufacturing device can produce multi-core optical fiber ribbons in which the rotation direction of the multi-core optical fibers is aligned with high precision.

Aspect 4 of the present invention is a manufacturing device for a multi-core optical fiber unit, characterized by comprising an alignment device according to aspect 1 or 2, and a connection part for connecting the multi-core optical fiber aligned by the alignment device to another optical component.

With this multi-core optical fiber unit manufacturing device, the rotation direction of the multi-core optical fiber is aligned with high precision, so the multi-core optical fiber can be connected to other optical components with the rotation direction properly aligned. Therefore, it is possible to manufacture a multi-core optical fiber unit in which a multi-core optical fiber with a rotation direction properly aligned is connected to other optical components.

Aspect 5 of the present invention is a method for aligning a multi-core optical fiber, comprising a fiber rotation step of changing the rotation angle of the 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 the 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.

According to this embodiment, similar to embodiment 1, the rotational alignment of the multi-core optical fiber can be performed with high precision.

Aspect 6 of the present invention is the method for aligning a multi-core optical fiber according to aspect 5, characterized in that in the fiber rotation step, the rotation angle is adjusted so that the skew value becomes a maximum or minimum value.

According to this embodiment, alignment can be achieved with higher precision, similar to embodiment 2.

Aspect 7 of the present invention is the method for aligning a multi-core optical fiber according to aspect 5 or 6, characterized in that the pair of cores is the most distant core pair among the multiple cores in the multi-core optical fiber.

If the arrangement direction of a pair of cores relative to the bending direction of the multi-core optical fiber is constant, the skew value of the light propagating through the most distant core pair will be the largest, and the change in the skew value will be large if the rotation angle of the multi-core optical fiber is shifted. Therefore, according to this embodiment, 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.

Aspect 8 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 rotational direction of at least one of the multi-core optical fibers sent out in the sending step by using the aligning method for a multi-core optical fiber according to any one of aspects 5 to 7; and a ribbonizing step of ribbonizing the multiple multi-core optical fibers aligned in the aligning step.

According to this aspect, as in aspect 3, it is possible to manufacture a multi-core optical fiber ribbon in which the rotation direction of the multi-core optical fiber is aligned with high precision.

Aspect 9 of the present invention is a method for manufacturing a multi-core optical fiber unit, comprising an alignment step for aligning the orientation of the multi-core optical fiber in the rotational direction by the alignment method for a multi-core optical fiber according to any one of aspects 5 to 7, and a connection step for connecting the multi-core optical fiber aligned in the alignment step to another optical component.

According to this aspect, as in aspect 4, a multi-core optical fiber unit can be manufactured in which a multi-core optical fiber with a properly aligned rotational direction is connected to other optical components.

Aspect 10 of the present invention is an inspection device for a multi-core optical fiber ribbon, characterized by 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 measurement unit that measures the skew value of light propagating through a pair of cores in at least one of the multi-core optical fibers; and a determination unit that determines whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range.

According to this aspect, misalignment of the multi-core optical fiber can be detected with high accuracy by detecting that the skew value is outside a predetermined range in the portion bent by the fiber bending section. In addition, 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 sending the multi-core optical fiber ribbon to the fiber bending section.

In aspect 10, it is preferable that the pair of cores is aligned perpendicular to the alignment direction of the multiple multi-core optical fibers.

Aspect 11 of the present invention is a method for inspecting a multi-core optical fiber ribbon, comprising: a fiber bending step for bending a multi-core optical fiber ribbon having one or more multi-core optical fibers, a skew measurement step for 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 for determining whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range.

According to this aspect, similar to aspect 10, misalignment of the multi-core optical fiber can be detected with high accuracy.

Aspect 12 of the present invention is a method for inspecting a multi-core optical fiber ribbon according to aspect 11, characterized in that the multi-core optical fiber ribbon comprises a plurality of optical fibers arranged in parallel, including the multi-core optical fiber, and the pair of cores are arranged perpendicular to the arrangement direction of the optical fibers.

Multi-core optical fiber ribbons are usually bent in a direction perpendicular to the arrangement of the optical fibers. Furthermore, 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.

