Optical fiber holding component, optical fiber coupling structure, optical connector, and optical coupling structure

Abstract

An optical fiber holding component (10) according to the present disclosure is disposed inside a ferrule (30) and holds a plurality of optical fibers (20), the optical fiber holding component comprising: an outer surface (S10) including a first end surface (10a) and a second end surface (10b) that are arranged in a first direction (X); a plurality of through-holes (11) that penetrates from the first end surface (10a) to the second end surface (10b) in the first direction (X) and are arranged side by side in a second direction (Y) crossing the first direction (X); and at least one air discharge hole (16) that extends from the outer surface (S10) so as to cross the plurality of through-holes (11).

Description

Optical fiber holding component, optical fiber coupling structure, optical connector, and optical coupling structure

[0001] The present disclosure relates to an optical fiber holding component, an optical fiber coupling structure, an optical connector, and an optical coupling structure. This application claims priority to Japanese Application No. 2022-187491 filed on November 24, 2022, and incorporates by reference all of the contents of said Japanese application.

[0002] Conventionally, there is known an optical fiber holding component for holding a plurality of optical fibers (for example, Patent Document 1). This optical fiber holding component is placed inside a ferrule while holding a plurality of optical fibers, and is fixed to the ferrule in this state to form a connector. For example, a hole array having a plurality of fiber holes for inserting a plurality of optical fibers may be used as such an optical fiber holding component. In this case, for example, with an optical fiber inserted into each fiber hole, a liquid adhesive is injected into the fiber holes, and the adhesive hardens to fix the optical fibers in the fiber holes.

[0003] International Publication No. 2018 / 135368

[0004] An optical fiber holding component according to one embodiment of the present disclosure is an optical fiber holding component that is disposed inside a ferrule and holds a plurality of optical fibers, and comprises an outer surface including a first end face and a second end face that are aligned in a first direction, a plurality of through holes that penetrate in the first direction between the first end face and the second end face and are aligned in a second direction that intersects the first direction, and into which a plurality of optical fibers can be respectively inserted, and at least one air exhaust hole that extends from the outer surface so as to intersect with the plurality of through holes and is configured to exhaust air between the inner surfaces of the plurality of through holes and the adhesive from the plurality of through holes to the outside when adhesive is injected into the plurality of through holes.

[0005] 1 is a perspective view showing holding equipment for optical fiber according to the first embodiment. Fig. 2 is a plan view showing holding equipment for optical fiber of Fig. 1. Fig. 3 is a cross-sectional view of holding equipment for optical fiber along line III-III of Fig. 2. Fig. 4 is a cross-sectional view showing optical fiber coupling structure according to the first embodiment. Fig. 5 is a cross-sectional view of optical fiber coupling structure along line V-V of Fig. 4. Fig. 6 is an exploded perspective view showing optical connector according to the first embodiment. Fig. 7 is a perspective view showing optical connector of Fig. 6. Fig. 8 is a cross-sectional view of optical connector along line VIII-VIII of Fig. 7. Fig. 9 is a perspective view showing optical coupling structure according to the first embodiment. Fig. 10 is a cross-sectional view showing holding equipment for optical fiber according to modified example 1 of the first embodiment. Fig. 11 is a plan view showing holding equipment for optical fiber according to modified example 2 of the first embodiment. Fig. 12 is a plan view showing holding equipment for optical fiber according to modified example 3 of the first embodiment. Fig. 13 is a cross-sectional view showing holding equipment for optical fiber according to modified example 4 of the first embodiment. Fig. 14 is a cross-sectional view showing an enlarged main part of holding equipment for optical fiber of Fig. 13. Fig. 15 is a perspective view showing holding equipment for optical fiber according to the second embodiment. Fig. 16 is a plan view showing holding equipment for optical fiber of Fig. 15. Fig. 17 is a cross-sectional view showing holding equipment for optical fiber along XVII-XVII of Fig. 16. Fig. 18 is a plan view showing holding equipment for optical fiber according to modified example 1 of the second embodiment. Fig. 19 is a plan view showing holding equipment for optical fiber according to modified example 2 of the second embodiment. Fig. 20 is a perspective view showing holding equipment for optical fiber according to a third embodiment. Fig. 21 is a cross-sectional view showing holding equipment for optical fiber of Fig. 20. Fig. 22 is a perspective view showing holding equipment for optical fiber according to a fourth embodiment. Fig. 23 is a plan view showing holding equipment for optical fiber of Fig. 22.

[0006] [Problem to be Solved by the Present Disclosure] When injecting a liquid adhesive into fiber holes in a hole array, it is difficult to fill the holes without leaving any gaps between the inner surface of the fiber hole and the optical fiber. If the adhesive hardens while the fiber hole is not sufficiently filled with adhesive and air remains inside the fiber hole, a cavity will form between the inner surface of the fiber hole and the optical fiber. Such cavities are particularly likely to form in locations where there is a large gap between the inner surface of the fiber hole and the optical fiber. The formation of such cavities can lead to problems such as a decrease in the adhesion of the optical fiber to the fiber hole and an increase in the load on the optical fiber due to thermal expansion of the air in the fiber hole, which may affect the reliability of the optical fiber.

[0007] The present disclosure provides an optical fiber holding component, an optical fiber coupling structure, an optical connector, and an optical coupling structure that can maintain the reliability of an optical fiber.

[0008] [Effects of the Present Disclosure] According to the holding equipment for optical fiber, the optical fiber coupling structure, the optical connector, and the optical coupling structure of the present disclosure, the reliability of the optical fiber can be maintained.

[0009] [Explanation of embodiments of the present disclosure] First, the contents of the embodiments of the present disclosure will be listed and explained. (1) Holding equipment for optical fiber according to one embodiment of the present disclosure is arranged inside a ferrule and holds a plurality of optical fibers, and comprises an outer surface including a first end face and a second end face aligned in a first direction, a plurality of through holes penetrating in the first direction between the first end face and the second end face and aligned in a second direction intersecting the first direction, and at least one air exhaust hole extending from the outer surface to intersect with the plurality of through holes.

[0010] The above-mentioned holding equipment for optical fiber includes at least one air exhaust hole extending from the outer surface to intersect with the plurality of through holes. This air exhaust hole is configured to exhaust air between the inner surfaces of the plurality of through holes and the adhesive from the plurality of through holes to the outside when the adhesive is injected into the plurality of through holes. By providing this air exhaust hole, when the liquid adhesive is injected into each through hole, the air inside the through hole can be exhausted to the outside of the through hole, so that the adhesive can be sufficiently filled without gaps between the inner surface of the through hole and the optical fiber. This reduces the adhesive hardening with air remaining between the inner surface of the through hole and the optical fiber. In other words, it reduces the formation of voids between the inner surface of the through hole and the optical fiber. As a result, it is possible to reduce the occurrence of problems such as a decrease in adhesion of the optical fiber to the inner surface of the through hole due to the formation of voids inside the through hole and an increase in load on the optical fiber due to thermal expansion of the air inside the through hole. As a result, it is possible to maintain the reliability of the optical fiber.

[0011] (2) In the holding equipment for optical fiber described in (1) above, the outer surface further includes a side surface extending along the first direction and the second direction between the first end face and the second end face. The side surface has an opening of at least one air exhaust hole. At least one air exhaust hole may extend from the side surface to a plurality of through holes. In this case, the air exhaust hole can be extended upward from the plurality of through holes to the side surface. Since the air inside the through hole is relatively more likely to move upward than the liquid adhesive, by configuring the air exhaust hole to extend upward, the air inside the through hole can be efficiently exhausted to the outside. Furthermore, with this configuration, it is also possible to make it difficult for the adhesive inside the through hole to leak onto the side surface from the air exhaust hole.

[0012] (3) In the holding equipment for optical fiber described in (1) or (2) above, at least one air exhaust hole may extend in a direction inclined from an imaginary line perpendicular to the central axes of the plurality of through holes extending in the first direction in a cross section perpendicular to the second direction. In this way, when the air exhaust hole extends in a direction inclined, the length of the air exhaust hole from the through hole to the side surface can be made longer compared to when the air exhaust hole extends along an imaginary line perpendicular to the central axes of the through holes. In this way, by increasing the distance of the path of the adhesive from the through hole to the side surface, it is possible to make it difficult for the adhesive inside the through hole to leak onto the side surface from the air exhaust hole.

[0013] (4) In the holding equipment for optical fiber described in any one of the above (1) to (3), one air exhaust hole may be provided as the at least one air exhaust hole, and one air exhaust hole may be connected to all of the plurality of through holes. In this case, when injecting adhesive into the through holes, the air inside the through holes can be more reliably exhausted to the outside through the air exhaust hole, so that the formation of cavities inside the through holes can be more effectively reduced.

[0014] (5) In the holding equipment for optical fiber described in any one of (1) to (3) above, at least one air exhaust hole may comprise a plurality of air exhaust holes arranged in the second direction corresponding to the plurality of through holes, and the plurality of air exhaust holes may be individually connected to the plurality of through holes. In this case, when adhesive is injected into each through hole, it is possible to reduce the adhesive leaking from one through hole to the adjacent through hole via the air exhaust hole. This makes it possible to reliably bond optical fibers individually to each through hole.

[0015] (6) In the holding equipment for optical fiber described in the above (5), the inner diameter of each of the plurality of air exhaust holes may be smaller than the inner diameter of each of the plurality of through holes. By making the inner diameter of the air exhaust holes smaller in this way, it is possible to make it difficult for the adhesive inside the through holes to leak out from the air exhaust holes onto the outer surface.

