JP2002014255A - Optical connector - Google Patents

Abstract

(57) [Problem] To provide an optical connector such as an MT type optical connector, it is possible to increase the number of optical fiber holes opened in the joint end face to increase the number of corresponding optical fibers. A technique for efficiently inserting an optical fiber into an optical fiber hole has not been established, and its development has been demanded. SOLUTION: A joining wall portion 7 on which a joining end surface 4 is formed.
Of the base 11 protruding in multiple stages from the window 10 opened on the side surface of the housing 3 other than the joint end surface 4 toward the internal space 6 of the housing 3 from
Provided is an optical connector 1 in which the protrusion dimension from the joint wall 7 is set to be larger as the distance from the window 10 increases, and the optical fiber guiding groove 12 of each base 11 can be observed from the window 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector.

[0002]

2. Description of the Related Art For example, in a so-called MT type optical connector (Mecanically Transferable) defined in JIS C5981, an optical fiber tip is inserted and fixed in an optical fiber hole opened at a joint end face of a plastic housing made of resin or the like. It has become. In such an optical connector, the number of optical fiber holes formed in the joint end face is increased in order to cope with more optical fibers. For example,
At present, MT-type optical connectors for 4-core and 8-core, which are frequently used, are configured such that a plurality of optical fiber holes are formed in a line in a joint end face. Such an optical connector corresponds to four bare fibers exposed at the tip of one four-core optical fiber tape, and eight bare fibers exposed at the tip of one eight-core optical fiber tape. By increasing the number of optical fiber holes arranged, it is possible to cope with even more optical fibers.

[0003]

However, in the optical connector as described above, the number of optical fiber holes arranged in a line is limited. It has been studied to form a plurality of rows in which a plurality of optical fiber holes are arranged in one row in multiple stages, and insert and fix optical fibers in the optical fiber holes in each row. With the optical connector having this configuration, it is possible to cope with a plurality of multi-core optical fibers by individually coping with multi-core optical fibers such as a multi-core optical fiber ribbon in units of rows. However, in the optical connector in which the rows of optical fiber holes are provided in multiple stages, the optical fiber inserted into the housing from the rear end side facing the joining end face is replaced with a fine optical fiber drilled in a wall near the joining end face. Until now, there has been no appropriate configuration for efficiently inserting the holes into the holes, and development of this technology has been demanded. That is, the inner diameter of the optical fiber hole is, for example, about 126 μm, which can accurately position an optical fiber (bare fiber) having a diameter of about 125 μm. It is not easy to accurately insert the optical fiber into this optical fiber hole. As described above, when a large number of optical fiber holes are formed in multiple stages, there is a problem that it becomes more difficult to select a target optical fiber hole and accurately insert an optical fiber.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and even if a plurality of rows of optical fiber holes are formed on a joint end face, the optical fibers of each row are formed in multiple stages. An object of the present invention is to provide an optical connector capable of efficiently inserting an optical fiber into a hole.

[0005]

