Optical fiber tape core wire, optical connection assembly, and method for manufacturing optical fiber tape core wire

Abstract

This optical fiber tape core wire comprises: a plurality of glass fibers; and a resin coating that covers the outer peripheral surfaces of the plurality of glass fibers. Each of the plurality of glass fibers has a coating part coated with the resin coating, and an exposed part exposed from the resin coating and including a tip surface. The exposed part has a bent part including a bent section maintained at a radius of curvature of 10 mm or less. When viewed in a direction perpendicular to a plane including an arrangement direction in which the coating parts of the plurality of glass fibers are arranged and an extension direction in which the coating parts extend, the bent part is bent in a direction crossing the extension direction.

Description

Optical fiber ribbon, optical connection assembly, and method for manufacturing optical fiber ribbon

[0001] This disclosure relates to an optical fiber ribbon, an optical connection assembly, and a method for manufacturing an optical fiber ribbon. This application claims priority to Japanese Application No. 2024-086299, filed May 28, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] As optical modules become smaller, there is a demand for a lower profile for optical fibers used near the optical module (i.e., for an optical fiber whose one end is vertically connected to the optical module, to have a lower height from the substrate.) In this case, it is conceivable to lower the height of the optical module from the substrate by bending a waveguide such as an optical fiber (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a fiber ribbon in which multiple bent optical fibers are integrated with a common resin. In this fiber ribbon, the multiple bent optical fibers are bent in a vertical direction perpendicular to the horizontal direction in which they are arranged. Patent Document 2 discloses an optical connection assembly that optically connects multiple optical fibers to multiple optical input / output units on a substrate. This optical connection assembly includes a fiber array block that holds multiple optical fibers and a glass plate having multiple waveguides therein. The multiple waveguides inside the glass plate are bent in a plane that is parallel to the vertical direction in which the multiple optical fibers are arranged.

[0004] International Publication No. 2023 / 119925 U.S. Patent Application Publication No. 2022 / 0326444

[0005] The optical fiber ribbon of the present disclosure includes a plurality of glass fibers and a resin coating covering the outer peripheral surfaces of the plurality of glass fibers. Each of the plurality of glass fibers has a coating portion covered with the resin coating and an exposed portion including a tip surface exposed from the resin coating. The exposed portion has a bent portion including a bent section maintained with a radius of curvature of 10 mm or less. When viewed along a direction perpendicular to a plane including the arrangement direction in which the coating portions of the plurality of glass fibers are arranged and the extension direction in which the coating portions extend, the bent portion is bent in a direction intersecting the extension direction.

[0006] FIG. 1A is a plan view showing an optical communications module of the present disclosure. FIG. 1B is a side view showing a portion of the optical communications module of the present disclosure. FIG. 2 is a perspective view showing an optical connection assembly of the optical communications module shown in FIG. 1A. FIG. 3A is a partial cross-sectional view showing the optical connection assembly of the present disclosure. FIG. 3B is a side view showing the optical connection assembly of the present disclosure. FIG. 4A is a perspective view showing an optical fiber ribbon of the present disclosure. FIG. 4B is a plan view showing an optical fiber ribbon of the present disclosure. FIG. 5A is a plan view showing an exposed portion of a glass fiber. FIG. 5B is a graph showing changes in curvature of a bent portion included in the exposed portion. FIG. 6A is a perspective view showing a manufacturing process of the optical fiber ribbon. FIG. 6B is a plan view showing the manufacturing process of FIG. 6A. FIG. 7A is a perspective view showing a manufacturing process subsequent to FIG. 6A. FIG. 7B is a plan view showing the manufacturing process of FIG. 7A. FIG. 8 is a perspective view showing the manufacturing process of FIG. 7A in more detail. FIG. 9 is a diagram for explaining the process from the manufacturing process of FIG. 6A to the manufacturing process of FIG. 7A. FIG. 10 is a diagram for explaining the process from the manufacturing process of FIG. 6A to the manufacturing process of FIG. 7A . FIG. 11 is a diagram for explaining the process from the manufacturing process of FIG. 6A to the manufacturing process of FIG. 7A . FIG. 12A is a diagram for explaining the function of a first holding member. FIG. 12B is a diagram for explaining the function of the first holding member. FIG. 13A is a perspective view showing an optical connection assembly according to a modified example. FIG. 13B is a side view showing an optical connection assembly according to a modified example. FIG. 13C is a bottom view showing an optical connection assembly according to a modified example. FIG. 14A is a perspective view showing a manufacturing process of an optical connection assembly according to a modified example. FIG. 14B is a perspective view showing a manufacturing process subsequent to the manufacturing process of FIG. 14A . FIG. 14C is a perspective view showing a manufacturing process subsequent to the manufacturing process of FIG. 14B .

[0007] [Problems to be Solved by the Present Disclosure] When multiple optical fibers are arranged horizontally and then bent vertically, as in the fiber ribbon of Patent Document 1, the horizontal width of the optical module increases depending on the number of optical fibers, making it difficult to meet the demand for further miniaturization. When two components, a fiber array block and a glass plate, are used, as in the optical connection assembly of Patent Document 2, the number of components increases and precise positioning between these two components is required, which may increase manufacturing costs. Furthermore, in this optical connection assembly, the glass plate must have a certain thickness, and it is difficult to form waveguides in multiple layers within the glass plate along the thickness direction, making it difficult to arrange waveguides at a high density.

[0008] The present disclosure provides an optical fiber ribbon, an optical connection assembly, and a method for manufacturing an optical fiber ribbon that enable further miniaturization, reduced manufacturing costs, and high-density arrangement of glass fibers.

[0009] [Effects of the Present Disclosure] According to the optical fiber ribbon, optical connection assembly, and method for manufacturing an optical fiber ribbon of the present disclosure, it is possible to achieve further miniaturization, reduce manufacturing costs, and arrange glass fibers at a high density.

[0010] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0011] (1) An optical fiber ribbon according to one aspect of the present disclosure includes a plurality of glass fibers and a resin coating covering the outer peripheral surfaces of the plurality of glass fibers. Each of the plurality of glass fibers has a coating portion covered with the resin coating and an exposed portion including a tip surface exposed from the resin coating. The exposed portion has a bent portion including a bent section maintained with a radius of curvature of 10 mm or less. When viewed along a direction perpendicular to a plane including the arrangement direction in which the coating portions of the plurality of glass fibers are arranged and the extension direction in which the coating portions extend, the bent portion is bent in a direction intersecting the extension direction.

