Optical connector

Abstract

An optical connector (10) according to the present disclosure comprises: a ferrule member (40) that holds a built-in fiber (43) fusion-spliced to another optical fiber (211); a cylindrical housing (31) that includes a front end (311) and a rear end (312) positioned on the opposite side from the front end (311), the housing (31) holding the ferrule member (40); and a fusion protective sleeve (12) that is accommodated in the housing (31), is disposed near the rear end (312) with respect to the ferrule member (40), and covers a fusion splicing part (11) between the built-in fiber (43) and the other optical fiber (211). The fusion protective sleeve (12) is disposed at a position that is offset in a direction from the rear end (312) toward the front end (311) inside the housing (31).

Description

Optical Connector

[0001] This application claims priority to Japanese Patent Application No. 2023-146072, filed on September 8, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] Patent Documents 1 to 4 disclose optical connectors to which an optical fiber cable including a plurality of optical fibers is assembled. For example, the optical connector disclosed in Patent Document 1 includes a ferrule member, a fusion protection sleeve, a front housing, and a rear housing. The ferrule member holds a plurality of internal fibers to be fusion-spliced ​​to each of the plurality of optical fibers. The fusion protection sleeve protects the fusion-spliced ​​portions between the plurality of optical fibers and the plurality of internal fibers. The front housing houses the ferrule member and a portion of the fusion protection sleeve. The rear housing is connected to the front housing and houses the fusion protection sleeve in cooperation with the front housing.

[0003] International Publication No. 2012 / 096246 JP 2011-075829 A JP 2013-109351 A JP 2013-134457 A

[0004] The optical connector of the present disclosure includes a ferrule member that holds an internal fiber fusion-spliced ​​to another optical fiber, a cylindrical housing having a front end and a rear end opposite the front end, and that holds the ferrule member, and a fusion protection sleeve that is accommodated in the housing and positioned closer to the rear end than the ferrule member and that covers the fusion-spliced ​​portion between the internal fiber and the other optical fiber. The fusion protection sleeve is positioned inside the housing at a position offset from the rear end in a direction toward the front end.

[0005] Fig. 1 is a perspective view showing the appearance of an optical connector according to an embodiment. Fig. 2 is a cross-sectional view showing an optical fiber cable of the optical connector. Fig. 3 is a plan view showing the front of the optical connector. Fig. 4 is a cross-sectional view showing the front of the optical connector. Fig. 5 is another cross-sectional view showing the front of the optical connector. Fig. 6 is a cross-sectional view showing the rear of the optical connector.

[0006] [Problem to be Solved by the Present Disclosure] When using the optical connector described above, for example, bending stress applied to the optical fiber cable can cause the rear housing to shift in position relative to the front housing, resulting in distortion of the optical connector originating from the connection between the front and rear housings. Such distortion increases the risk of the fusion protection sleeve interfering with other components inside the optical connector. Such internal interference of the fusion protection sleeve can result in problems such as damage to the optical fiber.

[0007] The present disclosure provides an optical connector that can reduce the risk of internal interference with the fusion protection sleeve.

[0008] Effect of the Present Disclosure According to the optical connector of the present disclosure, the risk of internal interference of the fusion protection sleeve can be reduced.

[0009] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described.

[0010] (1) An optical connector according to the present disclosure includes a ferrule member that holds an internal fiber fusion-spliced ​​to another optical fiber, a cylindrical housing having a front end and a rear end opposite the front end, the housing holding the ferrule member, and a fusion protection sleeve that is accommodated in the housing and positioned closer to the rear end than the ferrule member and covers the fusion-spliced ​​portion between the internal fiber and the other optical fiber. The fusion protection sleeve is positioned inside the housing at a position offset from the rear end in a direction toward the front end.