In order to solve the above-mentioned problems, the present invention provides a joint end face on which a tip of the optical fiber is positioned and fixed so as to be butt-connected to a side surface of a housing into which a plurality of optical fibers are inserted. An optical connector, wherein the housing has an interior space, a joining wall portion on which the joining end surface is formed, a window opened to a side surface other than the joining end surface and communicating with the internal space, and the joining wall. And a base portion protruded in multiple stages with different distances from the window toward the internal space from the portion, and in each base portion,
An optical fiber guiding groove for guiding the optical fiber from the inner space is formed in communication with an optical fiber hole formed through the bonding wall portion, and the base portion is more distant from the window than the bonding wall. The projecting dimension from the part is large, the optical fiber guiding groove of each base part can be observed from the window, and guide pins for positioning of the butt connection are inserted and fitted on opposite sides of the joining end face. A plurality of optical fiber holes formed in a region between the two guide pin holes, and a center connection line on both sides along a center connection line connecting the centers of the two guide pin holes. Are arranged symmetrically via the According to this optical connector, a plurality of pedestals protruded in multiple stages with different distances from the window from the joining wall toward the internal space,
The farther from the window, the larger the projecting dimension from the joining wall portion is, and the tip of the projecting portion from the joining wall portion of each stand is seen to be shifted from the window, and the optical fiber guiding groove of each stand is seen. Can be observed through the window. Therefore, for any of the optical fiber holes, the operation of inserting the optical fiber can be performed efficiently while observing the optical fiber guiding groove of each base from the window. Further, by arranging a plurality of the optical fiber holes symmetrically on both sides thereof along the center connection line connecting the centers of the two guide pin holes via the center connection line, the shrinkage strain at the time of the curing shrinkage of the molding resin is reduced. Act equally on the optical fiber holes on both sides of the center connection line, so that the position accuracy of each optical fiber hole positioned around the guide pin hole follows the accuracy of the resin molding die. Thus, an extremely accurate one can be easily obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical connector according to an embodiment of the present invention will be described below with reference to the drawings. 1 and 3
As shown in (a) to (d), the optical connector 1 has a joint end face 4 on the side surface of a housing 3 into which the optical fiber 2 is inserted, the tip end of the optical fiber 2 being positioned and fixed so as to be butt-connected. ing. The optical fiber 2 has a rear end opening 5 on the rear end side facing the joint end face 4 of the housing 3.
3 (b) and 3 (d), it is inserted into the internal space 6 of the housing 3 and further penetrates the joint wall 7 on which the joint end face 4 of the housing 3 is formed. It is inserted into the optical fiber hole 8. The rear end opening 5
It is also possible to insert and fix a boot for protecting the optical fiber 2 inserted into the internal space 6. The optical fiber 2 is a bare fiber or the like. In FIG. 1, the bare fiber is exposed at the tip of a multi-core optical fiber 9 which is a multi-core optical fiber ribbon (12 cores in FIG. 1). The housing 3 is generally made of a resin such as a plastic such as an epoxy resin or a thermoplastic resin.

A window 10 opened to the side surface of the housing 3 other than the joining end surface 4 and communicating with the internal space 6 is used for injecting an adhesive into the internal space 6 or the like. FIG.
As shown in (d), the base 11 protruded from the joining wall 7 toward the inner space 6 at different distances from the window 10 to the inner space 6 has a plurality of protruding portions. An optical fiber guiding groove 12 for communicating with the optical fiber 2 from the inner space 6 is formed. The base 11
The projection distance from the joining wall portion 7 increases as the distance from the window 10 increases. Therefore, the window 10
From above, the protruding tip of each base 11 from the joining wall 7 is seen to be shifted, and the optical fiber guiding groove 12 of each base 11 can be observed visually or the like.

A plurality of optical fiber guiding grooves 12 (twelve in FIGS. 3A to 3C) are formed in parallel on the surface of each base 11 facing the window 10. 1 at the joining end face 4
Two rows of optical fiber holes 8 opened in a plurality of places (12 places in FIGS. 3A to 3C) are formed in parallel. Guide pin holes 13 into which guide pins for positioning with respect to another optical connector to be butt-connected are inserted and fitted on opposite sides of the joint end face 4, and each optical fiber hole 8 is formed. Both are formed in a region between the two guide pin holes 13. The guide pin hole 13 extends from the joint end face 4 to the rear end face 1 on the rear end side facing the joint end face 4.
4 penetrates the housing 3. As the guide pins, it is preferable to adopt, for example, guide pins of an MT type optical connector stipulated in JIS C5981 from the viewpoint of cost reduction by common use of components.
The guide pin hole 13 has a configuration that can be fitted and fitted to the guide pin. The distance between the center axes of the guide pin holes 13 is, for example, about 4.6 mm, which is the same as that of a general MT optical connector defined in JIS C5981. 598
It is preferable in terms of connection compatibility with a general MT type optical connector set to 1.