[0016] (7) In the holding equipment for optical fiber described in the above (5) or (6), each of the plurality of air exhaust holes may be an elongated hole extending in the first direction between the first end face and the second end face. In this case, when injecting adhesive into the through hole, air can be exhausted to the outside from more parts of the through hole through the air exhaust holes, so that it is possible to more effectively reduce the formation of a cavity inside the through hole.

[0017] (8) In the holding equipment for optical fiber described in any one of the above (5) to (7), a recess is formed on the outer surface, extending in the second direction so as to intersect with all of the plurality of air exhaust holes, and each of the plurality of air exhaust holes may be open to the bottom surface of the recess. The existence of such a recess provides a space for storing adhesive leaked from the air exhaust holes, so that the leakage of adhesive from the air exhaust holes onto the outer surface can be more reliably reduced.

[0018] (9) In the holding equipment for optical fiber according to any one of (1) to (8) above, each of the plurality of through holes has a thin diameter portion capable of holding a coating-removed portion which is a part of the plurality of optical fibers from which the coating has been removed, a thick diameter portion extending in a first direction between the thin diameter portion and the second end face and capable of holding a coating portion which is the other part of the plurality of optical fibers from which the coating remains, and an expanded diameter portion connecting the thin diameter portion and the thick diameter portion and expanding in inner diameter from the thin diameter portion toward the thick diameter portion, and at least one air exhaust hole may be connected to the expanded diameter portion from the outer surface. In this case, since the gap between the optical fiber and the expanded diameter portion is particularly likely to be large, air is particularly likely to be left inside the expanded diameter portion when adhesive is injected into the through hole. Therefore, if the air exhaust hole is configured to be connected to the expanded diameter portion, air inside the through hole can be efficiently exhausted to the outside.

[0019] (10) In the optical fiber holding equipment described in (1) to (8) above, it further comprises a plurality of injection holes that extend from the outer surface to intersect with the plurality of through holes and are individually connected to the plurality of through holes, and can inject adhesive for adhering the plurality of optical fibers to the plurality of through holes, and each of the plurality of through holes has a thin diameter section that can hold a coating-removed section that is a part of the plurality of optical fibers from which the coating has been removed, and a thick diameter section that extends in a first direction between the holding section and the second end face and can hold a coated section that is the other part of the plurality of optical fibers from which the coating remains, and has an inner diameter larger than that of the thin diameter section, and an enlarged diameter section that connects between the thin diameter section and the thick diameter section in the first direction and whose inner diameter enlarges from the thin diameter section toward the thick diameter section in the first direction, and at least one air exhaust hole is connected to any of the thin diameter section, the thick diameter section, and the enlarged diameter section, and each of the plurality of injection holes may be connected to a section of the thin diameter section, the thick diameter section, and the enlarged diameter section that is different from the section to which at least one air exhaust hole is connected. In this case, the injection holes for injecting the adhesive extend intersecting the through holes and are individually connected to the through holes, allowing the adhesive to be individually injected into the through holes via a route separate from the through holes. In this configuration, by adjusting the position of the injection hole relative to the through holes and the amount of adhesive injected, etc., taking into account the fluidity of the adhesive, the adhesive can be reliably filled between the optical fiber and the through hole without gaps, and the adhesive can be distributed evenly around the optical fiber. This allows the stress generated when the adhesive hardens to act uniformly on the optical fiber, reducing the possibility of the optical fiber being subjected to the stress in one direction and causing it to shift in position. Furthermore, in the above configuration, the air exhaust hole is connected to a location different from the location of the through hole to which the injection hole is connected. The aforementioned voids are likely to form inside the through hole at a location away from the location where the adhesive is injected. Therefore, by configuring the air exhaust hole to be connected to a location different from the location to which the injection hole is connected, the formation of voids inside the through hole can be effectively reduced.

[0020] (11) In the holding equipment for optical fiber described in the above (10), at least one air exhaust hole may be connected to the expanded diameter part, and each of the plurality of injection holes may be connected to either the narrow diameter part or the large diameter part. In this case, by connecting the air exhaust hole to the expanded diameter part where air is particularly likely to be left behind, the air inside the through hole can be efficiently exhausted to the outside. This can effectively reduce the formation of cavities inside the through hole.

[0021] (12) In the holding equipment for optical fiber described in the above (10), at least one air exhaust hole may be connected to the small diameter part, and each of the plurality of injection holes may be connected to the large diameter part. When injecting adhesive into the through hole, air tends to be left behind in the small diameter part away from the large diameter part to which the injection hole is connected. Therefore, by connecting the air exhaust hole to the small diameter part, the air inside the through hole can be efficiently exhausted to the outside. This can effectively reduce the formation of cavities inside the through hole.

[0022] (13) In the holding equipment for optical fiber described in the above (10), at least one air exhaust hole may be connected to the large diameter part, and each of the plurality of injection holes may be connected to the small diameter part. When injecting adhesive into the through hole, air tends to be left behind in the large diameter part away from the small diameter part to which the injection hole is connected. Therefore, by connecting the air exhaust hole to the large diameter part, the air inside the through hole can be efficiently exhausted to the outside. This can effectively reduce the formation of cavities inside the through hole.

[0023] (14) In the holding equipment for optical fiber described in any of the above (9) to (13), the small diameter part may be configured to hold the coating removing part rotatably around the central axis of the coating removing part. In this case, by performing rotational alignment of the coating removing part of the optical fiber in the small diameter part of the through hole, the position of the rotational direction of the optical fiber with respect to the holding equipment for optical fiber can be determined.

[0024] (15) In the holding equipment for optical fiber according to any one of (1) to (8), the outer surface may further include a first wall surface between the first end face and the second end face, aligned with the first end face in the first direction, and a second wall surface between the first wall surface and the second end face, extending along the first and second directions so as to intersect with the first wall surface, and the plurality of through holes may penetrate between the first end face and the first wall surface in the first direction, and the second wall surface may be formed at a position offset from the plurality of through holes in a third direction intersecting both the first and second directions. In this case, the coating removal portion of the optical fiber can be inserted into the through hole from the first wall surface toward the first end face, and the coating portion of the optical fiber can be placed and fixed on the second wall surface. In this configuration, the length of the through hole can be shorter than in a configuration in which the through hole is formed from the first end face to the second end face. If the length of the through hole is shorter, air inside the through hole can more easily escape from the opening of the through hole to the outside, reducing the risk of air being left inside the through hole. This effectively reduces the formation of a cavity inside the through hole.

[0025] (16) An optical fiber coupling structure according to an embodiment of the present disclosure comprises: holding equipment for optical fiber according to any one of (1) to (15) above; a plurality of optical fibers inserted into a plurality of through holes, respectively; and an adhesive provided inside the plurality of through holes and fixing the plurality of optical fibers to the plurality of through holes. Since this optical fiber coupling structure comprises any one of the above-mentioned holding equipment for optical fiber, it is possible to maintain the reliability of the optical fiber as described above.

[0026] (17) In the optical fiber coupling structure described in (16) above, each of the plurality of optical fibers may have at least one core in an area shifted from the central axis. In this case, by performing rotational alignment of the optical fiber in the through hole, the position of the optical fiber in the rotational direction relative to the holding equipment for optical fiber can be determined.

[0027] (18) An optical connector according to an embodiment of the present disclosure may include the optical fiber coupling structure of (16) or (17) above and a ferrule that houses at least a part of the optical fiber coupling structure. Since this optical connector includes any of the above-mentioned holding components for optical fiber, it is possible to maintain the reliability of the optical fiber as described above.

[0028] (19) In the optical connector described in (18) above, the ferrule has a receiving hole for receiving holding equipment for optical fiber, and a plurality of fiber holding holes connected to the receiving hole in a first direction and each holding a plurality of optical fibers extending from holding equipment for optical fiber in the first direction, and the outer surface has a first side surface and a second side surface facing each other across a plurality of through holes in a third direction intersecting both the first direction and the second direction, and a third side surface connecting the first side surface and the second side surface in the third direction, and the receiving hole may include a first inner surface contacting the second side surface and a second inner surface contacting the third side surface. In this case, the second side surface and the third side surface of holding equipment for optical fiber contact the first inner surface and the second inner surface of the ferrule, respectively, so that the position of holding equipment for optical fiber with respect to the ferrule can be precisely determined.

[0029] (20) An optical coupling structure according to an embodiment of the present disclosure includes a first optical connector and a second optical connector as the optical connectors of (18) or (19), the first optical connector and the second optical connector facing each other across a gap in a first direction. In this way, when the first optical connector and the second optical connector are not connected by physical contact (PC), pressing force for connecting the first optical connector and the second optical connector by PC is not required, making it possible to easily connect a larger number of optical fibers at once.

[0030] [Details of the embodiment of the present disclosure] Specific examples of holding equipment for optical fiber, optical fiber coupling structure, optical connector, and optical coupling structure according to the embodiment 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 description of the drawings will be given the same reference numerals, and duplicated descriptions will be omitted as appropriate.

[0031] 1 is a perspective view of holding equipment for optical fiber 10 according to the first embodiment. Fig. 2 is a plan view showing holding equipment for optical fiber 10. Fig. 3 is a cross-sectional view of holding equipment for optical fiber 10 taken along line III-III in Fig. 2. Holding equipment for optical fiber 10 shown in Fig. 1, Fig. 2 and Fig. 3 is a part for holding a plurality of optical fibers 20. Holding equipment for optical fiber 10 is placed inside a ferrule 30 while holding a plurality of optical fibers 20 (see Fig. 7). Fig. 1 shows an XYZ orthogonal coordinate system for easy understanding. As shown in Fig. 1, holding equipment for optical fiber 10 has a rectangular parallelepiped appearance with the Y direction (second direction) as the longitudinal direction, the X direction (first direction) as the lateral direction and the Z direction (third direction) as the thickness direction, for example. In the following description, "up and down" may be defined by the relative position of the Z coordinate, "front and back" by the relative position of the X coordinate and "left and right" by the relative position of the Y coordinate. A larger Z coordinate is "up". A larger X coordinate is "front". The larger the Y coordinate, the "right."