[0011] In the above optical connector, it is assumed that when bending stress is applied, the posture of another component connected to the rear end of the housing changes, causing distortion in the optical connector. The fusion protection sleeve is positioned in a position offset toward the front end of the housing from the rear end, which is the origin of the distortion. In other words, in the above optical connector, the fusion protection sleeve is accommodated in the housing so as not to protrude from the rear end of the housing. When the fusion protection sleeve is positioned so as to fit inside the housing, the risk of the fusion protection sleeve interfering with other components due to a change in the posture of another component connected to the rear end of the housing is reduced compared to when the fusion protection sleeve protrudes from the rear end of the housing. Therefore, in the above optical connector, even if distortion occurs in the optical connector due to the application of bending stress, the risk of the fusion protection sleeve interfering internally is reduced.

[0012] (2) The optical connector described in (1) above includes a first housing that holds a ferrule member; a cylindrical second housing that includes an insertion portion inserted from the rear end of the first housing and an opposing portion facing the rear end; and a spring that is accommodated in the first housing and faces the ferrule member while covering the fusion protection sleeve. The insertion portion of the second housing may accommodate the fusion protection sleeve or may abut against the spring. In this way, if the insertion portion of the second housing extends into the first housing, the portion of the second housing that overlaps with the first housing is longer, making the orientation of the second housing relative to the first housing more stable. As a result, distortion that may occur in the optical connector when bending stress is applied can be reduced. This more effectively reduces the risk of internal interference with the fusion protection sleeve.

[0013] (3) The optical connector described in (1) or (2) above may include a first housing that holds a ferrule member; a cylindrical second housing that includes an insertion portion inserted from the rear end of the first housing and an opposing portion facing the rear end; and a cylindrical third housing that accommodates the first housing and is positioned closer to the front end than the rear end. The first housing may include a pair of outer wall surfaces exposed from the third housing and extending to the rear end. The pair of outer wall surfaces may be positioned at a pair of positions that sandwich the insertion portion, and each of the pair of outer wall surfaces may have a recess. In this case, the recesses in the pair of outer wall surfaces exposed from the third housing and extending to the rear end of the first housing can be used as gripping portions to be gripped with fingertips when connecting the optical connector to another optical connector. This improves the ease of connecting the optical connectors.

[0014] (4) The optical connector described in any one of (1) to (3) above may include a first housing that holds a ferrule member; a cylindrical second housing that includes an insertion portion inserted from the rear end of the first housing and an opposing portion facing the rear end; and a cylindrical third housing that accommodates the first housing and is positioned closer to the front end than the rear end. The first housing may include an outer wall surface that is exposed from the third housing and extends to the rear end. The outer wall surface may have an engagement hole that penetrates in a direction intersecting the outer wall surface. The insertion portion may have a latch that protrudes from the outer surface of the insertion portion and engages with the engagement hole. In this case, the engagement hole in the outer wall surface of the first housing that is exposed from the third housing and extends to the rear end, and the latch on the outer surface of the insertion portion of the second housing can be used as a connecting structure for connecting the first housing and the second housing. This connecting structure can be used to easily connect the first housing and the second housing.

[0015] [Details of the Embodiments of the Present Disclosure] Specific examples of the optical connector of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same elements in the description of the drawings will be given the same reference numerals, and redundant description will be omitted as appropriate. In the following description, "forward" means the direction from the optical connector toward another optical connector to be connected. "rearward" means the opposite direction.

[0016] 1 is a perspective view showing the appearance of an optical connector 10 according to the present embodiment. The optical connector 10 is connected to another optical connector by being inserted into an adapter. As shown in FIG. 1, the optical connector 10 includes, for example, an optical fiber cable 20, a housing 30, and a boot 50.

[0017] FIG. 2 is a diagram illustrating a cross section perpendicular to the central axis of the optical fiber cable 20. As shown in FIG. 2, the optical fiber cable 20 includes, for example, an optical fiber ribbon 21, a sheath (outer jacket) 22, and a tension member 23. The optical fiber ribbon 21 includes, for example, a plurality of (12, for example) optical fibers 211 and a resin coating 212 that collectively covers the plurality of optical fibers 211. The plurality of optical fibers 211 are aligned in a row along a direction D1 perpendicular to the central axis of the optical fiber cable 20. The sheath 22 is a resin layer that surrounds the optical fiber ribbon 21. The sheath 22 is, for example, cylindrical. The sheath 22 houses the optical fiber ribbon 21 therein. The tension member 23 is, for example, a fibrous member disposed between the optical fiber ribbon 21 and the sheath 22. When a pulling force is applied to the optical fiber cable 20, the tension member 23 resists the force, thereby preventing the optical fiber 211 from breaking.

