Optical connector, optical coupling structure, and method for producing optical connector

Abstract

An optical connector (1) according to the present disclosure comprises: a ferrule (20) which has a front end (21) and a rear end (22) that are opposite from each other in one direction and which has a boot insertion hole (24) that is formed at the rear end (22) and a plurality of fiber holding holes (25) that extend toward the front end from the boot insertion hole (24); a boot (30) which has a through hole (31) passing therethrough in the one direction and which is inserted into the boot insertion hole (24) from the rear end (22); and a plurality of optical fibers (10) which each have a core and / or a stress-imparting part at a position offset from the central axis thereof, which are inserted into the through hole (31) in the one direction, and which are respectively held by the plurality of fiber holding holes (25). An adhesive (A) which fixes the plurality of optical fibers (10) to the ferrule (20) is provided to the inside of the ferrule (20) between the boot (30) and the front end (21). Provided to the boot (30) is a seal member (35) which is disposed so as to close a gap between the inner surface of the through hole (31) and the plurality of optical fibers (10) as viewed along the one direction.

Description

Optical connector, optical coupling structure, and method for manufacturing optical connector

[0001] This application claims priority to Japanese Patent Application No. 2022-123798, filed August 3, 2022, and incorporates by reference all of the contents of that application.

[0002] Patent Document 1 discloses an optical connector in which multiple optical fibers are inserted into a ferrule via a boot. The boot is a cylindrical body having a through-hole through which the multiple optical fibers pass. The boot is used to protect the multiple optical fibers. The multiple optical fibers pass through the through-hole of the boot and are inserted into the ferrule. The multiple optical fibers are fixed to the ferrule by an adhesive injected into the ferrule.

[0003] Japanese Patent Application Laid-Open No. 2020-101613

[0004] An optical connector according to an embodiment of the present disclosure includes a ferrule having a front end and a rear end facing each other in one direction, and having a boot insertion hole formed in the rear end and a plurality of fiber holding holes extending from the boot insertion hole toward the front end; a boot having a through hole passing through in one direction and inserted into the boot insertion hole from the rear end; and a plurality of optical fibers each having at least one of a core and a stress-applying portion positioned offset from their respective central axes, inserted into the through hole in the one direction, and held in the plurality of fiber holding holes, respectively. An adhesive is provided inside the ferrule between the boot and the front end to secure the plurality of optical fibers to the ferrule. The boot is provided with a seal member arranged to seal gaps between the inner surface of the through hole and the plurality of optical fibers when viewed in one direction.

[0005] FIG. 1 is a perspective view of an optical connector according to a first embodiment. FIG. 2 is a cross-sectional view of the optical connector of FIG. 1. FIG. 3 is a cross-sectional view of the optical connector taken along line III-III in FIG. 2. FIG. 4 is a perspective view of an optical coupling structure including the optical connector of FIG. 1. FIG. 5 is a plan view showing a manufacturing process for the optical connector of FIG. 1. FIG. 6 is a plan view showing a manufacturing process subsequent to that of FIG. 5. FIG. 7 is a cross-sectional view showing a manufacturing process subsequent to that of FIG. 6. FIG. 8 is a cross-sectional view showing a manufacturing process subsequent to that of FIG. 7. FIG. 9 is a cross-sectional view of an optical connector according to a comparative example. FIG. 10 is a cross-sectional view of the optical connector taken along line X-X in FIG. 9. FIG. 11 is a cross-sectional view of an optical connector according to a second embodiment. FIG. 12 is a cross-sectional view of the optical connector taken along line XII-XII in FIG. 11. FIG. 13 is a plan view showing a manufacturing process for the optical connector of FIG. 11. FIG. 14 is a cross-sectional view showing a manufacturing process subsequent to that of FIG. 13. FIG. 15 is a cross-sectional view showing a manufacturing process subsequent to that of FIG. 14. FIG. 16 is a cross-sectional view showing a manufacturing process subsequent to that of FIG. 15. Fig. 17 is a cross-sectional view of an optical connector according to a modification of the first embodiment. Fig. 18 is a perspective view of holding equipment for optical fiber provided in the optical connector of Fig. 17. Fig. 19 is a cross-sectional view of an optical connector according to another modification of the first embodiment. Fig. 20 is a perspective view of holding equipment for optical fiber provided in the optical connector of Fig. 19. Fig. 21 is a cross-sectional view of an optical connector according to another modification of the first embodiment. Fig. 22 is a perspective view of holding equipment for optical fiber provided in the optical connector of Fig. 21. Fig. 23 is a cross-sectional view showing a modification of holding equipment for optical fiber. Fig. 24 is a cross-sectional view showing another modification of holding equipment for optical fiber. Fig. 25 is a cross-sectional view of an optical connector according to a modification of the second embodiment.

[0006] [Problem to be Solved by the Present Disclosure] When mounting multiple optical fibers that require rotational alignment in the ferrule described in Patent Document 1, the multiple optical fibers are rotated and aligned in a disassembled state, and then each optical fiber is inserted into the ferrule through a through-hole in the boot and fixed to the ferrule with an adhesive injected into the ferrule. When multiple optical fibers are inserted into the through-hole in a disassembled state in this manner, the optical fibers are likely to overlap. When such overlapping of the optical fibers occurs, the adhesive injected into the ferrule is likely to leak out along the optical fibers to the outside of the ferrule. If the adhesive that leaks out hardens while adhering to the optical fiber, the optical fiber may lose its flexibility, potentially reducing its bending resistance.

[0007] Effect of the Present Disclosure According to the optical connector, optical coupling structure, and method of manufacturing an optical connector according to the present disclosure, it is possible to suppress a decrease in the bending resistance of an optical fiber.

[0008] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0009] (1) An optical connector according to one embodiment of the present disclosure includes a ferrule having a front end and a rear end facing each other in one direction, a boot insertion hole formed in the rear end, and a plurality of fiber holding holes extending from the boot insertion hole toward the front end; a boot having a through hole passing through in one direction and inserted from the rear end into the boot insertion hole; and a plurality of optical fibers each having at least one of a core and a stress-applying portion positioned offset from their respective central axes, inserted into the through hole in the one direction, and held in the plurality of fiber holding holes, respectively. An adhesive is provided inside the ferrule between the boot and the front end to secure the plurality of optical fibers to the ferrule. The boot is provided with a seal member arranged to seal gaps between the inner surface of the through hole and the plurality of optical fibers when viewed in one direction.

[0010] In this optical connector, multiple optical fibers are inserted into through holes of a boot that is inserted into the boot insertion hole of the ferrule and are respectively held in multiple fiber holding holes of the ferrule. The boot is provided with a seal member that is arranged to seal gaps between the inner surface of the through hole and the multiple optical fibers when viewed in one direction. This prevents adhesive from leaking out of the ferrule through gaps between the inner surface of the through hole and the multiple optical fibers when adhesive is injected into the interior of the ferrule between the boot and the front end of the ferrule. This configuration, which includes such a seal member, can prevent adhesive from leaking out of the ferrule even when the optical fibers overlap. This prevents adhesive that leaks out of the ferrule from hardening while adhering to the optical fibers. As a result, a decrease in the bending resistance of the optical fibers due to hardening of the leaked adhesive can be prevented.