[0012] In the optical fiber ribbon, the exposed portion has a bent portion including a bent section with a curvature radius maintained at 10 mm or less. When viewed along a direction perpendicular to a plane including the arrangement direction of the coatings of the multiple glass fibers and the extension direction of the coatings, the bent portion is bent in a direction intersecting the extension direction. By forming such a bent portion, the optical fiber ribbon can be made low-profile. Furthermore, unlike a case where the bent portion is bent in a direction perpendicular to the plane (see, for example, Patent Document 1), the optical fiber ribbon can avoid an increase in width in a direction perpendicular to the plane (e.g., horizontal direction) even if the number of glass fibers is increased. This enables further miniaturization of the optical fiber ribbon. Unlike a case where a glass plate with a waveguide formed therein is used (see, for example, Patent Document 2), the optical fiber ribbon does not require multiple components (e.g., a fiber array block and a glass plate) to connect multiple glass fibers to a substrate, thereby simplifying the configuration of an optical connection assembly including the optical fiber ribbon. As a result, manufacturing costs can be reduced. Furthermore, by arranging a plurality of optical fiber ribbons in a direction perpendicular to the plane, it is possible to arrange many glass fibers at a high density. Therefore, the optical fiber ribbon can be further miniaturized, reduce manufacturing costs, and arrange glass fibers at a high density.

[0013] (2) In the optical fiber ribbon of (1), the bending directions of the respective bent portions of the plurality of glass fibers may be aligned in a single direction when viewed perpendicular to the plane, which makes it easy to form bent portions in each of the plurality of glass fibers.

[0014] (3) In the optical fiber ribbon described above in (1) or (2), the bent portions of the glass fibers may be positioned on a plane passing through the coating. In this case, the width of the optical fiber ribbon in a direction perpendicular to the plane (e.g., horizontally) can be kept smaller. This allows the optical fiber ribbon to be made even more compact.

[0015] (4) In the optical fiber ribbon according to any one of (1) to (3), the bent portion may include a first bent section having a curvature radius of 10 mm or less, and a second bent section having a curvature radius different from that of the first bent section. In this case, the change in the curvature radius in the bent portion can be made gradual. This can reduce the risk of breakage of the glass fiber when forming the bent portion in the glass fiber.

[0016] (5) In the optical fiber ribbon described in any one of (1) to (4), the exposed portion may include a first extending portion extending along the extending direction between the coating and the bent portion and a second extending portion extending in a direction intersecting the extending direction between the bent portion and the tip end surface. In this case, the first extending portion and the second extending portion allow the coating and the tip end surface of the glass fiber to be located away from the bent portion, which is heated during manufacturing of the optical fiber ribbon. This reduces the effect of heating during manufacturing of the optical fiber ribbon on the resin coating and the tip end surface.

[0017] (6) An optical connection assembly according to one aspect of the present disclosure may include the optical fiber ribbon according to any one of (1) to (5) above, and an optical connection component to which the tip ends, including the tip surfaces of the plurality of glass fibers, are connected. The optical connection assembly includes the optical fiber ribbon according to any one of (1) to (5) above, and therefore exhibits the above-mentioned effects.

[0018] (7) The optical connection assembly according to (6) above may further include a plurality of optical fiber ribbons. The plurality of optical fiber ribbons may be connected to the optical connection component in a state where they are arranged in a direction perpendicular to the plane. In this case, the optical fibers can be arranged at an even higher density.

[0019] (8) A method for manufacturing an optical fiber ribbon according to one aspect of the present disclosure includes the steps of: preparing an optical fiber ribbon including a plurality of glass fibers and a resin coating covering the outer peripheral surfaces of the plurality of glass fibers; and forming a bent portion in the exposed portion, including a bent section whose radius of curvature is maintained at 10 mm or less, by arranging the coating portions of the plurality of glass fibers covered with the resin coating and heating the exposed portions of the plurality of glass fibers that are exposed from the resin coating. In the step of forming the bent portion in the exposed portion, the bent portion is bent in a direction intersecting the extending direction when viewed along a direction perpendicular to a plane including the arrangement direction of the coating portions and the extension direction of the coating portions. This manufacturing method makes it possible to manufacture an optical fiber ribbon that can be further miniaturized, reduce manufacturing costs, and arrange glass fibers at a high density.

[0020] (9) In the method for manufacturing an optical fiber ribbon described in (8) above, in the step of forming a bent portion in the exposed portion, the bent portion may be formed in the exposed portion by rotating a second holding member holding the coating portions of the glass fibers around a first holding member while the position of the first holding member holding the exposed portions of the glass fibers is fixed when viewed in a direction perpendicular to the plane. In this case, the bending angle of the bent portion can be made smaller relative to the amount of rotation of the second holding member relative to the first holding member, compared to when the first holding member is rotated while the second holding member is fixed. This allows the radius of curvature of the bent portion to be adjusted more accurately. As a result, a bent portion maintaining a desired radius of curvature can be more reliably formed.

[0021] (10) In the method for manufacturing an optical fiber ribbon described in (9) above, in the step of forming the bent portion in the exposed portion, abutting members may be disposed in positions facing the respective tip surfaces of the plurality of glass fibers protruding from the first holding member, and the second holding member may be rotated around the first holding member while the abutting surfaces of the abutting members are abutted against the respective tip surfaces of the plurality of glass fibers. In this way, abutting the abutting surfaces of the abutting members against the respective tip surfaces of the plurality of glass fibers makes it possible to easily align the bent shapes of the bent portions formed in each of the plurality of glass fibers to a desired shape. This makes it possible to more reliably form bent portions in each of the plurality of glass fibers while maintaining a desired radius of curvature.

[0022] (11) In the manufacturing method of an optical fiber ribbon described in (10) above, in the step of forming the bent portion in the exposed portion, the abutting member may be arranged so that the angle of the abutting surface relative to the first holding member is variable when viewed along a direction perpendicular to the plane, and the second holding member may be rotated around the first holding member while changing the angle of the abutting surface with the abutting surface abutting against the tip end surface. In this case, by changing the angle of the abutting surface, the bent shape of the bent portion can be adjusted with high precision. This makes it possible to more reliably form bent portions in each of the multiple glass fibers while maintaining a desired radius of curvature.

[0023] [Details of the embodiments of the present disclosure] Specific examples of the optical fiber ribbon, optical connection assembly, and method of manufacturing the optical fiber ribbon of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same elements in the drawings will be given the same reference numerals, and duplicate descriptions will be omitted as appropriate.

[0024] 1A and 1B, the optical communications module 100 includes a substrate 11, a control circuit 12, a plurality of optical IC substrates 13, and a plurality of optical connection assemblies 10. For ease of explanation, an XYZ Cartesian coordinate system is shown in Fig. 1A. The X, Y, and Z directions intersect (e.g., are perpendicular to) each other.

