WO2018042812A1

WO2018042812A1 - Optical connector

Info

Publication number: WO2018042812A1
Application number: PCT/JP2017/021658
Authority: WO
Inventors: 修島川
Original assignee: 住友電気工業株式会社
Priority date: 2016-08-31
Filing date: 2017-06-12
Publication date: 2018-03-08

Abstract

An optical connector includes: a plurality of optical fibers having a resin coating and a non-coated part that extends from the end of the resin coating to an end face; a plurality of light guides each bonded onto the end face of the plurality of optical fibers; a ferrule having a fiber insertion hole for collectively receiving the plurality of optical fibers and a plurality of first fiber retention holes extending from the fiber insertion hole; and a protective member having a second fiber retention hole and inserted into the fiber insertion hole from the other end. The total length of the non-coated part and the light guide along the first direction is greater than the length of the ferrule along the same direction. A joint between each light guide and each optical fiber is positioned inside the first fiber retention hole, and the end of the resin coating of each optical fiber is positioned inside the second fiber retention hole.

Description

Optical connector

The present invention relates to an optical connector.
This application claims priority based on Japanese Patent Application No. 2016-169291 filed on August 31, 2016, and incorporates all the description content described in the above Japanese application.

Non-Patent Document 1 discloses a technology related to an MPO connector which is a multi-core PC (Physical Contact) connection type connector. In the MPO connector, a plurality of optical fibers are respectively inserted into a plurality of fiber insertion holes formed in the ferrule. The end faces of the plurality of optical fibers are exposed at the ferrule end face, and are pressed against the end faces of the plurality of optical fibers exposed from the ferrule end face of the optical connector on the connection partner side.

Patent Document 1 discloses a technique related to an optical connector. The optical connector includes an optical fiber for an optical connector to which a first optical fiber and a second optical fiber having a core diameter larger than the core diameter of the first optical fiber are connected. The optical fiber for an optical connector is inserted and fixed in the optical fiber insertion hole of the ferrule, and the connection portion between the first optical fiber and the second optical fiber is accommodated in the optical fiber insertion hole. The first optical fiber is a single mode fiber, and the second optical fiber is a graded index (GI) optical fiber.

Patent Document 2 discloses a technique related to a manufacturing method of an optical fiber collimator. In this manufacturing method, first, tip portions of a plurality of collimator members each having a GRIN lens fused to the tip of an optical fiber are inserted into each core of a multi-core ferrule and temporarily fixed. Next, in a state where the ferrule is pressed against the polishing film affixed on the elastic pad, the ferrule and the polishing film are relatively moved, and the tips of the plurality of GRIN lenses are polished into a spherical shape together with the ferrule. Then, a plurality of collimator members are extracted from the ferrule. Finally, an antireflection film is formed on the tip of the GRIN lens of each collimator member.

Non-Patent Document 2 discloses a technique related to an optical fiber fusion splicer. In this optical fiber fusion splicer, a pair of bare fibers from which the coating has been removed is placed on the V-groove and aligned with each other, and then these bare fibers are fused and connected by discharge.

JP 2005-308880 A JP 2009-047993 A

The optical connector of the present disclosure extends along the first direction, and includes a plurality of optical fibers having a resin coating portion and a coating removal portion extending from the end to the end surface of the resin coating portion, and extending along the first direction. A plurality of light guides respectively joined to end faces of the plurality of optical fibers, a fiber introduction hole formed at one end in the first direction and introducing the plurality of optical fibers in a lump, and the fiber introduction hole in the first direction A ferrule having a plurality of first fiber holding holes extending toward the other end of the fiber, a second fiber holding hole extending toward the other end in the first direction, and a protection inserted into the fiber introduction hole from the other end side A member. Each light guide is held in a state of being inserted into the corresponding first fiber holding hole, and each optical fiber is held in a state of being inserted into the corresponding first fiber holding hole and second fiber holding hole. The combined length of the coating removal portion and the light guide in the first direction is longer than the length of the ferrule in the same direction, and the joint between each light guide and each optical fiber is located in the first fiber holding hole, The end of the resin coating portion of each optical fiber is located in the second fiber holding hole.