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

FIG. 1 is a diagram showing an example of a cross-sectional view of a multi-core optical fiber. 2 is a diagram showing the multi-core optical fiber of FIG. 1 being bent; 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. 11 is a diagram showing the relationship between the angle between the arrangement direction of a pair of cores and the bending direction of a multi-core optical fiber, and the skew value per unit length. FIG. 1 is a diagram showing an example of a multi-core optical fiber ribbon according to a first embodiment of the present invention; FIG. 2 is a diagram showing a manufacturing apparatus for a multi-core optical fiber ribbon. FIG. 2 is a diagram showing the state of a fiber rotating unit. 1 is a flowchart showing a method for manufacturing a multi-core optical fiber ribbon. 5A and 5B are diagrams illustrating an example of a multi-core optical fiber unit according to a second embodiment of the present invention. 10 is a diagram showing a manufacturing apparatus for the multi-core optical fiber unit of FIG. 9. 1 is a flowchart showing a method for manufacturing a multi-core optical fiber unit. 13 is a diagram showing an inspection device for a multi-core optical fiber ribbon according to a third embodiment of the present invention. FIG. 4 is a flowchart showing a method for inspecting a multi-core optical fiber ribbon. A diagram showing a modified example of a multi-core optical fiber ribbon.

Below, preferred embodiments of the 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 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 interpretation of the present invention. The present invention can be modified and improved from the embodiments without departing from the spirit of the invention. For ease of understanding, the scales shown in the respective figures may differ from the scales described below.

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-sectional view of a multi-core optical fiber. As shown in Fig. 1, a multi-core optical fiber 1 in this description includes a plurality of cores 10 to 16, a cladding 18 surrounding the outer circumferential surfaces of each of the cores 10 to 16 without any gaps, 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 that 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 composed of a plurality of layers having different hardnesses from each other.

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. In addition, 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.

FIG. 2 is a diagram showing how the multi-core optical fiber 1 in FIG. 1 is bent. In FIG. 2, the protective layer 19 is omitted. Here, a predetermined radial direction from the center of the cladding 18 is defined as the x-axis, a radial direction perpendicular to the x-axis is defined as the y-axis, and the angle between the direction in which the multi-core optical fiber 1 is bent and the x-axis is defined as θ. In the examples of FIG. 1 and FIG. 2, the straight 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°.

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, a skew value S, which is a 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.

where L is the length of the optical fiber, c is the speed of light in a vacuum, N _1m is the group refractive index of core m, N _1n is the group refractive index of core n, _Rb is the bending radius of the multi-core optical fiber, B ₁ is the photoelastic coefficient for the ordinary ray in each core, B ₂ is the photoelastic coefficient for the extraordinary ray in each core, x _m , y _m are coordinate positions based on the center of the cladding 18 of core m, x _n , _yn are coordinate positions based on the center of the cladding 18 of core n, E is the Young's modulus of the core, and ν is the Poisson's ratio of the core.

This skew value S can be obtained 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 and the skew value S per unit length of light propagating through a pair of cores in the multi-core optical fiber 1 of Figs. 1 and 2. Fig. 3 shows the skew value S between the cores 11 and 14 of the multi-core optical fiber 1, the skew value S between the cores 11 and 13, and the skew value S between the cores 11 and 12. In creating Fig. 3, the bending direction was set to the x-axis direction, i.e., θ=180°. Furthermore, the group refractive indices N _1m and N _1n of the pair of cores 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 Fig. 3, the skew value S increases as the bending radius decreases, and the skew value S increases rapidly in an area where the bending radius is small.

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. FIG. 4 shows the skew value S of light propagating through two of the cores 10, 11, and 14 when the multi-core optical fiber 1 is bent at a predetermined bending radius _Rb . Note that in FIG. 4, the group refractive indexes of the respective cores are set to the same value. From FIG. 4, the skew value S is 0 when θ=90° or 270°, i.e., when bending in the y-axis direction, and the skew value S is maximum or minimum when θ=0° or 180°, i.e., when bending in the x-axis direction. That is, the absolute value of the skew value S when the pair of cores are arranged along the bending direction is larger than the skew value S when the pair of cores are arranged not along the bending direction. Also, the absolute value of the skew value S of the core 11-core 14 is larger than the absolute value of the skew value S of the core 11-core 10 and the absolute value of the skew value S of the core 14-core 10. That is, when the arrangement 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 of the pair of cores is larger. This is because, when bending a multi-core optical fiber, when the pair of cores are arranged along the bending direction or when the inter-core distance of the pair of cores is large, the difference in the curvature radius between the core located on the inner side of the bend and the core located on the outer side becomes larger than when they are not arranged, and the transmission path length difference and the effective group index difference 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 of the core 12-core 15 becomes the skew value S of the core 11-core 14 at θ=-60° (θ=300°).