[0025] The substrate 11 has a main surface 11a extending along the X and Z directions. The control circuit 12 is provided on the main surface 11a of the substrate 11. The control circuit 12 is, for example, an IC chip, and one example is a switch IC. A plurality of optical IC substrates 13 are arranged on the main surface 11a of the substrate 11 so as to surround the control circuit 12 and are electrically connected to the control circuit 12. Each optical IC substrate 13 is made of, for example, silicon, ceramic, or resin. A plurality of optical connection assemblies 10 are connected to a plurality of optical IC substrates 13, respectively. While the example of FIG. 1A shows a case in which four optical connection assemblies 10 are connected to four optical IC substrates 13, respectively, optical connection assemblies 10 may also be connected to other optical IC substrates 13, respectively.

[0026] 2 , 3A, and 3B , each of the optical connection assemblies 10 includes a plurality of optical connecting components 20 and a plurality of optical fiber ribbons 30. Each optical connecting component 20 is, for example, an adapter for connecting each optical fiber ribbon 30 to the optical IC substrate 13. Each optical connecting component 20 is disposed on the main surface 13a of the optical IC substrate 13 and is lined up in a row along the Z direction, for example. Each optical fiber ribbon 30 is lined up in a row along the Z direction corresponding to each optical connecting component 20. Each optical fiber ribbon 30 is connected to each optical connecting component 20 one by one. Each optical fiber ribbon 30 is connected to the optical IC substrate 13 by each optical connecting component 20.

[0027] As shown in FIGS. 3A and 3B , the optical fiber ribbon 30 includes a plurality of glass fibers 31, a plurality of resin coatings 32, and a ribbon resin 35. The glass fibers 31 are, for example, aligned in a row along the Y direction. The glass fibers 31 are, for example, single-mode fibers (SMF). The glass fibers 31 may be various optical fibers, such as polarization-maintaining optical fibers. The resin coatings 32 are provided on the outer peripheral surfaces 31 b (see FIG. 4B ) of the glass fibers 31, respectively. That is, each resin coating 32 covers the outer peripheral surface 31 b of each glass fiber 31. The resin coatings 32 may be, for example, integrated with one another.

[0028] The glass fiber 31 has an exposed portion 33 exposed from the resin coating 32 and a coated portion 34 coated with the resin coating 32. The exposed portion 33 includes a tip surface 31a of the glass fiber 31. A ribbon resin 35 collectively coats the multiple resin coatings 32. The coated portion 34 extends, for example, along the X direction. The exposed portion 33 is bent with respect to the X direction in which the coated portion 34 extends. As shown in FIG. 1B , the tip surface 31a is connected to the optical IC substrate 13 by an optical connecting part 20. The tip surface 31a is disposed to face the optical IC 13b on the main surface 13a of the optical IC substrate 13 and is optically connected to the optical IC 13b.

[0029] As shown in FIGS. 2 and 3A, the optical connecting part 20 entirely covers and holds the exposed portions 33 of the glass fibers 31. The optical connecting part 20 includes a main body 21, a protective part 22, and a cover 23. The main body 21 extends in the Z direction adjacent to the exposed portions 33 of the glass fibers 31. That is, the main body 21 extends so as to overlap the exposed portions 33 of the glass fibers 31 when viewed in the Z direction. The main body 21 includes a main body base 24 and a holding part 25. As shown in FIG. 2, the holding part 25 is a part of the main body 21 that faces the main surface 13a of the optical IC substrate 13. As shown in FIG. 3B, the holding part 25 is adjacent in the Z direction to the tip end 31c of the exposed portion 33, which includes the tip surface 31a. That is, when viewed along the Z direction, the holding portion 25 is disposed at a position overlapping with the respective tip ends 31 c of the plurality of glass fibers 31. The main body base 24 is a portion of the main body 21 located on the opposite side of the main surface 13 a with the holding portion 25 in between. The main body base 24 is adjacent to the main body 36 in the Z direction except for the tip end 31 c of the exposed portion 33 including the tip surface 31 a, and extends so as to overlap with the main body 36 in the Z direction. The material of each of the main body base 24 and the holding portion 25 includes, for example, glass or silicon.

[0030] 3B , the protective portion 22 is provided at a position facing the main surface 24a of the main body base 24 in the Z direction, sandwiching the exposed portions 33 of the multiple glass fibers 31. The protective portion 22 protects the exposed portions 33 of each glass fiber 31. The main body portion 36 of the exposed portions 33 of each glass fiber 31 is housed in an internal space formed by the main body base 24 and the protective portion 22. The material of the protective portion 22 is a protective resin containing, for example, UV (Ultra Violet) acrylic resin, epoxy resin, or silicone resin.

[0031] The lid portion 23 is provided at a position facing the main surface 25a of the holding portion 25 in the Z direction, sandwiching the tips 31c of the exposed portions 33 of the multiple glass fibers 31 between them. That is, the lid portion 23 is arranged to cover the main surface 25a of the holding portion 25, sandwiching the tips 31c of the exposed portions 33 of the multiple glass fibers 31 between them. The lid portion 23 and the holding portion 25 hold the tips 31c of the exposed portions 33 of each glass fiber 31. The main surface 25a of the holding portion 25 is formed with multiple V-grooves 25b extending along the Y direction. The multiple V-grooves 25b are aligned along the X direction. The tips 31c of the exposed portions 33 of the multiple glass fibers 31 are placed in the multiple V-grooves 25b, respectively. The material of the lid portion 23 includes, for example, glass or silicon.

[0032] Next, the configuration of the optical fiber ribbon 30 will be described in more detail. As shown in Figures 4A and 4B, the exposed portions 33 of the multiple glass fibers 31 include bent portions 41 that are bent relative to the X direction in which the coatings 34 extend. Here, an imaginary plane P is defined that includes the X direction in which the coatings 34 extend and the Y direction in which the coatings 34 are arranged. The plane P is set, for example, at a position that passes through the central axes C1 (see Figure 5A described later) of the coatings 34 of the multiple glass fibers 31 and is perpendicular to the Z direction. As shown in Figure 4B, the bent portions 41 of each glass fiber 31 are bent in the Y direction that intersects with the X direction in which the coatings 34 extend when viewed along the Z direction perpendicular to the plane P. Each bent portion 41 is located, for example, in the plane P that passes through the coatings 34 and is bent at the plane P. As such, in this embodiment, each bent portion 41 is bent in a direction along the plane P rather than in a direction perpendicular to the plane P.

[0033] "Each bent portion 41 is located on the plane P" means that at least a portion of each bent portion 41 is arranged to pass through the plane P. The bending direction of each bent portion 41 is a direction along the plane P that intersects with the X direction in which the covering portion 34 extends. The bending direction of each bent portion 41 is, for example, aligned in one direction (e.g., the Y direction) that intersects with the X direction on the plane P. Each bent portion 41 is bent, for example, in the Y direction that intersects with the X direction. In this case, each bent portion 41 is bent in a direction at 90 degrees relative to the X direction on the plane P. Each bent portion 41 may be bent in a direction at 45 degrees or less relative to the X direction on the plane P.

