JPH07318757A - Optical connector and its connecting method - Google Patents

Abstract

PURPOSE:To obtain an optical connector with which good physical contact(PC) connection is executed without using a matching agent by projecting the optical fiber end faces of one housing from the end face to be connected and recessing the optical fiber end faces of the other housing from the end face to be connected and setting the projecting quantity thereof equal to or larger than the recessing quantity. CONSTITUTION:A male type connector is produced by projecting the end faces of four pieces of the optical fibers 15 from the end face 22 to be connected of the housing 18a by as much as the thickness component of a spacer 20 in such a manner that the end faces are made flush with the end face to be connected. A female type connector is produced by recessing the end faces of four pieces of the optical fibers 15 to the inside of the end face 22 to be connected of the housing 18a by as much as the thickness component of the spacer 20 in such a manner that the end faces are made flush with the end face to be connected. In such a case, the projecting quantity is set equal to or larger than the recessing quantity. The connecting end faces 22 of the male type and female type connectors are butted against each other and the projecting optical fibers 15 of the male type connector are fitted into the fibers of the female type connector, by which alignment is automatically executed. The PC connection is thus executed with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical connector used in the field of optical communication and its connecting method.

[0002]

2. Description of the Related Art As an optical connector used for connecting an optical fiber, there is, for example, a fitting type optical connector as shown in FIG. In this fitting type optical connector, the fitting pin 103 is inserted into the pin insertion hole 102 provided in the connected end surface 101 of each connector main body 100 to position the optical fiber 104 of the optical fiber 104 inserted into the connector main body 100. By connecting the connected end surfaces of both connector bodies 100 to each other in a state where the fiber end surface is exposed to the connected end surface 101, the fiber end surfaces are brought into contact with each other, and the optical fibers are optically coupled to each other to be connected.

That is, as shown in FIG. 13A, the coating of the tape core wire 105 is removed by a predetermined length to expose the optical fiber 104, and the optical fiber 104 is inserted into the fiber hole 106 of the connector body 100. Then, an adhesive is applied between the two. When the insertion of the optical fiber 104 is completed, the optical fiber 104 is in a state of protruding from the connected end surface 101 of the connector body 100, as shown in FIG. At this time, the connected end surface 1 of the connector body 100
At 01, the adhesive 107 is in a state of being squeezed out. In this state, the adhesive is cured by heating.

Next, as shown in FIG. 14A, the optical fiber 104 protruding from the connected end surface 101 of the connector body 100 and the protruding adhesive 107 are removed by grinding, and then the connected end surface 101 is polished. Give. Finally, as shown in FIG. 14 (B), the end faces 101 to be connected of the two connector bodies 100 are butted to each other via the matching agent 108 for suppressing the loss and reflection of the transmitted light, so that the end faces of the fibers are butted to each other. , Optically couple optical fibers.

In the connection of the optical connector, as described above, the matching agent 108 is interposed between the connected end faces of the connector body 100 to maintain the continuity of the refractive index of the core of the optical fiber, or the end face of the optical fiber. It prevents the generation of voids between them and suppresses the loss and reflection of light.

[0006]

However, as shown in FIG.
The connection accuracy of the optical connector shown in FIG.
Is ensured by the accuracy of the fitting pin 103 with respect to and the positioning accuracy between the fiber hole and the pin insertion hole 102. Therefore, a connection loss occurs due to their accuracy error.

Also, the matching agent 10 is used when connecting the optical connector.
Even if 8 is interposed, if air is mixed into the matching agent 108 or the matching agent 108 itself evaporates and decreases with time, light loss and reflection occur at the connection portion. Therefore, it is impossible to maintain a stable and good connection state for a long period of time. Therefore, a PC (Physical Contact) connection without using the matching agent 108 or the like is desired, but when polishing the connected end surface 101, the polishing amount of the connected end surface 101 is different for each optical fiber. ,
As shown in FIG. 15, the positions of the fiber end faces after the polishing process are not aligned on the same plane, and good PC connection cannot be performed.

The present invention has been made in view of the above points, and provides an optical connector capable of making a good PC connection without using a matching agent and a connection method capable of accurately connecting the optical connector. The purpose is to do.