[0032] 10。 The holding equipment for optical fiber 10 is made of, for example, a resin that can transmit ultraviolet light, which is used when hardening adhesive A (see FIG. 4) described later. The holding equipment for optical fiber 10 may be made of, for example, quartz glass that can transmit ultraviolet light. "Transmittable to ultraviolet light" means that the transmittance of a material with a thickness of 3 mm for light of wavelength 350 nm to 400 nm is 40% or more. When such resin or quartz glass is used as the material of the holding equipment for optical fiber 10, the holding equipment for optical fiber 10 can be manufactured cheaply and with high precision. The holding equipment for optical fiber 10 is not limited to these materials, and may be made of metal. When metal is used as the material of the holding equipment for optical fiber 10, high dimensional precision can be maintained, so the holding equipment for optical fiber 10 can be manufactured with higher precision. Furthermore, when the holding equipment for optical fiber 10 is made of materials such as quartz glass and metal, frictional resistance between the holding equipment for optical fiber 10 and multiple optical fibers 20 can be reduced, so that the rotational alignment of multiple optical fibers 20 can be easily performed when multiple optical fibers 20 are placed in the holding equipment for optical fiber 10.

[0033] 1, the outer surface S10 of holding equipment 10 for optical fiber includes, for example, a front surface 10a (first end surface), a rear surface 10b (second end surface), an upper surface 10c (first side surface), a lower surface 10d (second side surface), a side surface 10e (third side surface), and a side surface 10f. The front surface 10a is the front end surface of holding equipment 10 for optical fiber in the X direction. The front surface 10a is, for example, a plane along the YZ plane. The rear surface 10b is the rear end surface of holding equipment 10 for optical fiber in the X direction, and is arranged side by side with the front surface 10a in the X direction. The rear surface 10b is, for example, a plane along the YZ plane. The normal direction of the rear surface 10b coincides, for example, with the normal direction of the front surface 10a.

[0034] The upper surface 10c is the upper end surface of holding equipment for optical fiber 10 in the Z direction. The upper surface 10c is, for example, a plane along the XY plane, and connects the front surface 10a and the rear surface 10b. The lower surface 10d is an end surface located at the lower end of holding equipment for optical fiber 10 in the Z direction, and is arranged side by side with the upper surface 10c in the Z direction. The upper surface 10c and the lower surface 10d are arranged on both sides of a plurality of through holes 11, which will be described later, in the Z direction. The lower surface 10d is, for example, a plane along the XY plane, and connects the front surface 10a and the rear surface 10b in the X direction at a position opposite to the upper surface 10c in the Z direction. The normal direction of the lower surface 10d coincides with the normal direction of the upper surface 10c, for example. The normal directions of the upper surface 10c and the lower surface 10d are, for example, perpendicular to the normal directions of the front surface 10a and the rear surface 10b. In this case, the upper surface 10c and the lower surface 10d are perpendicular to the front surface 10a and the rear surface 10b.

[0035] The side surface 10e is the right end surface of holding equipment for optical fiber 10 in the Y direction and faces the Y direction. The side surface 10e is, for example, a plane along the XZ plane and connects the front surface 10a and the rear surface 10b. The side surface 10f is, for example, the left end surface of holding equipment for optical fiber 10 in the Y direction and faces the opposite side of the Y direction. The side surface 10f is, for example, a plane along the XZ plane and connects the front surface 10a and the rear surface 10b at a position opposite to the side surface 10e in the Y direction. The normal direction of the side surface 10f coincides with the normal direction of the side surface 10e, for example. The normal directions of the side surfaces 10e and 10f are, for example, perpendicular to the normal directions of the front surface 10a and the rear surface 10b and the normal directions of the upper surface 10c and the lower surface 10d. In this case, the side surfaces 10e and 10f are perpendicular to the front surface 10a, the rear surface 10b, the upper surface 10c, and the lower surface 10d.

[0036] 1 and 2, the holding equipment for optical fiber 10 further comprises a plurality of through holes 11 for holding a plurality of optical fibers 20 (see FIG. 4), respectively. Each through hole 11 penetrates from the front surface 10a to the rear surface 10b along the X direction, and is arranged in a row in the Y direction between the front surface 10a and the rear surface 10b. For example, each through hole 11 is formed at a position closer to the upper surface 10c than to the lower surface 10d in the Z direction. As shown in FIG. 2, each through hole 11 extends linearly from the front surface 10a to the rear surface 10b along the X direction, and is open to the front surface 10a and the rear surface 10b. Each through hole 11 is, for example, circular when viewed in the X direction.

[0037] The front surface 10a has a plurality of openings 11a through which the plurality of through holes 11 are respectively opened. The openings 11a are arranged in a line in the Y direction corresponding to the respective through holes 11. The rear surface 10b has a plurality of openings 11b (see FIG. 2) through which the plurality of through holes 11 are respectively opened. The openings 11b are arranged in a line in the Y direction corresponding to the respective through holes 11. The inner diameter of each opening 11b is larger than the inner diameter of each opening 11a. Note that while FIGS. 1 and 2 illustrate an example in which twelve through holes 11 are arranged in a line at equal intervals in the Y direction, the number of through holes 11 is not limited to twelve and may be other numbers such as four, eight, or sixteen. Furthermore, the through holes 11 do not have to be arranged in a line but may be arranged in two or more lines.

[0038] 3, each through hole 11 has, for example, a small diameter portion 12a, an enlarged diameter portion 12b, and a large diameter portion 13. The small diameter portion 12a and the enlarged diameter portion 12b constitute a holding portion 12 for holding a coating removal portion 22 (see FIG. 4), which will be described later. The large diameter portion 13 is configured as a fixing portion for fixing a coating portion 23 (see FIG. 4), which will be described later.

[0039] The holding portion 12 is located between the front surface 10a and the rear surface 10b and closer to the front surface 10a in the X direction. The small-diameter portion 12a of the holding portion 12 extends linearly in the X direction from the front surface 10a toward the rear surface 10b. The small-diameter portion 12a has an inner diameter that allows the coating removal portion 22 of the optical fiber 20 to be inserted therein. The small-diameter portion 12a is configured to rotatably hold the coating removal portion 22 about the central axis L1 of the optical fiber 20. The small-diameter portion 12a being configured to rotatably hold the coating removal portion 22 about the central axis L1 means that the inner diameter of the small-diameter portion 12a is set large enough to allow rotation of the coating removal portion 22 about the central axis L1, and small enough to determine the position of the coating removal portion 22 in the YZ plane. The inner diameter of the small-diameter portion 12a is constant at each position along the X direction of the small-diameter portion 12a. In this specification, "a constant inner diameter" includes both a completely constant inner diameter and a substantially constant inner diameter within the range of manufacturing tolerances and the like.

[0040] The inner diameter of the thin-diameter part 12a is set larger than the outer diameter of the coating removal part 22, taking into consideration that rotational alignment of the optical fiber 20 is performed in the through-hole 11. On the other hand, if the inner diameter of the thin-diameter part 12a is too large, when mounting the holding equipment 10 for optical fiber in the ferrule 30, the central axis of the fiber holding hole 33 in the ferrule 30 and the central axis of the optical fiber 20 will not align, which may make the mounting work difficult (see Fig. 8). In consideration of these, for example, when the outer diameter of the coating removal part 22 is 124 µm or more and 126 µm or less, the inner diameter of the thin-diameter part 12a may be 126 µm or more and 156 µm or less.

[0041] The large-diameter portion 13 is located between the front surface 10a and the rear surface 10b and closer to the rear surface 10b in the X direction. The large-diameter portion 13 extends linearly in the X direction from the rear surface 10b toward the small-diameter portion 12a. The large-diameter portion 13 has an inner diameter that allows the coating 23 of the optical fiber 20 to be inserted therein. The large-diameter portion 13 is configured to hold the coating 23 rotatably about the central axis L1. Therefore, the inner diameter of the large-diameter portion 13 is set to be large enough to allow rotation of the coating 23 about the central axis L1, and small enough to determine the position of the coating 23 in the YZ plane. The inner diameter of the large-diameter portion 13 is constant at each position along the X direction.

[0042] The inner diameter of the large diameter part 13 is set to be larger than the outer diameter of the coating part 23, taking into consideration that rotational alignment of the optical fiber 20 is performed in the through hole 11. On the other hand, if the inner diameter of the large diameter part 13 is too large, when mounting holding equipment 10 for optical fiber in the ferrule 30, the central axis of the fiber holding hole 33 in the ferrule 30 and the central axis of the optical fiber 20 will not align, which may make the mounting work difficult (see Fig. 8). In consideration of these, for example, when the outer diameter of the coating part 23 is 190 µm or more and 210 µm or less, the inner diameter of the large diameter part 13 may be 210 µm or more and 240 µm or less.

[0043] The expanded diameter portion 12b is located between the thin diameter portion 12a and the thick diameter portion 13 in the X direction. The expanded diameter portion 12b connects the thin diameter portion 12a and the thick diameter portion 13. The inner diameter of the expanded diameter portion 12b is set to gradually increase from the thin diameter portion 12a toward the thick diameter portion 13 in the X direction. The inner diameter of the connection end of the expanded diameter portion 12b with the thin diameter portion 12a (i.e., the front end of the expanded diameter portion 12b in the X direction) is the same as the inner diameter of the thin diameter portion 12a, and the inner diameter of the connection end of the expanded diameter portion 12b with the thick diameter portion 13 (i.e., the rear end of the expanded diameter portion 12b in the X direction) is the same as the inner diameter of the thick diameter portion 13. The length of the expanded diameter portion 12b in the X direction may be, for example, 100 μm.