[0034] In this way, each bent portion 41 is located, for example, on a plane P including the X direction and the Y direction, and is bent from the X direction to the Y direction. Each bent portion 41 does not have to be located on the plane P. For example, each bent portion 41 may be located on another plane that is inclined with respect to the plane P and includes the X direction, as long as it is bent in a direction that intersects the X direction when viewed along the Z direction perpendicular to the plane P. In this case, the other plane may be inclined at an angle of 45 degrees or less with respect to the plane P, for example.

[0035] Not all of the bent portions 41 necessarily need to be located on the plane P, and any of the bent portions 41 may be positioned at a position shifted from the plane P. The bending directions of all of the bent portions 41 do not need to be aligned in the same direction (e.g., the Y direction) on the plane P. In other words, the bending direction of a first bent portion 41 among the multiple bent portions 41 may be shifted from the bending direction of a second bent portion 41. However, the bent portions 41 are positioned so as not to overlap with each other when viewed along a direction perpendicular to the plane P. When the first bent portion 41 is positioned more inward than the second bent portion 41, the radius of curvature of the first bent portion 41 (e.g., the minimum value of the radius of curvature) may be smaller than the radius of curvature of the second bent portion 41 (e.g., the minimum value of the radius of curvature), for example.

[0036] The exposed portion 33 of each glass fiber 31 has a bent portion 41 as well as a first extending portion 42 and a second extending portion 43. The bent portion 41 is formed, for example, in an intermediate portion of the exposed portion 33, away from the distal end surface 31a and the covering portion 34. The first extending portion 42 is located between the covering portion 34 and the bent portion 41 and extends along the X direction. The second extending portion 43 is located between the bent portion 41 and the distal end surface 31a and extends along the Y direction. FIGS. 5A and 5B show a boundary B1 between the bent portion 41 and the second extending portion 43 and a boundary B2 between the bent portion 41 and the first extending portion 42. The horizontal axis of FIG. 5B indicates the position in the central axis direction, which is the direction along the central axis C1 of the glass fiber 31. The vertical axis of FIG. 5B indicates the curvature of the glass fiber 31.

[0037] 5A and 5B , the bent portion 41 has a first bent section 41a and second bent sections 41b and 41c. The first bent section 41a is a section of the bent portion 41 that is distant from the first extending section 42 and the second extending section 43. The second bent section 41b is a section located between the second extending section 43 and the first bent section 41a. The second bent section 41c is a section located between the first bent section 41a and the first extending section 42.

[0038] The first curved section 41a is a section in which the curvature is maintained at 0.1 (1 / mm) or more (i.e., the radius of curvature is 10.0 mm or less). The curvature of the first curved section 41a is, for example, 0.1 (1 / mm) or more and 0.67 (1 / mm) or less. That is, the radius of curvature of the first curved section 41a is 1.5 mm or more and 10.0 mm or less. The first curved section 41a has a section in which the curvature is a constant value (e.g., 0.67 (1 / mm)) and a section in which the curvature changes.

[0039] The first bent section 41a is a section bent with a radius of curvature of 10.0 mm or less in a state in which no bending stress remains. The state in which no bending stress remains means a state in which distortion that occurs when the exposed portion 33 of the glass fiber 31 is bent is removed. For example, distortion that occurs in the exposed portion 33 can be removed by bending the exposed portion 33 while heating the exposed portion 33. In this case, the bent shape of the bent portion 41 can be maintained without fixing both ends of the bent portion 41, so no bending stress remains in the bent portion 41.

[0040] The second bent sections 41b and 41c are sections having a curvature different from that of the first bent section 41a. The second bent sections 41b and 41c are sections in which the curvature is maintained at, for example, less than 0.1 (1 / mm) (i.e., a radius of curvature greater than 10.0 mm). Therefore, the radius of curvature of the bent portion 41 is not constant at each position along the central axis direction of the glass fiber 31. The radius of curvature of the bent portion 41 may be constant (e.g., a radius of curvature of 10.0 mm) at each position along the central axis direction. The bent portion 41 may not have the second bent sections 41b and 41c, and may have only the first bent section 41a. In other words, the bent portion 41 may have only sections in which the radius of curvature is maintained at 10.0 mm or less.

[0041] When measuring the curvature of the bent portion 41, first, a projection image of the glass fiber 31 projected onto a plane is obtained. Next, an image (profile) showing the outline of the glass fiber 31 is generated based on the projection image. Next, based on the image showing the outline of the glass fiber 31, the trajectory along which the glass fiber 31 extends is obtained as a set of coordinates in an XY coordinate system. Finally, the curvature of the bent portion 41 is calculated for each coordinate based on the trajectory along which the glass fiber 31 extends. This allows the curvature of the bent portion 41 for each coordinate to be obtained. Therefore, the curvature in the present disclosure may be the curvature at one coordinate included in the trajectory along which the glass fiber 31 extends.

[0042] Next, a description will be given of a manufacturing method of the optical fiber ribbon 30. The manufacturing method of the optical fiber ribbon 30 includes a step of preparing the optical fiber ribbon 30 and a step of forming the bent portion 41. In the step of preparing the optical fiber ribbon 30, a predetermined length of part of the resin coating 32 and part of the ribbon resin 35 is removed from the tip end face 31 a to obtain the optical fiber ribbon 30 having the exposed portion 33 formed therein.

[0043] 6A, 6B, 7A, and 7B, in the step of forming bent portion 41, bent portion 41 is formed in exposed portion 33 using a bend forming device 60. Bend forming device 60 includes a base 61, a rotating stage 62, a first support table 63, a first holding member 64, a rotating table 65, a contact member 66, a second support table 67, a second holding member 68, and a third support table 69. Each component of bend forming device 60 will be described below.

[0044] The base 61 has a support surface 61a along the X and Y directions. The rotation stage 62 is placed on the support surface 61a. The rotation stage 62 is an annular stage and is rotatable around the center of the rotation stage 62. The rotation stage 62 has a support surface 62a along the X and Y directions. The support surface 62a is annular in shape and forms a step with respect to the support surface 61a by the thickness of the rotation stage 62. When viewed along the Z direction, the circular support surface 61a is exposed from the inside of the annular support surface 62a. The rotation stage 62 rotates, for example, by moving a handle 62b. As the rotation stage 62 rotates, the support surface 62a rotates relative to the support surface 61a.

[0045] The first support table 63 is placed on a support surface 61 a on the inner side of the rotation stage 62. The height of the first support table 63 from the support surface 61 a is greater than the height of the support surface 62 a from the support surface 61 a. The first holding member 64 is placed on the first support table 63. The first holding member 64 holds the exposed portions 33 of the plurality of glass fibers 31. The first holding member 64 may be fixed to the first support table 63. The first support table 63 may be fixed to the support surface 61 a.