FIG. 1 is a perspective view of an optical connector according to an embodiment as viewed obliquely from the rear. FIG. 2 is a perspective view of the optical connector according to the embodiment as viewed obliquely from the rear. FIG. 3 is a perspective view of the optical connector according to the embodiment as viewed obliquely from the front. 4 is a cross-sectional view taken along line IV-IV of the optical connector shown in FIG. FIG. 5 is a perspective view showing a pair of guide pins and a pin keeper provided in the optical connector. FIG. 6 is a perspective view showing an appearance of the optical connector according to the first modification. 7 is a cross-sectional view taken along line VII-VII of the optical connector shown in FIG. FIG. 8 is a perspective view illustrating an appearance of an optical connector according to a second modification. FIG. 9 is a cross-sectional view showing the structure of a general optical connector that does not include a light guide.

[Problems to be solved by the present disclosure]
As disclosed in Non-Patent Document 1, a general multi-core optical connector exposes end faces of a plurality of optical fibers from a ferrule and is PC-connected. On the other hand, as disclosed in Patent Documents 1 and 2, for example, there is an optical connector in which a light guide body such as a GI optical fiber is joined to the end face of each optical fiber and light enters and exits through the light guide body is there. According to this structure, the optical diameter between optical connectors can be expanded, and the fall of the optical coupling efficiency by the axial shift of optical connectors can be suppressed.

When joining a light guide such as a GI optical fiber to the end face of the optical fiber, it is necessary to remove the resin coating of the optical fiber. This is because, as shown in Non-Patent Document 2, it is necessary to align the optical fiber and the light guide with extremely high accuracy by a V-groove or the like. At this time, if the single optical fiber is used, the removal length of the resin coating may be about 6 mm, for example. However, when a plurality of optical fibers and a plurality of light guides are joined together, all the optical fibers are connected. In order to position with high accuracy, it is necessary to lengthen the removal length of the resin coating, for example, about 10 mm. However, the length of the MT ferrule generally used is about 8 mm. Therefore, when the optical fiber is housed in the fiber holding hole of the MT ferrule together with the light guide, the portion where the resin coating is removed protrudes 2 mm or more from the rear end of the MT ferrule, and the portion where the resin coating is removed is sufficiently protected. Can not do it. Although it is conceivable to newly produce an MT ferrule longer than 8 mm, it takes a lot of time and cost to newly design an MT ferrule, which is a precision part having a fine structure, and adjust the molding conditions.

This disclosure is intended to provide an optical connector that can sufficiently protect an optical fiber joined to a light guide using a normal ferrule.

[Effects of the present disclosure]
According to the optical connector according to the present disclosure, the optical fiber bonded to the light guide can be sufficiently protected using a normal ferrule.

[Description of Embodiment of Present Invention]
First, the contents of the embodiment of the present invention will be listed and described. An optical connector according to an embodiment extends along a first direction, and includes a plurality of optical fibers having a resin coating portion and a coating removal portion extending from an end to an end surface of the resin coating portion, and extending along the first direction. A plurality of light guides respectively joined to end faces of the plurality of optical fibers, a fiber introduction hole formed at one end in the first direction and introducing the plurality of optical fibers in a lump, and a first through the fiber introduction hole. A ferrule having a plurality of first fiber holding holes extending toward the other end in one direction and a second fiber holding hole extending toward the other end in the first direction are inserted into the fiber introduction hole from the other end side. And a protective member. Each light guide is held in a state of being inserted into the corresponding first fiber holding hole, and each optical fiber is held in a state of being inserted into the corresponding first fiber holding hole and second fiber holding hole. The combined length of the coating removal portion and the light guide in the first direction is longer than the length of the ferrule in the same direction, and the joint between each light guide and each optical fiber is located in the first fiber holding hole. The end of the resin coating portion of each optical fiber is located in the second fiber holding hole.

In this optical connector, a protective member is inserted into the fiber introduction hole of the ferrule. The protection member has a second fiber holding hole for holding the optical fiber, and the end of the resin coating portion of the optical fiber is located in the second fiber holding hole. Thereby, the part (coating removal part) from which the resin coating of the optical fiber was removed is suitably protected in both the ferrule and the protection member. Therefore, according to this optical connector, the optical fiber joined to the light guide can be sufficiently protected using a normal ferrule.

