JP2901517B2 - Multi-core optical fiber connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connector for connecting optical fibers to each other, and more particularly to a multi-core optical fiber connector using an optical fiber ribbon.

[0002]

2. Description of the Related Art With an increase in transmission capacity, the number of optical fibers has been increased, and a tape core for holding a plurality of optical fibers at once has been developed. As an optical fiber connector for connecting this tape core at a time, Japanese Patent Application Laid-Open
A multi-core optical fiber connector using a V-groove or molding as disclosed in JP-A-56619 and JP-A-3-179405 is known. FIG. 9 shows a perspective view of an example of a conventional optical fiber connector for a tape core. The ferrule 24 of the multi-core optical fiber connector has multi-core ferrules 25 formed at equal intervals to fix the strands of the optical fiber ribbon 26. By fitting the guide pins 29 into the alignment holes 28, it is possible to connect the optical fiber strands of the opposed multi-core ferrule with high accuracy.

[0003]

In the structure of the conventional multi-core optical fiber connector, the multi-core ferrule 24 has a multi-core ferrule small diameter hole 25 formed therein. The strand is adhesively fixed, and the end face 27 of the ferrule is polished to a mirror surface. Alternatively, as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 3-179405, the wire portion 2 of the optical tape is inserted into a V-groove formed on a ceramic or the like.
9 has an adhesively fixed configuration.

[0004] In order to assemble such an optical fiber connector, it is necessary to remove excess adhesive from the ferrule end face portion 27 after bonding and fixing the optical fiber, and to grind the tip of the optical fiber to a mirror surface. Therefore, when assembling an optical fiber connector at a site where an optical fiber is laid, it is necessary to bring a polishing machine to the site. Therefore, there is a problem that an optical fiber connector cannot be assembled in a place where it is difficult to secure a power supply and a space in a building or on a road. Further, there is also a problem that the time required for polishing is long and the assembling time is also long.

Further, the conventional multi-core optical fiber connector has a structure in which the optical fiber ribbon is fixed to the ferrule with an adhesive. Normally, the adhesive has a time limitation in use called a pot life, and the assembling time may be limited by the pot life. Also,
Even if a photo-curable adhesive is used, it is usually necessary to block light, so that the storage and use of the adhesive are limited. Furthermore, in the case of a thermosetting adhesive, a thermosetting device is required, and in the case of a photocuring adhesive, a light irradiator is indispensable, which also causes a problem in workability in construction on site. .

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the conventional optical fiber connector, and has as its object to provide a simple and easy-to-assemble multi-core optical fiber connector and a method of connecting optical fibers using the same.

[0007]

In order to solve the above-mentioned problems, a multi-core optical fiber connector according to the present invention has a short optical fiber housed in a multi-core ferrule in advance, and a rear end of the short optical fiber is connected to the ferrule. Popping out. The protruding portions of the short optical fibers are respectively arranged on arrangement grooves formed at predetermined intervals and fixed in advance. An optical matching agent (matching agent) is applied to the rear end of the short optical fiber. On the other hand, the end face side has a mirror-polished and sub-assembled structure. In the arrangement groove of the sub-assembled ferrule, an optical fiber of a tape core is arranged in a bare state so that the front end thereof abuts against the rear end surface of the short optical fiber. Then, the tape core is fixed by a cover that fits into a case in which the arrangement grooves are arranged.

As described above, since the ferrule end face has already been polished to a mirror surface, it is only necessary to abut each of the multi-core optical fibers of the tape core against the corresponding short optical fiber on the arrangement groove. Thereafter, the optical fiber connector can be assembled by fixing the multi-core optical fiber on the line side by using a fastening mechanism for pushing in. here,
Since the adhesive is not used not only between the optical fibers but also when fixing the multi-core optical fiber, the assembly can be easily performed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-core optical fiber connector according to the present invention will be described.
This will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of a multi-core optical fiber connector according to the present invention. FIG. 2 is a longitudinal sectional view of FIG.

