Optical connector

Abstract

The present invention provides an optical connector that has multiple internal fibers and multiple connecting fibers that are fusion-spliced, and that can improve assembly efficiency. [Solution] The optical connector comprises: a plurality of ferrules, each having a connection end face and a fiber hole opening to the connection end face; a plurality of internal fibers inserted through the fiber holes of the plurality of ferrules; a plurality of connecting fibers fusion-spliced ​​to the plurality of internal fibers; a pitch changing mechanism that holds the plurality of ferrules and changes the pitch of the plurality of internal fibers from a first pitch, which is the pitch of the plurality of internal fibers at the connection end face, to a pitch smaller than the first pitch; and a heat-shrinkable sleeve that shrinks when heated, positions the plurality of connection points where the plurality of internal fibers and the plurality of connecting fibers are fusion-spliced ​​inside, and is fixed to the pitch changing mechanism.

Description

Technical Field

[0001] The present invention relates to an optical connector.

Background Art

[0002] Patent Document 1 discloses an optical connector (fusion splicing type connector) configured to fusion splice a built-in fiber held by a ferrule to another optical fiber (connection fiber) and protect the connection point with a heat shrink sleeve. Conventionally, it is also known to create a duplex LC connector by fixing two fusion splicing type connectors with a duplex clip.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Due to the need for high-density wiring, the demand for cords containing multiple optical fibers (e.g., 2-core cords) is increasing. The fusion splice connector described in Patent Document 1 is for single-core cords. A duplex LC connector, which consists of two single-core fusion splice connectors fixed together with a duplex clip, cannot be attached to a 2-core cord. To accommodate 2-core cords, it is conceivable to create a duplex LC connector with a configuration in which two fusion-spliced ​​internal fibers and two connecting fibers are provided on a single optical connector. The two internal fibers are each held in two ferrules, separated from each other. Therefore, the two internal fibers and the two connecting fibers must be fusion-spliced ​​individually, increasing the time required for fusion splicing. In addition, two heat-shrink sleeves are required to protect the connection points between the internal fibers and the connecting fibers, and the time required for heating and shrinking the heat-shrink sleeves also increases. The same applies when creating optical connectors that accommodate cords containing multiple optical fibers other than 2-core cords. Thus, there is room for improvement in improving the assembly efficiency of optical connectors.

[0005] This invention has been made in consideration of these circumstances and aims to provide an optical connector that can improve assembly efficiency in an optical connector comprising a plurality of internal fibers and a plurality of connecting fibers that are fusion-spliced. [Means for solving the problem]

[0006] To solve the above problems, an optical connector according to embodiment 1 of the present invention comprises: a plurality of ferrules, each having a connection end face and a fiber hole opening to the connection end face; a plurality of internal fibers inserted through the fiber holes of the plurality of ferrules; a plurality of connecting fibers fusion-spliced ​​to the plurality of internal fibers; a pitch changing mechanism that holds the plurality of ferrules and changes the pitch of the plurality of internal fibers from a first pitch, which is the pitch of the plurality of internal fibers at the connection end face, to a pitch smaller than the first pitch; and a heat-shrinkable sleeve that shrinks by heating, positions a plurality of connection points where the plurality of internal fibers and the plurality of connecting fibers are fusion-spliced ​​inside, and is fixed to the pitch changing mechanism.

[0007] Furthermore, in embodiment 2 of the present invention, in the optical connector of embodiment 1, the pitch changing mechanism changes the pitch of the plurality of built-in fibers from the first pitch to a second pitch which is the pitch of the plurality of built-in fibers at the connection point.

[0008] Furthermore, in embodiment 3 of the present invention, in the optical connector of embodiment 1 or 2, the ferrule and the pitch changing mechanism are formed separately.

[0009] Furthermore, in embodiment 4 of the present invention, in any one of embodiments 1 to 3, the pitch changing mechanism has a sleeve fixing portion to which the heat shrink sleeve is fixed, the sleeve fixing portion has a base-end insertion hole through which the plurality of internal fibers are inserted, and the sleeve fixing portion has a positioning projection that fits between the coatings of the plurality of internal fibers on the inside of the base-end insertion hole.