The optical connector may further include a rubber boot that fits into a recess formed at one end of the protective member in the first direction, and the rubber boot has a third fiber holding hole for holding a plurality of optical fibers. It may be provided therein, and at least a part of the resin coating portions of the plurality of optical fibers may be accommodated in the third fiber holding hole. Such a rubber boot can more reliably protect the resin-coated portion of the optical fiber, and such a reliable protection of the resin-coated portion prevents external influences on the resin removal portion extending from the resin-coated portion. It can be reduced to protect it. Further, the rubber boot may be fitted into the recess so that the end surface on one end side in the first direction is flush with the end surface on one end side in the first direction of the protection member. According to this configuration, when a coil spring or the like is disposed on one end side of the protective member or the like, the pressing force can be stably applied to the optical connector, and the influence on the optical fiber accommodated therein is reduced. Thus, the protection can be achieved. Furthermore, in the above optical connector, the plurality of optical fibers may be arranged in a region having a second direction that intersects the first direction as a longitudinal direction, and the concave portion may penetrate in the second direction. Thereby, the width | variety of the rubber boot in the sequence direction of the longitudinal side of a some optical fiber can be taken wide, and the number of the optical fibers in this sequence direction can be increased.

In the above optical connector, the protection member may further include a hole extending in the third direction intersecting the first direction and reaching the second fiber holding hole, and the end of the resin coating portion of the optical fiber is in the hole. May be located. Thereby, the adhesive for adhering the optical fiber and the ferrule easily flows from the ferrule to the second fiber holding hole, and the adhesive easily reaches the end of the resin coating portion. Alternatively, it is possible to introduce an adhesive from the hole. Therefore, the resin-coated portion end in the protective member can be more reliably protected by the adhesive.

In the above optical connector, the end face of each optical fiber and each light guide may be fused to each other. Thereby, the connection loss between each optical fiber and each light guide can be reduced, and the reliability can be increased.

In the above optical connector, the ferrule and the protection member may be made of the same material. Thereby, since the thermal expansion coefficient of a ferrule and a protection member becomes equal, the influence by the change of ambient temperature can be suppressed. Further, the ferrule and the protection member may be made of different materials having a difference in thermal expansion coefficient within 5 × 10 ⁻⁵ / K. Thereby, like the case where it consists of the same material, the influence by the change of ambient temperature can be suppressed.

In the above optical connector, the ferrule and the protective member may be bonded or welded to each other. When the ferrule and the protective member are bonded to each other, the protective member can be fixed to the ferrule at the same time in the process of bonding and fixing the optical fiber to the ferrule, so that the number of manufacturing steps can be reduced. Further, when the ferrule and the protective member are welded to each other, the ferrule and the protective member can be more firmly fixed, so that the reliability of the optical connector is increased and the handling is facilitated.

In the above optical connector, the second fiber holding hole may have a plurality of openings arranged in a third direction intersecting the first direction. In this case, since a plurality of optical fibers (tape fibers) can be accommodated in multiple stages, an optical connector that can connect more optical fibers can be obtained.

[Details of the embodiment of the present invention]
Specific examples of the optical connector according to the embodiment of the present invention will be described below with reference to the drawings. The present invention is not limited to these exemplifications, 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 reference numerals are given to the same elements in the description of the drawings, and redundant descriptions are omitted. In the following description, each drawing shows an XYZ orthogonal coordinate system as necessary, and the Z-axis is along the connection direction.

1 to 5 are diagrams showing the configuration of an optical connector 1A according to an embodiment of the present invention. 1 and 2 are perspective views of the optical connector 1A as viewed obliquely from the rear. FIG. 3 is a perspective view of the optical connector 1A as viewed obliquely from the front. 2 and 3, the pair of guide pins 51 and 52 and the guide pin keeper 53 provided in the optical connector 1A are not shown. 4 is a cross-sectional view taken along line IV-IV of the optical connector 1A shown in FIG. FIG. 5 is a perspective view showing a pair of guide pins 51 and 52 and a guide pin keeper 53 provided in the optical connector 1A.

As shown in FIGS. 1 to 5, the optical connector 1A of the present embodiment includes a plurality of optical fibers 11, a plurality of light guides 12 (see FIG. 4), a ferrule 20, a protective member 30, A rubber boot 40, a pair of guide pins 51 and 52, a guide pin keeper 53, and a coil spring 54 are provided.