[0044] 1 and 2, the holding equipment for optical fiber 10 further comprises a plurality of air exhaust holes 16. Each air exhaust hole 16 is arranged in a row in the Y direction corresponding to each through hole 11, and extends from the upper surface 10c in the Z direction and is individually connected to each through hole 11. "Each air exhaust hole 16 is individually connected to each through hole 11" means that one air exhaust hole 16 is connected to one through hole 11, and one air exhaust hole 16 is not connected to two or more through holes 11. The shape of the air exhaust hole 16 seen in the Z direction is, for example, circular.

[0045] The air exhaust hole 16 extends linearly in the Z direction from the upper surface 10c to the through hole 11, for example, so as to intersect with the through hole 11. The central axis L2 of the air exhaust hole 16 is, for example, perpendicular to the central axis L1 of the through hole 11. An opening 16a of the air exhaust hole 16 is formed in the upper surface 10c. The air exhaust hole 16 extends downward from the opening 16a in the Z direction, for example, and is connected to the expanded diameter portion 12b of the through hole 11. Therefore, when viewed in the Z direction, the air exhaust hole 16 is arranged to overlap the expanded diameter portion 12b.

[0046] The air exhaust hole 16 is configured to exhaust air that may be left inside the through hole 11 when the adhesive A (see FIG. 4) is injected into the through hole 11 to the outside of the through hole 11. Specifically, the air exhaust hole 16 has an inner diameter that allows the air inside the through hole 11 to pass through, and forms a path that allows the air to pass from the upper surface 10c to the through hole 11. The inner diameter that allows the air to pass through means an inner diameter that is large enough that the air inside the through hole 11 can flow inside the air exhaust hole 16 and flow out of the holding equipment for optical fiber 10 from the opening 16a. The inner diameter of the air exhaust hole 16 may be constant at each position along the Z direction of the air exhaust hole 16, for example. The size of the inner diameter of the air exhaust hole 16 may be large enough to allow air to pass through, but if the inner diameter of the air exhaust hole 16 is excessively large, there is a concern that the liquid adhesive A injected into the through hole 11 will flow through the air exhaust hole 16 and leak out onto the upper surface 10c. Therefore, the inner diameter of the air exhaust hole 16 is selected to be large enough to allow air to pass through and to prevent the liquid adhesive A from flowing and leaking out onto the upper surface 10c.

[0047] For example, the inner diameter of the air exhaust hole 16 may be smaller than the inner diameter of the through hole 11. Here, the inner diameter of the through hole 11 may be the smallest inner diameter among the inner diameters of the through hole 11 at each portion along the X direction (i.e., the minimum inner diameter of the through hole 11). In this embodiment, the minimum inner diameter of the through hole 11 refers to the inner diameter of the thin-diameter portion 12a. Therefore, the inner diameter of the air exhaust hole 16 may be smaller than the inner diameter of the thin-diameter portion 12a. Therefore, the inner diameter of the opening 16a may be smaller than the inner diameter of the opening 11a. Note that if the inner diameter of the air exhaust hole 16 varies at each position along the Z direction, the smallest inner diameter among the inner diameters of the air exhaust hole 16 at each portion along the X direction (i.e., the minimum inner diameter of the air exhaust hole 16) may be used. The inner diameter of the air exhaust hole 16 may be, for example, 10 μm or more, which allows air to be exhausted. Furthermore, to avoid a situation in which adjacent through holes 11 communicate with each other via air exhaust holes 16, the inner diameter of air exhaust holes 16 may be equal to or smaller than the pitch of through holes 11 (e.g., the distance between the centers of through holes 11). For example, if the pitch of through holes 11 is 250 μm, the inner diameter of air exhaust holes 16 may be equal to or smaller than 250 μm. The inner diameter of air exhaust holes 16 may be equal to or larger than the inner diameter of narrow diameter portion 12 a or the inner diameter of large diameter portion 13.

[0048] The air exhaust holes 16 do not necessarily have to be connected to the expanded diameter portions 12b of the through holes 11, but may be connected to the narrow diameter portions 12a or the wide diameter portions 13 of the through holes 11. Although FIGS. 1 and 2 show a case in which twelve air exhaust holes 16 are arranged in a row in the Y direction corresponding to the twelve through holes 11 arranged in a row in the Y direction, the number of air exhaust holes 16 may vary depending on the number of through holes 11. The number of air exhaust holes 16 does not necessarily have to be the same as the number of through holes 11, and may be greater than the number of through holes 11. In this case, two or more air exhaust holes 16 may be connected to one through hole 11. For example, the air exhaust holes 16 may be connected to two or more different portions of the narrow diameter portion 12a, the expanded diameter portion 12b, and the wide diameter portion 13 of the through hole 11.

[0049] 4 is a cross-sectional view showing an optical fiber coupling structure 25 according to this embodiment. The optical fiber coupling structure 25 comprises the above-mentioned holding equipment for optical fiber 10 and a plurality of optical fibers 20. Each optical fiber 20 is, for example, an optical fiber that requires rotational alignment (i.e., adjustment of the position around the central axis L1) in the holding equipment for optical fiber 10. Each optical fiber 20 is, for example, a multi-core fiber (MCF). Each optical fiber 20 may be, for example, a polarization maintaining fiber (PMF).

[0050] Figure 5 is a cross-sectional view of the optical fiber coupling structure 25 taken along line V-V in Figure 4. As shown in Figure 5, the optical fiber 20 has at least one core 14a in a region excluding the central axis L1 (i.e., a region shifted from the central axis L1). In the example shown in Figure 5, the optical fiber 20 has one core 14a on the central axis L1, and further has a plurality of (e.g., six) cores 14a equally spaced around the central axis L1. The optical fiber 20 further has a cladding 14b covering these cores 14a and a coating 14c surrounding the cladding 14b.

[0051] The coating portion 23 of the optical fiber 20 is the portion of the optical fiber 20 where the coating 14c remains. Therefore, the coating portion 23 is composed of a plurality of cores 14a, a cladding 14b, and the coating 14c. On the other hand, the coating-removed portion 22 of the optical fiber 20 shown in FIG. 4 is the portion of the optical fiber 20 where a predetermined length of the coating 14c has been removed from the tip surface 20a (see FIG. 6) of the optical fiber 20, exposing the glass portion. Therefore, the coating-removed portion 22 is composed of a plurality of cores 14a and a cladding 14b. In the coating-removed portion 22, the surface of the cladding 14b is exposed to the outside. The outer diameter of the coating portion 23 is larger than the outer diameter of the coating-removed portion 22 by the thickness of the coating 14c.

[0052] 4, when manufacturing the optical fiber coupling structure 25, first, rotational alignment of the optical fiber 20 is performed in a state where the optical fiber 20 is inserted into the through hole 11 of holding equipment for optical fiber 10. In a state where the optical fiber 20 is inserted into the through hole 11, the coating removed part 22 of the optical fiber 20 is placed in the small diameter part 12a of the through hole 11, and the coating part 23 of the optical fiber 20 is placed in the large diameter part 13 of the through hole 11. By rotational alignment of the optical fiber 20, the position of the optical fiber 20 in the XY plane relative to the holding equipment for optical fiber 10 is determined, and the position (angle) of the optical fiber 20 around the central axis L1 is also determined. Then, for example, a liquid adhesive A is injected into the through hole 11 from the opening 11b of the rear surface 10b. The adhesive A is, for example, a cured product of ultraviolet (UV) curable resin. The adhesive A may also be a cured product of thermosetting resin.

[0053] 11。 Adhesive A injected into the through hole 11 spreads from the large diameter part 13 to the small diameter part 12a of the through hole 11, and fills the gap between the inner surface of the through hole 11 and the optical fiber 20. The adhesive A is hardened by irradiating ultraviolet light from the outside of holding equipment for optical fiber 10 while filled in the through hole 11. As a result, the coating removed part 22 and the coating part 23 of the optical fiber 20 are adhered and fixed to the small diameter part 12a and the large diameter part 13 of the through hole 11, respectively. In this way, an optical fiber coupling structure 25 in which each optical fiber 20 is fixed to holding equipment for optical fiber 10 is obtained. Note that the state in which adhesive A is filled in the through hole 11 means that adhesive A is distributed without gaps in the region between the inner surface of the through hole 11 and the optical fiber 20. In the state in which adhesive A is filled in the through hole 11, adhesive A does not protrude from the through hole 11 in the X direction, and does not protrude above the opening 16a of the air exhaust hole 16.

[0054] Fig. 6 is an exploded perspective view showing the optical connector 2 according to this embodiment. Fig. 7 is a perspective view showing the optical connector 2. The optical connector 2 includes, for example, a ferrule 30, a first optical fiber coupling structure 25A, and a second optical fiber coupling structure 25B. The first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B have the same configuration as the optical fiber coupling structure 25 described above. Note that Fig. 6 omits the second optical fiber coupling structure 25B. As shown in Fig. 7 , the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B are inserted into the ferrule 30 while being stacked on top of each other in the Z direction, for example. The first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B are stacked on top of each other in the Z direction, for example, so that their upper surfaces 10c face each other.

[0055] 8 is a cross-sectional view of the optical connector 2 taken along line VIII-VIII in FIG. 7. As shown in FIG. 8, the ferrule 30 has, for example, a substantially rectangular parallelepiped appearance. The ferrule 30 has a front surface 30a located at the front end in the X direction and a rear surface 30b located at the rear end in the X direction. The front surface 30a is, for example, slightly inclined with respect to the XZ plane. For example, the front surface 30a is almost level with the tip surfaces 20a of the optical fibers 20. The rear surface 30b has an opening 31 formed therein that can receive a stack of first optical fiber coupling structures 25A and second optical fiber coupling structures 25B stacked in the Z direction.