Next, we will explain multi-core optical fiber ribbons.

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, the 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.

The multi-core optical fibers 1 are arranged in parallel to each other. 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 on the center of the cladding 18. In this example, the pair of cores 11, 13 are arranged along a direction perpendicular to the arrangement direction of the multiple multi-core optical fibers 1. The pair of cores 11, 13, together with the cores 12, 14, are the furthest 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 multiple multi-core optical fibers 1.

The ribbon coating 21 covers the outer peripheral 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-sectional shape perpendicular to the longitudinal direction is roughly an 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 the protective layer 19, or a different type of resin.

Next, we will explain how to manufacture the multi-core optical fiber ribbon 2.

FIG. 6 is a diagram showing a manufacturing apparatus for a multi-core optical fiber ribbon 2. As shown in FIG. 6, the manufacturing apparatus 3 for a multi-core optical fiber ribbon 2 of this embodiment mainly comprises a sending section 31, a winding section 32, an alignment device 4, and a ribbonizing section 33.

The sending unit 31 is, for example, made of a reel around which one end of the multiple multi-core optical fibers 1 is wound in parallel. The sending unit 31 can send out multiple multi-core optical fibers 1 by rotating. The sending unit 31 is, for example, made of 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 multi-core optical fibers 1 by an optical rotary joint incorporated in the sending 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 sending unit 31 rotates. The sending unit 31 may be made of multiple reels arranged in parallel.

The alignment device 4 is a device that aligns the direction of rotation of the axial center of the multi-core optical fiber 1 sent out from the sending section 31. Details of the alignment device 4 will be described later.

The ribbonizing section 33 ribbonizes the multiple multi-core optical fibers 1 aligned by the alignment device 4. The ribbonizing section 33 is composed of, for example, a die that applies uncured resin to the outer peripheral surface of each multi-core optical fiber 1 to become the ribbon coating 21, and a curing section that cures the resin applied to the multi-core optical fiber 1 that has passed through the die. The resins applied to the multi-core optical fibers 1 are integrated when they are sent out from the die, and the multiple multi-core optical fibers 1 are ribbonized into the 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.

The winding unit 32 is made of, for example, a reel, and can wind 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 multi-core optical fibers 1 by an optical rotary joint incorporated in the winding unit 32. Therefore, even if the winding unit 32 rotates, the optical connection between the multi-core optical fibers 1 and the multi-core optical fibers 32F can be maintained.

The alignment 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.

The fiber rotation unit 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 rotation unit 41. As shown in FIG. 7, the fiber rotation unit 41 mainly includes a pulley 41P, a pulley shaft 41A, and a drive unit 41D. The pulley 41P is a disk-shaped member with a V-groove on the side. The multi-core optical fiber 1 sent out from the sending 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 drive unit 41D. The drive unit 41D includes, for example, a stepping motor, and can change the longitudinal angle of the pulley shaft 41A as shown by the dashed line in FIG. 7. This change in the angle of the pulley shaft 41A causes the angle of the pulley 41P to change as shown by the dashed line, and the rotation angle of the axis of the multi-core optical fiber 1 that is sandwiched in the groove of the pulley 41P changes as shown by the dotted line.

FIG. 7 shows a configuration for changing the rotation angle of one multi-core optical fiber 1, but the fiber rotation unit 41 has the same number of configurations as in FIG. 7 as the number of multi-core optical fibers 1, and can change the rotation angles of multiple multi-core optical fibers 1 individually. 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 in a curved shape and that the radius of curvature of the bottom is a U-groove that 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 around its axis.

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 in 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 sent out from the fiber rotating unit 41 are bent 360° by the pulleys 42a and 42b in the fiber bending unit 42. Each multi-core optical fiber 1 may be wound around the pulleys 42a and 42b multiple times and bent 360° or more. The radii of the pulleys 42a and 42b may be different from each other, and the multi-core optical fiber 1 may be bent with different curvature radii.