[0018] 1 again, the housing 30 is a housing that houses the front end of the optical fiber cable 20. The housing 30 is made of, for example, a resin material. The housing 30 has, for example, a hollow cylindrical shape.

[0019] The boot 50 is, for example, cylindrical in shape, with an outer diameter that gradually decreases toward the rear end. The boot 50 is attached to the rear end of the housing 30. The boot 50 surrounds and protects the portion of the optical fiber cable 20 that extends from the housing 30. The boot 50 is made of, for example, a flexible resin material.

[0020] Fig. 3 is a plan view showing the front part of the optical connector 10. Fig. 4 is a cross-sectional view of the front part of the optical connector 10, showing a side cross-section along the central axis of the optical fiber ribbon 21. Fig. 5 shows another side cross-section along the central axis of the optical fiber ribbon 21. For convenience, the tip of an embedded fiber 43, which will be described later, is not shown in Fig. 4.

[0021] As shown in Figures 3, 4, and 5, the housing 30 includes, for example, a front housing 31 (first housing), a rear housing 32 (second housing), and an outer housing 33 (third housing). Each of the front housing 31, the rear housing 32, and the outer housing 33 is, for example, hollow and cylindrical. The front housing 31, the rear housing 32, and the outer housing 33 extend along direction D2 (front-rear direction) along the central axis of the optical fiber cable 20 and are connected to one another. The front housing 31 is disposed forward of the rear housing 32. The front housing 31 is housed in the outer housing 33. The outer housing 33 is attached to the outside of the front housing 31 so as to be freely movable in direction D2.

[0022] As shown in FIGS. 4 and 5 , the ferrule member 40 is held in an opening H311 formed in the front end 311 of the front housing 31. Therefore, in this embodiment, the "housing" that holds the ferrule member 40 is the front housing 31. The ferrule member 40 protrudes forward from the opening H311. An insertion portion R32 of the rear housing 32, which is a separate member from the front housing 31, is inserted into the opening H312 formed in the rear end 312 of the front housing 31. That is, the insertion portion R32 of the rear housing 32 is inserted into the front housing 31 from the rear end 312 of the front housing 31. The rear housing 32 includes a facing portion 322 that faces the rear end 312 of the front housing 31 in the direction D2. The facing portion 322 is, for example, a flange portion that protrudes from the outer surface of the rear housing 32.

[0023] The outer housing 33 is disposed at a position shifted toward the front end 311 in the direction D2 relative to the rear end 312 of the front housing 31, i.e., at a position shifted forward relative to the rear end 312. The outer housing 33 is disposed, for example, to accommodate a central portion of the front housing 31. Therefore, the front end 331 of the outer housing 33 is located rearward of the front end 311 of the front housing 31. The rear end 332 of the outer housing 33 is located forward of the rear end 312 of the front housing 31.

[0024] The rear portion R312 of the front housing 31 extends rearward beyond the rear end 332 of the outer housing 33. The rear end 312 of the front housing 31 is exposed to the outside. The rear portion R312 includes, for example, a pair of outer wall surfaces 313, 313 and a pair of outer wall surfaces 315, 315. As shown in FIGS. 3 and 4 , the outer wall surfaces 313, 313 are disposed at both ends of the rear portion R312 in the direction D1 and are aligned along the direction D1. The outer wall surfaces 313, 313 extend in a direction intersecting the direction D1. A recess 314 is formed in each of the outer wall surfaces 313, 313.