The optical fiber hole 8 has two guide pin holes 1.
Along the center connection line x (virtual line) connecting the centers of the three, a plurality (in this case, twelve) are symmetrically arranged via the center connection line x. As a result, in the optical connector 1, the shrinkage strain of the molding resin upon curing shrinkage acts uniformly on the optical fiber holes 8 on both sides of the center connection line x, and as a result, the positioning is performed around the guide pin holes 13. The position accuracy of each optical fiber hole 8 to be formed follows the accuracy of the resin molding die, and an extremely accurate one can be easily obtained. If the positional accuracy of the optical fiber hole 8 is ensured, connection loss can be reduced, for example, when connecting connectors such as optical connectors. Center connection line x
In the optical connector (optical connector ferrule) having the multi-dimensionally arranged optical fiber holes according to the present invention, the influence of the shrinkage strain of the molding resin on both sides symmetrical via the optical fiber appears on the entire joint end face 4, so that the conventional general This is remarkable in comparison with an optical connector ferrule of a type in which optical fiber holes are arranged in a line. If the number of hole rows in which the optical fiber holes 8 are arranged along the center connection line x is an even number, the influence of shrinkage distortion of the molding resin can be exerted uniformly, and there is no problem. When the number of rows is odd, the center row can be arranged on the center connecting line x between the guide pin holes 13.

Each of the optical fiber guiding grooves 12 penetrates from the optical fiber hole 8 to the tip of the base 11 in the protruding direction from the joint wall 7. As the optical fiber guiding groove 12,
For example, as shown in FIG. 2, it is a round groove having a semicircular cross section, but is not limited thereto. For example, a U groove, a V groove, a square groove,
Various configurations can be employed. 1 and 3 (a),
(B), optical fiber guiding groove 12 of round groove exemplified in (d)
Specifically, the optical fiber hole 8 communicates with the optical fiber hole 8 via a tapered hole 15 in which the internal space 6 side of the optical fiber hole 8 is tapered. The inner diameter of the optical fiber hole 8 is, for example, 12
The semicircular cross section of the optical fiber guiding groove 12, which is a round groove, is approximately 126 μm, which is capable of precisely positioning the bare fiber as the optical fiber 2 of 5 μm, and is a part of a circle having a diameter of about 250 μm. The optical fiber guiding groove 12 is formed simultaneously with the tapered hole 15 and the optical fiber hole 8 by using, for example, a pin inserted during molding of the resin forming the housing 3 as a mold.

In order to insert the optical fiber 2 into the optical fiber hole 8, the leading end of the multi-core optical fiber 9 from which the optical fiber 2 is led out is inserted into the internal space 6 from the rear end opening 5, and the window 1 is opened.
The optical fiber 2 is inserted into the target optical fiber guiding groove 12 while observing from the point 0, and the optical fiber 2 is further connected to the bonding end face 4.
Just push it in the direction. The optical fiber 2 inserted into the optical fiber guiding groove 12 is smoothly guided into the optical fiber hole 8 from the tapered hole 15, is inserted into the optical fiber hole 8 by further pushing, and the tip reaches the joining end face 4. I do. However, the optical fiber hole 8 and the optical fiber guiding groove 1
The insertion of the optical fiber 2 into the optical fiber 2 is preferably performed in order from the optical fiber guiding groove 12 of the pedestal 11 far from the window 10. Observation of the optical fiber guiding groove 12 may be performed by visual observation if possible, but it is preferable to use a microscope.
The workability of inserting the optical fiber 2 into the selected optical fiber guiding groove 12 can be improved.

Thick covering portion 9a of multi-core optical fiber 9
However, when it comes into contact with the protruding tip of each base portion 11 from the joining wall portion 7, further pushing of the optical fiber 2 is restricted.
In a multi-core optical fiber 9 in which a plurality of optical fibers 2 inserted into a plurality of optical fiber holes 8 in the same row are led out,
A coating portion 9a for integrally fixing each optical fiber 2 is provided with a partition 16 between the optical fiber guiding grooves 12 of the base portion 11 (see FIG. 2).
Also, by contacting the tip end surfaces 17 (see FIGS. 3A, 3B, and 3D) of the respective base portions 11 protruding from the joint wall 7, the pushing in the direction of the joint end surface 4 is regulated. Thereby, the tip of the optical fiber 2 is flush with the joint end face 4 or the joint end face 4
Is positioned in a protruding state. The distal end face of the optical fiber 2 which has been inserted into the optical fiber hole 8 is made flush with the joint end face 4 by cutting off the protruding portion from the joint end face 4 and polishing the joint end face 4.