In this embodiment, the multi-core optical fiber 1 is wound around the pulleys 42a and 42b so 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.

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

The channel selector 44 is connected to a plurality of the optical fibers 43a and a plurality of optical fibers 44a and 44b for emission. The optical fibers 44a and the optical fibers 44b are the same in number 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 are the same length. Light incident from one optical fiber 43a is incident on either the optical fiber 44a or 44b in one pair. The channel selector 44 switches whether the light incident from the optical fiber 43a is output to either the optical fiber 44a or 44b in each pair. A fan-in device 45 is connected between each of the optical fibers 44a and 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 individually optically connected to the 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 to the core 13 of each multi-core optical fiber 1 via the fan-in device 45 and the multi-core optical fiber 31F.

With the above configuration, the light entering 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 enters either one of the cores 11 or 13 of each multi-core optical fiber 1 individually.

The channel selector 47 has the same configuration as the channel selector 44. However, instead of the multiple optical fibers 43a, the same number of output optical fibers 43b are connected to the channel selector 47, and instead of the multiple pairs of optical fibers 44a, 44b, the same number of pairs of input optical fibers 47a, 47b are connected. The optical fibers 47a and 47b have the same characteristics and are the same length. Light incident from either the optical fibers 47a or 47b in one pair is incident on one optical fiber 43b. The channel selector 47 switches whether the light to be output to the optical fiber 43b is incident from either the optical fiber 47a or 47b in each pair. A fan-out device 46 is connected between the multiple multi-core optical fibers 32F of the optical rotary joint of the winding section 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.

With the above configuration, the light emitted from either the core 11 or 13 of each multi-core optical fiber 1 is individually incident on the network analyzer 43 via the multi-core optical fiber 32F, the fan-out device 46, and the channel selector 47.

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 a calculation device having a differential circuit. The calculation unit 48 calculates the 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.

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 measurement unit 40 configured as described above.

The control unit 49 is composed of 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. When an NC device is used, the control unit 49 may or may not use a machine learning device. The control unit 49 controls the fiber rotation unit 41 based on a signal indicating the skew value S output from the calculation unit 48. Specifically, the control unit 49 controls the fiber rotation unit 41 to adjust the rotation angle of the axis center 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.

Next, we will explain the manufacturing method of the multi-core optical fiber ribbon 2.

FIG. 8 is a flowchart showing a method for manufacturing a multi-core optical fiber ribbon 2. As shown in FIG. 8, the method for manufacturing a multi-core optical fiber ribbon 2 in this embodiment includes a sending step S1, an aligning step S2, and a ribbonizing step S3. The aligning step S2 also 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 rotational direction of the multi-core optical fiber 1.

(Sending step S1)
This step is a step of feeding out a plurality of multi-core optical fibers 1. Specifically, the winding 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 feeding unit 31. Note that a ribbon take-up machine may be provided in front of the winding unit 32, and the multi-core optical fiber ribbon 2 may be pulled by the ribbon take-up machine.

(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 rotating unit 41. In the fiber rotating unit 41, as described with reference to Fig. 7 , when the multi-core optical fiber 1 enters the groove of the pulley 41P and the inclination of the pulley 41P changes, the rotation angle around the axis of the multi-core optical fiber 1 changes by the amount of the change in the inclination. The inclination of the pulley 41P is appropriately changed by an instruction from the control unit 49. Therefore, the rotation angle of the multi-core optical fiber 1 is also appropriately changed 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 rotating unit 41 while roughly maintaining the rotation angle.

(Fiber bending step S22)
This step is a step of bending the multi-core optical fiber 1 whose rotation angle has been changed in a predetermined direction. The multi-core optical fiber 1 sent out from the fiber rotation unit 41 is sent to 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 varies 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. In this case, the angle θ between the bending direction and the arrangement direction of the cores 11 and 13 in FIG. 4 becomes approximately 0°, and the skew value S becomes approximately maximum. It is preferable that each multi-core optical fiber 1 is wound around the pulleys 42a, 42b multiple times as described above, since this increases the skew value S. Each multi-core optical fiber 1 is bent by the fiber bending unit 42 and then sent out from the fiber bending unit 42.