[0010] Furthermore, aspect 5 of the present invention is an optical connector in any one of aspects 1 to 4, wherein the pitch changing mechanism includes a ferrule holding portion for holding the plurality of ferrules and a sleeve fixing portion provided on the proximal end side of the ferrule holding portion and for which the heat shrink sleeve is fixed, wherein the ferrule holding portion has a plurality of tip-side insertion holes through which the plurality of internal fibers are each inserted, and the sleeve fixing portion has a proximal end insertion hole through which the plurality of internal fibers are inserted, and the number of proximal end insertion holes is less than the number of tip-side insertion holes.

[0011] Furthermore, in embodiment 6 of the present invention, in any one of embodiments 1 to 5 of the optical connector, the pitch changing mechanism has a sleeve fixing portion to which the heat shrink sleeve is fixed, and a plurality of protrusions are formed on the outer surface of the sleeve fixing portion. [Effects of the Invention]

[0012] According to the above aspects of the present invention, an optical connector is provided that has multiple built-in fibers and multiple connecting fibers to be fusion-spliced, and is capable of improving assembly efficiency. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing an optical connector according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view taken along the line II-II arrow in Figure 1. [Figure 3] This is a cross-sectional view taken along the line III-III in Figure 1. [Figure 4] This is a perspective view showing a ferrule according to an embodiment of the present invention. [Figure 5] This is a perspective view showing a pitch changing mechanism according to an embodiment of the present invention. [Figure 6] This is a view of a pitch changing mechanism according to an embodiment of the present invention, as seen from the base end. [Modes for carrying out the invention]

[0014] The following describes an optical connector according to one embodiment, based on the drawings. As shown in Figures 1 to 3, the optical connector 1 comprises a plurality of ferrules 10, a pitch changing mechanism 20, a heat shrink sleeve 30, a plug frame 40, a stop ring (spring push) 50, a plurality of biasing members 60, a boot 70, a plurality of internal fibers F1, and a plurality of connecting fibers F2. The optical connector 1 is provided at the end of the optical fiber cable C. In the illustrated example, the optical connector 1 has two ferrules 10, biasing members 60, internal fibers F1, and connecting fibers F2. However, the optical connector 1 may have three or more ferrules 10, biasing members 60, internal fibers F1, and connecting fibers F2.

[0015] The ferrule 10 has a connection end face 10a and a fiber hole 11 opening into the connection end face 10a. An internal fiber F1 is inserted through the fiber hole 11. The internal fiber F1 is exposed to the connection end face 10a. The internal fiber F1 is fixed to the fiber hole 11 of the ferrule 10, for example, by adhesive. The optical connector 1 can be optically connected to the other connector by the connection end face of another connector coming into contact with the connection end face 10a.

[0016] (direction definition) In this embodiment, the direction in which the fiber hole 11 extends is referred to as the longitudinal direction Z. The side of the connection end face 10a (+Z side) in the longitudinal direction Z is referred to as the front or tip side. The opposite side (-Z side) is referred to as the rear or base end side. The direction in which the multiple ferrules 10 are arranged is referred to as the first direction X. The first direction X is perpendicular to the longitudinal direction Z. The direction perpendicular to both the longitudinal direction Z and the first direction X is referred to as the second direction Y.

[0017] The ferrule 10 holds the built-in fiber F1. As shown in FIG. 4, the ferrule 10 has a ferrule main body portion 10A and a ferrule flange 10B. In the present embodiment, the ferrule main body portion 10A and the ferrule flange 10B are formed separately. However, the ferrule main body portion 10A and the ferrule flange 10B may be integrally formed.

[0018] The ferrule main body portion 10A is a cylindrical member extending in the longitudinal direction Z. As the material of the ferrule main body portion 10A, for example, zirconia can be adopted. The connection end face 10a is located at the tip of the ferrule main body portion 10A. The fiber hole 11 is formed in the ferrule main body portion 10A. The fiber hole 11 penetrates the ferrule main body portion 10A in the longitudinal direction Z.

[0019] The ferrule flange 10B holds the rear end portion of the ferrule main body portion 10A. The ferrule flange 10B has a flange portion 12 and a sliding cylinder portion 13.

[0020] The flange portion 12 is cylindrical and surrounds the rear end portion of the ferrule main body portion 10A. The ferrule main body portion 10A is fitted inside the flange portion 12. The flange portion 12 has a regulated surface 12a facing forward and a biasing surface 12b facing rearward.