[0025] The recess 314 is recessed in the direction D1 from the outer wall surface 313. When viewed in a direction D3 (see FIG. 5 ) intersecting the directions D1 and D2, the recess 314 has, for example, an arc shape that bulges toward the center of the front housing 31 in the direction D1. The recesses 314, 314 formed in the outer wall surfaces 313, 313 are formed, for example, to be line-symmetrical with respect to the center of the front housing 31. The recesses 314, 314 function as a knob to be gripped with fingertips when connecting the optical connector 10 to another optical connector as a connection target.

[0026] As shown in FIG. 5 , the outer wall surfaces 315 are arranged at both ends of the rear portion R312 in the direction D3 and are aligned in the direction D3. The outer wall surfaces 315 extend in a direction intersecting the direction D3. An engagement hole 316 is formed in each of the outer wall surfaces 315. The engagement hole 316 is, for example, a through-hole that penetrates the front housing 31 from the outer wall surface 315 in the direction D3. When viewed in the direction D3, the engagement hole 316 has, for example, an arrow shape that points toward the front end 311 in the direction D2 (see FIG. 3 ). When viewed in the direction D3, the engagement hole 316 is not limited to an arrow shape and may have other shapes, such as a circle, a rectangle, a triangle, or another polygonal shape. The engagement holes 316 formed in the outer wall surfaces 315 are formed at a pair of positions that sandwich the insertion portion R32 of the rear housing 32 in the direction D3.

[0027] The insertion portion R32 of the rear housing 32 includes a pair of outer surfaces 323. The outer surfaces 323 are disposed at positions facing the outer wall surfaces 315 of the front housing 31 in the direction D3. A latch 324 is formed on each of the outer surfaces 323. The latch 324 is, for example, a protrusion that protrudes from the outer surface 323 in the direction D3 and engages with the engagement hole 316. The latches 324 formed on the outer surfaces 323 are formed at a pair of positions corresponding to the engagement holes 316. When the rear housing 32 is connected to the front housing 31, the latches 324 are engaged with the engagement holes 316 in the direction D2 by being engaged with the engagement holes 316. When the rear housing 32 is removed from the front housing 31, the latches 324, 324 are disengaged from the engagement holes 316, 316.

[0028] 4 and 5 , the optical fiber ribbon 21 extends forward from the tip of the optical fiber cable 20 in the internal space formed by the front housing 31 and the rear housing 32. At the tip of the optical fiber ribbon 21, the resin coating 212 is removed, so that the plurality of optical fibers 211 are exposed from the resin coating 212.

[0029] The optical connector 10 further includes, for example, a fusion protection sleeve 12 , a compression coil spring 13 (spring), a ferrule member 40 , and a pin keeper 44 .

[0030] The ferrule member 40 is provided at the front end of the optical connector 10. A front end face 41 of the ferrule member 40 abuts against a ferrule member of another optical connector to which the optical connector 10 is to be connected. A pair of guide pins 42, 42 protrude from the front end face 41 for positioning with the ferrule member of the other optical connector. The ferrule member 40 is formed, for example, from a resin material. The material of the ferrule member 40 may be, for example, an engineering plastic such as polyphenylene sulfide (PPS).

[0031] As shown in FIG. 4 , the ferrule member 40 has a plurality of through holes 48 for inserting the plurality of embedded fibers 43, respectively. The ferrule member 40 holds each embedded fiber 43 by accommodating the tip end of each embedded fiber 43 in each through hole 48. The number of embedded fibers 43 is the same as the number of optical fibers 211. The plurality of embedded fibers 43 are aligned in a row along direction D1. First end faces of the plurality of embedded fibers 43 are exposed at the front end face 41 of the ferrule member 40 and abut against end faces of a plurality of optical fibers held in a ferrule member of another optical connector. As a result, each of the plurality of embedded fibers 43 is optically coupled to a plurality of optical fibers of the other optical connector, respectively.

[0032] The pin keeper 44 is made of a metal material. The pin keeper 44 is formed, for example, by subjecting a metal plate to sheet metal processing and bending. The pin keeper 44 is disposed to face the rear end surface 46 of the ferrule member 40 and holds the base end of the guide pin 42 inserted into the ferrule member 40. The pin keeper 44 may also be made of a resin material.