(Skew measurement step S23)
This step is a step of inputting light to a pair of cores 11 and 13 of the multi-core optical fiber 1 and receiving each of the lights output from the pair of cores 11 and 13 to measure the skew value S of each light. The network analyzer 43 inputs light of a predetermined wavelength to each optical fiber 43a. In the channel selector 44, for example, a channel is first set so that the light from the optical fiber 43a propagates to the optical fiber 44a. For this reason, 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 and the fan-in device 45, etc. A group delay occurs in the light propagating through the core 11. The light output from the cores 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. In the network analyzer 43, the group delay of each light is measured, and a signal including the group delay of each light is output to the calculation unit 48. Next, the channel selector 44 sets a channel so that the light from the optical fiber 43a propagates to each optical fiber 44b. Therefore, each light is incident on the core 13 of each multi-core optical fiber 1. A group delay occurs in the light propagating through the core 13, and the group delay of each light incident on the network analyzer 43 is measured, and a signal including the group delay of each light is output to the calculation unit 48. The group delay changes depending on the curvature radius of the core through which the light propagates. Therefore, in the fiber bending unit 42, the group delay of the light propagating through the core 11 differs from that of the light 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.

The control unit 49 controls the fiber rotation unit 41 based on a 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 rotation unit 41 is controlled so that the skew value S becomes a maximum. When the skew value S becomes small, the control unit 49 controls the drive unit 41D of the fiber rotation unit 41 to change the rotation angle of the multi-core optical fiber 1, for example, so that the arrangement direction of the cores 11 and 13 moves to the +θ side. At this time, when the skew value S becomes further small, the rotation angle of the multi-core optical fiber 1 is changed so that the arrangement direction of the cores 11 and 13 moves to the -θ side. 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 arrangement 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.

(Ribbonization step S3)
This step is a step of ribbonizing the multiple multi-core optical fibers 1 aligned in the aligning step S2. The rotational direction of each multi-core optical fiber 1 is aligned in the aligning step S2, 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 to ribbonize the multiple multi-core optical fibers 1. In this manner, the multi-core optical fiber ribbon 2 shown in FIG. 5 is manufactured.

The multi-core optical fiber ribbon 2 is wound around the winding section 32.

As described above, in the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1 of this embodiment, the rotation angle of the axis center 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 the light propagating through the 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 a predetermined value. By adjusting the rotation angle so that the skew value S becomes a predetermined value, the arrangement direction of the pair of cores can be set to a predetermined direction with respect to the bending 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 leaked light, the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1 of this embodiment can perform alignment in the rotation direction with high precision.

In addition, in the aligning device 4 of the multi-core optical fiber 1 and the aligning method of the multi-core optical fiber 1 of this embodiment, the rotation angle is adjusted so that the skew value S becomes the maximum value. 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 than when the rotation angle is adjusted so that the skew value S becomes a predetermined value between the maximum value and the minimum value, and the resolution of the skew value S can be increased, and alignment can be performed with higher accuracy. In addition, when the arrangement direction of the pair of cores 11, 13 is along the bending direction, the skew value S becomes maximum or minimum. Therefore, the arrangement direction of the pair of cores 11, 13 is along the bending direction, making it easy to grasp the arrangement direction of the pair of cores 11, 13, and the aligned multi-core optical fiber 1 can be easily handled. Unlike this embodiment, in the aligning device 4 of the multi-core optical fiber 1 and the aligning method of the multi-core optical fiber 1, the rotation angle may be adjusted so that the skew value S becomes a predetermined value that is not maximum. 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 fiber 1 in the multi-core optical fiber ribbon 2. For example, the rotation angle may be adjusted so that the skew value S is zero. In this case, the arrangement direction of the cores 11, 13 is along the arrangement direction of the multi-core optical fiber 1. Alternatively, the rotation angle may be adjusted so that the arrangement direction of the cores 11, 13 has a skew value S that is, for example, 45° with respect to the arrangement direction of the multi-core optical fiber 1.