The plurality of optical fibers 11 are, for example, single mode optical fibers. The mode field diameter (MFD) of the optical fiber 11 at the wavelength of 1.31 μm is, for example, 8 μm to 10 μm. Each optical fiber 11 extends along the Z direction. Each optical fiber 11 includes a resin-coated portion 11a and a bare fiber 11b extending from an end (hereinafter referred to as a coated end) 11c of the resin-coated portion 11a to an end surface. The bare fiber 11b is a portion where the coating resin is removed from the optical fiber 11. The bare fiber 11b is made of glass and includes a core and a clad covering the core. The resin coating portion 11a includes a core and a clad, and a resin film that covers the clad. The outer diameter of the bare fiber 11b is, for example, 125 μm, and the outer diameter of the resin coating portion 11a is, for example, 250 μm.

The plurality of optical fibers 11 are arranged in a region whose longitudinal direction is the X direction intersecting the Z direction. Specifically, an optical fiber array in which M (M is an integer of 3 or more) optical fibers 11 are arranged in the X direction has N stages (N is an integer of 1 or more, N <M) in the Y direction. Has been placed. The length of the array of optical fibers 11 in the X direction is longer than the length of the array of optical fibers 11 in the Y direction. In the figure, the case of M = 12, N = 2 is illustrated. The optical fiber array in the resin coating portion 11 a constitutes the tape fiber 13.

The plurality of light guides 12 are elongated glass bodies having a circular cross section extending along the Z direction. Each end surface in the Z direction of the plurality of light guides 12 is joined to each end surface of the plurality of optical fibers 11. In the present embodiment, the end face of each optical fiber 11 and each light guide 12 are joined together by fusion, but the form of joining is not limited to this. The outer diameter of each light guide 12 is equal to the outer diameter of the bare fiber 11 b of the optical fiber 11. The total length of the bare fiber 11b and the light guide 12 in the Z direction is longer than the length of the ferrule 20 in the same direction.

Examples of the light guide 12 bonded to the optical fiber 11 include the following. That is, (1) a GI fiber that functions as a lens for the optical fiber 11 that is a single mode fiber, (2) a GRIN lens that functions as a lens for the optical fiber 11 that is a single mode fiber, and (3) an optical fiber 11. A single mode fiber having a larger MFD (eg, 20 μm). In the case of (3), a TEC process is performed to reduce connection loss at the interface between the optical fiber 11 and the light guide 12. The TEC process is a process that mainly diffuses the core dopant on the optical fiber 11 side by applying heat with a burner, discharge, laser, etc., and moderates the MFD change at the interface. According to the above (1) to (3), the optical diameter between the optical connectors can be enlarged, the optical loss due to the axis deviation can be reduced, and the optical loss due to the fine dust adhering to the tip surface can be reduced. The length of the GI fiber and the GRIN lens is, for example, 1 mm or less.

The ferrule 20 is a resin member that holds the plurality of optical fibers 11 and the plurality of light guides 12. The ferrule 20 is made of, for example, PPS resin. Ferrule 20 has a substantially rectangular parallelepiped appearance, front end surface 20a and rear end surface 20b facing each other in the Z direction, a pair of side surfaces 20c and 20d facing each other in the X direction, and an upper surface facing each other in the Y direction. 20e and a lower surface 20f. A single fiber introduction hole 21 for introducing a plurality of optical fibers 11 at a time is formed in the rear end face 20b. The front portion of the fiber introduction hole 21 is open to the upper surface 20e. That is, the fiber introduction hole 21 penetrates between the rear end surface 20b and the upper surface 20e.

As shown in FIG. 4, the ferrule 20 further has a plurality of fiber holding holes 22. The plurality of fiber holding holes 22 extend from the fiber introduction hole 21 toward the front end face 20a. In the present embodiment, these fiber holding holes 22 penetrate from the fiber introduction hole 21 to the front end face 20a, and have an opening in the front end face 20a. The openings of the plurality of fiber holding holes 22 in the front end face 20 a are arranged in a one-dimensional or two-dimensional manner depending on the arrangement of the plurality of optical fibers 11. The inner diameter of the fiber holding hole 22 is substantially equal to the outer diameter of the bare fiber 11 b of the optical fiber 11 and the outer diameter of the light guide 12. The front end face 20a faces the front end face of the ferrule on the connection partner side, and abuts in one example.