The multi-core ferrule 3 has a short optical fiber 2
Small holes 1 having an inner diameter slightly larger than the outer diameter of are formed at equal intervals. In the present embodiment, a quartz optical fiber which is generally used is used for the short optical fiber 2 and its outer diameter is 125 μm, so that a small-diameter hole of 126 μm is formed. In this embodiment, a four-core optical fiber connector will be described.

Four short optical fibers 2 are inserted into the small-diameter holes 1 and fixed by bonding. The end face side is mirror-polished diagonally with the end face portion 4 of the multi-core ferrule 3 in order to prevent reflection of light after connection. The end face of the short optical fiber 2 has a structure protruding from the end face part 4 of the multi-core ferrule 3 on the same plane or by about sub-μm. On the other hand, the rear end face of the short optical fiber 2 is continuous with the multi-core ferrule 3 and is fixed in the middle of an alignment groove 5 formed at equal intervals so that the optical axis of the short optical fiber 2 is equal to that of the short optical fiber 2. , Its end face is cut into a mirror-like shape. The end face of the short optical fiber 2 on the side of the end face portion 4 can be mirror-polished into a convex shape. Also, the rear end face may be mirror-polished instead of cut.

An optical matching agent (matching agent) having a refractive index substantially equal to the refractive index of the optical fiber core of 1.42 is applied to the rear end face of the short optical fiber 2.

On the other hand, as shown in FIG. 1, the multi-core ferrule 3 has a shape in which the upper surface is cut from the middle to the rear end surface. It has a U-shaped cross section and an open top so as to cover this rear part. Here, a case 7 formed of an elastic body is fixed. Further, a hook 10 is provided on the inner peripheral side surface of the upper end of the elastic case 7.
Are formed.

The cover 8 has a structure that can be fitted inside the elastic band case 7 so that the tape core 9 can be fixed inside from the upper part of the multi-core ferrule 3. Further, the hook 10 of the elastic body case 7 is formed with a recess 11 which can be fitted. A block-shaped elastic body is arranged on the bottom surface of the cover 8, and presses the strand portion 12 of the tape from the upper surface at the position of the rear end surface of the short optical fiber 2.
Thus, the short optical fiber 2 and the optical axis are aligned and fixed in the alignment groove 6.

A core fixing groove A15 and a core fixing groove B16 are formed in the elastic body case 7 and the cover 8, respectively, so that the core part 14 of the tape core 9 can be included therein. In the middle of each groove, the core 1 of the tape core 9
4 so that they can be fixed by crimping by fitting.
18 are formed.

Next, a method for connecting multi-core optical fibers using the multi-core optical fiber connector of the present invention will be described. To assemble and connect the multi-core optical fiber connector of the present invention at an optical fiber installation site or the like,
First, the end of the core wire of the tape core wire 9 to be assembled is removed by a predetermined amount, and the end face A19 is cut into a mirror surface.
Thereafter, the fiber is slid along the groove 5 of the multi-core ferrule 3 toward the end face 4 of the multi-core ferrule 1, and the end face B 2 of the short optical fiber 2 is slid.
Hit 0. And cover 8 is multi-core ferrule 3
Into the elastic case 7 from above. By the abnormal work, the multi-core optical fiber connector can be assembled.

FIG. 3 is a vertical cross-sectional view when the tape core is assembled, and FIG. 4 is a cross-sectional view of a portion A in FIG. Figures 3 and 4
As shown in FIG. 5, the convex portions A17 and B18 are formed with a vertical front end and a wedge-shaped oblique end so that the tape core wire 9 does not easily come off by pulling. . The cover 8 is, as shown in FIG.
Stoppers 21 are formed on the left and right sides of the block-shaped elastic body 13, and function as stoppers so that the strand portions 12 and the core portions 14 of the tape core wire 9 are not crushed more than necessary. The connection between the tape core 9 and the short optical fiber 2 has a structure in which an optical matching agent (matching agent) 6 is fixed to the end face of the short optical fiber 2. The optical matching agent can prevent reflection from occurring at the connection point between the multi-core optical fiber and the short optical fiber.