[0046] The second support table 67 is placed on the support surface 62a of the rotation stage 62. The height of the second support table 67 from the support surface 61a is higher than the height of the support surface 62a from the support surface 61a, and is, for example, the same as the height of the first support table 63 from the support surface 61a. The second holding member 68 is placed on the second support table 67. The second holding member 68 holds the resin coatings 32 and the ribbon resin 35 of each of the multiple glass fibers 31. The second holding member 68 may be fixed to the second support table 67. The second support table 67 may be fixed to the support surface 62a.

[0047] The third support table 69 is placed on the outer support surface 61 a of the rotary stage 62. The third support table 69 extends from the outer support surface 61 a of the rotary stage 62, passing above the rotary stage 62, so as to be connected to the first support table 63 inside the rotary stage 62. The height of the third support table 69 from the support surface 61 a is higher than the height of the support surface 62 a from the support surface 61 a, and is, for example, lower than the height of the first support table 63 from the support surface 61 a.

[0048] The rotating table 65 is placed on a third support table 69. The rotating table 65 can be rotated around its center by, for example, moving a handle 65a. The outer diameter of the rotating table 65 is smaller than the outer diameter of the rotation stage 62. The rotating table 65 rotates in the same direction as the rotation direction of the rotation stage 62. The rotating table 65 may be fixed to the third support table 69. The third support table 69 may be fixed to the first support table 63 and the support surface 61a.

[0049] The abutting member 66 is placed on the rotating table 65. The abutting member 66 is fixed to the rotating table 65 and rotates together with the rotating table 65. The abutting member 66 is, for example, a rectangular plate member having an abutting surface 66a as a main surface, and is disposed so that the abutting surface 66a faces the first holding member 64. By rotating the abutting member 66 together with the rotating table 65, the angle of the abutting surface 66a relative to the first holding member 64 when viewed along the Z direction can be changed. The angle of the abutting surface 66a can be adjusted by adjusting the rotation angle of the rotating table 65. The abutting surface 66a abuts against the tip surfaces 31a of the multiple glass fibers 31 extending from the first holding member 64. The material of the abutting member 66 includes, for example, ceramic or metal.

[0050] As shown in FIG. 8 , the first holding member 64 has a support portion 64a and a lid portion 64b. The support portion 64a has a main surface 64c aligned along the X and Y directions. A plurality of grooves 64d extending along the Y direction are formed in the main surface 64c. The grooves 64d are aligned along the X direction. Each groove 64d is, for example, a V-shaped groove. The exposed portions 33 of the glass fibers 31 are placed in the grooves 64d formed in the main surface 64c. The lid portion 64b is disposed facing the main surface 64c in the Z direction and covers the exposed portions 33. The first holding member 64 includes, for example, a material that has low friction with the glass fibers 31, such as zirconia, glass, or silicon. This makes the exposed portions 33 less likely to be damaged when coming into contact with the first holding member 64. Each exposed portion 33 is movable along each groove 64d while being sandwiched between the support portion 64a and the cover portion 64b. Therefore, the first holding member 64 holds each exposed portion 33 in a state in which each exposed portion 33 is movable along the direction in which each groove 64d extends (the Y direction in the example of FIG. 8).

[0051] The second holding member 68 has a holding portion 68a and a lid portion 68b. The holding portion 68a has a main surface 68c aligned along the X and Y directions. A groove 68d extending along the X direction is formed in the main surface 68c. The groove 68d is, for example, a rectangular groove. The resin coating 32 and the ribbon resin 35 are placed in the groove 68d. The lid portion 68b is disposed facing the main surface 68c in the Z direction and covers the resin coating 32 and the ribbon resin 35. The holding portion 68a and the lid portion 68b sandwich and hold the resin coating 32 and the ribbon resin 35 placed in the groove 68d in the Z direction. In this state, the resin coating 32 and the ribbon resin 35 are fixed so as not to move relative to the second holding member 68.

[0052] Next, the step of forming the bent portion 41 will be described in detail. As shown in Figures 6A and 6B, in the step of forming the bent portion 41, the coatings 34 of the plurality of glass fibers 31 are arranged along the X direction, and the exposed portions 33 of the plurality of glass fibers 31 are heated to form the bent portion 41 in the exposed portions 33. As a result, as shown in Figures 7A and 7B, when viewed along the Z direction, the bent portion 41 is bent in the X direction intersecting with the Y direction. The step of forming the bent portion 41 includes, for example, the steps of placing a first holding member 64 and a second holding member 68 and moving the second holding member 68 relative to the first holding member 64.

[0053] 6A and 6B , in the step of placing the first holding member 64 and the second holding member 68, the first support table 63 and the third support table 69 are placed on the support surface 61 a of the pedestal 61, and the second support table 67 is placed on the support surface 62 a of the rotation stage 62. Then, the first holding member 64 is placed on the first support table 63, and the rotation table 65 and the abutment member 66 are placed on the third support table 69. The second holding member 68 is placed on the second support table 67. The exposed portions 33 of each glass fiber 31 are held by the first holding member 64. The resin coatings 32 of each glass fiber 31 and the ribbon resin 35 are held by the second holding member 68. In this state, the exposed portions 33 of each glass fiber 31 are not bent and extend linearly along the Y direction.

[0054] 7A and 7B , in the step of moving the second holding member 68 relatively to the first holding member 64, the second holding member 68 is moved relatively to the first holding member 64 so that a bent portion 41 is formed in the exposed portion 33 when viewed along the Z direction. In this embodiment, the exposed portion 33 is bent by rotating the second holding member 68 around the first holding member 64 while keeping the position of the first holding member 64 fixed when viewed along the Z direction. For example, the exposed portion 33 is bent by moving the handle 62b of the rotation stage 62 and rotating only the second holding member 68.

[0055] 9 , 10 , and 11 , in this step, the contact surface 66 a of the contact member 66 is brought into contact with the tip end surface 31 a of each glass fiber 31 protruding from the first holding member 64, and the second holding member 68 is rotated around the first holding member 64 while changing the angle of the contact surface 66 a relative to the first holding member 64. As the second holding member 68 rotates, the exposed portion 33 of each glass fiber 31 moves along the Y direction on the first holding member 64. The angle of the contact surface 66 a changes so that the tip end surface 31 a of each exposed portion 33 remains in contact with the contact surface 66 a. This allows the position of each tip end surface 31 a to be determined, thereby determining the desired bend shape (i.e., radius of curvature) of the bent portion 41. In this way, the abutment member 66 has the function of determining the bend shape of the bent portion 41. By adjusting the movement condition of the contact member 66 (i.e., the angle of the contact surface 66a), the bent shape of the bent portion 41 (i.e., the radius of curvature) can be adjusted.