[0011] (2) In the optical connector described in (1) above, the sealing member may be disposed inside the through hole and may cover the multiple optical fibers. In this case, the multiple optical fibers can be inserted into the through hole while covered with the sealing member, thereby positioning the sealing member to close any gaps between the inner surface of the through hole and the multiple optical fibers. In this way, by covering the multiple optical fibers with the sealing member before inserting them into the through hole, the multiple optical fibers can be inserted into the through hole together in an aligned state after being rotationally aligned. In this case, the insertion of the multiple optical fibers into the ferrule can be performed more easily than when the multiple optical fibers are inserted into the through hole in a state where they are separated into individual fibers for rotational alignment.

[0012] (3) In the optical connector described in (1) above, the sealing member may be provided on a rear surface of the boot facing away from the plurality of fiber holding holes in one direction, and may close the opening of the through hole formed on the rear surface. In this case, after the plurality of optical fibers are inserted into the through holes of the boot, the sealing member that closes the gap between the inner surface of the through hole and the plurality of optical fibers can be easily formed by simply applying the sealing member material to close the opening on the rear surface of the boot.

[0013] (4) In the optical connector described in any one of (1) to (3) above, the sealing member may be made of a material different from the adhesive material. A relatively hard material is suitable for the adhesive material in order to fix multiple optical fibers to the ferrule. On the other hand, a relatively soft material is suitable for the sealing member provided in the boot in order to ensure the bending resistance of the optical fibers. Therefore, by using a material different from the adhesive material for the sealing member in consideration of the differences in each application, it is possible to select a type of material suitable for the sealing member.

[0014] (5) In the optical connector according to any one of (1) to (4), each of the optical fibers may have a coating portion covered with a coating. The coating portions of the optical fibers may extend to the outside of the ferrule on the side opposite the inside of the ferrule with respect to the sealing member in one direction, and may be covered on the outside by a resin layer. In this way, by covering the coating portions of the optical fibers extending to the outside with a resin layer, it is possible to protect the coating portions of the optical fibers exposed to the outside from external forces.

[0015] (6) The optical connector according to any one of (1) to (5) above may further include an optical fiber holding component disposed between the plurality of fiber holding holes and the boot inside the ferrule to hold the plurality of optical fibers. By disposing such an optical fiber holding component inside the ferrule, the operation of inserting the plurality of optical fibers into the ferrule becomes easier.

[0016] (7) In the optical connector described in (6) above, each of the plurality of optical fibers may have a coating portion covered with a coating. The holding equipment for optical fiber may be a resin layer covering the coating portions of the plurality of optical fibers. In this case, by covering the coating portions of the plurality of optical fibers with the resin layer, bending resistance of each optical fiber can be ensured.

[0017] (8) In the optical connector described in (6) above, each of the plurality of optical fibers may have a coating-removed portion where a predetermined length of coating is removed from the tip face. The holding equipment for optical fiber may be a resin layer covering the coating-removed portions of the plurality of optical fibers. In this case, by covering the coating-removed portions of the plurality of optical fibers with the resin layer, bending resistance of each optical fiber can be ensured.

[0018] (9) In the optical connector described in (6) above, the holding equipment for optical fiber may have a plurality of V-grooves extending in one direction. A plurality of optical fibers may be accommodated in the plurality of V-grooves, respectively. In this case, by accommodating a plurality of optical fibers in the plurality of V-grooves of the holding equipment for optical fiber, the positions and rotation angles of the plurality of optical fibers relative to the ferrule can be precisely defined.

[0019] (10) In the optical connector described in (6) above, the holding equipment for optical fiber may have a plurality of fiber through holes penetrating in one direction. A plurality of optical fibers may be inserted into the plurality of fiber through holes. In this case, by inserting a plurality of optical fibers into the plurality of fiber through holes of the holding equipment for optical fiber, the positions and rotation angles of the plurality of optical fibers with respect to the ferrule can be precisely defined.

[0020] (11) In the optical connector described in any one of (1) to (10) above, the optical fiber may be any one of a multicore fiber, a polarization-maintaining fiber, and a bundle fiber. When such optical fibers requiring rotational alignment are used, overlapping of the optical fibers is likely to occur. In contrast, the optical connector described above can prevent the adhesive from leaking out of the ferrule even when overlapping of the optical fibers occurs. This can prevent a decrease in the bending resistance of the optical fiber due to hardening of the leaked adhesive.

[0021] (12) 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 described in any one of (1) to (11). The first optical connector is arranged to face the second optical connector in one direction and is optically coupled to the second optical connector. Because this optical coupling structure includes the first optical connector and the second optical connector as the optical connectors, it is possible to prevent a decrease in the bending resistance of the optical fiber, as described above.

[0022] (13) A method for manufacturing an optical connector according to an embodiment of the present disclosure includes the steps of: preparing a ferrule having a front end and a rear end facing each other in one direction, the ferrule having a boot insertion hole formed in the rear end and a plurality of fiber holding holes extending from the boot insertion hole toward the front end; a boot having a through hole passing through in one direction and inserted from the rear end into the boot insertion hole; and a plurality of optical fibers, each having at least one of a core and a stress-applying portion positioned offset from its central axis; inserting the plurality of optical fibers into the ferrule so that the plurality of optical fibers are inserted into the through hole and held in the plurality of fiber holding holes, respectively; forming a seal member disposed to seal gaps between the inner surface of the through hole and the plurality of optical fibers as viewed in one direction; and fixing the plurality of optical fibers to the ferrule by injecting an adhesive that fixes the plurality of optical fibers to the ferrule into the ferrule between the boot and the front end. According to this method for manufacturing an optical connector, the seal member can prevent the adhesive from leaking out of the ferrule, thereby preventing the adhesive that leaks out of the ferrule from hardening while adhering to the optical fibers. As a result, it is possible to suppress a decrease in the bending resistance of the optical fiber caused by hardening of the leaked adhesive.

[0023] (14) In the method for manufacturing an optical connector described in (13) above, the step of inserting the plurality of optical fibers into the interior of the ferrule may be performed after the step of forming a seal member and before the step of fixing the plurality of optical fibers to the ferrule, and the step of forming a seal member may include forming a seal member that covers the plurality of optical fibers, and the step of inserting the plurality of optical fibers into the interior of the ferrule may include disposing the seal member inside the through hole when inserting the plurality of optical fibers into the through hole. In this way, if the plurality of optical fibers are covered with the seal member before being inserted into the through hole, the plurality of optical fibers can be inserted into the through hole in an aligned state together, which makes it easier to insert the plurality of optical fibers into the ferrule than when the plurality of optical fibers are inserted into the through hole in a state where they are separated into single fibers for rotational alignment.

[0024] (15) In the method for manufacturing an optical connector described in (13) above, the step of forming the seal member may be performed after the step of inserting the plurality of optical fibers into the ferrule and before the step of fixing the plurality of optical fibers to the ferrule, and in the step of forming the seal member, after the plurality of optical fibers are inserted into the through holes, a seal member may be formed on a rear surface of the boot facing away from the plurality of fiber holding holes in one direction so as to close the openings of the through holes. In this case, after the plurality of optical fibers are inserted into the through holes of the boot, the seal member that closes the openings of the through holes can be easily formed by performing the simple task of applying a seal member material to the rear surface of the boot so as to close the openings.

[0025] [Details of the embodiments of the present disclosure] Specific examples of an optical connector, an optical coupling structure, and a method of manufacturing an optical connector according to embodiments of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same elements in the drawings will be given the same reference numerals, and duplicate descriptions will be omitted as appropriate.