The multi-core ferrule 3 is molded from plastic, and the multi-core ferrule 1 is integrally formed in a cylindrical shape. Further, as shown in FIG. 5, the alignment groove 5 has a structure having a semicircular groove 5a having the same diameter as the multi-core ferrule 1 and formed by integral molding of the same mold. As shown in FIG. 6, when the short optical fiber 2 fixed to the multi-core ferrule 1 is arranged, this alignment groove is a V-groove formed so that the optical axis of the multi-core optical fiber coincides with the optical axis. It may be.

In the multi-core optical fiber connector of the present invention, in addition to the above-described embodiment, the multi-core ferrule 3 can be formed of silicon or ceramics. In this case, the ferrule 3 for multicore also has a shape in which the ferrule end face side 4 is divided into two upper and lower portions in a plane horizontal to the axis of the optical fiber, and the short optical fiber is inserted into the alignment groove 5 having the V groove 5a. 2 is fixed. The V groove 5a can be formed by precision machining, but can also be formed by anisotropic etching using a silicon substrate.

The elastic body case 7 can be formed using an elastic metal or plastic. The block-like elastic body 13 is made of rubber such as silicon rubber,
Is made of an alloy 13a such as an aluminum alloy having a shape as shown in FIG.

FIG. 8 is a cross-sectional view showing a second embodiment of the multicore optical fiber connector according to the present invention. In this embodiment,
The fit between the cover and the case is upside down. The cover 22 has a U-shape and is open at the lower surface, and is formed of an elastic body. The cover 22 is assembled by covering the multi-core ferrule 23. The hook 10b formed at the lower end of the cover 22 is a multi-core ferrule 2
3 is fixed by fitting it into the recess 11b. In the above-described embodiment of the present invention, it is needless to say that an adhesive can be used in combination in order to strengthen the fixation of the tape core wire.

[0023]

As described above, the multi-core optical fiber connector of the present invention has a structure in which the ferrule has a short optical fiber built in the multi-core ferrule in advance and the ferrule end face is polished to a mirror surface. Even at the time of on-site assembly at a laying construction site or the like, a polishing step is not required at all, so that multi-core optical fibers can be easily connected.
For this reason, not only can the working time be greatly saved, but also in places where it is difficult to bring in a polishing machine, the multi-core optical fiber can be assembled to the tape.

Further, since the optical fiber and the optical fiber are fixed by fitting the elastic case and the cover, an adhesive is not required for fixing the optical fiber, and the optical fiber and the core can be easily and easily fixed. The optical fiber connector can be assembled.

Since the optical matching agent for preventing reflection at the connection point is in the ferrule, it is hardly affected by outside. Also, when the optical fiber connector is attached or detached, it is not necessary to apply the optical matching agent again. Furthermore, the end face of the ferrule is mirror-polished diagonally or convexly together with the short optical fiber, and the end faces of the optical fibers are directly abutted, so that a connection with low loss and low reflection can be made.

Further, even if the cover is pressed down, the optical fiber is provided with a stopper, so that no extra force is applied and stable assembly can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a multi-core optical fiber connector of the present invention.

FIG. 2 is a longitudinal sectional view of FIG.

FIG. 3 is a longitudinal sectional view showing a structure after assembly of one embodiment of the multicore optical fiber connector of the present invention.

FIG. 4 is a transverse sectional view of a portion A in FIGS. 3 and 4;

FIG. 5 is a cross-sectional view of an alignment groove having a semicircular shape used in the multicore optical fiber connector of the present invention.

FIG. 6 is a cross-sectional view of an alignment groove having a V-shaped groove used in the multicore optical fiber connector of the present invention.