[0056] In FIG. 9 , each exposed portion 33 extends linearly along the Y direction, and the arrangement direction D, in which the distal end surfaces 31 a are arranged, coincides with the X direction. In contrast, as shown in FIGS. 10 and 11 , by rotating the second holding member 68 and the abutting member 66 in the same direction, the inclination angle of the arrangement direction D with respect to the X direction increases as the bent portion 41 is formed. By rotating the abutting member 66 and the second holding member 68 while the distal end surfaces 31 a of each glass fiber 31 are abutting the abutting surface 66 a, the risk of the distal end surfaces 31 a moving in an unintended direction as the bent portion 41 is formed can be avoided, thereby more reliably forming the desired bent shape of the bent portion 41. As a result, it is possible to prevent the exposed portions 33 from interfering with each other and, for example, from adhering to each other.

[0057] In the step of moving the second holding member 68 relative to the first holding member 64, the exposed portion 33 is repeatedly heated and cooled while gradually bending the exposed portion 33. This allows the distortion generated in the exposed portion 33 to be gradually removed, thereby preventing the exposed portion 33 from breaking. When heating the exposed portion 33, the exposed portion 33 is heated by two discharge electrodes 70, 70 shown in FIG. 8. When cooling the exposed portion 33, the exposed portion 33 is placed inside a cooling chamber and a coolant is passed through it. At this time, the surface temperature of the bent portion of the exposed portion 33 is cooled at a rate of 100°C / s or more until it drops from the maximum temperature during heating to 1000°C or lower.

[0058] As shown in FIGS. 12A and 12B , the spacing between the multiple exposed portions 33 protruding from the first holding member 64 is determined according to the spacing between the multiple grooves 64d of the first holding member 64, regardless of the spacing between the multiple covered portions 34 (see FIG. 4B ). In other words, the first holding member 64 has the function of determining the spacing between the exposed portions 33. In FIGS. 12A and 12B , the spacing between the multiple covered portions 34 is 250 μm. In FIG. 12A , the spacing between the multiple exposed portions 33 protruding from the first holding member 64 is 500 μm. In FIG. 12B , the spacing between the multiple exposed portions 33 protruding from the first holding member 64 is 270 μm. In this way, by preparing multiple types of first holding members 64 with different spacings between the grooves 64d, the spacing between the exposed portions 33 can be adjusted to a desired size by selecting a first holding member 64 having a spacing between the grooves 64d that corresponds to the required spacing between the exposed portions 33.

[0059] The effects obtained by the optical fiber ribbon 30, optical connection assembly 10, and manufacturing method of the optical fiber ribbon 30 according to the present embodiment described above will now be described. In this embodiment, the exposed portion 33 has a bent portion 41 including a first bent section 41a whose radius of curvature is maintained at 10 mm or less. When viewed along the Z direction perpendicular to a plane P including the Y direction in which the coatings 34 of the multiple glass fibers 31 are arranged and the X direction in which the coatings 34 extend, the bent portion 41 is bent in the Y direction intersecting the X direction. By forming such a bent portion 41, the optical fiber ribbon 30 can be made low-profile. Furthermore, unlike when the bent portion 41 is bent in the Z direction perpendicular to the plane P (see, for example, Patent Document 1), this embodiment can avoid an increase in the width in the Z direction perpendicular to the plane P (e.g., the horizontal direction) even if the number of glass fibers 31 is increased, thereby enabling further miniaturization of the optical fiber ribbon 30. Unlike the case where a glass plate having a waveguide formed therein is used (see, for example, Patent Document 2), this embodiment does not require multiple components (e.g., a fiber array block and a glass plate) to connect multiple glass fibers 31 to the optical IC substrate 13, thereby simplifying the configuration of the optical connection assembly 10 including the optical fiber ribbon 30. As a result, manufacturing costs can be reduced. Furthermore, by arranging multiple optical fiber ribbons 30 along the Z direction perpendicular to the plane P, many glass fibers 31 can be arranged at high density. Therefore, this embodiment makes it possible to achieve further miniaturization, reduce manufacturing costs, and arrange the glass fibers 31 at high density.

[0060] Conventionally, a configuration has been known in which a plurality of glass fibers are arranged in the horizontal Z direction, and the bent portion of each glass fiber is bent in the vertical Y direction. In this configuration, the Z-direction width of the optical fiber ribbon increases depending on the number of glass fibers. Therefore, while maintaining the number of glass fibers, the horizontal width of the optical fiber ribbon cannot be made smaller than the sum of the outer diameters of the plurality of glass fibers. In comparison with this configuration, in this embodiment, when the plane P is positioned perpendicular to the horizontal Z direction, the bent portion 41 bends in the vertical Y direction, not in the horizontal Z direction. In this way, when the plurality of glass fibers 31 are arranged so as not to be aligned in the Z direction, the Z-direction width of the optical fiber ribbon 30 does not increase even if the number of glass fibers 31 increases. In other words, in this embodiment, the Z-direction width of the optical fiber ribbon 30 can be made smaller while maintaining the number of glass fibers 31. As a result, when the boundary line L is defined in the optical IC substrate 13 shown in Figure 2, the width of the optical fiber ribbon 30 when viewed along the Y direction can be made smaller than the length of the boundary line L, and therefore the index (e.g., Shoreline Bandwidth Density or Beach Front Bandwidth Density) obtained by dividing the total signal capacity that can pass through the boundary line L by the boundary line length can be increased.

[0061] As in this embodiment, the bending direction of each of the bent portions 41 of the plurality of glass fibers 31 may be aligned in one direction (for example, the Y direction) when viewed along the Z direction perpendicular to the plane P. In this case, the bent portions 41 can be easily formed for each of the plurality of glass fibers 31.

[0062] As in this embodiment, the bent portions 41 of the plurality of glass fibers 31 may be located on the plane P passing through the coating 34. In this case, the width of the optical fiber ribbon 30 in the Z direction perpendicular to the plane P can be kept small. This allows the optical fiber ribbon 30 to be made even more compact.

[0063] As in the present embodiment, the bent portion 41 may include a first bent section 41a having a curvature radius of 10 mm or less, and second bent sections 41b and 41c having curvature radii different from that of the first bent section 41a. In this case, the change in the curvature radius in the bent portion 41 can be made gentle. This reduces the risk of breakage of the glass fiber 31 when forming the bent portion 41 in the glass fiber 31.

[0064] As in the present embodiment, the exposed portion 33 may include a first extending portion 42 extending in the X direction between the coating 34 and the bent portion 41, and a second extending portion 43 extending in the Y direction between the bent portion 41 and the tip end face 31 a. In this case, the first extending portion 42 and the second extending portion 43 allow the coating 34 and the tip end face 31 a of the glass fiber 31 to be located away from the bent portion 41, which is heated during the manufacturing of the optical fiber ribbon 30. This reduces the effect of heating during the manufacturing of the optical fiber ribbon 30 on the resin coating 32 and the tip end face 31 a.