[0056] The ferrule 30 has an accommodating hole 32 and a plurality of fiber holding holes 33 therein. The accommodating hole 32 is a hole extending in the X direction from the opening 31, and holds a stack of the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B introduced through the opening 31. The accommodating hole 32 has a pair of inner surfaces 32a (first inner surfaces) facing each other in the Z direction, and a pair of inner surfaces 32b (second inner surfaces) facing each other in the Y direction. For example, the inner surface 32a is a plane along the XY plane, and the inner surface 32b is a plane along the XZ plane. For example, the inner surface 32a is perpendicular to the inner surface 32b.

[0057] When the stack of the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B is placed in the receiving hole 32, the lower surface 10d of the first optical fiber coupling structure 25A and the lower surface 10d of the second optical fiber coupling structure 25B are in contact with a pair of inner surfaces 32a of the receiving hole 32, respectively. This defines the positions of the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B in the Z direction relative to the receiving hole 32. Furthermore, the side surface 10e of the first optical fiber coupling structure 25A and the side surface 10f of the second optical fiber coupling structure 25B are in contact with one inner surface 32b of the receiving hole 32, and the side surface 10f of the first optical fiber coupling structure 25A and the side surface 10e of the second optical fiber coupling structure 25B are in contact with the other inner surface 32b of the receiving hole 32. This defines the positions of the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B in the Y direction relative to the receiving hole 32.

[0058] As shown in FIG. 8 , the plurality of fiber holding holes 33 penetrate in the X direction between the receiving hole 32 and the front surface 30a. The plurality of fiber holding holes 33 are, for example, two-dimensionally arranged on the front surface 30a. The plurality of fiber holding holes 33 are arranged in two rows corresponding to the plurality of optical fibers 20 aligned in a row in the first optical fiber coupling structure 25A and the plurality of optical fibers 20 aligned in a row in the second optical fiber coupling structure 25B. The sheath-removed portions 22 of the plurality of optical fibers 20 extending forward from the first optical fiber coupling structure 25A and the sheath-removed portions 22 of the plurality of optical fibers 20 extending forward from the second optical fiber coupling structure 25B are inserted into the plurality of fiber holding holes 33. The ferrule 30 also has a pair of guide holes 34 (see FIG. 6 ). The pair of guide holes 34 penetrate the ferrule 30 in the X direction from the front surface 30a to the rear surface 30b, and are formed on both sides of the plurality of fiber holding holes 33 in the Y direction.

[0059] A window 35 for injecting an adhesive is formed on the top surface of the ferrule 30. Although the adhesive is omitted in Fig. 8, the adhesive used here may be the same as the adhesive A described above. The adhesive injected through the window 35 hardens in each fiber holding hole 33 into which the coating removal portion 22 of each optical fiber 20 is inserted, thereby fixing the coating removal portion 22 of each optical fiber 20 to the fiber holding hole 33. This results in an optical connector 2 in which the first optical fiber coupling structure 25A and the second optical fiber coupling structure 25B are fixed in the ferrule 30.

[0060] 9 is a perspective view showing an optical coupling structure 1 according to this embodiment. The optical coupling structure 1 includes a first optical connector 2A, a second optical connector 2B, a pair of guide pins 40, and a spacer 50. The first optical connector 2A and the second optical connector 2B have the same configuration as the optical connector 2 described above. In the optical coupling structure 1, the front surface 30a of the first optical connector 2A and the front surface 30a of the second optical connector 2B face each other in the X direction with a gap therebetween. The pair of guide pins 40 fit into a pair of guide holes 34 of the first optical connector 2A and a pair of guide holes 34 of the second optical connector 2B. This defines the positions of the first optical connector 2A and the second optical connector 2B in the YZ plane.

[0061] The spacer 50 is a plate-like member having an opening 50a, and is disposed between the front surface 30a of the first optical connector 2A and the front surface 30a of the second optical connector 2B in the X direction. The opening 50a allows a plurality of optical paths extending between the first optical connector 2A and the second optical connector 2B to pass through. The spacer 50 abuts against the front surface 30a of the first optical connector 2A and the front surface 30a of the second optical connector 2B in the X direction, thereby defining a gap between the first optical connector 2A and the second optical connector 2B in the X direction.

[0062] The effects obtained by the holding equipment for optical fiber 10, the optical fiber coupling structure 25, the optical connector 2, and the optical coupling structure 1 according to this embodiment explained above will be explained.

[0063] As described above, the holding equipment for optical fiber 10 has the air exhaust hole 16 intersecting the through hole 11. The air exhaust hole 16 is configured to exhaust air between the inner surface of the through hole 11 and the adhesive A from the through hole 11 to the outside when the adhesive A is injected into the through hole 11. By providing the air exhaust hole 16, when the liquid adhesive A is injected into the through hole 11, the air inside the through hole 11 can be exhausted to the outside of the through hole 11, so the adhesive A can be sufficiently filled without any gaps between the inner surface of the through hole 11 and the optical fiber 20. This can reduce the adhesive A from hardening with air remaining between the inner surface of the through hole 11 and the optical fiber 20. In other words, it can reduce the formation of voids between the inner surface of the through hole 11 and the optical fiber 20. As a result, it can reduce the occurrence of problems such as a decrease in adhesion of the optical fiber 20 to the inner surface of the through hole 11 caused by the formation of voids inside the through hole 11 and an increase in load on the optical fiber 20 due to thermal expansion of the air inside the through hole 11. As a result, it is possible to maintain the reliability of the optical fiber 20.

[0064] As in the present embodiment, the air exhaust hole 16 may extend from the upper surface 10c to the through hole 11. In this case, the air exhaust hole 16 can be extended upward from the through hole 11 to the upper surface 10c. Because the air inside the through hole 11 tends to move upward relatively more easily than the liquid adhesive A due to the influence of gravity, by configuring the air exhaust hole 16 to extend upward, the air inside the through hole 11 can be efficiently exhausted to the outside. Furthermore, this configuration can also make it less likely that the adhesive A inside the through hole 11 will leak out onto the upper surface 10c from the air exhaust hole 16.

[0065] As in the present embodiment, each air exhaust hole 16 may be individually connected to each through hole 11. In this case, when adhesive A is injected into each through hole 11, it is possible to reduce leakage of adhesive A from one through hole 11 to an adjacent through hole 11 via the air exhaust hole 16. This makes it possible to reliably bond the optical fibers 20 individually to each through hole 11.

[0066] As in this embodiment, the inner diameter of each air exhaust hole 16 may be smaller than the inner diameter of each through hole 11. By making the inner diameter of the air exhaust hole 16 smaller in this way, it is possible to make it less likely for the adhesive A inside the through hole 11 to leak from the air exhaust hole 16 onto the upper surface 10c.

[0067] As in this embodiment, each air exhaust hole 16 may be connected from the upper surface 10c to the expanded diameter portion 12b of each through hole 11. Because the gap between the optical fiber 20 and the expanded diameter portion 12b is particularly likely to become large, air is particularly likely to be left behind inside the expanded diameter portion 12b when the adhesive A is injected into the through hole 11. Therefore, if the air exhaust hole 16 is configured to be connected to the expanded diameter portion 12b, it becomes possible to efficiently exhaust the air inside the through hole 11 to the outside.

[0068] As in this embodiment, the small diameter part 12a may be configured to rotatably hold the coating removal part 22 around the central axis L1 of the coating removal part 22. In this case, by performing rotational alignment of the coating removal part 22 in the small diameter part 12a, the position of the rotational direction of the optical fiber 20 relative to the holding equipment for optical fiber 10 can be determined.

[0069] As in this embodiment, each optical fiber 20 may have at least one core in an area shifted from the central axis L1. In this case, by performing rotational alignment of the optical fiber 20 in the through hole 11, the position of the optical fiber 20 in the rotational direction relative to the holding equipment for optical fiber 10 can be determined.

[0070] As in this embodiment, the receiving hole 32 of the ferrule 30 may include an inner surface 32a that contacts the lower surface 10d and an inner surface 32b that contacts the side surface 10e. In this case, the lower surface 10d and the side surface 10e of holding equipment for optical fiber 10 contact the inner surface 32a and the inner surface 32b of the ferrule 30, respectively, so that the position of holding equipment for optical fiber 10 with respect to the ferrule 30 can be determined with high precision.

[0071] As in this embodiment, the first optical connector 2A and the second optical connector 2B face each other across a gap in the X direction. In this way, when the first optical connector 2A and the second optical connector 2B are not connected by physical contact (PC), the pressing force for connecting the first optical connector 2A and the second optical connector 2B by PC is not required, so that it is possible to easily connect a larger number of optical fibers 20 at once.

[0072] 10 is a cross-sectional view showing holding equipment for optical fiber 10A according to the first modification. In holding equipment for optical fiber 10A, the extending direction of air exhaust hole 16A is different from that of holding equipment for optical fiber 10 described above. In the XZ cross section shown in Fig. 10, the air exhaust hole 16A extends in a direction tilted from the Z direction perpendicular to the through hole 11 extending in the X direction. In other words, the central axis L1 of the air exhaust hole 16A extends in a direction tilted from the imaginary line VL perpendicular to the central axis L1 of the through hole 11 in the XZ cross section. The central axis L1 of the air exhaust hole 16A extends in a direction tilted in both the X direction and the Z direction in the XZ cross section. When the air exhaust hole 16A is tilted like this, the length of the air exhaust hole 16A from the through hole 11 to the upper surface 10c can be made longer than when the air exhaust hole extends along the imaginary line VL perpendicular to the central axis L1 of the through hole 11. In this way, by increasing the distance of the path of adhesive A from the through hole 11 to the upper surface 10c, it is possible to make it less likely that adhesive A inside the through hole 11 will leak from the air exhaust hole 16A onto the upper surface 10c.