[0021] The sliding cylinder portion 13 extends rearward from the flange portion 12. The outer diameter of the sliding cylinder portion 13 is smaller than the outer diameter of the flange portion 12. The sliding cylinder portion 13 is disposed slidably in the longitudinal direction Z inside a surrounding cylinder portion 22 of a pitch changing mechanism 20 described later. A plurality of regulating protrusions 14 protruding outward from the outer peripheral surface of the sliding cylinder portion 13 are provided on the sliding cylinder portion 13. Also, a pair of retaining portions 15 protruding outward in the second direction Y from the outer peripheral surface of the sliding cylinder portion 13 are provided on the sliding cylinder portion 13. The retaining portions 15 are disposed on the base end side (-Z side) with respect to the regulating protrusions 14.

[0022] As shown in Figures 2 and 3, the ferrule flange 10B has a communication hole 16 through which the built-in fiber F1 is inserted. The communication hole 16 penetrates the ferrule flange 10B in the longitudinal direction Z. The communication hole 16 communicates with the fiber hole 11 of the ferrule body 10A. The ferrule flange 10B also has a first deflection space S1 that allows for deflection of the built-in fiber F1. In the illustrated example, the first deflection space S1 is formed by a slit 17 provided in the sliding cylinder portion 13. The slit 17 communicates with the communication hole 16 and extends toward one side in the first direction X, opening to the outer circumferential surface of the sliding cylinder portion 13. It may also extend at an angle with respect to the first direction X.

[0023] The internal fiber F1 is inserted through the fiber hole 11 and the communication hole 16, and extends from the ferrule 10 toward the base end (in the direction opposite to the connection end face 10a). The connecting fiber F2 is built into the optical fiber cable C and is fusion spliced ​​to the rear end of the internal fiber F1. In other words, the optical connector 1 according to this embodiment is a fusion splice type connector having fibers F1 and F2 that are fusion spliced ​​at the connection point P.

[0024] Each of the internal fiber F1 and connecting fiber F2 is an optical fiber having a bare fiber f1 and a cladding f2 (see Figure 6). The bare fiber f1 is formed of, for example, quartz glass. The bare fiber f1 has a core and a cladding. The cladding f2 partially covers the bare fiber f1 and serves to protect it. The cladding f2 is formed of, for example, resin. For example, the material of the cladding f2 may be a UV-curable resin.

[0025] At the front end of the internal fiber F1, there is no covering f2, and the bare fiber f1 is exposed. This exposed bare fiber f1 is inserted into the fiber hole 11 of the ferrule 10. Similarly, at the rear end of the internal fiber F1 and the front end of the connecting fiber F2, there is no covering f2, and the bare fiber f1 is exposed. These bare fibers f1 of the internal fiber F1 and connecting fiber F2 are fusion spliced ​​together.

[0026] Furthermore, the work of attaching the optical connector 1 to the end of the optical fiber cable C, that is, the work of fusion splicing the built-in fiber F1 and the connecting fiber F2, may be performed at the optical fiber cable C installation site. Therefore, the work of heating the heat shrink sleeve 30, which is performed after fusion splicing, may also be performed at the optical fiber cable C installation site.

[0027] The pitch changing mechanism 20 holds the rear end of the ferrule 10. The pitch changing mechanism 20 is formed separately from the ferrule 10. Multiple internal fibers F1 are inserted through the pitch changing mechanism 20.

[0028] As shown in Figure 2, the pitch changing mechanism 20 changes the pitch of the multiple internal fibers F1 from a first pitch D1 to a pitch smaller than the first pitch D1. The first pitch D1 is the pitch (spacing) between the central axes of the multiple internal fibers F1 at the connection end face 10a. In the illustrated example, the pitch changing mechanism 20 changes the pitch of the multiple internal fibers F1 from a first pitch D1 to a second pitch D2 which is smaller than the first pitch D1. The second pitch D2 is the pitch (spacing) between the central axes of the multiple internal fibers F1 at the connection point P. For example, the second pitch D2 is equal to the diameter of the internal fiber F1 including the sheath f2. The second pitch D2 is equal to the pitch (spacing) between the central axes of the multiple connecting fibers F2 embedded in the optical fiber cable C. The second pitch D2 is set to a pitch that allows the multiple internal fibers F1 and the multiple connecting fibers F2 to be fused together by a fusion splicer, for example, 200 μm or 250 μm.