4, the front end face 20a and the end face of the light guide 12 are perpendicular to the center axis of the fiber holding hole 22 (that is, the optical axis of the optical fiber 11). In that case, in order to suppress the reflected return light from the end face of the light guide body 12, the front end face 20a and the end face of the light guide body 12 may be subjected to non-reflection treatment (for example, AR coating). Alternatively, the normal lines of the front end face 20 a and the end face of the light guide 12 may be slightly inclined with respect to the central axis of the fiber holding hole 22. In that case, the reflected return light from the end face of the light guide 12 is suppressed by the inclination, so that the non-reflection treatment is not necessary. However, even in that case, non-reflection treatment may be applied to the front end face 20a and the end face of the light guide 12 in order to suppress the Fresnel reflection loss.

The protective member 30 is a resin member inserted into the fiber introduction hole 21. The protection member 30 has a substantially rectangular parallelepiped appearance, and faces the front end face 30a and the rear end face 30b facing each other in the Z direction, a pair of side faces 30c and 30d facing each other in the X direction, and faces each other in the Y direction. It has an upper surface 30e and a lower surface 30f. The protection member 30 is inserted into the fiber introduction hole 21 from the other end (front end face 30 a) side in the Z direction and is fitted to the fiber introduction hole 21. As shown in FIG. 4, the protection member 30 has a recess 31 and a fiber holding hole 32. The recess 31 is formed at one end (rear end surface 30 b) of the protection member 30 in the Z direction and is fitted with the rubber boot 40. The fiber holding hole 32 extends from the recess 31 toward the other end (front end surface 30a) in the Z direction, and penetrates between the recess 31 and the front end surface 30a. The fiber holding holes 32 extend in the X direction according to the number of optical fibers 11 arranged in the X direction, and collectively accommodate the rows of optical fibers 11 aligned in the Z direction (that is, the tape fibers 13). In the present embodiment, the fiber holding hole 32 is composed of two (two steps) openings arranged in the Y direction (up and down), but may be composed of one opening or three ( (3 steps) or more openings. The width of the fiber holding hole 32 in the Y direction is substantially equal to the outer diameter of the resin coating portion 11 a of the optical fiber 11.

Ferrule 20 and protective member 30 may be made of the same material (for example, PPS resin). Alternatively, the protective member 30 may be made of another material having a thermal expansion coefficient close to that of the constituent material of the ferrule 20, that is, a difference in thermal expansion coefficient within 5 × 10 ⁻⁵ / K. The ferrule 20 and the protection member 30 are bonded to each other via an adhesive or are welded by heating.

Each optical fiber 11 is held in a state of being inserted from the corresponding fiber holding hole 22 to the fiber holding hole 32. The coated end 11c of each optical fiber 11 (that is, the starting point of the bare fiber 11b) is located in each fiber holding hole 32. That is, the bare fiber 11 b is held from the fiber holding hole 22 to the fiber holding hole 32, and the resin coating portion 11 a is held in the fiber holding hole 32. Each optical fiber 11 is fixed to the ferrule 20 and the protection member 30 by an adhesive (for example, thermosetting epoxy adhesive) injected from the opening of the fiber introduction hole 21 formed in the upper surface 20e. This adhesive enters the fiber holding hole 22 and the fiber holding hole 32 from the inside of the fiber introduction hole 21, and fixes the optical fiber 11 to the ferrule 20 and the protection member 30 in the fiber holding hole 22 and the fiber holding hole 32. . Moreover, when the ferrule 20 and the protection member 30 are fixed by adhesion, as the adhesive, for example, the same adhesive as that used for adhesion between the optical fiber 11 and the ferrule 20 is used. That is, the optical fiber 11 and the ferrule 20 are bonded together with the adhesive injected from the opening of the fiber introduction hole 21 formed in the upper surface 20e, and at the same time, the ferrule 20 and the protection member 30 are bonded.

Each light guide 12 is held in a state of being inserted into the corresponding fiber holding hole 22. The front end face of each light guide 12 is exposed at the front end face 20a of the ferrule 20, and allows light to enter and exit. In one example, the front end face of each light guide 12 and the front end face 20a of the ferrule 20 are flush with each other. As shown in FIG. 4, the joint 15 between each light guide 12 and each optical fiber 11 is located in each fiber holding hole 22. Since the joint portion 15 is inferior in strength to other portions, the joint portion 15 is located in the fiber holding hole 22 with a small amount of the surrounding adhesive, which is caused by stress due to curing shrinkage of the adhesive, temperature expansion shrinkage, or the like. It is possible to suppress breakage of the joining portion 15 to be performed.