[0033] The multiple embedded fibers 43 extend rearward from the rear end face 46 of the ferrule member 40 through openings formed in the pin keeper 44. The second end face of each of the multiple embedded fibers 43 is fusion-spliced ​​to the end face of each of the multiple other optical fibers 211. Therefore, a fusion spliced ​​portion 11 is formed between each embedded fiber 43 and each of the other optical fibers 211. The fusion protection sleeve 12 covers and protects the fusion spliced ​​portion 11, the portion of the other optical fibers 211 that is exposed from the resin coating 212, and the embedded fiber 43.

[0034] The fusion protection sleeve 12 faces the rear end surface 46 of the ferrule assembly 40, with the pin keeper 44 sandwiched therebetween. The front end 121 of the fusion protection sleeve 12 may abut against the pin keeper 44 in the direction D2, or may be spaced apart from the pin keeper 44 in the direction D2. The fusion protection sleeve 12 is, for example, tubular. The fusion protection sleeve 12 is formed, for example, from a heat-shrinkable resin.

[0035] The compression coil spring 13 covers the fusion protection sleeve 12 so as to surround the periphery of the fusion protection sleeve 12. A first end of the compression coil spring 13 abuts against the pin keeper 44 in the direction D2. A second end of the compression coil spring 13 abuts against the front end 321 of the insertion portion R32 of the rear housing 32 in the direction D2. The front end 321 of the rear housing 32 faces the rear end surface 46 of the ferrule member 40 in the direction D2, with the compression coil spring 13 and the pin keeper 44 sandwiched between them.

[0036] The compression coil spring 13 biases the ferrule member 40 forward. When the ferrule member 40 abuts against a ferrule member of another optical connector, the compression coil spring 13 contracts, thereby causing the ferrule member 40 to abut with an appropriate pressing force. When the ferrule member 40 is not abutting against a ferrule member of another optical connector, a flange portion 45 provided at the rear of the ferrule member 40 abuts against the area surrounding the opening H311 of the front housing 31, thereby receiving the biasing force of the compression coil spring 13.

[0037] The front housing 31 holds the ferrule member 40 and accommodates a portion of the ferrule member 40, multiple embedded fibers 43, a pin keeper 44, the exposed portion of the other optical fiber 211 from the resin coating 212, the fusion protection sleeve 12, and the compression coil spring 13.

[0038] In this embodiment, the fusion protector sleeve 12 is positioned at a position offset in a direction toward the front end 311 from the rear end 312 of the front housing 31 that holds the ferrule assembly 40. Figures 4 and 5 show a position P122 of the rear end 122 of the fusion protector sleeve 12 and a position P312 of the rear end 312 of the front housing 31. As shown in Figures 4 and 5, the position P122 of the rear end 122 of the fusion protector sleeve 12 is positioned forward of the position P312 of the rear end 312 of the front housing 31 (i.e., in the direction D2 from the rear end 312 toward the front end 311).

[0039] Therefore, in this embodiment, the rear end 122 of the fusion protection sleeve 12 is contained within the front housing 31 without protruding rearward from the rear end 312 of the front housing 31. The rear end 312 of the front housing 31 is a portion that is connected to the rear housing 32, which is a separate member from the front housing 31. Therefore, for example, when bending stress is applied to the optical fiber cable 20, the bending stress may cause the rear housing 32 to fluctuate in position, which may change the assembly angle of the rear housing 32 relative to the front housing 31. In this case, the rear housing 32 may bend relative to the front housing 31, starting from the rear end 312 of the front housing 31.

[0040] In contrast, in the optical connector 10 of this embodiment, the fusion protection sleeve 12 is positioned to fit inside the front housing 31 to avoid internal interference of the fusion protection sleeve 12 due to movement of the rear housing 32. In the optical connector 10 of this embodiment, the length of each component housed in the front housing 31 in the direction D2 is designed to be short so that the rear end 122 of the fusion protection sleeve 12 is positioned forward of the rear end 312 of the front housing 31. The length of the front housing 31 in the direction D2 (i.e., the distance in the direction D2 from the front end 311 to the rear end 312) is, for example, 20 mm or more and 35 mm or less. In contrast, the length of the ferrule member 40 in the direction D2 is, for example, 4 mm. The thickness in the direction D2 of the metal plate constituting the pin keeper 44 is, for example, 0.25 mm or more and 1 mm or less. The length of the fusion protection sleeve 12 in the direction D2 is, for example, 12 mm or more and 20 mm or less.