[0065] As in the present embodiment, in the step of forming the bent portion 41 in the exposed portion 33, the bent portion 41 may be formed in the exposed portion 33 by rotating the second holding member 68, which holds the coatings 34 of the plurality of glass fibers 31, around the first holding member 64 while the position of the first holding member 64, which holds the exposed portions 33 of the plurality of glass fibers 31, is fixed when viewed along the Z direction perpendicular to the plane P. In this case, the bending angle of the bent portion 41 can be made smaller relative to the amount of rotation of the second holding member 68 relative to the first holding member 64, compared to when the first holding member 64 is rotated while the second holding member 68 is fixed. This allows the radius of curvature of the bent portion 41 to be adjusted more accurately. As a result, the bent portion 41, which maintains the desired radius of curvature, can be more reliably formed.

[0066] As in this embodiment, in the step of forming the bent portions 41 in the exposed portions 33, the abutting members 66 may be disposed in positions facing the respective tip surfaces 31 a of the plurality of glass fibers 31 protruding from the first holding member 64, or the second holding member 68 may be rotated around the first holding member 64 with the abutting surfaces 66 a of the abutting members 66 abutting against the respective tip surfaces 31 a of the plurality of glass fibers 31. In this manner, by abutting the abutting surfaces 66 a of the abutting members 66 against the respective tip surfaces 31 a of the plurality of glass fibers 31, it is possible to easily align the bent shapes of the bent portions 41 formed in each of the plurality of glass fibers 31 to a desired shape. This makes it possible to more reliably form bent portions 41 in each of the plurality of glass fibers 31 while maintaining a desired radius of curvature.

[0067] As in the present embodiment, in the step of forming the bent portion 41 in the exposed portion 33, the abutting member 66 may be disposed so that the angle of the abutting surface 66a relative to the first holding member 64 is variable when viewed along the Z direction perpendicular to the plane P. Alternatively, the second holding member 68 may be rotated around the first holding member 64 while changing the angle of the abutting surface 66a with the abutting surface 66a abutting against the tip end surface 31a. In this case, by changing the angle of the abutting surface 66a, the bent shape of the bent portion 41 can be adjusted with high precision. This makes it possible to more reliably form bent portions 41 in each of the multiple glass fibers 31, each maintaining a desired radius of curvature.

[0068] The present disclosure is not limited to the above-described embodiment, and various other modifications are possible. In the above-described embodiment, the optical connection assembly 10 includes multiple optical connecting parts 20. However, as shown in Figures 13A, 13B, and 13C, the optical connection assembly 10A may include a single optical connecting part 20A. The optical connecting part 20A is an adapter to which the tip ends 31c of the multiple glass fibers 31 in the multiple optical fiber ribbons 30 (see Figures 14A and 14B) are connected. The multiple optical fiber ribbons 30 are connected to the optical connecting part 20A while being arranged along the Z direction.

[0069] The optical connecting component 20A includes a holding portion 26, a housing portion 27, and a protective portion 28. The holding portion 26 holds the tip portions 31c of the exposed portions 33 of the optical fiber ribbons 30. As shown in FIG. 13C , the holding portion 26 has a plurality of through holes 26a. The through holes 26a are aligned along the X and Z directions to correspond to the tip portions 31c. The through holes 26a open to a bottom surface 26b of the holding portion 26. As shown in FIG. 13A , the bottom surface 26b of the holding portion 26 is, for example, a plane extending along the X and Z directions and facing the main surface 13a of the optical IC substrate 13 in the Y direction. The tip portions 31c are inserted into the through holes 26a and fixed to the holding portion 26. The tip surfaces 31a do not protrude from the bottom surface 26b of the holding portion 26, but are located on the same plane as the bottom surface 26b. That is, each tip surface 31a is flush with the bottom surface 26b without any step. Each tip surface 31a may protrude from the bottom surface 26b of the holder 26. The material of the holder 26 includes, for example, glass or silicon.

[0070] The accommodating section 27 accommodates the exposed portion 33 of each optical fiber ribbon 30 except for the tip portion 31c. The material of the accommodating section 27 includes, for example, engineering plastic, PPS (polyphenylene sulfide), or LCP (liquid crystal polymer). The protective section 28 protects the exposed portion 33 of each optical fiber ribbon 30 except for the tip portion 31c. The protective section 28 is provided inside the accommodating section 27. The material of the protective section 28 is, for example, a resin filled inside the accommodating section 27. The exposed portion 33 of each optical fiber ribbon 30 except for the tip portion 31c is embedded inside the protective section 22. The material of the protective section 28 includes, for example, an acrylic resin, an epoxy resin, or a silicone resin.

[0071] A manufacturing method of the optical connection assembly 10A according to the modified example will be described. First, as shown in FIG. 14A , multiple optical fiber ribbons 30 manufactured in the same manner as in the above embodiment are prepared, and a holding section 26 and a housing section 27 are also prepared. Next, as shown in FIG. 14B , with the multiple optical fiber ribbons 30 stacked in the Z direction, the tip end 31 c of the exposed portion 33 of each optical fiber ribbon 30 is inserted from the housing section 27 into each through-hole 26 a of the holding section 26. Next, as shown in FIG. 14C , for example, an ultraviolet-curable resin is injected into the housing section 27 and irradiated with ultraviolet light to form a protective section 28, which is a solidified ultraviolet-curable resin. Thereafter, the tip end 31 c protruding from the bottom surface 26 b of the holding section 26 is cut off, so that the tip end surface 31 a of each optical fiber ribbon 30 is flush with the bottom surface 26 b of the holding section 26. Finally, each tip end surface 31 a is mirror-polished.

[0072] The optical connection assembly 10A according to the modified example includes the optical fiber ribbon 30 described in the above embodiment, and therefore provides the same effects as those of the above embodiment.

[0073] In the optical connection assembly 10A according to the modified example, the multiple optical fiber ribbons 30 are connected to the optical connecting part 20B in a state where they are arranged along the Z direction perpendicular to a plane P including the X direction and the Y direction. This allows the glass fibers 31 to be arranged at an even higher density.

[0074] In the optical connection assembly 10A according to the modified example, the tip faces 31 a of the optical fiber ribbons 30 are aligned in a direction inclined with respect to the X direction and along the Z direction. The tip portions 31 c of the optical fiber ribbons 30 are inserted into the through holes 26 a. When the tip faces 31 a of the optical fiber ribbons 30 are aligned along the X direction and the Z direction, the tip portions 31 c of all the optical fiber ribbons 30 need to be aligned with all the through holes 26 a simultaneously. However, the tip portions 31 c of the optical fiber ribbons 30 can be inserted into the through holes 26 a in rows along the X direction. Therefore, the tip portions 31 c of the optical fiber ribbons 30 can be easily inserted into the through holes 26 a.

[0075] In the above-described embodiment and modified examples, the exposed portion 33 of each glass fiber 31 may not have the first extending portion 42 and the second extending portion 43, and may have only the bent portion 41. The bent shapes of the bent portions 41 of each glass fiber 31 may not be the same as each other.