In the aligning device 4 for the multi-core optical fiber 1 and the aligning method for the multi-core optical fiber 1 of this embodiment, the pair of cores 11, 13 for which the skew value S is measured is the most distant core pair among the multiple cores 11 to 14 in the multi-core optical fiber 1. Therefore, when the rotation angle of the multi-core optical fiber 1 is shifted, the change in the skew value S becomes large. Therefore, the skew value S can be measured with higher accuracy, and alignment can be performed with higher accuracy. The core pair for which the skew value S is measured does not have to be the most distant core pair. For example, the skew value S of the light propagating through the cores 11, 12 may be measured. In this case, if the rotation angle is adjusted so that the skew value S is maximized, the cores 11, 12 are aligned along a direction perpendicular to the alignment direction of the multi-core optical fiber 1, and the cores 11, 13 are aligned in a direction that forms an angle of 45° with respect to the direction perpendicular to the alignment direction of the multi-core optical fiber 1.

The manufacturing apparatus 3 for the multi-core optical fiber ribbon 2 and the manufacturing method for the multi-core optical fiber ribbon 2 of this embodiment send out a plurality of multi-core optical fibers 1, align the orientation in the rotation direction of the sent-out multi-core optical fibers 1 by the above-mentioned alignment, and ribbonize the aligned multi-core optical fibers 1. According to the manufacturing apparatus 3 and manufacturing method for the 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.

In this embodiment, the rotational 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 alignment of some of the multi-core optical fibers 1 included in the multi-core optical fiber ribbon 2 is performed, and the alignment of the other multi-core optical fibers 1 is not performed. In this case, only the multi-core optical fibers 1 to be aligned are sent from the sending unit 31 to the ribbonizing unit 33 via the alignment device 4, and the other multi-core optical fibers 1 not to be aligned are sent from the sending unit 31 to the ribbonizing unit 33 without going through the alignment device 4. In this case, the fiber rotation unit 41, the fiber bending unit 42, and the skew measurement unit 40 only need to have a configuration capable of aligning the multi-core optical fiber 1 to be aligned.

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 are given the same reference numerals and will not be described again unless otherwise specified.

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. 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 in FIG. 9, the arrangement of the individual cores is shown diagrammatically, and the protective layer 19 is omitted.

FIG. 10 is a diagram showing a manufacturing apparatus for a multi-core optical fiber unit 100 according to this embodiment. As shown in FIG. 10, the manufacturing apparatus 5 for a multi-core optical fiber unit 100 according to this embodiment mainly comprises a sending section 31, a winding section 32, an alignment device 4, and a connection section 50.

The manufacturing apparatus 5 of this embodiment manufactures a multi-core optical fiber unit 100 by individually connecting 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 sending section 31, and the winding section 32 winds up one multi-core optical fiber 1. Therefore, the alignment device 4 aligns one multi-core optical fiber 1 in the rotational direction.

The connection unit 50 connects the multi-core optical fiber 1 aligned by the alignment device 4 to another multi-core optical fiber 101. The connection unit 50 of this embodiment has a pulley 51, a fiber rotation/fixation/movement 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 rotation/fixation/movement 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 of the axial center 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 rotation/fixation/movement unit 52 can move the end of the multi-core optical fiber 1 formed by the cut to the welding unit 54 as shown by the dashed line.

The 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.

The welding portion 54, for example, has a pair of discharge electrodes facing each other across the end of the multi-core optical fiber 1 and the end of the multi-core optical fiber 101, and welds the end of the multi-core optical fiber 1 and the end of the multi-core optical fiber 101 by heating caused by discharge from these discharge electrodes. Note that welding of the welding portion 54 may be performed by other methods.

Next, we will explain the manufacturing method of the multi-core optical fiber unit 100.

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

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

(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 delivery unit 31 stops delivering the multi-core optical fiber 1. In a state in which the movement of the multi-core optical fiber 1 has stopped, the fiber rotation/fixing/moving 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 in which the rotation direction is aligned.

(Fiber moving step S42)
This step is a step of moving the end of the multi-core optical fiber 1 to the welded part 54. The fiber rotation, fixation, and movement 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 located at the welded part 54. At this time, the fiber rotation, fixation, and movement unit 52 rotates, for example, by approximately 90° so as to suppress a change in tension applied to the multi-core optical fiber 1.

(Welding step S43)
This step is a step of fusing 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 alignment step S2, alignment is performed so that the cores 11 to 14 and the cores 111 to 114 face each other individually after the fiber moving step S42. In this step, for example, an end of the multi-core optical fiber 1 and an end of the multi-core optical fiber 101 are melted by discharge or the like, and the respective ends are brought into contact with each other, thereby fusing the multi-core optical fiber 1 and the multi-core optical fiber 101. At this time, the cores 11 to 14 and the cores 111 to 114 face each other individually, so that 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.