[0009]

The first invention of the present invention is as follows:
In an optical connector in which optical fibers are connected to each other by bringing the connected end faces of the connector body into contact with each other,
A male connector in which the fiber end surface projects from the connected end surface of the connector body by a first distance, and a female connector in which the fiber end surface is recessed from the connected end surface of the connector body by a second distance. And a mold connector, wherein the first distance is equal to or greater than the second distance.

The first invention of the present invention has a ferrule for inserting and fixing a plurality of optical fibers so as to have a first reference surface and project from the first reference surface. A plurality of optical fibers inserted in, and a fiber hole for positioning the plurality of optical fibers and a pair of alignment pin holes, the ferrule of the ferrule when the optical fiber is inserted into the fiber hole Two connectors each comprising a housing having a second reference surface that directly abuts against the first reference surface or abuts via a spacer member are provided, and one connector is connected to the connected end surface of the housing. On the other hand, the fiber end surface is a male connector that projects by a first distance, and the other connector has a fiber end surface that is second with respect to the connected end surface of the housing. A female connector is recessed just away, to provide an optical connector in which the first distance being greater or equal to the second distance.

Here, as a material for the connector body and the ferrule, an epoxy resin containing a glass filler or the like can be used. Further, ceramics, cemented carbide, or the like can be used as the material of the alignment pin.

The first distance is set to be equal to or larger than the second distance. The difference between the first distance and the second distance is preferably 20 μm or less. This is because if the difference in distance exceeds 20 μm, the connection accuracy may be reduced and the fiber end surface of the optical fiber may be damaged. It should be noted that this difference needs to be large if the condition of axis deviation or the usage environment is severe.

A second aspect of the present invention is a ferrule having a first reference surface for inserting and fixing a plurality of optical fibers so as to project from the first reference surface, and the ferrule. A plurality of optical fibers inserted in, and a fiber hole for positioning the plurality of optical fibers and a pair of alignment pin holes, the ferrule of the ferrule when the optical fiber is inserted into the fiber hole The optical fiber inserted into the fiber hole of one of the housings comprises a housing having a second reference surface that directly abuts against the first reference surface or abuts via a spacer member. The optical fiber protruding from the connected end surface of one housing by a first distance and inserted into the fiber hole of the other housing is Using two connectors whose end surface is recessed inward by a second distance from the connected end surface of the other housing, and where the first distance is equal to or greater than the second distance By abutting the end faces, the optical fiber protruding from the connected end face of the one housing is inserted into a portion recessed inward from the connected end face of the other housing, and the fiber of the optical fiber in the other housing is inserted. Provided is a method for connecting an optical connector, which is in contact with an end face and is optically connected.

[0014]

In the present invention, the optical fiber of one of the housings has the fiber end surface protruding from the connected end surface, and the optical fiber of the other housing has the fiber end surface recessed inward from the connected end surface. The amount of protrusion is equal to or larger than the amount of depression.

The fiber end surface of the optical fiber of one housing is projected from the connected end surface, and the fiber end surface of the optical fiber of the other housing is recessed inward from the connected end surface, whereby the fiber end surface is recessed inward. The optical fiber can be connected in the fiber hole, and it is possible to obtain a highly accurate optical connector connection that could not be realized with the fitting pin.

Further, since the amount of protrusion is equal to or greater than the amount of depression, it is possible to reliably connect the optical connectors to the PC even if there are multiple fibers. The alignment function of the optical fiber can be specifically described as follows.

In the connection of the conventional optical connector, as shown in FIG. 16, even if the centers of the pin insertion holes 102 of the connector bodies 100a and 100b are aligned, that is, the distance S between the centers of the respective pin insertion holes 102. Are equal,
Distance m between the center of the pin insertion hole 102 and the center of the fiber hole
Or the error of n or the distance k _{1 to} k ₆ between the centers of the fiber holes
Error, etc., causes axial deviations t ₁ , t ₂ , and t ₃ of the optical fiber.

However, in the connection of the optical connector of the present invention, as shown in FIG.
The distance between the centers of the fiber holes of the pin insertion hole as shown in FIG. 16 b m, even when there is an error in the distance k ₁ to k ₆ between the centers of the error and fiber holes of n, the fiber housing 10b The projection 12 of the optical fiber of the housing 10a is fitted into the recess 11 of the hole, and the projected optical fiber and the optical fiber in the fiber hole of the housing 10b are connected to each other, whereby the fiber end surfaces of the optical fiber are aligned with each other. . Therefore, the connection accuracy can be improved. At this time, the amount of protrusion of the protrusion 12 is equal to or larger than the amount of recess of the recess 11, so that the PC connection between the both can be reliably performed.