[0073] 11 is a plan view showing holding equipment for optical fiber 10B according to modification 2. In holding equipment for optical fiber 10B, the shape of the air exhaust hole 16B is different from that of holding equipment for optical fiber 10 described above. In holding equipment for optical fiber 10B, the shape of the air exhaust hole 16B is an elongated hole extending along the X direction. That is, the air exhaust hole 16B is formed so as to extend along the X direction at a position where it overlaps with the through hole 11 in the Z direction. More specifically, the air exhaust hole 16B extends continuously in the X direction from the thin diameter part 12a through the expanded diameter part 12b so as to overlap with all of the thick diameter part 13 in the Z direction. The air exhaust hole 16B extends downward from the top surface 10c and is connected to all parts of the thin diameter part 12a, the expanded diameter part 12b and the thick diameter part 13. The shape of the air exhaust hole 16B seen from above downward is, for example, a rectangular shape extending in the X direction, but is not limited to this and may be another shape such as an ellipse. When the air exhaust hole 16B is shaped like a long hole in this manner, when adhesive A is injected into the through hole 11, air can be exhausted to the outside from more parts of the through hole 11 through the air exhaust hole 16B, thereby more effectively reducing the formation of cavities inside the through hole 11.

[0074] 12 is a plan view showing holding equipment for optical fiber 10C according to modification 3. Holding equipment for optical fiber 10C is different from holding equipment for optical fiber 10 described above in that it has one air exhaust hole 16C. As shown in Fig. 12, the air exhaust hole 16C is an elongated hole extending along the Y direction. The air exhaust hole 16C extends in the Y direction so as to intersect with all of the through holes 11 when viewed from above downward. The air exhaust hole 16C extends in the Z direction from the upper surface 10c and is connected to all of the through holes 11. The air exhaust hole 16C extends in the Y direction so as to overlap with the expanded diameter parts 12b of all of the through holes 11 in the Z direction, for example, and is connected to the expanded diameter parts 12b of all of the through holes 11 in the Z direction. The air exhaust hole 16C when viewed from above downward is, for example, a rectangular shape extending in the Y direction. In this way, when air exhaust holes 16C are provided that are connected to all of the multiple through holes 11, when adhesive A is injected into the through holes 11, the air inside the through holes 11 can be more reliably exhausted to the outside through the air exhaust holes 16C, thereby more effectively reducing the formation of cavities inside the through holes 11.

[0075] 13 is a plan view showing holding equipment for optical fiber 10D according to modification 4. Fig. 14 is a cross-sectional view showing an enlarged main part of holding equipment for optical fiber 10D. In holding equipment for optical fiber 10D, a recess 17 extending in the Y direction is formed on the top surface 10c. When viewed from above, the recess 17 extends in the Y direction so as to intersect with all of the through holes 11. For example, the recess 17 extends linearly along the Y direction so as to overlap with the large diameter parts 13 of all of the through holes 11 in the Z direction. The recess 17 is formed on the top surface 10c at a position shifted toward the front surface 10a from the rear surface 10b where the openings 11b of the large diameter parts 13 are formed. When viewed from above, the recess 17 is, for example, a rectangle extending in the Y direction. A bottom surface 17a of the recess 17 is recessed downward from the top surface 10c, forming a step with respect to the top surface 10c. The bottom surface 17 a is a plane along the XY plane, for example, and is located between the top surface 10 c and the through-hole 11 .

[0076] 10c。 In the holding equipment for optical fiber 10D, instead of the recess 17, a hole extending in the Y direction may be formed so as to intersect with all of the air exhaust holes 16D. In this case, the hole may be formed between the upper surface 10c and the through holes 11 so as to intersect with all of the air exhaust holes 16D. For example, the holes may extend in the Y direction so as to intersect with the upper ends of all of the air discharge holes 16D (specifically, the portions of the air discharge holes 16D that are shifted downward from the upper surface 10c). Even in this configuration, the holes provide a space for storing adhesive A that leaks from the air discharge holes 16D. This makes it possible to more reliably reduce the leakage of adhesive A onto the upper surface 10c.

[0077] [Second embodiment] Next, the holding equipment for optical fiber 110 according to the second embodiment will be explained. In the following explanation of the second embodiment, the explanation of the overlapping parts with the first embodiment will be omitted as appropriate, and the different parts from the first embodiment will be mainly explained.

[0078] Fig. 15 is a perspective view showing holding equipment for optical fiber 110 according to the second embodiment. Fig. 16 is a plan view showing holding equipment for optical fiber 110. Fig. 17 is a cross-sectional view showing holding equipment for optical fiber 110 along XVII-XVII in Fig. 16. As shown in Fig. 15 and Fig. 16, holding equipment for optical fiber 110 has a plurality of injection holes 15 in addition to a plurality of air exhaust holes 16 according to the first embodiment. Each injection hole 15 is a hole for injecting adhesive A into each through hole 11. Each injection hole 15 is arranged in a line in the Y direction corresponding to each through hole 11, and extends from the top surface 10c in the Z direction and is individually connected to each through hole 11. "Each injection hole 15 is individually connected to each through hole 11" means that one injection hole 15 is connected to one through hole 11, and one injection hole 15 is not connected to two or more through holes 11. Therefore, each injection hole 15 is provided independently for each through hole 11, and adhesive A injected into one injection hole 15 is introduced into only one through hole 11 connected to that one injection hole 15.

[0079] As shown in FIG. 17 , injection hole 15 extends linearly in the Z direction from upper surface 10c to through hole 11, intersecting with through hole 11, for example. An opening of injection hole 15 is formed in upper surface 10c. As shown in FIGS. 17 and 18 , injection hole 15 extends downward from upper surface 10c in the Z direction and connects to narrow diameter portion 12a of through hole 11. Therefore, when viewed in the Z direction, injection hole 15 is positioned so as to overlap narrow diameter portion 12a. In this way, injection hole 15 is connected to a portion (e.g., narrow diameter portion 12a) different from the portion (e.g., enlarged diameter portion 12b) to which air discharge hole 16 is connected. When viewed in the Z direction, injection hole 15 has a circular shape, for example.

[0080] The inner diameter of injection hole 15 is large enough to introduce adhesive A into through hole 11. The size large enough to introduce adhesive A into through hole 11 means a size large enough to allow liquid adhesive A to flow through injection hole 15 and reach through hole 11. The inner diameter of injection hole 15 is set, for example, to be smaller than the pitch between through holes 11. The inner diameter of injection hole 15 is, for example, larger than the inner diameter of narrow diameter portion 12a and smaller than the inner diameter of wide diameter portion 13. Therefore, the inner diameter of injection hole 15 is larger than the inner diameter of air discharge hole 16. The inner diameter of injection hole 15 may be, for example, 10 μm or more, which allows the adhesive to be introduced. Furthermore, to avoid adjacent through holes 11 from communicating with each other through injection hole 15, the inner diameter of injection hole 15 may be smaller than the pitch between through holes 11 (e.g., the distance between the centers of adjacent through holes 11). For example, if the pitch of through holes 11 is 250 μm, the inner diameter of injection hole 15 may be 250 μm or less. The inner diameter of injection hole 15 may be equal to or smaller than the inner diameter of narrow diameter portion 12 a or equal to or larger than the inner diameter of thick diameter portion 13, as long as adhesive A can be introduced into through holes 11.

[0081] 10. In the holding equipment for optical fiber 110, the injection holes 15 for injecting adhesive A extend to intersect with the through holes 11 and are individually connected to the through holes 11, so that adhesive A can be individually injected into the through holes 11 from a route separate from the through holes 11. In this configuration, by adjusting the position of the injection hole 15 relative to the through holes 11 and the injection amount of adhesive A, etc., in consideration of the fluidity of adhesive A, adhesive A can be reliably filled between the optical fiber 20 and the through holes 11 without gaps, and adhesive A can be distributed evenly around the optical fiber 20. As a result, stress generated when adhesive A hardens can be applied uniformly to the optical fiber 20, so that the position of the optical fiber 20 can be reduced from being subjected to the stress in one direction. Furthermore, in the above configuration, the air exhaust hole 16 is connected to a position different from the position of the through hole 11 to which the injection hole 15 is connected. When adhesive A is injected into the through hole 11, cavities are likely to be formed inside the through hole 11 at a location away from the location where adhesive A is injected. Therefore, by configuring the air exhaust hole 16 to be connected to the narrow diameter portion 12a, which is different from the enlarged diameter portion 12b to which the injection hole 15 is connected, the formation of a cavity inside the through hole 11 can be effectively reduced.

[0082] 18 is a cross-sectional view showing holding equipment for optical fiber 110A according to modification 1. In holding equipment for optical fiber 110A, the arrangement of injection hole 15 and air exhaust hole 16 is different from that of holding equipment for optical fiber 110. In holding equipment for optical fiber 110A, the injection hole 15 extends in the Z direction from the upper surface 10c and is connected to the large diameter part 13 of the through hole 11. Therefore, when viewed in the Z direction, the injection hole 15 is arranged to overlap with the large diameter part 13. On the other hand, the air exhaust hole 16 extends in the Z direction from the upper surface 10c and is connected to the small diameter part 12a of the through hole 11. Therefore, when viewed in the Z direction, the air exhaust hole 16 is arranged to overlap with the small diameter part 12a. When viewed in the Z direction, the air exhaust hole 16 is arranged at a position shifted toward the rear surface 10b from the front surface 10a where the opening 11a of the small diameter part 12a is formed.