[0026] [First embodiment] Fig. 1 is a perspective view of an optical connector 1 according to a first embodiment. Fig. 2 is a cross-sectional view of the optical connector 1. Fig. 3 is a cross-sectional view of the optical connector 1 taken along line III-III in Fig. 2. In the following description, for convenience of explanation, the longitudinal direction of the optical connector 1 is referred to as the X direction (an example of "one direction"), the short side direction of the optical connector 1 as the Y direction, and the height direction of the optical connector 1 as the Z direction. The X direction, Y direction, and Z direction intersect with each other (in one example, orthogonal to each other). In the following description, one side in the Z direction may be referred to as "upper", the other side in the Z direction as "lower", one side in the X direction as "front", and the other side in the X direction as "rear".

[0027] As shown in Figures 1, 2, and 3, the optical connector 1 includes, for example, a ribbon fiber T, a ferrule 20, and a boot 30. The ribbon fiber T includes a plurality of optical fibers 10 extending in the X direction and aligned in the Y direction. Each of the plurality of optical fibers 10 is a cable that transmits an optical signal. In this embodiment, a case where 12 optical fibers 10 are aligned in a row in the Y direction is illustrated. However, the number of the plurality of optical fibers 10 is not limited to 12, and may be other numbers such as 4, 8, or 24. The plurality of optical fibers 10 may be aligned in two or more rows.

[0028] As shown in FIG. 2 , each optical fiber 10 has a tip end face 11, a coating-removed portion 12, and a coating portion 13. The tip end face 11 is an end face located at the tip of the optical fiber 10 in the X direction. The coating-removed portion 12 is a portion of the optical fiber 10 from which a predetermined length of resin coating 15 (an example of "coating", see FIG. 3 ) has been removed from the tip end face 11. The coating portion 13 is a portion of the optical fiber 10 where the resin coating 15 remains. The coating portion 13 is provided on the opposite side of the coating-removed portion 12 from the tip end face 11. In the coating-removed portion 12, the cladding 16 (see FIG. 3 ) of the optical fiber 10 is exposed. In the coating portion 13, the cladding 16 of the optical fiber 10 is covered with the resin coating 15.

[0029] The optical fiber 10 is an optical fiber that requires rotational alignment with respect to the central axis L. In this embodiment, a multi-core fiber (MCF) is exemplified as the optical fiber 10 that requires rotational alignment. In this case, as shown in FIG. 3 , the optical fiber 10 has a plurality of cores 17 covered with a cladding 16. In the example shown in FIG. 3 , two cores 17 are each disposed at a position offset from the central axis L. The state in which the cores 17 are offset from the central axis L may be defined as a state in which the centers of the cores 17 do not coincide with the central axis L when viewed in the X direction.

[0030] The number and arrangement of the multiple cores 17 are not limited to the example shown in FIG. 3 and can be changed as appropriate. For example, the number of the multiple cores 17 is not limited to two, but may be four, six, eight, or more. The multiple cores 17 may have a central core arranged on the central axis L. In addition to multicore fibers, examples of the optical fiber 10 that require rotational alignment include bundle fibers and polarization-maintaining fibers (PMFs). When the optical fiber 10 is a polarization-maintaining fiber, the optical fiber 10 has a stress-applying portion at a position offset from the central axis L. In this case, for example, the optical fiber 10 has a core arranged on the central axis L, and a pair of stress-applying portions are arranged on both sides of the core.

[0031] The ferrule 20 is a component that holds the ends of multiple optical fibers 10, and is, for example, an MT ferrule. The ferrule 20 has a substantially rectangular parallelepiped shape. The ferrule 20 is made of a resin such as PPS (Polyphenylene Sulfide). The ferrule 20 has, for example, a front end face 21, a rear end face 22, a pair of guide holes 23, 23 (see FIG. 1 ), a boot insertion hole 24, and multiple fiber holding holes 25.

[0032] The front end face 21 is an end face located at the front end of the ferrule 20 in the X direction. The rear end face 22 is an end face located at the rear end of the ferrule 20 in the X direction. The front end face 21 and the rear end face 22 extend along the Y and Z directions and are aligned in the X direction. A pair of guide holes 23, 23 open at both ends of the front end face 21 in the Y direction and extend in the X direction from the front end face 21 toward the rear end face 22 (see FIG. 1 ). An opening 22a capable of accepting multiple optical fibers 10 collectively is formed in the rear end face 22. That is, the opening 22a can accept multiple optical fibers 10 grouped together.

[0033] The boot insertion hole 24 is a hole for inserting the boot 30 and extends forward from the opening 22a of the rear end face 22. A wall surface 26 is formed inside the ferrule between the front end face 21 and the rear end face 22, and the boot insertion hole 24 extends in the X direction from the opening 22a to the wall surface 26. The wall surface 26 may be, for example, a flat surface extending along the Y direction and the Z direction. The boot insertion hole 24 has, for example, a rectangular shape when viewed in the X direction. The coatings 13 of the multiple optical fibers 10 are inserted into the boot insertion hole 24 collectively in the X direction via the boots 30, i.e., with the coatings 13 of the multiple optical fibers 10 grouped together.

[0034] The plurality of fiber holding holes 25 are connected to the boot insertion hole 24 in the X direction and extend from the boot insertion hole 24 to the front end face 21 in the X direction. The plurality of fiber holding holes 25 penetrate from the wall surface 26 to the front end face 21 in the X direction and open at the front end face 21. The plurality of fiber holding holes 25 are lined up in the Y direction between the pair of guide holes 23, 23 in correspondence with the plurality of optical fibers 10. Each of the plurality of fiber holding holes 25 has, for example, a circular shape when viewed in the X direction. The inner diameter of each of the plurality of fiber holding holes 25 is set to be the same as or slightly larger than the outer diameter of the coating removal portion 12. The coating removal portions 12 of the plurality of optical fibers 10 are inserted into and held in the plurality of fiber holding holes 25, respectively.

[0035] 2 and 3 , the boot 30 is a tubular member having a through hole 31 through which a plurality of optical fibers 10 pass. The boot 30 is inserted in the X direction into the boot insertion hole 24 from the rear end face 22. The boot 30 has, for example, a rectangular shape when viewed in the X direction, and fits snugly into the rectangular boot insertion hole 24. The boot 30 is fixed in the boot insertion hole 24, and the rear end of the boot 30 protrudes slightly rearward from the rear end face 22.

[0036] The boot 30 has a front surface 32 and a rear surface 33 aligned in the X direction. The front surface 32 is an end surface located at the front end (one end) of the boot 30 in the X direction. The rear surface 33 is an end surface located at the rear end (other end) of the boot 30 in the X direction. When the boot 30 is inserted into the boot insertion hole 24, the front surface 32 is disposed inside the boot insertion hole 24 and faces in the X direction a wall surface 26 in which the multiple fiber holding holes 25 are formed. The rear surface 33 is disposed outside the boot insertion hole 24 and is disposed rearward of the rear end surface 22. The through hole 31 penetrates in the X direction from the front surface 32 to the rear surface 33. The through hole 31 has, for example, a rectangular shape when viewed in the X direction. An opening 32a and an opening 33a of the through hole 31 are formed in the front surface 32 and the rear surface 33, respectively. The coatings 13 of the plurality of optical fibers 10 are inserted into the through-hole 31 in the X direction together, that is, in a state where the coatings 13 of the plurality of optical fibers 10 are grouped together.