[0019]

Embodiments of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) As shown in FIG. 2, the coating of a 4-core optical fiber tape core wire 13 having a diameter of 125 μm was peeled off by a predetermined length L _1, and a predetermined length L was applied to a ferrule 10 made of epoxy resin containing glass filler. After inserting only ₂ , glue 1
The optical fiber tape core wire 13 is fixed in the ferrule 10 by using 4a or the like. At this time, the optical fiber 15 extends from the connected end surface 16 of the ferrule 10 by L ₁ -L ₂ .

Next, as shown in FIG. 3, a fiber hole 17 having a length of 1 mm, an inner diameter of 126 μm and a guide pin hole 23 having an inner diameter of 700 μm, which determines the position of the optical fiber with high accuracy, is prepared from an epoxy resin containing glass filler. The ferrule 10 is attached to the housing 18 such that the optical fiber 15 extending into the fiber hole 17 is inserted. At this time, in order to adjust the relative positions of the ferrule 10 and the housing 18 in the fiber axis direction, the outer reference surface 16 of the ferrule 10 and the inner reference surface 1 of the housing 18 are adjusted.
A spacer 20 such as a copper foil having a thickness of 500 μm (δ) as shown in FIG.

Next, the ferrule 10 and the housing 18
a is temporarily temporarily fixed by a fixing means such as a leaf spring 21a for temporary fixing as shown in FIG. 5, and the connected end surface 22 of the housing 18a is polished. The state at this time is shown in FIG.
In order to prevent the optical fiber 15 from being broken during polishing, the fiber end surface of the optical fiber 15 has a housing 18a.
The end surface 22 to be connected is located inside by λ. This λ is preferably 10 to 30 μm. This is because when λ is less than 10 μm, the assembly accuracy when assembling the ferrule and the housing becomes strict, and λ is 30
This is because when the thickness exceeds μm, the polishing amount increases and the positioning accuracy deteriorates.

In the polishing process, first, a # 3000 diamond metal bond grindstone is used to polish the optical fiber 15 to a polishing amount of about 40 μm. afterwards,
Finish polishing is performed using a liquid bond grindstone made of # 8000 cerium oxide. By this polishing treatment, new fiber end faces are exposed, and all the fiber end faces are accurately aligned on the same plane. Since the accuracy of the parallelism between the optical fiber 15 and the fiber hole 17 is about 1 μm, the squareness of the outer reference surface 16 and the inner reference surface 19 of the ferrule 10 and the housing 18a with respect to the axial direction of the fiber hole 17 is set. By setting the accuracy to 1 μm or less, the spacer 2 before and after polishing the connected end surface 22 of the housing 18a
The breakage of the optical fiber 15 due to the presence or absence of 0 can be prevented.

After the polishing process, as shown in FIG. 7, the temporary spring leaf 21a is removed, the spacer 20 is removed,
The outer reference surface 16 of the ferrule 10 and the inner reference surface 19 of the housing 18a are abutted against each other, and both are fixed with an adhesive 14b. As a result, the four optical fibers 15 are aligned by the thickness of the spacer 20, that is, 500 μm, and protrude from the connected end face 22 of the housing 18a. In this way, the optical connector 1a which is a male connector is manufactured.

Next, in the same manner as described above, the housing 18b
Attach ferrule 10 to. At this time, the outer reference surface 16 of the ferrule 10 and the inner reference surface 19 of the housing 18b.
Spacer 20 is not arranged between and. Then, in the same manner as described above, the ferrule 10 and the housing 18b are temporarily fixed by the temporary spring leaf 21a, and the connected end surface 22 of the housing 18b is polished.

After the polishing process, as shown in FIG. 8, the temporary spring leaf 21a is removed, and the outer reference surface 1 of the ferrule 10 is removed.
6 and the inner reference surface 19 of the housing 18b, a spacer 20 is arranged, and both are fixed with an adhesive 14b. As a result, the four optical fibers 15 are aligned by the thickness of the spacer 20, that is, 500 μm, and are recessed inside the connected end face 22 of the housing 18. In this way, the optical connector 1b, which is a female connector, is manufactured.