[0041] In this way, by designing the components housed in the front housing 31 so that their lengths in the direction D2 are short, a configuration is realized in which the fusion protection sleeve 12 fits inside the front housing 31. As a result of the above design, the length in the direction D2 of the rear portion R312 of the front housing 31 extending rearward of the outer housing 33 becomes somewhat long. Therefore, in this embodiment, from the perspective of effectively utilizing the area of ​​this rear portion R312, the recesses 314, 314 and the engagement holes 316, 316 described above are formed in the rear portion R312.

[0042] FIG. 6 is a cross-sectional view showing the rear portion of the optical connector 10. As shown in FIG. 6, the optical connector 10 further includes a substantially cylindrical crimping seat 60 and an annular ring 70. The crimping seat 60 and the ring 70 are located inside the rear housing 32 near the rear end. The crimping seat 60 and the ring 70 are provided to sandwich and secure the distal end of the sheath 22 and the distal end of the strength member 23 peeled from the optical fiber ribbon 21. For this purpose, the ring 70 is disposed around the crimping seat 60 and is fitted to the crimping seat 60 with the distal end of the sheath 22 and the distal end of the strength member 23 sandwiched between the ring 70 and the crimping seat 60. The strength member 23 is not shown in FIG. The crimping seat 60 and the ring 70 are formed, for example, from a metal material or a resin material.

[0043] The effects of the optical connector 10 of the present embodiment described above will now be described. In this embodiment, it is assumed that when bending stress is applied, the rear housing 32, which is a separate member connected to the rear end 312 of the front housing 31, changes in posture, causing distortion in the optical connector 10. The fusion protection sleeve 12 is positioned at a position offset toward the front end 311 from the rear end 312 of the front housing 31, which is the origin of the distortion. That is, in this embodiment, the fusion protection sleeve 12 is housed in the front housing 31 so as not to protrude from the rear end 312 of the front housing 31. When the fusion protection sleeve 12 is positioned so as to be housed inside the front housing 31, the risk of the fusion protection sleeve 12 interfering with other components inside the rear housing 32 due to a change in posture of the rear housing 32 is reduced compared to when the fusion protection sleeve 12 protrudes from the rear end 312 of the front housing 31. Therefore, in this embodiment, even when distortion occurs in the optical connector 10 due to the application of bending stress, the risk of the fusion protection sleeve 12 causing internal interference is reduced.

[0044] As in this embodiment, the insertion portion R32 of the rear housing 32 may house the fusion protection sleeve 12 or may abut against the compression coil spring 13 that covers the fusion protection sleeve 12. When the insertion portion R32 of the rear housing 32 extends into the front housing 31 in this way, the portion of the rear housing 32 that overlaps with the front housing 31 becomes longer, making it easier to stabilize the posture of the rear housing 32 relative to the front housing 31. As a result, it is possible to reduce distortion that may occur in the optical connector 10 when bending stress is applied. This more effectively reduces the risk of internal interference with the fusion protection sleeve 12.

[0045] As in this embodiment, the front housing 31 may include a pair of outer wall surfaces 313, 313 that are exposed from the outer housing 33 and extend to the rear end 312. The outer wall surfaces 313, 313 may be arranged at a pair of positions that sandwich the insertion portion R32. Each of the outer wall surfaces 313, 313 may have a recess 314 formed therein. In this case, the recesses 314, 314 of the outer wall surfaces 313, 313 that are exposed from the outer housing 33 and extend to the rear end 312 of the front housing 31 can be used as knobs to be gripped with fingertips when connecting the optical connector 10 to another optical connector. This improves the ease of connecting the optical connector 10.