[0037] The boot 30 is made of an elastic material such as rubber or elastic resin. With this configuration, even if bending stress is applied to the optical fibers 10 inserted into the boot 30, the boot 30 absorbs the bending stress, preventing the optical fibers 10 from being suddenly bent. This improves the bending resistance of the optical fibers 10. Furthermore, since the boot 30 fits snugly into the boot insertion hole 24, the adhesive A injected into the internal space R of the ferrule 20 is prevented from leaking out of the ferrule 20. In this way, the boot 30 has the function of protecting the optical fibers 10 and the function of preventing the adhesive A from leaking out.

[0038] The internal space R is a space formed inside the ferrule 20 between the front end face 21 and the boot 30. The internal space R may include, for example, an internal space of the boot insertion hole 24 located between the front face 32 and the wall surface 26, and the internal spaces of the multiple fiber holding holes 25. A window 28 communicating with the internal space R is formed in the top surface 27 of the ferrule 20. The top surface 27 is, for example, a flat surface along the XY plane and extends in the X direction between the front end face 21 and the rear end face 22. The window 28 is an introduction hole for introducing adhesive A into the internal space R. The adhesive A is used to fix the multiple optical fibers 10 to the ferrule 20 and is made of, for example, a resin material such as a thermosetting resin. The adhesive A is filled in at least the space between the front face 32 and the wall surface 26 of the internal space R. The adhesive A may also be filled inside the multiple fiber holding holes 25.

[0039] In this embodiment, as shown in FIGS. 2 and 3 , a seal member 35 is provided inside the through hole 31 of the boot 30. The seal member 35 is a resin layer provided inside the through hole 31 so as to collectively cover the coatings 13 of the multiple optical fibers 10, i.e., the coatings 13 of the multiple optical fibers 10 as a whole. The seal member 35 is provided to prevent the adhesive A injected into the internal space R from leaking out of the ferrule 20 along the multiple optical fibers 10 in the through hole 31. The seal member 35 has a rectangular tubular shape that fits into the through hole 31 in the X direction. As viewed in the X direction, the size of the seal member 35 is set to be the same as the size of the through hole 31, for example. As viewed in the X direction, the seal member 35 may be in contact with the inner surface of the through hole 31 along its periphery. As viewed in the X direction, the seal member 35 is arranged so as to fill gaps between the inner surface of the through hole 31 and the coatings 13 of the multiple optical fibers 10.

[0040] The state in which the seal member 35 closes the gap between the inner surface of the through hole 31 and the covering portion 13 includes a state in which the seal member 35 seals the gap between the inner surface of the through hole 31 and the covering portion 13 without any gap, and a state in which the seal member 35 liquid-tightly seals the gap so that the liquid adhesive A injected into the internal space R does not pass through the gap and flow out to the outside of the ferrule 20. In the state in which the seal member 35 liquid-tightly seals the gap, a small gap may exist between the inner surface of the through hole 31 and the covering portion 13 that does not allow the liquid adhesive A to flow out from the internal space R to the outside of the ferrule 20.

[0041] In the present embodiment, the seal member 35 is provided throughout the entire internal space of the through hole 31 in the XZ cross section. However, the seal member 35 may be provided in only a portion of the internal space of the through hole 31 in the XZ cross section, as long as the seal member 35 is disposed so as to close the gap between the inner surface and the covering portion 13 when viewed in the X direction. Alternatively, the seal member 35 may be provided outside the through hole 31 (for example, on the front surface 32 or rear surface 33 of the boot 30). In the example shown in FIG. 2 , the seal member 35 is disposed so as to protrude slightly forward and backward from the through hole 31 in the X direction.

[0042] The sealing member 35 is made of, for example, the same material as the tape-forming resin 18 that constitutes the tape fiber T. The tape-forming resin 18 is a resin layer that collectively covers the coatings 13 of the multiple optical fibers 10, i.e., bundles the coatings 13 of the multiple optical fibers 10 in a row. The tape-forming resin 18 is provided rearward of the front ends of the coatings 13 of the multiple optical fibers 10. The tape-forming resin 18 collectively covers the coatings 13 of the multiple optical fibers 10 extending rearward from the through hole 31 to the outside of the ferrule 20, bundling them in a row. The tape-forming resin 18 holds the coatings 13 of the multiple optical fibers 10 together to suppress positional fluctuations among the multiple optical fibers. With the multiple optical fibers 10 held in the tape-forming resin 18, rotational alignment of the multiple optical fibers 10 ahead of the tape-forming resin 18 can be performed. With the ends of the optical fibers 10 inserted into the ferrule 20, the tape-forming resin 18 is positioned a predetermined distance rearward from the rear surface 33 of the boot 30. The sealing member 35 may be in contact with the resin tape 18 in the X direction or may be spaced apart from the resin tape 18. The sealing member 35 may bundle the coatings 13 of the optical fibers 10 in a row, similar to the resin tape 18.

[0043] The resin tape 18 is typically made of a soft, flexible material such as a urethane-based resin, a silicone-based resin, a modified silicone-based resin, or a rubber-based resin, in order to ensure bending resistance of the optical fibers 10. On the other hand, the adhesive A is typically made of a relatively hard material such as an epoxy resin or an acrylic resin, in order to secure the optical fibers 10 to the ferrule 20. The sealing member 35 is also made of the same material as the resin tape 18, in order to ensure bending resistance of the optical fibers 10. As a result, the sealing member 35 is made of a material different from the adhesive A, specifically, a material softer than the adhesive A. The sealing member 35 may be made of the same material as the adhesive A, or may be made of a material different from the resin tape 18 and the adhesive A. For example, the material of the sealing member 35 may be a material different from the tape resin 18, selected from urethane-based resin, silicone-based resin, modified silicone-based resin, and rubber-based resin.

[0044] 4 is a perspective view of an optical coupling structure 100 according to this embodiment. The optical coupling structure 100 includes, for example, a first optical connector 1a, a second optical connector 1b, a pair of guide pins 40, 40, and a spacer 50. The first optical connector 1a and the second optical connector 1b have the same configuration as the optical connector 1 described above. In the optical coupling structure 100, the front end face 21 of the first optical connector 1a and the front end face 21 of the second optical connector 1b face each other in the X direction with a gap therebetween. The pair of guide pins 40, 40 fit into a pair of guide holes 23, 23 of the first optical connector 1a and a pair of guide holes 23, 23 of the second optical connector 1b. This defines the positions of the first optical connector 1a and the second optical connector 1b in the YZ plane.

[0045] The spacer 50 is a plate-like member having an opening 50a. The spacer 50 is disposed between the front end face 21 of the first optical connector 1a and the front end face 21 of the second optical connector 1b. The opening 50a allows a plurality of optical paths extending between the first optical connector 1a and the second optical connector 1b to pass through. This optically couples the first optical connector 1a and the second optical connector 1b. The spacer 50 abuts against the front end face 21 of the first optical connector 1a and the front end face 21 of the second optical connector 1b. This defines a gap between the first optical connector 1a and the second optical connector 1b in the X direction.

[0046] Next, a method for manufacturing the optical connector 1 will be described with reference to Figures 5, 6, 7, and 8. Figure 5 is a plan view showing a manufacturing process for the optical connector 1. Figure 6 is a plan view showing a manufacturing process subsequent to Figure 5. Figure 7 is a cross-sectional view showing a manufacturing process subsequent to Figure 6. Figure 8 is a cross-sectional view showing a manufacturing process subsequent to Figure 7.