[0029] As shown in Figure 5, the pitch changing mechanism 20 includes a ferrule holding portion 21, a sleeve fixing portion 23 provided on the base end side of the ferrule holding portion 21, and a connecting cylinder portion 24 that connects the ferrule holding portion 21 and the sleeve fixing portion 23.

[0030] The ferrule holding portion 21 holds a plurality of ferrules 10 so that they can move relative to each other in the longitudinal direction Z. Specifically, the ferrule holding portion 21 has a plurality of surrounding cylindrical portions 22, each holding a plurality of ferrules 10. The plurality of surrounding cylindrical portions 22 are arranged in a first direction X. Each surrounding cylindrical portion 22 has a tip-side insertion hole 22a that penetrates the surrounding cylindrical portion 22 in the longitudinal direction Z. The rear end of the sliding cylindrical portion 13 is inserted into the tip-side insertion hole 22a. The tip-side insertion hole 22a communicates with the communication hole 16 and slit 17 of the ferrule flange 10B. The built-in fiber F1 extending from the fiber hole 11 is inserted through the tip-side insertion hole 22a. That is, the ferrule holding portion 21 has a plurality of tip-side insertion holes 22a through which a plurality of built-in fibers F1 are each inserted.

[0031] Each surrounding cylindrical portion 22 has a pair of holes 22b that penetrate the surrounding cylindrical portion 22 in the second direction Y. The holes 22b extend in the longitudinal direction Z. As shown in Figure 3, a retaining element 15 provided on the sliding cylindrical portion 13 is placed inside each hole 22b. This connects the ferrule 10 (sliding cylindrical portion 13) and the pitch changing mechanism 20 (surrounding cylindrical portion 22).

[0032] In the longitudinal direction Z, the dimensions of the retaining element 15 are smaller than the dimensions of the hole 22b. When the retaining element 15 is positioned on the front end side of the hole 22b, a gap in the longitudinal direction Z is provided between the rear end surface of the retaining element 15 and the hole 22b. In this state, the ferrule 10 (sliding cylinder portion 13) can move (slide) backward relative to the pitch changing mechanism 20 (surrounding cylinder portion 22). Also, as shown in Figure 2, a restricting projection 14 provided on the sliding cylinder portion 13 is positioned on the tip side of the front end surface 22c of the surrounding cylinder portion 22. The restricting projection 14 contacts the front end surface 22c from the tip side, restricting the backward movement of the ferrule 10 (sliding cylinder portion 13) relative to the pitch changing mechanism 20 (surrounding cylinder portion 22) beyond a predetermined amount.

[0033] The sleeve fixing portion 23 is a cylindrical member extending rearward from the connecting cylinder portion 24. The sleeve fixing portion 23 has a base-side insertion hole 23a through which multiple internal fibers F1 are inserted. The base-side insertion hole 23a penetrates the sleeve fixing portion 23 in the longitudinal direction Z. The number of base-side insertion holes 23a is less than the number of tip-side insertion holes 22a. Multiple internal fibers F1 extending from multiple tip-side insertion holes 22a are inserted together into the base-side insertion hole 23a. As shown in Figure 6, in the base-side insertion hole 23a, the multiple internal fibers F1 are arranged so that their coverings f2 are in contact with each other.

[0034] The front end of the heat-shrinkable sleeve 30 is fixed to the sleeve fixing portion 23. The sleeve fixing portion 23 has a plurality of protrusions 23b that project outward from the outer circumferential surface of the sleeve fixing portion 23. The plurality of protrusions 23b are arranged at intervals in the longitudinal direction Z.

[0035] As shown in Figure 6, a positioning projection 23c is formed at the base end of the sleeve fixing portion 23, projecting inward from the inner circumferential surface of the base end insertion hole 23a. The positioning projection 23c fits between the coverings f2 of the multiple built-in fibers F1 inside the base end insertion hole 23a. As a result, the multiple built-in fibers F1 are positioned inside the base end insertion hole 23a at the base end of the sleeve fixing portion 23.

[0036] The connecting cylinder portion 24 is positioned between the multiple surrounding cylinder portions 22 and the sleeve fixing portion 23 in the longitudinal direction Z. As shown in Figure 2, the connecting cylinder portion 24 has a communication hole 24a through which multiple internal fibers F1 are inserted. The communication hole 24a connects the tip-side insertion holes 22a and the base-side insertion holes 23a of the multiple surrounding cylinder portions 22. That is, the tip-side insertion holes 22a of the multiple surrounding cylinder portions 22 are in communication with the base-side insertion holes 23a via the communication hole 24a. When viewed from the second direction Y, the communication hole 24a is tapered, with its width decreasing in the first direction X as it approaches the base end side (-Z side). The interior of the communication hole 24a forms a second bending space S2 that allows for the bending of the internal fibers F1.