Next, as shown in FIG. 9, the connected end faces 2 of the optical connectors 1a and 1b obtained as described above.
The optical connectors 1a and 1b are connected by abutting the two and fitting the fitting pin 24 into the pin insertion hole 23. further,
The optical connectors 1a and 1b are fixed by the connecting leaf spring 21b. At this time, when the protruding optical fiber 15 of the optical connector 1a is fitted into the fiber hole 17 of the optical connector 1b, centering is automatically performed and PC connection can be performed with extremely high accuracy.

In this embodiment, the copper foil is used as the spacer 20, but the material is not limited as long as it functions as the spacer 20 described above. Also, ferrule 10
Also, the material and manufacturing method of the housings 18a, 18b are not particularly limited, and those formed by using metal or ceramics may be used.

In this embodiment, as shown in FIGS. 10A and 10B, the fiber hole 17 of the housing 18 is formed so as to become larger toward the connected end face 22 side of the optical connector 1b, and is polished. It is possible to facilitate the insertion of the protruding optical fiber after the processing and allow the positional deviation in the fiber hole by the bending of the optical fiber to realize the accurate connector connection. (Example 2) In Example 1, the optical connectors 1a and 1b were used.
Although the spacers 20 having the same thickness were used in manufacturing the above, the thickness of the spacer used for manufacturing the optical connector 1a (protruding side) was set to, for example, 502 μm, and the spacer used for manufacturing the optical connector 1b (concave side) was For example, the thickness is 500
By setting the thickness of the spacer of the optical connector 1a to be thicker than the thickness of the spacer of the optical connector 1b, more reliable PC connection can be performed. (Third Embodiment) In the first embodiment, the optical fiber itself is projected or recessed from the connected end face 22 of the housing 18, but the fiber end face of the optical fiber inserted into one optical connector 1a is convex. Shaped and the other optical connector 1
Even if the fiber end surface of the optical fiber inserted in b is formed into a concave shape, reliable PC connection can be performed. In order to make the fiber end surface convex, as shown in FIG.
The conventional ferrule 10 is made of a material softer than that of the optical fiber, and a polishing method using loose abrasive grains is used to project the fiber end surface of the optical fiber 15 from the outer reference surface of the ferrule to form a convex shape. By doing so, a male connector is manufactured. Further, in order to make the end face of the fiber concave, as shown in FIG. 11 (B), the mechanochemical polishing effect of the fixed abrasive grains of cerium oxide is used for the conventional ferrule 10 so that the outer reference of the ferrule is not used. A female connector is produced by making the fiber end surface of the optical fiber 15 concave rather than the surface to make it concave. (Embodiment 4) In Embodiment 1, the case where the fiber end face of the optical fiber 15 is substantially perpendicular to the axial direction of the optical fiber has been described. The fiber end surface of the fiber 15 may have a predetermined angle with respect to the axial direction of the optical fiber. In this case, the angle formed by the fiber end surface of the optical fiber inserted in one optical connector with respect to the axial direction of the optical fiber, and the fiber end surface of the optical fiber inserted in the other optical connector The angle with respect to the axial direction must be almost equal.

[0029]

As described above, in the optical connector of the present invention, the optical fiber inserted into the fiber hole of the one housing has its fiber end surface protruding by the first distance from the connected end surface of the one housing. The optical fiber inserted into the fiber hole of the other housing has its fiber end surface recessed inward by a second distance from the connected end surface of the other housing, and the first distance is equal to or larger than the second distance. When connecting the optical connectors, the end faces of the optical fibers can be connected in the fiber holes of one of the optical connectors, so the optical fiber itself has a direct alignment effect, and the optical connectors are connected with extremely high accuracy. And shows good optical connection characteristics.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the operation of an optical connector according to the present invention.

FIG. 2 is a perspective view showing a connector body used in the optical connector of the present invention.

FIG. 3 is a perspective view showing a housing used for the optical connector of the present invention.

FIG. 4 is a perspective view showing a spacer used in the optical connector of the present invention.