[0047] First, a plurality of optical fibers 10, a ferrule 20, and a boot 30 are prepared. Then, as shown in Fig. 5 , in order to rotationally align the plurality of optical fibers 10 included in the tape fiber T, the portion of the tape fiber T to be inserted into the ferrule 20 is unwrapped from the tape state into individual optical fibers. At this time, tape-forming resin 18 remains behind the coating portions 13 of the plurality of optical fibers 10. In this state, the plurality of optical fibers 10 are each rotationally aligned about the central axis L.

[0048] Next, as shown in Fig. 6, with the rotationally aligned optical fibers 10 aligned in a row in the Y direction, a material for a sealing member 35 is applied so as to cover the coatings 13 of the optical fibers 10 in front of the tape-forming resin 18. In this state, the material for the sealing member 35 is cured to form the sealing member 35 that holds the coatings 13 of the optical fibers 10 together. As a result, the optical fibers 10 that have been separated into individual fibers are re-taped with the sealing member 35. Therefore, the sealing member 35 can also be said to be a re-taping resin for re-taping the optical fibers 10 that have been separated into individual fibers.

[0049] 7 , the multiple optical fibers 10 held by the seal member 35 are inserted into the ferrule 20 through the through hole 31 of the boot 30. At this time, the seal member 35 holding the coating portions 13 of the multiple optical fibers 10 is inserted into the through hole 31 of the boot 30 in the X direction. The coating-removed portions 12 of the multiple optical fibers 10 are inserted into the multiple fiber holding holes 25 of the ferrule 20 in the X direction, respectively. In this state, the seal member 35 is positioned so as to close the gap between the inner surface of the through hole 31 and the multiple optical fibers 10 when viewed in the X direction.

[0050] Next, as shown in Fig. 8, liquid adhesive A is injected into the internal space R of the ferrule 20 through the window 28 of the ferrule 20. At this time, the interior of the through hole 31 is sealed with the seal member 35, preventing the liquid adhesive A from leaking out of the ferrule 20 along the multiple optical fibers 10 inserted into the through hole 31. Therefore, the adhesive A fills the internal space R without flowing out beyond the seal member 35. When the adhesive A hardens in this state, the multiple optical fibers 10 are fixed to the ferrule 20, and the optical connector 1 shown in Fig. 2 is obtained.

[0051] The effects obtained by the optical connector 1, the optical coupling structure 100, and the manufacturing method of the optical connector 1 according to this embodiment, as explained above, will be explained together with the problems of the comparative example.

[0052] FIG. 9 is a cross-sectional view of an optical connector 200 according to a comparative example. FIG. 10 is a cross-sectional view of the optical connector 200 taken along line X-X in FIG. 9. Unlike the optical connector 1 according to this embodiment, the optical connector 200 does not include a sealing member 35. In this case, multiple optical fibers 10 are inserted into the ferrule 20 through the through-hole 31 of the boot 30 in a state in which they are separated into single fibers for rotational alignment. When multiple optical fibers 10 are inserted into the through-hole 31 in this separated state, it is difficult to maintain the multiple optical fibers 10 precisely aligned in the Y direction inside the through-hole 31. Therefore, as shown in FIG. 10, overlapping of the optical fibers 10 is likely to occur.

[0053] When such overlapping of the optical fibers 10 occurs, gaps are likely to occur between the inner surface of the through hole 31 and the optical fibers 10. In this case, when liquid adhesive A is injected into the inside of the ferrule 20, the adhesive A is likely to leak from the gap along the optical fibers 10 to the outside of the ferrule 20. If the adhesive A that has leaked to the outside of the ferrule 20 hardens while adhering to the optical fibers 10, the flexibility of the optical fibers 10 may be lost, and the bending resistance of the optical fibers 10 may be reduced. As a result, problems such as the optical fibers 10 easily breaking may occur when bending stress is applied to the optical fibers 10.

[0054] 2 and 3 , the boot 30 is provided with a seal member 35 that is arranged to seal the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10 when viewed in the X direction. This prevents the adhesive A from leaking out of the ferrule 20 through the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10 when liquid adhesive A is injected into the internal space R of the ferrule 20. The configuration in which the seal member 35 is provided prevents the adhesive A from leaking out of the ferrule 20. This prevents the adhesive A that has leaked out of the ferrule 20 from hardening while adhering to the optical fibers 10. As a result, a decrease in the bending resistance of the optical fibers 10 due to hardening of the leaked adhesive A can be prevented.

[0055] As in the present embodiment, the seal member 35 may be disposed inside the through hole 31, or may collectively cover the plurality of optical fibers 10. In this case, by inserting the plurality of optical fibers 10 into the through hole 31 with the seal member 35 collectively covered, the seal member 35 can be disposed so as to close the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10. In this way, by collectively covering the plurality of optical fibers 10 with the seal member 35 before inserting the plurality of optical fibers 10 into the through hole 31, the plurality of rotationally aligned optical fibers 10 can be inserted into the through hole 31 in an aligned state. In this case, the insertion of the plurality of optical fibers 10 into the ferrule 20 can be performed more easily than when the plurality of optical fibers 10 are inserted into the through hole 31 in a state where they are separated into individual fibers for rotational alignment. Furthermore, by aligning the plurality of optical fibers 10 using the seal member 35, the plurality of optical fibers 10 can be arranged inside the through hole 31 so as not to overlap each other. This more reliably prevents the adhesive A from leaking out of the ferrule 20 through gaps formed between the optical fibers 10 .

[0056] As in this embodiment, the seal member 35 may be made of a material different from the material of the adhesive A. A relatively hard material is suitable for the material of the adhesive A in order to fix the plurality of optical fibers 10 to the ferrule 20. On the other hand, a relatively soft material is suitable for the material of the seal member 35 provided in the boot 30 in order to ensure the bending resistance of the optical fibers 10. Therefore, by using a material different from the material of the adhesive A as the material of the seal member 35 in consideration of the differences in each application, it becomes possible to select a type of material suitable for the seal member 35.

[0057] As in this embodiment, the coatings 13 of the multiple optical fibers 10 may extend to the outside of the ferrule 20 on the opposite side of the internal space R with respect to the seal member 35 in the X direction, and may be collectively covered on the outside by the resin tape 18. In this way, the coatings 13 of the multiple optical fibers 10 extending to the outside are collectively covered by the resin tape 18, so that the coatings 13 of the multiple fibers exposed to the outside can be protected from external forces.

[0058] As in the present embodiment, each of the optical fibers 10 may be any of a multicore fiber, a polarization-maintaining fiber, and a bundle fiber. When such optical fibers 10 that require rotational alignment are used, overlapping of the optical fibers 10 is likely to occur. In contrast, the optical connector described above can prevent the adhesive A from leaking out of the ferrule 20 even when overlapping of the optical fibers 10 occurs. This can prevent a decrease in the bending resistance of the optical fibers 10 due to hardening of the leaked adhesive A.

[0059] Second Embodiment Next, an optical connector 1A according to a second embodiment will be described. In the following description of the second embodiment, descriptions of parts that overlap with the first embodiment will be omitted as appropriate, and differences from the first embodiment will be mainly described.