[0037] In the pitch changing mechanism 20, multiple internal fibers F1 are inserted into multiple tip-side insertion holes 22a, and then inserted together into the base-side insertion hole 23a via a communication hole 24a. As a result, the pitch changing mechanism 20 changes the pitch of the multiple internal fibers F1 from the first pitch D1 to the second pitch D2.

[0038] The heat-shrinkable sleeve 30 is a cylindrical member that extends in the longitudinal direction Z and can be shrunk by heating. Although not shown in the illustration, an adhesive layer is provided on the inner circumferential surface of the heat-shrinkable sleeve 30. This adhesive layer is made of a material that melts when heated and solidifies again when cooled.

[0039] The heat-shrinkable sleeve 30 is fixed to the sleeve fixing portion 23 of the pitch changing mechanism 20 by shrinking due to heating. At this time, the heat-shrinkable sleeve 30 is heat-shrinkable so as to tighten the projection 23b. As a result, the heat-shrinkable sleeve 30 is firmly fixed to the sleeve fixing portion 23. Furthermore, the heat-shrinkable sleeve 30 is heat-shrinkable so that multiple connection points P, in which multiple internal fibers F1 and multiple connecting fibers F2 are fused together, are located inside. As a result, the heat-shrinkable sleeve 30 is fixed to the internal fibers F1 and connecting fibers F2. Figures 2 and 3 show the state after the heat-shrinkable sleeve 30 has been heat-shrinkable.

[0040] The heat-shrinkable sleeve 30 protects the easily brittle connection point P and also serves to fix the fibers F1 and F2 to the pitch changing mechanism 20. Furthermore, as shown in Figure 3, a rod-shaped or plate-shaped tensile strength member T extending in the longitudinal direction Z and positioned to align with the connection point P may be housed inside the heat-shrinkable sleeve 30.

[0041] The stop ring 50 is a cylindrical member. The stop ring 50 has a housing cylinder portion 51 and a plurality of extensions 52 extending forward from the housing cylinder portion 51. The housing cylinder portion 51 houses at least a part of the pitch changing mechanism 20 and at least a part of the heat shrink sleeve 30. The housing cylinder portion 51 is locked to the plug frame 40. The plurality of extensions 52 are arranged in a first direction X. The plurality of extensions 52 are provided corresponding to each of the plurality of ferrules 10. Each extension 52 extends longitudinally Z along the sliding cylinder portion 13 of the ferrule 10. Each extension 52 faces the flange portion 12 of the ferrule 10 in the longitudinal direction Z. A biasing surface 52a facing forward is formed at the tip of the extension 52. The biasing surface 52a faces the biased surface 12b of the flange portion 12 in the longitudinal direction Z.

[0042] The biasing member 60 has the function of biasing the ferrule 10 toward the tip. The biasing member 60 is, for example, a coil spring. The biasing member 60 is positioned between the biased surface 12b and the biasing surface 52a in the longitudinal direction Z. In other words, the biasing member 60 is sandwiched between the biased surface 12b and the biasing surface 52a in the longitudinal direction Z. The biasing member 60 is compressed between the biased surface 12b and the biasing surface 52a. As a result, the biased surface 12b of the flange portion 12 is biased toward forward. Therefore, the ferrule 10 as a whole receives a biasing force toward forward from the biasing member 60.

[0043] The plug frame 40 houses at least a portion of the multiple ferrules 10, the pitch changing mechanism 20, and at least a portion of the stop ring 50. The plug frame 40 has a base end cylindrical portion 41 and multiple ferrule housing cylindrical portions 42 extending forward from the base end cylindrical portion 41. Each of the multiple ferrule housing cylindrical portions 42 houses at least a portion of the multiple ferrules 10. A restricting portion 43 protruding inward is formed on the inner circumferential surface of the ferrule housing cylindrical portion 42. The restricting portion 43 has a restricting surface 43a facing backward. The ferrule housing cylindrical portion 42 is also provided with a latch 44 that engages with an adapter or the like used when connecting the optical connector 1 to other connectors, etc.