The rubber boot 40 is a rubber member for protecting the resin coating portion 11a (tape fiber 13) of the optical fiber 11. The rubber boot 40 has a substantially rectangular parallelepiped shape, and fits into a recess 31 formed in the rear end surface 30b of the protection member 30. The rubber boot 40 has a hole 41 through which the tape fiber 13 is inserted. The hole 41 is a fiber holding hole for storing and holding the resin coating portions 11a of the plurality of optical fibers 11 (tape fibers 13) therein. With this rubber boot 40, even when a force is applied to the rear optical fiber 11, the optical fiber 11 is not bent suddenly, and damage to the optical fiber 11 can be avoided.

The pair of guide pins 51 and 52 pass through the pair of guide

pin insertion holes

23a and 23b formed in the ferrule 20, respectively. The tip portions of the pair of guide pins 51 and 52 protrude forward in the Z direction from the front end face 20a of the ferrule 20 and fit into the guide pin insertion holes of the ferrule on the connection partner side. As a result, the ferrule 20 and the connection partner ferrule 20 are positioned with high accuracy. The rear ends of the pair of guide pins 51 and 52 are fixed to a guide pin keeper 53 as shown in FIG. The guide pin keeper 53 covers the outer peripheral surface (the lower surface 30f and the side surfaces 30c and 30d) of the protective member 30 protruding rearward from the ferrule 20, and is in contact with the rear end surface 20b of the ferrule 20. The guide pins 51 and 52 are made of metal, for example.

The coil spring 54 is disposed on the rear end side of the guide pin keeper 53, and urges the guide pin keeper 53, the protection member 30, and the rubber boot 40 forward in the Z direction. As a result, a biasing force forward in the Z direction is applied to the ferrule 20 via the guide pin keeper 53, the protective member 30, and the rubber boot 40, and a pressing force against the ferrule 20 on the other side is generated.

In this embodiment, the rear end surface 30b of the protection member 30 and the rear end surface of the rubber boot 40 are flush with each other. Thereby, the pressing force by the coil spring 54 can be stabilized. However, these rear end surfaces do not necessarily need to be flush with each other, and the rubber boot 40 may protrude rearward from the rear end surface 30b of the protective member 30, or the protective member 30 may protrude rearward from the rear end surface of the rubber boot 40. .

The assembly procedure of the optical connector 1A according to this embodiment is as follows. First, the tape fiber 13 is inserted through the rubber boot 40 and the protection member 30. Next, the bare resin 11 b is formed by removing the coating resin at the tip of the tape fiber 13. Then, the end face of the bare fiber 11b and the light guide 12 are joined (for example, fusion). Subsequently, the plurality of light guides 12 and the plurality of bare fibers 11b are collectively introduced from the fiber introduction holes 21 of the ferrule 20, and the light guides 12 and the bare fibers 11b are introduced into the fiber holding holes 22 of the ferrule 20. Insert. Subsequently, the protection member 30 is inserted into the fiber introduction hole 21 of the ferrule 20, and the rubber boot 40 is inserted into the recess 31 of the protection member 30. Subsequently, an adhesive is poured from the opening of the fiber introduction hole 21 formed in the upper surface 20e and cured. Thereafter, the front end face 20a of the ferrule 20 is polished.

The effect obtained by the optical connector 1A according to the present embodiment will be described. FIG. 9 is a cross-sectional view showing the structure of a general optical connector 100 that does not include the light guide 12. In the optical connector 100, the tape fiber 13 (resin coating portion 11 a) is introduced from the fiber introduction hole 21, and the bare fiber 11 b is inserted into each fiber holding hole 22. The tape fiber 13 is protected by a rubber boot 102 inserted into the fiber introduction hole 21 of the ferrule 20.