[0060] FIG. 11 is a cross-sectional view of the optical connector 1A according to the second embodiment. FIG. 12 is a cross-sectional view of the optical connector 1A taken along line XII-XII in FIG. 11 . In the optical connector 1A according to the second embodiment, unlike the optical connector 1 according to the first embodiment, the seal member 35A is not disposed inside the through hole 31 of the boot 30 but is disposed outside the through hole 31. Specifically, the seal member 35A is provided on the rear surface 33 of the boot 30 and disposed so as to block the opening 33a formed in the rear surface 33. "Disposing the seal member 35A so as to block the opening 33a" means that the seal member 35A covers the opening 33a so as to fill the gap between the outer edge of the opening 33a and the coatings 13 of the multiple optical fibers 10 when viewed in the X direction. As a result, the seal member 35A is disposed so as to block the gap between the inner surface of the through hole 31 and the coatings 13 of the multiple optical fibers 10 when viewed in the X direction.

[0061] In FIG. 12 , the outer edge of the sealing member 35A is indicated by a dotted line. As shown in FIG. 12 , when viewed in the X direction, the sealing member 35A has a size sufficient to encompass the through hole 31 of the boot 30. When viewed in the X direction, the sealing member 35A may be larger than the through hole 31 and smaller than the boot 30. When viewed in the X direction, the sealing member 35A may have a size sufficient to encompass the tape resin 18. The sealing member 35A is in contact with the rear surface 33 and has a predetermined thickness in the X direction from the rear surface 33. The sealing member 35A is disposed, for example, between the rear surface 33 and the tape resin 18 in the X direction. In this case, the sealing member 35A may be in contact with the rear surface 33 and the tape resin 18 in the X direction. The sealing member 35A may be disposed so as to cover the tape resin 18. In this case, the sealing member 35A may be in contact with the outer peripheral surface of the tape resin 18.

[0062] Next, a manufacturing method of the optical connector 1A will be described with reference to Figures 13, 14, 15, and 16. Figure 13 is a plan view showing a manufacturing process of the optical connector 1A. Figure 14 is a cross-sectional view showing a manufacturing process subsequent to Figure 13. Figure 15 is a cross-sectional view showing a manufacturing process subsequent to Figure 14. Figure 16 is a cross-sectional view showing a manufacturing process subsequent to Figure 15.

[0063] 13 , in order to rotationally align the multiple optical fibers 10 included in the tape fiber T, the multiple optical fibers 10 in the portion of the tape fiber T to be inserted into the ferrule 20 are first separated from the tape state into individual fibers. At this time, the tape resin 18 remains behind the coating portions 13 of the multiple optical fibers 10. In this state, the multiple optical fibers 10 are each rotationally aligned around the central axis L.

[0064] 14 , the plurality of optical fibers 10 in a state in which they have been separated into individual fibers are inserted into the inside of the ferrule 20 through the through-hole 31 of the boot 30. At this time, the coating portions 13 of the plurality of optical fibers 10 are inserted in the X direction into the through-hole 31 of the boot 30, and the coating-removed portions 12 of the plurality of optical fibers 10 are inserted in the X direction into the plurality of fiber holding holes 25 of the ferrule 20, respectively. In this state, the tape-formed resin 18 is disposed outside the through-hole 31.

[0065] 15 , the material of the sealing member 35A is applied around the plurality of optical fibers 10 so as to close the opening 33 a in the rear surface 33 of the boot 30. By hardening the material of the sealing member 35A while it is closing the opening 33 a, the sealing member 35A is formed so as to close the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10 when viewed in the X direction.

[0066] Next, as shown in Fig. 16, liquid adhesive A is injected into the internal space R of the ferrule 20 through the window 28 of the ferrule 20. At this time, the opening 33a of the through hole 31 is sealed with the seal member 35A, preventing the liquid adhesive A from leaking out of the ferrule 20 along the multiple optical fibers 10 inserted into the through hole 31. Therefore, the adhesive A fills the internal space R without flowing out beyond the seal member 35A. When the adhesive A hardens in this state, the multiple optical fibers 10 are fixed to the ferrule 20, and the optical connector 1A shown in Fig. 11 is obtained.

[0067] According to the optical connector 1A of this embodiment, even when the optical fibers 10 overlap each other, the sealing member 35A can prevent the adhesive A from leaking out of the ferrule 20. This can prevent the adhesive A that has leaked out of the ferrule 20 from hardening while adhering to the optical fiber 10. As a result, it is possible to prevent a decrease in the bending resistance of the optical fiber 10 due to hardening of the leaked adhesive A.

[0068] As in the present embodiment, the sealing member 35A may close the opening 33 a formed in the rear surface 33 of the boot 30. In this case, after the plurality of optical fibers 10 are inserted into the through hole 31 of the boot 30, the sealing member 35A arranged to close the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10 can be easily formed by performing the simple operation of applying the material of the sealing member 35A so as to close the opening 33 a in the rear surface 33 of the boot 30.

[0069] In the present embodiment, the seal member 35A may be formed on the front surface 32 of the boot 30 instead of the rear surface 33 of the boot 30. In this case, the seal member 35A is disposed on the front surface 32 so as to close the opening 32a formed in the front surface 32. Even in this configuration, the seal member 35A can prevent the adhesive A from leaking out of the ferrule 20, thereby achieving the same effect as described above.

[0070] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the claims.

[0071] Fig. 17 is a cross-sectional view of an optical connector 1B according to a modified example of the first embodiment. Fig. 18 is a perspective view of holding equipment for optical fiber 60 included in the optical connector 1B. The optical connector 1B includes the optical connector 1 according to the first embodiment, as well as holding equipment for optical fiber 60 shown in Fig. 18. The holding equipment for optical fiber 60 is configured as a separate body from the ferrule 20, and is placed inside the ferrule 20. The holding equipment for optical fiber 60 is made of a material such as resin or metal. The holding equipment for optical fiber 60 includes, for example, a front surface 60a, a rear surface 60b, an upper surface 60c, a lower surface 60d, a side surface 60e, and a side surface 60f.

[0072] 4. The front surface 60a is an end surface located at the front end of holding equipment for optical fiber 60 in the X direction. The rear surface 60b is an end surface located at the rear end of holding equipment for optical fiber 60 in the X direction. The front surface 60a and the rear surface 60b are, for example, planes along the YZ plane, and are arranged side by side along the X direction. The top surface 60c is an end surface located at the top end of holding equipment for optical fiber 60 in the Z direction. The bottom surface 60d is an end surface located at the bottom end of holding equipment for optical fiber 60 in the Z direction. The top surface 60c and the bottom surface 60d are, for example, planes along the XY plane, and are arranged side by side along the Z direction. The side surface 60e is an end surface located at one end of holding equipment for optical fiber 60 in the Y direction. The side surface 60f is an end surface located at the other end of holding equipment for optical fiber 60 in the Y direction. The side surface 60e and the side surface 60f are, for example, planes along the XZ plane, and are arranged side by side along the Y direction.

[0073] 1. The holding equipment for optical fiber 60 has a fixing surface 60g for fixing the coating parts 13 of multiple optical fibers 10 together in a part closer to the rear surface 60b in the X direction. The fixing surface 60g is, for example, a plane along the XY plane, and forms a step with respect to the upper surface 60c. The fixing surface 60g and the upper surface 60c are connected via a step surface 60s. The step surface 60s is, for example, a plane along the YZ plane, and is formed perpendicular to the fixing surface 60g and the upper surface 60c. The fixing surface 60g extends from the step surface 60s to the rear surface 60b in the X direction. The holding equipment for optical fiber 60 has a plurality of V-grooves 60h for holding the coating removal parts 12 of multiple optical fibers 10 respectively in a part closer to the rear surface 60b in the X direction. The plurality of V-grooves 60h are formed in the upper surface 60c. The plurality of V-shaped grooves 60h extend in the X direction from the front surface 60a to the step surface 60s on the upper surface 60c and are arranged side by side along the Y direction.