[0076] In the above-described embodiment and modified example, the bent portion 41 is formed on the exposed portion 33 while the coating portions 34 of the multiple glass fibers 31 are arranged along the X direction. The bent portion 41 may be formed on the exposed portion 33 while the coating portions 34 of the multiple glass fibers 31 are arranged along a direction other than the X direction (e.g., the Y direction). In this case, the bent portion 41 may be bent in a direction (e.g., the X direction) that intersects with a direction other than the X direction (e.g., the Y direction) when viewed along the Z direction. In the above-described embodiment and modified example, the first holding member 64 is fixed while the second holding member 68 is rotated. However, this is not limiting. The first holding member 64 may be rotated while the second holding member 68 is fixed, or both the first holding member 64 and the second holding member 68 may be rotated. The optical fiber ribbon 30 may be manufactured without using the bend forming device 60. For example, the optical fiber ribbon 30 may be manufactured by a device other than the bend forming device 60 or by a worker other than the bend forming device 60.

[0077] In the above-described embodiment and modified examples, the exposed portion 33 of the glass fiber 31 may be heated by a method other than arc discharge, for example, by a burner, a CO2 laser, or a heater. The exposed portion 33 may be cooled by a method other than a cooling chamber, for example, by directly spraying an inert gas (e.g., nitrogen) onto the exposed portion 33. In the above-described embodiment and modified examples, the heating and cooling of the exposed portion 33 are performed simultaneously with the step of moving the second holding member 68 relative to the first holding member 64, but this is not limiting. For example, the heating and cooling of the exposed portion 33 may be performed before or after the step of moving the support surface 62a relative to the first holding member 64.

[0078] DESCRIPTION OF SYMBOLS 10, 10A...Optical connection assembly 11...Substrate 11a...Main surface 12...Control circuit 13...Optical IC substrate 13a...Main surface 13b...Optical IC 20, 20A...Optical connection part 21...Main body 22...Protective part 23...Cover part 24...Main body base 24a...Main surface 25...Holding part 25a...Main surface 25b...V-groove 26...Holding part 26a...Through hole 26b...Bottom surface 27...Storage part 28...Protective part 30...Optical fiber ribbon 31...Glass fiber 31a...Tip surface 31b...Outer surface 31c...Tip part 32...Resin coating 33...Exposed part 34...Coating part 35...Ribbon resin 36...Main body 41...Bent part, first bent part, second bent part 41a...First bent section 41b, 41c...Second bent section DESCRIPTION OF THE REFERENCE NUMERALS 42...First extension portion 43...Second extension portion 60...Bending device 61...Base 61a...Support surface 62...Rotating stage 62a...Support surface 62b...Handle 63...First support base 64...First holding member 64a...Support portion 64b...Cover portion 64c...Main surface 64d...Groove portion 65...Rotating base 65a...Handle 66...Abutting member 66a...Abutting surface 67...Second support base 68...Second holding member 68a...Holding portion 68b...Cover portion 68c...Main surface 68d...Groove portion 69...Third support base 70...Discharge electrode 100...Optical communication module B1...Boundary B2...Boundary C1...Central axis D...Arrangement direction L...Boundary line P...Plane

Claims

1. An optical fiber ribbon comprising: a plurality of glass fibers; and a resin coating covering the outer peripheral surfaces of the plurality of glass fibers, wherein each of the plurality of glass fibers has a coated portion coated with the resin coating and an exposed portion including a tip surface exposed from the resin coating, wherein the exposed portion has a bent portion including a bent section maintained with a radius of curvature of 10 mm or less, and when viewed along a direction perpendicular to a plane including an arrangement direction in which the coated portions of the plurality of glass fibers are arranged and an extension direction in which the coated portions extend, the bent portion is bent in a direction intersecting the extension direction.

2. The optical fiber ribbon according to claim 1, wherein the bending direction of each of the bent portions of the plurality of glass fibers is aligned in one direction when viewed along a direction perpendicular to the plane.

3. An optical fiber ribbon according to claim 1 or 2, wherein the bent portions of each of the plurality of glass fibers are located on the plane passing through the coating portion.

4. An optical fiber ribbon according to any one of claims 1 to 3, wherein the bent portion includes a first bent section, which is the bent section maintained at a radius of curvature of 10 mm or less, and a second bent section maintained at a radius of curvature different from that of the first bent section.

5. An optical fiber ribbon according to any one of claims 1 to 4, wherein the exposed portion further includes: a first extending portion extending along the extending direction between the coated portion and the bent portion; and a second extending portion extending in a direction intersecting the extending direction between the bent portion and the tip surface.

6. An optical connection assembly comprising: an optical fiber ribbon according to any one of claims 1 to 5; and an optical connection part to which the tip portions including the tip faces of each of the plurality of glass fibers are connected.

7. The optical connection assembly according to claim 6, comprising a plurality of said optical fiber ribbons, said plurality of said optical fiber ribbons being connected to said optical connection component in a state where they are arranged along a direction perpendicular to said plane.

8. A method for manufacturing an optical fiber ribbon, comprising: a step of preparing an optical fiber ribbon comprising a plurality of glass fibers and a resin coating covering the outer surfaces of the plurality of glass fibers; and a step of arranging the coating portions of the plurality of glass fibers covered with the resin coating and heating the exposed portions of the plurality of glass fibers exposed from the resin coating to form a bent portion in the exposed portion, the bent portion including a bent section maintained at a radius of curvature of 10 mm or less, wherein in the step of forming the bent portion in the exposed portion, when viewed along a direction perpendicular to a plane including the arrangement direction in which the coating portions are arranged and the extension direction in which the coating portions extend, the bent portion is bent in a direction intersecting the extension direction.

9. A method for manufacturing an optical fiber ribbon as described in claim 8, wherein in the step of forming the bent portion in the exposed portion, the bent portion is formed in the exposed portion by rotating a second holding member that holds the coated portions of the plurality of glass fibers around a first holding member while fixing the position of the first holding member that holds the exposed portions of the plurality of glass fibers when viewed along a direction perpendicular to the plane.

10. A method for manufacturing an optical fiber ribbon as described in claim 9, wherein in the step of forming the bent portion in the exposed portion, an abutting member is placed in a position facing the tip surface of each of the plurality of glass fibers protruding from the first holding member, and the second holding member is rotated around the first holding member while the abutting surface of the abutting member is abutted against the tip surface of each of the plurality of glass fibers.

11. A method for manufacturing an optical fiber ribbon as described in claim 10, wherein in the step of forming the bent portion in the exposed portion, the abutment member is positioned so that the angle of the abutment surface relative to the first holding member is variable when viewed along a direction perpendicular to the plane, and with the abutment surface abutting the tip surface, the second holding member is rotated around the first holding member while changing the angle of the abutment surface.

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