However, when the light guide body 12 such as a GI optical fiber is bonded to the end face of the optical fiber 11, the bare fiber 11b protrudes from the rear end face 20b of the ferrule 20 as described above, and thus the bare fiber 11b is sufficiently protected. I can't. In contrast, in the optical connector 1A of the present embodiment, as shown in FIG. 4, the protection member 30 is inserted into the fiber introduction hole 21 of the ferrule 20. The protection member 30 has a fiber holding hole 32 for holding the optical fiber 11, and the coated end 11 c of the optical fiber 11 is located in the fiber holding hole 32. Thereby, the bare fiber 11 b of the optical fiber 11 is suitably protected by both the ferrule 20 and the protection member 30. Therefore, according to this optical connector 1 </ b> A, the optical fiber 11 joined to the light guide 12 can be sufficiently protected using the existing ferrule 20.

1 A of optical connectors are further provided with the rubber boot 40 fitted to the recessed part 31 formed in the rear end of the protection member 30, and this rubber boot 40 has the hole 41 for hold | maintaining the some optical fiber 11 in it. And the hole 41 accommodates at least a part of the resin coating portions 11 a of the plurality of optical fibers 11. Such a rubber boot 40 can more reliably protect the resin-coated portion 11a of the optical fiber 11, and the bare fiber extending from the resin-coated portion 11a by such reliable protection and holding of the resin-coated portion 11a. It is also possible to reduce the influence from the outside on 11b and to protect it. The rubber boot 40 is fitted in the recess so that the end surface on the rear end side is flush with the rear end surface of the protection member 30. For this reason, when the coil spring 54 is disposed at the rear end of the protective member 30 or the like, the pressing force can be stably applied to the optical connector 1A, and the influence on the optical fiber 11 accommodated therein is reduced. Thus, the protection can be achieved.

In the optical connector 1A, the end face of each optical fiber 11 and each light guide 12 may be fused together. Thereby, the connection loss between each optical fiber 11 and each light guide 12 can be reduced, and reliability can be improved. However, the form of joining between the end face of the optical fiber 11 and the light guide 12 is not limited to fusion, and other joining methods such as adhesion may be applied.

In the optical connector 1A, the ferrule 20 and the protection member 30 may be made of the same material. Thereby, since the thermal expansion coefficient of the ferrule 20 and the protection member 30 becomes equal, the influence (peeling of the protection member 30, peeling, etc.) by the change of ambient temperature can be suppressed.

In the optical connector 1A, the ferrule 20 and the protection member 30 may be bonded or welded to each other. When the ferrule 20 and the protection member 30 are bonded to each other, the protection member 30 can be fixed to the ferrule 20 at the same time in the process of bonding and fixing the optical fiber 11 to the ferrule 20, thereby reducing the number of manufacturing steps. be able to. Further, when the ferrule 20 and the protective member 30 are welded to each other, the ferrule 20 and the protective member 30 can be more firmly fixed, so that the reliability of the optical connector 1A is increased and the handling is facilitated.

(First modification)
FIG. 6 is a perspective view showing an appearance of an optical connector 1B according to a first modification of the optical connector 1A. FIG. 7 is a cross-sectional view taken along line VII-VII of the optical connector 1B shown in FIG. As shown in FIGS. 6 and 7, the protection member 30 </ b> B of this modification has a slit (hole) 33 that extends in the X direction and reaches the fiber holding hole 32. In this modification, the slit 33 is formed on the upper surface of the protection member 30B, but the slit may be formed on the side surface or the lower surface. The coated end 11c of each optical fiber 11 (that is, the starting point of the bare fiber 11b) is located in the slit 33.

In the above embodiment, it is important from the viewpoint of reliability that the coated end 11c of the optical fiber 11 is securely fixed by the adhesive. According to this modification, the air in the fiber holding hole 32 can escape from the slit 33, so that the adhesive for bonding the optical fiber 11 and the ferrule 20 can easily flow from the ferrule 20 to the fiber holding hole 32. It becomes easy to reach the covering end 11c. Alternatively, it is possible to introduce an adhesive from the slit 33. Therefore, the covering end 11c in the protection member 30B can be more reliably protected by the adhesive. It is also possible to visually recognize whether or not the adhesive has reached the covering end 11c in the protective member 30B through the slit 33. Other configurations of the protection member 30 </ b> B are the same as those of the protection member 30.