[0044] The ferrule 10 receives a biasing force directed forward as a whole from the biasing member 60. At this time, the restricted surface 12a of the flange portion 12 comes into contact with the restricting portion 43 (restricting surface 43a) of the plug frame 40. This restricts the relative forward movement of the ferrule 10 with respect to the plug frame 40, preventing the ferrule 10 from falling off the plug frame 40.

[0045] Furthermore, when the optical connector 1 is connected to another connector, the connection end face 10a of the ferrule 10 abuts against the connection end face of the ferrule of the other connector. At this time, the restricted surface 12a and the restricted surface 43a of the plug frame 40 separate, and the ferrule 10 retracts against the forward biasing force of the biasing member 60. In other words, the ferrule 10 moves backward relative to the plug frame 40 while compressing the biasing member 60 in the longitudinal direction Z. At this time, the built-in fiber F1 can bend in the first bending space S1 provided in the ferrule flange 10B and the second bending space S2 provided in the pitch changing mechanism 20. This makes it possible to suppress damage to the built-in fiber F1.

[0046] As described above, the optical connector 1 according to this embodiment comprises: a plurality of ferrules 10, each having a connection end face 10a and a fiber hole 11 opening to the connection end face 10a; a plurality of built-in fibers F1 inserted through the fiber holes 11 of the plurality of ferrules 10; a plurality of connecting fibers F2 fused to the plurality of built-in fibers F1; a pitch changing mechanism 20 that holds the plurality of ferrules 10 and changes the pitch of the plurality of built-in fibers F1 from a first pitch D1, which is the pitch of the plurality of built-in fibers F1 at the connection end face 10a, to a pitch smaller than the first pitch D1; and a heat shrink sleeve 30 that shrinks by heating, positions a plurality of connection points P, to which the plurality of built-in fibers F1 and the plurality of connecting fibers F2 are fused to each other, and is fixed to the pitch changing mechanism 20.

[0047] With this optical connector 1, the pitch changing mechanism 20 changes the pitch of the multiple internal fibers F1 to a pitch smaller than the first pitch D1, which is the pitch of the multiple internal fibers F1 at the connection end face 10a. This allows the pitch of the multiple internal fibers F1 at connection point P to be changed to a pitch that allows the multiple internal fibers F1 and multiple connecting fibers F2 to be fused together by a fusion splicer. By fusion splicing the multiple internal fibers F1 and multiple connecting fibers F2 together in this way, the time required for fusion splicing can be reduced compared to when the multiple internal fibers and multiple connecting fibers are fused together individually. In addition, multiple connection points P, where the multiple internal fibers F1 and multiple connecting fibers F2 are fused together, can be positioned inside the heat shrink sleeve 30. Therefore, the time required for heating and shrinking the heat shrink sleeve 30 can also be reduced compared to when a heat shrink sleeve protecting the connection points between the internal fibers and connecting fibers is provided individually. As a result, the assembly efficiency of the optical connector 1 can be improved.

[0048] Furthermore, the pitch changing mechanism 20 changes the pitch of the multiple internal fibers F1 from the first pitch D1 to the second pitch D2, which is the pitch of the multiple internal fibers F1 at the connection point P. With this configuration, it becomes easier to fusion splice the multiple internal fibers F1 and the multiple connection fibers F2 together using a fusion splicer, thereby improving the assembly efficiency of the optical connector 1.

[0049] Furthermore, the ferrule 10 and the pitch changing mechanism 20 are formed separately. This configuration improves the mechanical strength of the optical connector 1.

[0050] Furthermore, the pitch changing mechanism 20 has a sleeve fixing portion 23 to which the heat shrink sleeve 30 is fixed. The sleeve fixing portion 23 has a base-side insertion hole 23a through which multiple internal fibers F1 are inserted. The sleeve fixing portion 23 has a positioning projection 23c that fits between the coverings f2 of the multiple internal fibers F1 inside the base-side insertion hole 23a. With this configuration, the positioning projection 23c can position the multiple internal fibers F1 inside the base-side insertion hole 23a, and twisting of the internal fibers F1 can be suppressed.