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 this embodiment, the cores 11 to 14 of the multi-core optical fiber 1 aligned by the alignment apparatus 4 or the above-mentioned alignment 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.

In addition, in this embodiment, the connection unit 50 has the pulley 51, the fiber rotation/fixation/movement unit 52, the fiber cutting unit 53, and the welding unit 54, but these are not essential as long as the cores 11 to 14 of the multi-core optical fiber 1 aligned by the alignment device 4 can be connected to other optical components. For example, in this embodiment, an example of connection by welding is shown, but connection by crimping may also be used. In this case, the connection unit 50 has a crimping unit instead of the welding unit 54, and the connection step S4 has 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.

In addition, in this 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. In addition, the optical component may be optically connected to only some of the cores 11 to 14 of the multi-core optical fiber 1.

Also, the optical component may be, such as a ferrule, not optically coupled with the cores 11 to 14, so long as it is connected to the multi-core optical fiber 1. For example, when the optical component is a ferrule, the connection section 50 has an insertion section instead of the welding section 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 section 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, and the multi-core optical fiber 1 and the ferrule are connected. Therefore, a multi-core optical fiber unit in which the multi-core optical fiber 1 and the ferrule are connected is manufactured in a state in which the alignment of the rotational direction of the multi-core optical fiber 1 is aligned with high accuracy. When this ferrule is accommodated in the housing of the optical fiber connector, the optical fiber connector becomes a multi-core optical fiber unit.

In addition, in this embodiment, an example in which one multi-core optical fiber 1 is connected to an optical component has been described. However, multiple multi-core optical fibers 1 may be aligned in the rotational direction and connected to an optical component. The alignment of multiple multi-core optical fibers 1 may be performed, for example, by the alignment device 4 in the first embodiment.

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 are given the same reference numerals and will not be described again unless otherwise specified.

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 comprises a sending section 31, a fiber bending section 42, a winding section 32, a network analyzer 43, channel selectors 44 and 47, a fan-in device 45, a fan-out device 46, a calculation section 48, and a judgment section 60.

The multi-core optical fiber ribbon 2 is wound around the sending section 31 of this embodiment. One end of each multi-core optical fiber 1 of the multi-core optical fiber ribbon 2 is optically 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 and 42b in the fiber bending section 42 of this embodiment have a groove width larger than the width of the multi-core optical fibers 1 of the multi-core optical fiber ribbon 2 in the arrangement direction, and the bottom of the groove is formed flat. Therefore, the multi-core optical fiber ribbon 2 can be bent in a direction perpendicular to the arrangement direction of the multi-core optical fibers 1.

The calculation unit 48 of this embodiment outputs the calculated skew value S to the determination unit 60. The determination unit 60 has a configuration similar to that of the control unit 49, for example, and determines whether the skew value S is outside the predetermined range. In this 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 above-mentioned 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 at which longitudinal position of which multi-core optical fiber 1 the skew value S is outside the predetermined range.

Next, we will explain the inspection method for the multi-core optical fiber ribbon 2.

FIG. 13 is a flowchart showing the method for inspecting the multi-core optical fiber ribbon 2 according to this embodiment. As shown in FIG. 13, the method for inspecting the multi-core optical fiber ribbon 2 according to this embodiment includes a sending step S1, a fiber bending step S22, a skew measurement step S23, and a judgment step S5.

(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 section 31 .

(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 each of the pulleys 42a, 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, 13.

(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 of the lights outputted 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.

(Determination step S5)
This step is a step of 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 or not, and when the skew value S is within the predetermined range, for example, outputs no particular signal, and when the skew value S is outside the predetermined range, 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.

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 this embodiment, the misalignment of the multi-core optical fiber 1 is detected by using the fact that the skew value S is outside a predetermined range in the part bent at the fiber bending section 42, so that the misalignment of the multi-core optical fiber 1 can be detected with high accuracy.