When the insertion operation of the optical fiber 2 is completed, an adhesive is injected from the window 10 into the optical fiber guiding groove 12, and the optical fiber 2 on the base 11 and the multi-core optical fiber 9 near the base 11 are removed. It is adhesively fixed to the base 11 and the housing 3 around the base 11. Thereby, the pulling out of the optical fiber 2 from the optical fiber hole 8 and the pulling out of the multi-core optical fiber 9 from the housing 3 are restricted.

According to the optical connector 1, the optical fiber guiding groove 12 is observed while observing the optical fiber guiding groove 12 from the window 10.
The optical fiber 2 can be inserted into the optical fiber 2 and pushed into the optical fiber hole 8 from the optical fiber guiding groove 12. Moreover, in the optical connector 1, the optical fiber guiding grooves 12 of the plurality of bases 11 in the internal space 4 can be observed from the window 10,
After all, the optical fiber guiding grooves 1 related to all the optical fiber holes 8
Since the optical fiber 2 can be observed, the insertion work of the optical fiber 2 can be efficiently performed for all the optical fiber holes 8.

When the joining end faces 4 of the pair of optical connectors 1 into which the optical fibers 2 are inserted and fixed are abutted with each other, the optical fibers 2 are abutted and connected, whereby the multi-core optical fibers 9 are optically connected with each other. The connection between the optical connectors 1 is made in the same manner as the connection between the MT optical connectors defined in JIS C5981. Specifically, both optical connectors 1 are precisely positioned by inserting and fitting the guide pins into the guide pin holes 13 of both optical connectors 1 so as to bridge them. More specifically, the tips of all the optical fibers 2 exposed on the joint end face 4 are precisely positioned between the two optical connectors 1. Here, by joining the joining end surfaces 4 of both optical connectors 1, all the optical fibers 2 of both optical connectors 1 are butt-connected. By applying a butt force to the two connected optical connectors 1 to press the joint end surfaces 4 therebetween, a desired low connection loss between the optical fibers 2 can be obtained. Various mechanisms can be adopted as the mechanism for applying the butting force. As shown in FIG. 1 and the like, an optical device having a housing 3 having an outer shape similar to the MT type optical connector defined in JIS C5981 is used. In the connector 1, it is possible to apply a butt force by sandwiching the two optical connectors 1 in a connected state by a clamp spring applied to the MT type optical connector defined in JIS C5981. The flange portion 18 near the rear end face 14 is used for engaging a clamp spring, positioning and holding the optical connector 1 at the time of engaging work, and the like.

The present invention is not limited to the above embodiment, and it goes without saying that various modifications are possible. For example, the outer shape of the housing, the shape of the internal space of the housing, and the like can be appropriately changed. The number of pedestals protruding from the joint wall may be three or more. In this case, the number of optical fiber holes opened in the joint end face may be three or more in accordance with the position of the base. Various configurations can be adopted as the configuration of the optical fiber guiding groove.For example, the optical fiber guiding groove of each base portion does not match the row of optical fiber holes on the joint end surface, and the optical fiber guiding grooves of a plurality of base portions are the same. It is also possible to adopt a configuration in which the optical fiber holes of the same row communicate with the optical fiber holes of the row, or the optical fiber guiding grooves of the same base communicate with the optical fiber holes of the plurality of rows. In FIG. 3B and the like, the positions of the optical fiber guiding grooves and the partition walls between the optical fiber guiding grooves coincide with each other between the plurality of pedestals observed from the window 10. However, the present invention is not limited to this. However, a configuration in which the optical fiber guiding grooves of one base are arranged in a staggered manner so that the optical fiber guiding grooves of the other base are located at the positions of the partition walls between the optical fiber guiding grooves of the other base can also be adopted. In the above embodiment, the configuration in which the optical fiber guiding groove of each base and the corresponding optical fiber hole correspond to the optical fiber having the same diameter is exemplified, but the present invention is not limited thereto. It is also possible that the diameter of the optical fiber that can be accommodated by the optical fiber hole is different for each stage.