[0051] Furthermore, the pitch changing mechanism 20 includes a ferrule holding portion 21 that holds a plurality of ferrules 10, and a sleeve fixing portion 23 provided on the base end side of the ferrule holding portion 21, to which the heat shrink sleeve 30 is fixed. The ferrule holding portion 21 has a plurality of tip-side insertion holes 22a through which a plurality of internal fibers F1 are inserted. The sleeve fixing portion 23 has a base-side insertion hole 23a through which a plurality of internal fibers F1 are inserted. The number of base-side insertion holes 23a is less than the number of tip-side insertion holes 22a. With this configuration, the pitch of the plurality of internal fibers F1 can be easily changed by the pitch changing mechanism 20.

[0052] Furthermore, the pitch changing mechanism 20 has a sleeve fixing portion 23 to which the heat shrink sleeve 30 is fixed. Multiple protrusions 23b are formed on the outer surface of the sleeve fixing portion 23. With this configuration, the heat shrink sleeve 30 can be firmly fixed to the sleeve fixing portion 23 by heat shrinking so as to tighten against the protrusions 23b.

[0053] The technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0054] For example, the pitch of the multiple built-in fibers F1 that is changed in the pitch changing mechanism 20 only needs to be set so that the pitch between the central axes of the multiple built-in fibers F1 at the connection point P is the second pitch D2, and it does not have to be the second pitch D2.

[0055] Furthermore, in the above embodiment, there are two tip-side insertion holes 22a and one base-side insertion hole 23a. However, the present invention is not limited thereto. If the optical connector 1 has three or more ferrules 10, built-in fibers F1, and connecting fibers F2, the number of tip-side insertion holes 22a may be three or more, and the number of base-side insertion holes 23a may be less than the number of tip-side insertion holes 22a, for example, two or more.

[0056] Furthermore, without departing from the spirit of the present invention, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described embodiments and modifications may be combined as appropriate. [Explanation of Symbols]

[0057] 1…Optical connector 10…Ferrule 10a…Connecting end face 11…Fiber hole 20…Pitch changing mechanism 21…Ferrule holding part 22…Enclosing tube part 22a…Through hole on the tip side 23…Sleeve fixing part 23a…Through hole on the base side 30…Heat shrink sleeve D1…First pitch D2…Second pitch F1…Built-in fiber F2…Connecting fiber P…Connection point

Claims

1. A plurality of ferrules, each having a connecting end face and a fiber hole opening into the connecting end face, A plurality of built-in fibers, each inserted into the fiber hole of the plurality of ferrules, Multiple connecting fibers that are fusion-spliced ​​to each of the multiple built-in fibers, A pitch changing mechanism that holds the plurality of ferrules and changes the pitch of the plurality of internal fibers from a first pitch, which is the pitch of the plurality of internal fibers at the connection end face, to a pitch smaller than the first pitch, An optical connector comprising: a heat-shrinkable sleeve that shrinks upon heating, positioning multiple connection points inside which the multiple internal fibers and the multiple connecting fibers are fused together; and which is fixed to the pitch changing mechanism.

2. The optical connector according to claim 1, wherein the pitch changing mechanism changes the pitch of the plurality of built-in fibers from the first pitch to a second pitch which is the pitch of the plurality of built-in fibers at the connection point.

3. The optical connector according to claim 1 or 2, wherein the ferrule and the pitch changing mechanism are formed separately.

4. The pitch changing mechanism has a sleeve fixing portion to which the heat shrink sleeve is fixed, The sleeve fixing portion is provided with a base end insertion hole through which the plurality of internal fibers are inserted. The optical connector according to claim 1 or 2, wherein the sleeve fixing portion has a positioning projection that fits between the coatings of the plurality of built-in fibers on the inside of the base end insertion hole.

5. The pitch changing mechanism includes a ferrule holding portion that holds the plurality of ferrules, and a sleeve fixing portion provided on the base end side of the ferrule holding portion, to which the heat shrink sleeve is fixed. The ferrule holding portion is provided with a plurality of tip-side insertion holes through which each of the plurality of internal fibers is inserted. The sleeve fixing portion is provided with a proximal end insertion hole through which the plurality of internal fibers are inserted. The optical connector according to claim 1 or 2, wherein the number of base-side insertion holes is less than the number of tip-side insertion holes.

6. The pitch changing mechanism has a sleeve fixing portion to which the heat shrink sleeve is fixed, The optical connector according to claim 1 or 2, wherein a plurality of protrusions are formed on the outer surface of the sleeve fixing portion.

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