[0083] When adhesive A is injected from the injection hole 15 into the large diameter part 13, air inside the small diameter part 12a near the front surface 10a is easily discharged to the outside through the opening 11a of the front surface 10a. Therefore, by arranging the air exhaust hole 16 at a position farther from the front surface 10a than near the front surface 10a, air inside the small diameter part 12a can be efficiently discharged to the outside by the air exhaust hole 16. When viewed in the Z direction, the air exhaust hole 16 is arranged, for example, at the center of the small diameter part 12a in the X direction. In the holding equipment for optical fiber 110A, when adhesive A is injected into the through hole 11, air tends to be left behind in the small diameter part 12a away from the large diameter part 13 to which the injection hole 15 is connected. Therefore, by connecting the air exhaust hole 16 to the small diameter part 12a, air inside the through hole 11 can be efficiently discharged to the outside. This can effectively reduce the formation of a cavity inside the through hole 11.

[0084] 19 is a cross-sectional view showing holding equipment for optical fiber 110B according to modification 1. In holding equipment for optical fiber 110B, the arrangement of injection hole 15 and air exhaust hole 16 is different from that of holding equipment for optical fiber 110. In holding equipment for optical fiber 110B, the injection hole 15 extends in the Z direction from the upper surface 10c and is connected to the thin diameter part 12a of the through hole 11. Therefore, when viewed in the Z direction, the injection hole 15 is arranged to overlap with the thin diameter part 12a. On the other hand, the air exhaust hole 16 extends in the Z direction from the upper surface 10c and is connected to the thick diameter part 13 of the through hole 11. Therefore, when viewed in the Z direction, the air exhaust hole 16 is arranged to overlap with the thick diameter part 13. When viewed in the Z direction, the air exhaust hole 16 is arranged at a position shifted toward the front surface 10a from the rear surface 10b where the opening 11b of the thick diameter part 13 is formed.

[0085] When adhesive A is injected into the thin diameter part 12a from the injection hole 15, air inside the thick diameter part 13 near the rear surface 10b is easily discharged to the outside from the opening 11b of the rear surface 10b. Therefore, by arranging the air exhaust hole 16 at a position farther from the rear surface 10b than near the rear surface 10b, air inside the thick diameter part 13 can be efficiently discharged to the outside by the air exhaust hole 16. When viewed in the Z direction, the air exhaust hole 16 is arranged, for example, at the center of the thick diameter part 13 in the X direction. In the holding equipment for optical fiber 110B, when adhesive A is injected into the through hole 11, air tends to be left behind in the thick diameter part 13 away from the thin diameter part 12a to which the injection hole 15 is connected. Therefore, by connecting the air exhaust hole 16 to the thick diameter part 13, air inside the through hole 11 can be efficiently discharged to the outside. This can effectively reduce the formation of a cavity inside the through hole 11.

[0086] [Third embodiment] Next, the third embodiment of holding equipment for optical fiber 210 will be explained. In the following explanation of the second embodiment, the explanation of the overlapping parts with the first embodiment will be omitted as appropriate, and the different parts from the first embodiment will be mainly explained.

[0087] Fig. 20 is a plan view showing holding equipment for optical fiber 210 according to the second embodiment. Fig. 21 is a cross-sectional view showing holding equipment for optical fiber 210. Holding equipment for optical fiber 210 includes a wall surface 10h (first wall surface) aligned with the front surface 10a in the X direction between the front surface 10a and the rear surface 10b, and a wall surface 10g (second wall surface) extending along the XY plane between the front surface 10a and the rear surface 10b so as to be perpendicular to the front surface 10a. The wall surface 10g is located closer to the rear surface 10b in the X direction between the front surface 10a and the rear surface 10b. The wall surface 10g is, for example, a plane along the XY plane and forms a step with respect to the upper surface 10c. The wall surface 10g extends, for example, parallel to the upper surface 10c. The wall surface 10g is located at a position shifted toward the lower surface 10d from the through hole 11A in the Z direction. That is, the wall surface 10g is provided at a position lower than the through hole 11A with respect to the position of the lower surface 10d in the Z direction.

[0088] The position lower than the through hole 11A may specifically be the position of one end (lower end) of the inner surface constituting the through hole 11A that is closer to the lower surface 10d in the Z direction. As a result, the wall surface 10g is located at a height between the through hole 11A (specifically, the lower end of the inner surface constituting the through hole 11A) and the lower surface 10d in the Z direction. The wall surface 10h connects the wall surface 10g and the upper surface 10c in the Z direction. The wall surface 10h is, for example, a plane along the YZ plane, and is formed perpendicular to the upper surface 10c and the wall surface 10g. The openings 11b of each through hole 11A are formed in the wall surface 10h. Therefore, in the holding equipment for optical fiber 210, each through hole 11A penetrates from the front surface 10a to the wall surface 10h in the X direction.

[0089] As shown in Fig. 21, the through hole 11A does not have a structure corresponding to the large diameter part 13 (see Fig. 2), and has only a small diameter part 12a and an expanded diameter part 12b. When fixing the optical fiber 20 to the holding equipment for optical fiber 210, the coating removal part 22 of the optical fiber 20 is inserted into the through hole 11A while aligning the coating part 23 of the optical fiber 20 along the wall surface 10g. Then, for example, using an adhesive, the coating removal part 22 is fixed to the through hole 11A, and the coating part 23 is fixed to the wall surface 10g. Therefore, the wall surface 10g functions as a fixing surface (fixing part) for fixing the coating parts 23 of multiple optical fibers 20.

[0090] 21 , air exhaust hole 16 is formed at a position overlapping with thin-diameter portion 12a of through-hole 11A in the Z direction and is connected to thin-diameter portion 12a in the Z direction. Air exhaust hole 16 is located, for example, at a position shifted toward rear surface 10b from front surface 10a where opening 11a of thin-diameter portion 12a is formed. For example, when adhesive A is injected through opening 11b, air inside thin-diameter portion 12a near front surface 10a is likely to be exhausted to the outside through opening 11a of front surface 10a. Therefore, by arranging air exhaust hole 16 at a position farther from front surface 10a than near front surface 10a, air inside thin-diameter portion 12a can be efficiently exhausted to the outside through air exhaust hole 16.

[0091] In the holding equipment for optical fiber 210, the coating removal part 22 of each optical fiber 20 can be inserted into each through-hole 11A while aligning the coating part 23 of each optical fiber 20 along the wall surface 10g, so that the insertion work of the coating removal part 22 into the through-hole 11A becomes easy. Furthermore, by aligning the coating part 23 of each optical fiber 20 along the wall surface 10g, the posture of the coating removal part 22 with respect to the through-hole 11A can be stabilized, so that bending stress generated in the coating removal part 22 when inserting the coating removal part 22 into the through-hole 11A can be reduced. Furthermore, in the case where the through-hole 11A is formed from the front surface 10a to the wall surface 10h as in the holding equipment for optical fiber 210, the length of the through-hole 11A can be shorter than when the through-hole is formed from the front surface 10a to the rear surface 10b. If the length of the through hole 11A is shortened, the air inside the through hole 11A can more easily escape to the outside through the opening 11a or the opening 11b of the through hole 11A, thereby reducing the risk of air being left behind inside the through hole 11A, thereby effectively reducing the formation of a cavity inside the through hole 11A.

[0092] [Fourth embodiment] Next, the fourth embodiment of holding equipment for optical fiber 310 will be explained. In the following explanation of the fourth embodiment, the explanation of the overlapping parts with the first embodiment will be omitted as appropriate, and the parts different from the first embodiment will be mainly explained.

[0093] Fig. 22 is a perspective view showing holding equipment for optical fiber 310 according to the fourth embodiment. Fig. 23 is a plan view showing holding equipment for optical fiber 310. Holding equipment for optical fiber 310 has one fixing hole 18 connected to multiple through holes 11A. As in the third embodiment, the through hole 11A does not have a structure corresponding to the large diameter part 13, and has only the small diameter part 12a and the expanded diameter part 12b. The fixing hole 18 penetrates from the rear surface 10b to multiple through holes 11A in the X direction, and is connected to all of the through holes 11A in the X direction.

[0094] As shown in Fig. 22, the fixing hole 18 forms an opening 18a on the rear surface 10b. The opening 18a is, for example, an oval shape with the Y direction as the longitudinal direction. The opening 18a has a size that includes all the through holes 11A when viewed in the X direction. The coating parts 23 of multiple optical fibers 20 are inserted into the fixing holes 18. When fixing the optical fibers 20 to the holding equipment for optical fiber 310, the coating part 23 of the optical fiber 20 is aligned with the fixing hole 18, and the coating removal part 22 of the optical fiber 20 is inserted into the small diameter part 12a of the through hole 11A. Then, for example, using an adhesive, the coating removal part 22 is fixed to the through hole 11A, and the coating part 23 is fixed to the fixing hole 18.

[0095] 23 , air exhaust hole 16 is formed at a position overlapping with thin-diameter portion 12a of through-hole 11A in the Z direction and is connected to thin-diameter portion 12a in the Z direction. Air exhaust hole 16 is located, for example, at a position shifted toward rear surface 10b from front surface 10a where opening 11a of thin-diameter portion 12a is formed. For example, when adhesive A is injected through opening 11b, air inside thin-diameter portion 12a near front surface 10a is likely to be exhausted to the outside through opening 11a of front surface 10a. Therefore, by arranging air exhaust hole 16 at a position farther from front surface 10a than near front surface 10a, air inside thin-diameter portion 12a can be efficiently exhausted to the outside through air exhaust hole 16.