FIG. 7 is a cross-sectional view of an aluminum alloy block-shaped elastic body used for an alignment groove of the multicore optical fiber connector of the present invention.

FIG. 8 is a cross-sectional view of a multi-core optical fiber connector according to a second embodiment of the present invention.

FIG. 9 is a perspective view of a conventional multi-core optical fiber connector.

[Explanation of symbols]

 Reference Signs List 1 small diameter hole 2 short optical fiber 3 multi-core ferrule 4 ferrule end face 5 alignment groove 5a semicircular groove 5b V groove 6 optical matching agent 7 elastic body case 8 cover 9 tape core wire 10 hook 10b hook 11 recess 11b recess DESCRIPTION OF SYMBOLS 12 Element part 13 Block-shaped elastic body 13a Aluminum alloy 14 Core part 15 Core fixing groove A 16 Core fixing groove B 17 Convex part A 18 Convex part B 19 End face A 20 End face B 21 Stopper 22 Elastic body cover 23 Many Core ferrule 24 Multi-core ferrule 25 Multi-core ferrule 26 Tape core wire 27 Ferrule end face 28 Alignment hole 29 Guide pin

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-278004 (JP, A) JP-A-55-108609 (JP, A) JP-A-58-75104 (JP, A) JP-A 62-78104 203106 (JP, A) JP-A-62-269108 (JP, A) JP-A-2-146605 (JP, U)

Claims (12)

(57) [Claims] 1. A plurality of short optical fibers, and a hole having an inner diameter slightly larger than the outer diameter of the short optical fibers are formed in parallel, the plurality of short optical fibers are respectively inserted and fixed, and a front end face is formed. A multi-core ferrule machined to match the end face of the short optical fiber, and having a plurality of arrangement grooves, portions of the short optical fiber protruding from the rear end face of the multi-core ferrule are aligned in the respective arrangements. An optical fiber arranging means, comprising a plurality of optical fiber strands, a tape core optical fiber in which the end face of the optical fiber strand is respectively butted against the rear end face of the short optical fiber arranged in the arrangement groove, A multi-core optical fiber connector comprising: the short optical fiber; and fixing means for pressing the optical fiber strand from above the optical fiber arrangement means. 2. The multi-core optical fiber connector according to claim 1, wherein an outer diameter of said short optical fiber is substantially equal to an outer diameter of said optical fiber. 3. The multi-core optical fiber connector according to claim 2, wherein said fixing means includes a fastening means for fastening to said ferrule. 4. The multi-core optical fiber connector according to claim 2, wherein an optical matching agent is arranged between a rear end face of said short optical fiber and said optical fiber. 5. The multi-core optical fiber connector according to claim 2, wherein the arrangement groove has a semicircular shape substantially equal to an outer diameter of the short optical fiber. 6. The multi-fiber optical fiber connector according to claim 2, wherein said array groove is a V-groove. 7. The multi-fiber optical fiber connector according to claim 6, wherein said optical fiber arranging means comprises a silicon substrate. 8. The multi-core light according to claim 2, wherein the rear end face of the short optical fiber and the front end face of the optical fiber are slanted with respect to a center line of the optical fiber. Fiber connector. 9. The multi-core optical fiber connector according to claim 2, wherein the rear end face of the short optical fiber and the front end face of the optical fiber have a convex shape. 10. The multi-core optical fiber connector according to claim 3, wherein said fixing means includes a rear end of said multi-core ferrule and has a U-shaped cross section opened upward. . 11. The multi-core ferrule according to claim 11, wherein the fastening means has an elastic body case in which a hook is arranged on an inner peripheral side surface of an upper end of the fixing means, and a concave portion which fits the hook on a side face. 11. The multi-fiber optical fiber connector according to claim 10, further comprising a cover that is fitted to the taken portion from above and fixed to the elastic body case. 12. The multi-fiber optical fiber connector according to claim 3, wherein said fastening means includes a cover having a hook for holding a bottom surface of said optical fiber arranging means.