In addition, in this embodiment, since the multi-core optical fiber ribbon 2 is sequentially sent to the fiber bending section 42, misalignment of the multi-core optical fiber 1 can be detected along the longitudinal direction. Therefore, the section in which the alignment of the multi-core optical fiber 1 in the rotational direction is misaligned can be detected with high accuracy. Note that sending the multi-core optical fiber ribbon 2 to the fiber bending section 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 fiber 1 hardly changes in the longitudinal direction, the multi-core optical fiber 1 in the multi-core optical fiber ribbon 2 is bent in the fiber bending section 42 and the skew value S is measured, so that the multi-core optical fiber 1 in which misalignment in the rotational direction occurs can be identified.

In this embodiment, the above-mentioned 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 does 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 value of the skew value S and makes it possible to detect misalignment in the rotational direction of the multi-core optical fiber 1 with higher accuracy.

In this embodiment, misalignment of multiple 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 performed need only be connected to the skew measurement unit 40. In this case, the skew measurement unit 40 only needs to have a configuration capable of measuring the skew value of the multi-core optical fiber 1 for which misalignment detection is performed.

The present invention has been described above using examples of embodiments, but the present invention is not limited to these.

For example, the number and arrangement of the cores of 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 in a linear, annular, or lattice pattern.

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. In addition, 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 alignment device 4 aligns at least one multi-core optical fiber 1 in the rotational direction.

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 where there are two multi-core optical fibers 1, there may be three or more multi-core optical fibers 1. 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. In this modified example, the multi-core optical fiber ribbon 2 may also include one or more multi-core optical fibers 1 and one or more single-core optical fibers.

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

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

Furthermore, the sending section and the winding section 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 that is not damaged, and may be taken up in a similar state instead of being wound.

The skew measurement unit 40 may also have other configurations as long as it is capable of measuring the skew value S of the light propagating through a pair of cores of the multi-core optical fiber 1.

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

Claims (12)

1. a fiber rotation unit that changes a rotation angle of the multi-core optical fiber about 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;
   An aligning device for a multi-core optical fiber comprising:
2. The multi-core optical fiber aligning device according to claim 1 , wherein the control unit adjusts the rotation angle so that the skew value becomes a maximum value or a minimum value.
3. A sending unit that sends out one or more multi-core optical fibers;
   3. The multi-core optical fiber aligning device according to claim 1, which aligns the orientation of at least one of the multi-core optical fibers sent out from the sending unit in a rotation direction;
   a ribbonizing unit that ribbonizes a plurality of optical fibers including the multi-core optical fiber aligned by the alignment device;
   A manufacturing apparatus for a multi-core optical fiber ribbon, comprising:
4. An aligning device according to claim 1 or 2;
   a connection portion for connecting the multi-core optical fiber aligned by the alignment device to another optical component;
   A manufacturing apparatus for a multi-core optical fiber unit comprising:
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 with the changed rotation angle in a predetermined direction;
   a skew measuring step of measuring a skew value of light propagating through a pair of cores of the multi-core optical fiber;
   a rotation angle of the multi-core optical fiber being adjusted so that the skew value becomes a predetermined value,
6. 6. The method for aligning a multi-core optical fiber according to claim 5, wherein in the fiber rotating step, the rotation angle is adjusted so that the skew value becomes a maximum value or a minimum value.
7. 7. The method for aligning a multi-core optical fiber according to claim 5, 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.
8. A launching step of 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 a rotation direction, the at least one multi-core optical fiber being fed out in the feeding step, by the aligning method for 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 alignment step;
   A method for manufacturing a multi-core optical fiber ribbon, comprising:
9. an aligning step of aligning the direction of the multi-core optical fiber in a rotation direction by the aligning method of 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;
   A method for manufacturing a multi-core optical fiber unit comprising:
10. a fiber bending unit for bending a multi-core optical fiber ribbon having one or more multi-core optical fibers, the multi-core optical fiber being bent;
    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;
    An inspection device for a multi-core optical fiber ribbon comprising:
11. 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;
    a determining step of determining whether the skew value in at least one of the multi-core optical fibers is outside a predetermined range;
    A method for inspecting a multi-core optical fiber ribbon, comprising:
12. The multi-core optical fiber ribbon includes a plurality of optical fibers arranged in parallel, the optical fibers including the multi-core optical fiber,
    12. The method for inspecting a multi-core optical fiber ribbon according to claim 11, wherein the pair of cores are arranged perpendicular to the arrangement direction of the optical fibers.

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