[0074] 17, holding equipment for optical fiber 60 is placed inside the ferrule 20 through the boot insertion hole 24 of the ferrule 20. Holding equipment for optical fiber 60 is placed inside the ferrule 20 between a plurality of fiber holding holes 25 and the boot 30. For example, the front surface 60a of holding equipment for optical fiber 60 is separated from the wall surface 26 where a plurality of fiber holding holes 25 are formed. The rear surface 60b of holding equipment for optical fiber 60 is in contact with the front surface 32 of the boot 30. Holding equipment for optical fiber 60 holds a plurality of optical fibers 10 extending between the wall surface 26 and the front surface 32. The plurality of V-grooves 60h of holding equipment for optical fiber 60 accommodate the coating removed parts 12 of the plurality of optical fibers 10, respectively. The coating parts 13 of the plurality of optical fibers 10 are placed on the fixing surface 60g of holding equipment for optical fiber 60. A rectangular plate-shaped cover 61 that covers the coating parts 13 of the plurality of optical fibers 10 is provided on the plurality of V-grooves 60h. The coating removal portion 12 and the coating portion 13 are fixed to the V-groove 60h and the fixing surface 60g, respectively, with an adhesive.

[0075] Even in this configuration, the same effect as that of the optical connector 1 according to the first embodiment can be obtained. That is, since the sealing member 35 can prevent the adhesive A from leaking out of the ferrule 20, it is possible to prevent the adhesive A leaked out of the ferrule 20 from hardening while adhering to the optical fiber 10. As a result, it is possible to prevent a decrease in the bending resistance of the optical fiber 10 due to hardening of the leaked adhesive A. Furthermore, if the holding equipment 60 for optical fiber as described above is placed inside the ferrule 20, it becomes easier to insert multiple optical fibers 10 into the ferrule 20. Furthermore, the holding equipment 60 for optical fiber has multiple V-grooves 60h. In this case, by accommodating multiple optical fibers 10 in the multiple V-grooves 60h, the positions and rotation angles of the multiple optical fibers 10 relative to the ferrule 20 can be precisely defined.

[0076] 19 is a cross-sectional view of an optical connector 1C according to another modification of the first embodiment. Fig. 20 is a perspective view of holding equipment for optical fiber 60A included in the optical connector 1C. The optical connector 1C is provided with holding equipment for optical fiber 60A of Fig. 20 instead of holding equipment for optical fiber 60 of the optical connector 1B. Unlike holding equipment for optical fiber 60, holding equipment for optical fiber 60A does not have a fixing surface 60g. The upper surface 60c extends from the front surface 60a to the rear surface 60b. A plurality of V-grooves 60i formed on the upper surface 60c extend from the front surface 60a to the rear surface 60b. The plurality of V-grooves 60i accommodate the coatings 13 of a plurality of optical fibers 10 extending between the wall surface 26 and the front surface 32 of the boot 30. Rectangular plate-shaped covers 61 are provided on the plurality of V-grooves 60i to cover the coatings 13 of a plurality of optical fibers 10. Even in this configuration, the same effect as that of the optical connector 1 according to the first embodiment can be obtained. The holding equipment 60A for optical fiber may have a plurality of V-grooves for respectively accommodating the coating removed portions 12 of a plurality of optical fibers 10 extending between the wall surface 26 and the front surface 32.

[0077] Fig. 21 is a cross-sectional view of an optical connector 1D according to another modification of the first embodiment. Fig. 22 is a perspective view showing holding equipment for optical fiber 60B included in the optical connector 1D. The optical connector 1D is equipped with holding equipment for optical fiber 60B of Fig. 22 instead of holding equipment for optical fiber 60 of the optical connector 1B. Unlike holding equipment for optical fiber 60, holding equipment for optical fiber 60B does not have a fixing surface 60g. The upper surface 60c extends from the front surface 60a to the rear surface 60b. Holding equipment for optical fiber 60B is equipped with a plurality of fiber through holes 62 instead of a plurality of V-grooves 60h. The plurality of fiber through holes 62 penetrate in the X direction from the front surface 60a to the rear surface 60b, and are lined up along the Y direction. A plurality of optical fibers 10 are inserted into the plurality of fiber through holes 62, respectively.

[0078] 22 , each fiber through hole 62 has, for example, a small diameter portion 62a and a large diameter portion 62b. The coating removal portion 12 of the optical fiber 10 extending between the wall surface 26 and the front surface 32 of the boot 30 is inserted into the small diameter portion 62a. The large diameter portion 62b has an inner diameter larger than that of the small diameter portion 62a. The coating portion 13 of the optical fiber 10 extending between the wall surface 26 and the front surface 32 of the boot 30 is inserted into the large diameter portion 62b. Even in this configuration, the same effect as that of the optical connector 1 according to the first embodiment can be obtained. Furthermore, by using an optical fiber holding component 60B having a plurality of fiber through holes 62, the positions and rotation angles of the optical fibers 10 relative to the ferrule 20 can be precisely determined by inserting the optical fibers 10 into the plurality of fiber through holes 62, respectively. The fiber through hole 62 may have only the small diameter portion 62a, or the small diameter portion 62a may hold only the coating removal portion 12. Alternatively, the fiber through-hole 62 may have only the large diameter portion 62b, and only the coating portion 13 may be held by the large diameter portion 62b.

[0079] 23 is a cross-sectional view showing a modification of holding equipment for optical fiber 60. As shown in FIG. 23, holding equipment for optical fiber 60C may be used as a modification of holding equipment for optical fiber 60. Holding equipment for optical fiber 60C is a resin layer that collectively covers the coatings 13 of multiple optical fibers 10 extending between the wall surface 26 and the front surface 32 of the boot 30, i.e., bundling the coatings 13 of multiple optical fibers 10 in a row. Holding equipment for optical fiber 60C integrally holds the coatings 13 of multiple optical fibers 10. Holding equipment for optical fiber 60C may be made of the same material as the tape resin 18, for example. Even in this form, the same effect as the optical connector 1 according to the first embodiment can be obtained. Furthermore, since the coatings 13 of multiple optical fibers 10 are covered by holding equipment for optical fiber 60C, bending resistance of each optical fiber 10 can be ensured.

[0080] 24 is a cross-sectional view showing another modified example of holding equipment for optical fiber 60. As shown in FIG. 24, holding equipment for optical fiber 60D may be used as a modified example of holding equipment for optical fiber 60. Holding equipment for optical fiber 60D is a resin layer that collectively covers the coating removal parts 12 of multiple optical fibers 10 extending between the wall surface 26 and the front surface 32 of the boot 30, i.e., that bundles the coating removal parts 12 of multiple optical fibers 10 in a row. Holding equipment for optical fiber 60D integrally holds the coating removal parts 12 of multiple optical fibers 10. Holding equipment for optical fiber 60D may be made of the same material as the tape resin 18, for example. Even in this form, the same effect as that of the optical connector 1 according to the first embodiment can be obtained. Furthermore, by covering the coating removal parts 12 of multiple optical fibers 10 with holding equipment for optical fiber 60D, bending resistance of each optical fiber 10 can be ensured.