(Second modification)
FIG. 8 is a perspective view showing an appearance of the optical connector 1C according to the second modification of the optical connector 1A. As shown in FIG. 8, in this modification, the recess 31 of the protection member 30C penetrates in the X direction. In other words, the pair of

side surfaces

40c, 40d of the rubber boot 40 is exposed from the pair of

side surfaces

30c, 30d of the protection member 30C.

When a plurality of optical fibers 11 are arranged in a region having the X direction as the longitudinal direction, the recess 31C may penetrate in the X direction as in the present modification. Thereby, the width | variety of the rubber boot 40 in the sequence direction of the longitudinal side of the some optical fiber 11 can be taken wide, and the number of the optical fibers 11 in this sequence direction can be increased.

The optical connector according to the present invention is not limited to the embodiment described above, and various other modifications are possible. For example, the above-described embodiments and modifications may be combined with each other according to the necessary purpose and effect. Further, as long as the optical fiber can be accurately protected by the protection member, a configuration in which the rubber boot is not provided in the concave portion of the protection member is also possible.

DESCRIPTION OF

SYMBOLS

1A, 1B, 1C ... Optical connector, 11 ... Optical fiber, 11a ... Resin coating | coated part, 11b ... Bare fiber, 11c ... Covered end, 12 ... Light guide, 13 ... Tape fiber, 15 ... Joint part, 20 ... Ferrule, 20a ... front end face, 20b ... rear end face, 20c, 20d ... side face, 20e ... top face, 20f ... bottom face, 21 ... fiber introduction hole, 22 ... fiber holding hole, 23a, 23b ... guide pin insertion hole, 30, 30B, 30C Protective member 30a Front end surface 30b Rear end surface 30c

30d Side surface

30e Upper surface

30f Lower surface

31, 31C Recess 32 Fiber holding hole 33 Slit 40 Rubber boot 40c 40d ... side face, 41 ... hole, 51, 52 ... guide pin, 53 ... guide pin keeper.

Claims

A plurality of optical fibers extending along the first direction and having a resin coating portion and a coating removal portion extending from an end to an end surface of the resin coating portion;
A plurality of light guides extending along the first direction and respectively joined to the end faces of the plurality of optical fibers;
A fiber introduction hole formed at one end in the first direction and collectively introducing the plurality of optical fibers; and a plurality of first fiber holding holes extending from the fiber introduction hole toward the other end in the first direction. Having a ferrule,
A second fiber holding hole extending toward the other end in the first direction, and a protective member inserted into the fiber introduction hole from the other end side,
Each light guide is held in a state of being inserted into the corresponding first fiber holding hole,
Each optical fiber is held in a state inserted into the corresponding first fiber holding hole and the second fiber holding hole,
The combined length of the coating removal portion and the light guide in the first direction is longer than the length of the ferrule in the same direction,
An optical connector in which a joint portion between each light guide and each optical fiber is located in the first fiber holding hole, and an end of the resin coating portion of each optical fiber is located in the second fiber holding hole.
A rubber boot that fits into a recess formed at one end of the protective member in the first direction;
The rubber boot has a third fiber holding hole for holding the plurality of optical fibers therein, and at least a part of the resin coating portion of the plurality of optical fibers is accommodated in the third fiber holding hole. To
The optical connector according to claim 1.
The rubber boot is fitted into the recess so that an end surface on one end side in the first direction is flush with an end surface on one end side in the first direction of the protection member.
The optical connector according to claim 2.
The plurality of optical fibers are arranged in a region whose longitudinal direction is a second direction intersecting the first direction,
The recess penetrates in the second direction;
The optical connector according to claim 2 or claim 3.
The protective member further includes a hole extending in a third direction intersecting the first direction and reaching the second fiber holding hole;
An end of the resin coating portion of the plurality of optical fibers is located in the hole portion,
The optical connector according to any one of claims 1 to 4.
The end face of each optical fiber and each light guide are fused together,
The optical connector according to any one of claims 1 to 5.
The ferrule and the protective member are made of the same material.
The optical connector according to any one of claims 1 to 6.
The ferrule and the protective member are made of different materials having a difference in thermal expansion coefficient within 5 × 10 −5 / K.
The optical connector according to any one of claims 1 to 6.
The ferrule and the protective member are bonded or welded together,
The optical connector according to any one of claims 1 to 8.
The second fiber holding hole has a plurality of openings arranged in a third direction intersecting the first direction.
The optical connector according to any one of claims 1 to 9.