5A is a perspective view showing a leaf spring for temporary fixing used in the optical connector of the present invention, and FIG. 5B is a perspective view showing a connection leaf spring used in the optical connector of the present invention.

FIG. 6 is a perspective view showing a state in which a connection end surface of the housing is subjected to polishing processing.

FIG. 7 is a perspective view showing an optical connector in which an optical fiber projects from a connected end surface of a housing.

FIG. 8 is a perspective view showing an optical connector in which an optical fiber is recessed inward from a connected end face of a housing.

9 is a perspective view showing a connection state between the optical connector shown in FIG. 7 and the optical connector shown in FIG.

10A and 10B are schematic views showing another example of a housing used in the optical connector of the present invention.

11A is a schematic diagram for explaining the production of a convex fiber end surface, and FIG. 11B is a schematic diagram for explaining a production of a concave fiber end surface.

FIG. 12 is a perspective view for explaining the configuration of an optical connector.

13A and 13B are schematic views for explaining a conventional method for manufacturing an optical connector.

14A and 14B are schematic diagrams for explaining a conventional method for manufacturing an optical connector.

FIG. 15 is a schematic diagram for explaining a problem of a conventional optical connector.

FIG. 16 is a schematic diagram for explaining a problem of the conventional optical connector.

[Explanation of symbols]

1a, 1b ... Optical connector, 10, 10a, 10b ... Ferrule, 11 ... Recess of fiber hole, 12 ... Protrusion of optical fiber, 13 ... Optical fiber tape core wire, 14 ... Adhesive,
15 ... Optical fiber, 16 ... Outer reference plane, 17 ... Fiber hole, 18a, b ... Housing, 19 ... Inner reference plane, 20 ...
Spacer, 21a ... Leaf spring for temporary fixing, 21b ... Leaf spring for connection, 22 ... End surface to be connected, 23 ... Pin insertion hole, 24 ...
Mating pin.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Mikijo Ishihara 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Hiroyuki Yamada 2-6-1, Marunouchi, Chiyoda-ku, Tokyo No. Furukawa Electric Co., Ltd. (72) Inventor Shinji Nagasawa 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An optical connector in which optical fibers are connected to each other by bringing the connected end surfaces of the connector body into contact with each other, the fiber end surface projecting a first distance from the connected end surface of the connector body. And a female connector in which the fiber end surface is recessed by a second distance with respect to the connected end surface of the connector body, and the first distance is the second distance. Optical connector characterized by being equal to or larger than. 2. A ferrule having a first reference surface for inserting and fixing a plurality of optical fibers so as to project from the first reference surface, and a plurality of optical fibers inserted in the ferrule. A fiber hole for positioning the plurality of optical fibers and a pair of alignment pin holes, and directly contacts the first reference surface of the ferrule when the optical fiber is inserted into the fiber hole. Alternatively, the connector is provided with two connectors including a housing having a second reference surface that abuts via a spacer member, and one of the connectors has a fiber end surface at a first distance from the connected end surface of the housing. And the other connector is a female connector in which the fiber end face is recessed by a second distance from the connected end face of the housing. A Kuta, optical connector, wherein the first distance is greater than or equal to the second distance. 3. A ferrule having a first reference surface for inserting and fixing a plurality of optical fibers so as to project from the first reference surface, and a plurality of optical fibers inserted in the ferrule. A fiber hole for positioning the plurality of optical fibers and a pair of alignment pin holes, and directly contacts the first reference surface of the ferrule when the optical fiber is inserted into the fiber hole. Alternatively, the optical fiber is formed of a housing having a second reference surface that abuts via a spacer member, and the fiber end surface of the optical fiber inserted into the fiber hole of the one housing is more than the connected end surface of the one housing. The optical fiber inserted into the fiber hole of the other housing by protruding by the first distance has the fiber end surface of the other housing. Than the connecting end face of which is recessed inwardly by a second distance,
By using two connectors in which the first distance is equal to or larger than the second distance and the connected end faces of the two housings are butted against each other, the optical fiber protruding from the connected end faces of the one housing is the other end. The method for connecting an optical connector, wherein the optical connector is inserted into a portion of the housing that is recessed inward of the end face to be connected and is brought into contact with the fiber end face of the optical fiber in the other housing to be optically connected.