[0096] In the holding equipment for optical fiber 310 according to this embodiment, fixing holes 18 into which the coatings 23 of a plurality of optical fibers 20 are inserted are provided, so that the coatings 23 of each optical fiber 20 can be easily inserted into the fixing holes 18. Furthermore, when the through hole 11A is formed from the front surface 10a to the wall surface 10h, the length of the through hole 11A can be made shorter than when the through hole is formed from the front surface 10a to the rear surface 10b. The shorter the length of the through hole 11A, the easier it is for the air inside the through hole 11A to escape to the outside through the opening 11a or opening 11b of the through hole 11A, so the risk of air being left behind inside the through hole 11A can be reduced. This can effectively reduce the formation of a cavity inside the through hole 11A.

[0097] The present disclosure is not limited to the above-described embodiments and modifications, and various other modifications are possible. For example, the above-described embodiments and modifications may be combined with each other within a consistent range according to the required purpose and effect. Furthermore, the configuration of holding equipment for optical fiber is not limited to the above-described embodiments and modifications. For example, the air exhaust hole does not need to be formed to extend from the upper surface, but may be formed to extend from another outer surface such as the lower surface. The inner diameter of the air exhaust hole does not need to be constant at each position along the air exhaust hole, but may vary at each position along the air exhaust hole. The shape of the air exhaust hole as viewed in the Z direction does not need to be circular, but may be other shapes such as elliptical, rectangular, polygonal, etc.

[0098] The holding equipment for optical fiber may have air exhaust holes extending from the upper surface and air exhaust holes extending from the lower surface. For example, when optical fibers arranged in two rows are fixed to the holding equipment for optical fiber, the through holes are also arranged in two rows corresponding to the arrangement of the optical fibers. In this case, the first row of through holes may be connected to the air exhaust holes extending from the upper surface, and the second row of through holes may be connected to the air exhaust holes extending from the lower surface.

[0099] As can be understood from the description of the above-mentioned embodiments, this specification includes the disclosure of the following aspects: (Supplementary Note 1) Holding equipment for optical fiber that is arranged inside a ferrule and holds a plurality of optical fibers, comprising: an outer surface including a first end face and a second end face aligned in a first direction, a plurality of through holes that penetrate in the first direction between the first end face and the second end face and are aligned in a second direction intersecting the first direction, and into which the plurality of optical fibers can be inserted, and at least one air exhaust hole that extends from the outer surface so as to intersect with the plurality of through holes, and is configured to exhaust air between the inner surfaces of the plurality of through holes and the adhesive from the plurality of through holes to the outside when an adhesive is injected into the plurality of through holes.

[0100] 1... Optical coupling structure 2... Optical connector 2A... First optical connector 2B... Second optical connector 10, 10A, 10B, 10C, 10D, 110, 110A, 110B, 210, 310... Optical fiber holding part 10a... Front surface (first end surface) 10b... Rear surface (second end surface) 10c... Top surface (first side surface) 10d...Bottom surface (second side surface) 10e...Side surface (third side surface) 10f...Side surface 10g...Wall surface (second wall surface) 10h...Wall surface (first wall surface) 11, 11A...Through hole 11a, 11b, 16a, 18a, 31, 50a...Opening 12...Holding part 12a...Slim diameter part 12b...Enlarged diameter part 13...Large diameter part 14a...Core 14b...Clad 14c...Coating 15...Injection hole DESCRIPTION OF SYMBOLS 16, 16A, 16B, 16C, 16D...Air exhaust hole 17...Recess 17a...Bottom surface 18...Fixing hole 20...Optical fiber 20a...Tip surface 22...Coating removal portion 23...Coating portion 25...Optical fiber coupling structure 25A...First optical fiber coupling structure 25B...Second optical fiber coupling structure 30...Ferrule 30a...Front surface 30b...Rear surface 32...Accommodation hole 32a, 32b...Inner surface 33...Fiber holding hole 34...Guide hole 35...Window 40...Guide pin 50...Spacer A...Adhesive L1, L2...Central axis S10...Outer surface VL...Imaginary straight line

Claims

1. An optical fiber holding component disposed inside a ferrule for holding a plurality of optical fibers, comprising: an outer surface including a first end face and a second end face arranged in a first direction; a plurality of through holes penetrating between the first end face and the second end face in the first direction and arranged side by side in a second direction intersecting the first direction; at least one air discharge hole extending from the outer surface so as to intersect the plurality of through holes.

2. The outer surface further includes a side surface extending along the first direction and the second direction between the first end face and the second end face, the side surface has an opening of the at least one air discharge hole, the at least one air discharge hole extends from the side surface to the plurality of through holes. The optical fiber holding component according to claim 1.

3. The at least one air discharge hole extends in a direction inclined from a virtual straight line perpendicular to the plurality of through holes extending in the first direction in a cross section perpendicular to the second direction. The optical fiber holding component according to claim 1.

4. Comprising one air discharge hole as the at least one air discharge hole, the one air discharge hole is connected to all of the plurality of through holes. The optical fiber holding component according to any one of claims 1 to 3.

5. Comprising a plurality of air discharge holes arranged side by side in the second direction corresponding to the plurality of through holes as the at least one air discharge hole, the plurality of air discharge holes are individually connected to the plurality of through holes. The optical fiber holding component according to any one of claims 1 to 3.

6. The inner diameter of each of the plurality of air discharge holes is smaller than the inner diameter of each of the plurality of through holes. The optical fiber holding component according to claim 5.

7. Each of the plurality of air discharge holes has an elongated hole shape extending in the first direction between the first end face and the second end face. The optical fiber holding component according to claim 5.

8. A recess extending in the second direction is formed on the outer surface so as to intersect all of the plurality of air discharge holes, each of the plurality of air discharge holes opens to the bottom surface of the recess. The optical fiber holding component according to claim 5.

9. Each of the plurality of through holes a small-diameter portion capable of holding a coating-removed portion which is a part of the plurality of optical fibers with the coating removed, It extends in the first direction between the small-diameter portion and the second end face, and can hold a coating portion which is the other part of the plurality of optical fibers where the coating remains, and has a large-diameter portion with an inner diameter larger than that of the small-diameter portion, It has an expanding portion that connects between the small-diameter portion and the large-diameter portion and whose inner diameter expands as it goes from the small-diameter portion to the large-diameter portion, The at least one air discharge hole is connected to the expanding portion from the outer surface. The optical fiber holding component according to any one of claims 1 to 3.

10. It further includes a plurality of injection holes that extend from the outer surface so as to intersect the plurality of through holes and are individually connected to the plurality of through holes, and into which an adhesive for adhering the plurality of optical fibers to the plurality of through holes can be injected. Each of the plurality of through holes has a small-diameter portion that can hold a coating-removed portion which is a part of the plurality of optical fibers from which the coating has been removed, It extends in the first direction between the holding portion and the second end face, and can hold a coating portion which is the other part of the plurality of optical fibers where the coating remains, and has a large-diameter portion with an inner diameter larger than that of the small-diameter portion, It has an expanding portion that connects between the small-diameter portion and the large-diameter portion in the first direction and whose inner diameter expands as it goes from the small-diameter portion to the large-diameter portion in the first direction, The at least one air discharge hole is connected to any one of the small-diameter portion, the large-diameter portion, and the expanding portion, Each of the plurality of injection holes is connected to a portion different from the portion to which the at least one air discharge hole is connected among the small-diameter portion, the large-diameter portion, and the expanding portion. The optical fiber holding component according to any one of claims 1 to 3.

11. The at least one air discharge hole is connected to the expanding portion, Each of the plurality of injection holes is connected to either the small-diameter portion or the large-diameter portion. The optical fiber holding component according to claim 10.

12. The at least one air discharge hole is connected to the small-diameter portion, Each of the plurality of injection holes is connected to the large-diameter portion. The optical fiber holding component according to claim 10.

13. The at least one air discharge hole is connected to the large-diameter portion, Each of the plurality of injection holes is connected to the small-diameter portion. The optical fiber holding component according to claim 10.

14. The optical fiber holding component according to claim 9, wherein the small-diameter portion is configured to rotatably hold the coating removal portion around the central axis of the coating removal portion.

15. The outer surface includes a first wall surface that is aligned with the first end surface in the first direction between the first end surface and the second end surface, and further includes a second wall surface that extends along the first direction and the second direction so as to intersect the first wall surface between the first wall surface and the second end surface. The plurality of through holes penetrate between the first end surface and the first wall surface in the first direction. The optical fiber holding component according to any one of claims 1 to 3, wherein the second wall surface is formed at a position displaced from the plurality of through holes in a third direction that intersects both the first direction and the second direction.

16. The optical fiber holding component according to claim 1, the plurality of optical fibers respectively inserted into the plurality of through holes, and an adhesive provided inside the plurality of through holes for fixing the plurality of optical fibers to the plurality of through holes, an optical fiber coupling structure.

17. In the optical fiber coupling structure according to claim 16, each of the plurality of optical fibers has at least one core in a region displaced from the central axis.

18. The optical fiber coupling structure according to claim 16 or claim 17, and a ferrule that houses at least a part of the optical fiber coupling structure, an optical connector.

19. The ferrule has a housing hole for housing the optical fiber holding component, and a plurality of fiber holding holes that are connected to the housing hole in the first direction and respectively hold the plurality of optical fibers extending from the optical fiber holding component in the first direction. The outer surface has a first side surface and a second side surface that face each other with the plurality of through holes interposed therebetween in a third direction that intersects both the first direction and the second direction, and a third side surface that connects the first side surface and the second side surface in the third direction. The optical connector according to claim 18, wherein the housing hole includes a first inner surface in contact with the second side surface and a second inner surface in contact with the third side surface.

20. Comprising a first optical connector and a second optical connector as the optical connector according to claim 18, the first optical connector and the second optical connector are opposed to each other with a gap therebetween in the first direction, an optical coupling structure.