[0046] As in this embodiment, the front housing 31 may include an outer wall surface 315 that is exposed from the outer housing 33 and extends to the rear end 312. The outer wall surface 315 may have an engagement hole 316 formed therein that penetrates in a direction intersecting the outer wall surface 315. The insertion portion R32 may have a latch 324 formed therein that protrudes from the outer surface 323 of the insertion portion R32 and engages with the engagement hole 316. In this case, the engagement hole 316 of the outer wall surface 315 of the front housing 31 that is exposed from the outer housing 33 and extends to the rear end 312, and the latch 324 of the insertion portion R32 of the rear housing 32 can be used as a connecting structure for connecting the front housing 31 and the rear housing 32. Using this connecting structure, the front housing 31 and the rear housing 32 can be easily connected.

[0047] The present disclosure is not limited to the above-described embodiment, and various other modifications are possible. For example, in the above-described embodiment, the recess 314 and the engagement hole 316 are formed in the rear portion R312 of the front housing 31. However, the recess 314 and the engagement hole 316 may be formed in a portion other than the rear portion R312, or may be formed in a component other than the front housing 31.

[0048] REFERENCE SIGNS LIST 10...optical connector 11...fusion splice portion 12...fusion protection sleeve 20...optical fiber cable 21...optical fiber ribbon 22...sheath (outer jacket) 23...tensile member 30...housing 31...front housing (first housing) 32...rear housing (second housing) 33...outer housing (third housing) 40...ferrule member 41...front end face 42...guide pin 43...built-in fiber 44...pin keeper 45...flange portion 46...rear end face 48...through hole 50...boot 60...crimping seat 70...ring 121, 311, 321, 331...front end 122, 312, 332...rear end 211...optical fiber 212...resin coating 313, 315...outer wall surface 314...recess 316...engagement hole 322...facing portion 323...outer surface 324...Latch D1, D2, D3...Direction H311, H312...Opening P122, P312...Position R32...Insertion part R312...Rear

Claims

1. An optical connector comprising: a ferrule member that holds an embedded fiber fusion-spliced ​​to another optical fiber; a cylindrical housing including a front end and a rear end opposite the front end, the housing holding the ferrule member; and a fusion protection sleeve contained in the housing, positioned toward the rear end relative to the ferrule member, and covering the fusion-spliced ​​portion between the embedded fiber and the other optical fiber, the fusion protection sleeve being positioned inside the housing at a position shifted toward the front end from the rear end.

2. An optical connector as described in claim 1, comprising: a first housing which holds the ferrule member; a cylindrical second housing including an insertion portion inserted from the rear end of the first housing and an opposing portion opposing the rear end; and a spring which is accommodated in the first housing and faces the ferrule member while covering the fusion protection sleeve, wherein the insertion portion of the second housing accommodates the fusion protection sleeve and abuts against the spring.

3. An optical connector as described in claim 1 or claim 2, comprising: a first housing which holds the ferrule member; a cylindrical second housing which includes an insertion portion inserted from the rear end of the first housing and an opposing portion opposing the rear end; and a cylindrical third housing which accommodates the first housing and is positioned at a position closer to the front end than the rear end, wherein the first housing includes a pair of outer wall surfaces exposed from the third housing and extending to the rear end, the pair of outer wall surfaces being positioned at a pair of positions sandwiching the insertion portion, and each of the pair of outer wall surfaces having a recess formed therein.

4. An optical connector as described in any one of claims 1 to 3, comprising: a first housing which holds the ferrule member; a cylindrical second housing which includes an insertion portion inserted from the rear end of the first housing and an opposing portion opposing the rear end; and a cylindrical third housing which accommodates the first housing and is positioned closer to the front end than the rear end, wherein the first housing includes an outer wall surface exposed from the third housing and extending to the rear end, an engagement hole is formed in the outer wall surface which penetrates in a direction intersecting the outer wall surface, and the insertion portion is formed with a latch which protrudes from the outer surface of the insertion portion and engages with the engagement hole.

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