The optical fiber applied to the optical connector according to the present invention is not limited to the bare fiber exposed at the end of the optical fiber ribbon, and may be, for example, a bare fiber itself, a bare fiber exposed at the end of the optical fiber, A bare fiber exposed at the tip of various multi-core optical fibers such as an optical fiber cord other than the optical fiber ribbon may be used. Also, from a plurality of optical fiber guiding grooves on the same base to the optical fiber hole,
It is also possible to insert a plurality of single-core or multi-core bare fibers at the end of an optical fiber. Further, not only a single mode optical fiber but also a multimode optical fiber can be applied.

The optical connector according to the present invention is, for example, JI
It is also possible to incorporate it into the housing of the MPO optical connector defined in SC5982. Since this optical connector has the same outer shape as the MT optical connector defined in JIS C5981, it can be incorporated without changing the housing of the MPO optical connector.

[0019]

As described above, according to the optical connector of the present invention, a plurality of pedestals protruding in multiple stages at different distances from the window from the joining wall toward the internal space are provided. The farther from the window, the larger the projected dimension from the joining wall portion, the optical fiber guiding groove of each base portion can be observed from the window, and all the optical fiber guiding grooves can be observed from the window. With respect to the optical fiber hole relating to the optical fiber guiding groove, the optical fiber insertion operation can be performed efficiently while observing the optical fiber guiding groove of each base from this window. Further, by arranging a plurality of the optical fiber holes symmetrically on both sides thereof along the center connection line connecting the centers of the two guide pin holes via the center connection line, the shrinkage strain at the time of the curing shrinkage of the molding resin is reduced. Act equally on the optical fiber holes on both sides of the center connection line, so that the position accuracy of each optical fiber hole positioned around the guide pin hole follows the accuracy of the resin molding die. Since an extremely high-precision one can be easily obtained, an excellent effect such as a reduction in connection loss at the time of connecting connectors such as optical connectors can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical connector according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an example of an optical fiber guiding groove shape of the optical connector of FIG. 1;

FIGS. 3A and 3B are views showing the optical connector of FIG.
Is a side view as viewed from the rear end face side, (b) is a plan view, (c) is a side view as viewed from the joining end face side, and (d) is a front sectional view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical connector, 2 ... Optical fiber (bare fiber), 3 ...
Housing, 4 ... joining end face, 6 ... internal space, 7 ... joining wall, 8 ... optical fiber hole, 9 ... optical fiber (optical fiber tape core wire, 10 ... window, 11 ... base, 12 ... optical fiber guiding groove , 13: guide pin hole, x: center connection line (virtual line).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Arikawa 1440 Mutsuzaki, Sakura City, Chiba Prefecture Inside Fujikura Sakura Office Co., Ltd. F-term (reference) 2H036 JA02 QA12 QA18 QA49

Claims (1)

[Claims] An optical connector having a joint end face (4) on the side surface of a housing (3) into which a plurality of optical fibers (2) are inserted, the end face of which is positioned and fixed so that the ends of the optical fibers can be butt-connected. The housing has an internal space (6), a joint wall (7) on which the joint end surface is formed, and a window (10) opened to a side surface other than the joint end surface and communicating with the internal space.
And a pedestal (11) protruding in multiple stages with different distances from the window from the joining wall toward the internal space.
And an optical fiber guiding groove (12) for guiding the optical fiber from the inner space is formed in each base portion in communication with an optical fiber hole (8) formed through the joint wall portion. And
The pedestal portion, the farther from the window, the larger the projected dimension from the joining wall portion, the observable optical fiber guiding groove of each pedestal portion from the window, and the opposite side of the joining end face, A guide pin hole (13) into which a guide pin for positioning for butt connection is inserted and fitted is formed, and the plurality of optical fiber holes formed in a region between the two guide pin holes are provided. An optical connector (1), characterized in that the optical connector (1) is symmetrically arranged on both sides along a center connection line (x) connecting centers.