[0081] 25 is a cross-sectional view of an optical connector 1E according to a modified example of the second embodiment. The optical connector 1E includes, in addition to the optical connector 1A according to the second embodiment, holding equipment for optical fiber 60 shown in FIG. 18. Similar to the optical connector 1A, the holding equipment for optical fiber 60 is arranged between a plurality of fiber holding holes 25 and the boot 30 inside the ferrule 20. The holding equipment for optical fiber 60 holds a plurality of optical fibers 10 extending between the wall surface 26 and the front surface 32 of the boot 30. The plurality of V-grooves 60h of the holding equipment for optical fiber 60 accommodate the coating removal parts 12 of the plurality of optical fibers 10, respectively. The coating parts 13 of the plurality of optical fibers 10 are placed on the fixing surface 60g of the holding equipment for optical fiber 60. In the optical connector 1E, after the plurality of optical fibers 10 are inserted into the ferrule 20 in this way, a seal member 35A is formed to close the opening 33a of the rear surface 33 of the boot 30.

[0082] Even with this configuration, the same effect as that of the optical connector 1A according to the second embodiment can be obtained. That is, since the seal member 35A can prevent the adhesive A from leaking out of the ferrule 20, it is possible to prevent the adhesive A leaked out of the ferrule 20 from hardening while adhering to the optical fiber 10. As a result, it is possible to prevent a decrease in the bending resistance of the optical fiber 10 due to hardening of the leaked adhesive A. Furthermore, if the seal member 35A is configured to close the opening 33a of the rear surface 33 of the boot 30, it is possible to easily form the seal member 35A arranged to close the gap between the inner surface of the through hole 31 and the plurality of optical fibers 10 by performing a simple operation of applying the material of the seal member 35A so as to close the opening 33a of the rear surface 33 of the boot 30. The optical connector 1E may be provided with any of holding equipment for optical fiber 60A, 60B, 60C, and 60D instead of the holding equipment for optical fiber 60.

[0083] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C, 1D, 1E...Optical connector 1a...First optical connector 1b...Second optical connector 10...Optical fiber 11...Tip face 12...Coating removal portion 13...Coating portion 15...Resin coating 16...Cladding 17...Core 18...Tape-formed resin 20...Ferrule 21...Front end face 22...Rear end face 22a, 32a, 33a, 50a...Opening 23...Guide hole 24...Boot insertion hole 25...Fiber holding hole 26...Wall surface 27, 60c...Upper surface 28...Window 30...Boot 31...Through hole 32, 60a...Front surface 33, 60b...Rear surface 35, 35A...Sealing member 40...Guide pin 50...Spacer 60, 60A, 60B, 60C, 60D...Optical fiber holding component 60d...Lower surface 60e, 60f... Side surface 60g... Fixing surface 60s... Step surface 62a... Thin diameter portion 62b... Thick diameter portion 60h, 60i... V-groove 62... Fiber through-hole 100... Optical coupling structure A... Adhesive L... Central axis R... Internal space T... Ribbon fiber

Claims

1. a ferrule having a front end and a rear end opposed to each other in one direction, a boot insertion hole formed in the rear end, and a plurality of fiber holding holes extending from the boot insertion hole toward the front end; a boot having a through hole penetrating in the one direction and inserted into the boot insertion hole from the rear end; a plurality of optical fibers each having at least one of a core and a stress applying portion at a position shifted from a central axis of the optical fiber; the optical fibers being inserted into the through hole in the one direction and held in the plurality of fiber holding holes; Equipped with an adhesive disposed within the ferrule between the boot and the front end to secure the optical fibers to the ferrule; the boot is provided with a seal member disposed so as to close a gap between an inner surface of the through hole and the plurality of optical fibers when viewed in the one direction; Optical connector.

2. the sealing member is disposed inside the through hole and covers the optical fibers.

2. The optical connector according to claim 1.

3. the sealing member is provided on a rear surface of the boot facing away from the plurality of fiber holding holes in the one direction, and closes an opening of the through hole formed on the rear surface.

2. The optical connector according to claim 1.

4. The sealing member is made of a material different from that of the adhesive.

2. The optical connector according to claim 1.

5. Each of the plurality of optical fibers has a coating portion covered with a coating, the coating portions of the optical fibers extend to the outside of the ferrule on the opposite side to the inside of the ferrule with respect to the seal member in the one direction, and the outside is covered with a resin layer; 2. The optical connector according to claim 1.

6. an optical fiber holding component arranged between the plurality of fiber holding holes and the boot inside the ferrule and holding the plurality of optical fibers; 2. The optical connector according to claim 1.

7. Each of the plurality of optical fibers has a coating portion covered with a coating, The optical fiber holding equipment is a resin layer covering the coating parts of the optical fibers.

7. The optical connector according to claim 6.

8. Each of the plurality of optical fibers has a coating removal portion in which a predetermined length of coating is removed from a tip surface, The optical fiber holding equipment is a resin layer covering the coating removal parts of the optical fibers.

7. The optical connector according to claim 6.

9. The holding equipment for optical fiber has a plurality of V-grooves extending in the one direction, The plurality of optical fibers are housed in the plurality of V-grooves, respectively.

7. The optical connector according to claim 6.

10. The holding equipment for optical fiber has a plurality of fiber through holes penetrating in the one direction, The optical fibers are inserted into the fiber through holes.

7. The optical connector according to claim 6.

11. Each of the optical fibers is any one of a multicore fiber, a polarization maintaining fiber, and a bundle fiber. The optical connector according to any one of claims 1 to 10.

12. The optical connector according to any one of claims 1 to 10, comprising a first optical connector and a second optical connector; The first optical connector is disposed opposite the second optical connector in the one direction and is optically coupled to the second optical connector.

13. preparing a ferrule having a front end and a rear end facing each other in one direction, the ferrule having a boot insertion hole formed in the rear end and a plurality of fiber holding holes extending from the boot insertion hole toward the front end, a boot having a through hole penetrating in the one direction and inserted into the boot insertion hole from the rear end, and a plurality of optical fibers each having at least one of a core and a stress applying portion at a position offset from a central axis of the optical fiber; inserting the optical fibers into the ferrule such that the optical fibers are inserted into the through holes and held in the fiber holding holes, respectively; forming a seal member disposed so as to close gaps between an inner surface of the through hole and the plurality of optical fibers when viewed in the one direction; securing the optical fibers to the ferrule by injecting an adhesive into an interior portion of the ferrule between the boot and the front end, the adhesive securing the optical fibers to the ferrule; Equipped with A method for manufacturing an optical connector.

14. the step of inserting the plurality of optical fibers into the inside of the ferrule is performed after the step of forming the seal member and before the step of fixing the plurality of optical fibers to the ferrule; In the step of forming the seal member, the seal member is formed to cover the plurality of optical fibers, In the step of inserting the plurality of optical fibers into the inside of the ferrule, the sealing member is disposed inside the through hole when the plurality of optical fibers are inserted into the through hole. The method for manufacturing the optical connector according to claim 13.

15. the step of forming the seal member is performed after the step of inserting the plurality of optical fibers into the interior of the ferrule and before the step of fixing the plurality of optical fibers to the ferrule; In the step of forming the seal member, and after the plurality of optical fibers are inserted into the through holes, the sealing member is formed on a rear surface of the boot facing the opposite side to the plurality of fiber holding holes in the one direction so as to close the opening of the through hole formed on the rear surface. The method for manufacturing the optical connector according to claim 13.