JPH0440166Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of an optical fiber multi-core connector for collectively butt-connecting a plurality of optical fibers.

[Prior Art and Problems] For example, as shown in FIG. 5, a tape-type core wire is made by arranging about 5 to 10 optical fibers 11 in parallel and covering them all together with a common coating to form a tape shape. 10 has recently attracted attention as a subscriber cable guard wire for public telephone lines because it can be stacked to form a high-density aggregate.

This type of cable inevitably has many connection points, and there is a strong desire to develop a connector that is simple, compact, and has low connection loss, and several proposals have already been made.

FIG. 5 is an explanatory diagram showing a specific configuration of such a conventional connector. The connector includes a base body 1 having a plurality of V-grooves 2 for receiving optical fibers in the central part.
and a holding plate 3 which presses down the optical fibers 11, 11' which are butt arranged in the V-groove 2 from above the V-groove, and a stop plate which holds and fixes the tape-shaped core wires 10, 10' to be connected to the base body 1. 4 and 4'. With such a connector, tape type core wire 1
0 and 10', the optical fibers 11 and 11' to be connected are stripped and exposed,
The ends of the optical fibers are trimmed so that their end faces abut each other in the respective grooves of the V-grooves 2 formed in the number corresponding to the number of cores of the optical fiber, and the core fibers 1
0 and 10' are temporarily fixed using retaining plates 4 and 4' and screws 5. At this temporary fixing stage, the core wires 10, 10'
Tighten the screws so that they can be moved in the axial direction.

At the abutting portions of the optical fibers 11 and 11' arranged abutting in the V-groove 2, a gap of about several mm is initially provided, and a refractive index matching agent is dripped in between to improve connection loss. . Next, the optical fibers 11 and 11' in the V-groove 2 are held down with the holding plate 3 from above, and the holding plate 3 is lightly tightened with screws to the extent that the optical fibers do not come off from the V-groove 2, and then the optical fibers 11 and 11' are held in the temporarily fixed state. One stop plate 4'
to firmly fix the tape-shaped core wire 10'. In this state, one of the tape-shaped core wires 10, which is still temporarily fixed, is moved by pushing it in the axial direction, and each optical fiber 1 is inserted into the V-groove 2.
The end surfaces of 1 and 11' are fully abutted against each other, and the holding plate 3 is firmly fixed in that position.
Finally, the connection is completed by tightening the stopper plate 4 and firmly fixing the tape-shaped core wire 10 to the base body 1.

However, the V-groove 2 of the above-mentioned conventional connector is made of metal, and in that case, the optical fiber 1 to be butt-connected is
There is no problem if 1 and 11' have the same diameter, but if the outer diameters of one optical fiber 11 and the other optical fiber 11' are different as shown in FIG.
The centers of each are shifted by e in the figure when they are butted. For example, one optical fiber 11 has an outer diameter of 124 μm and the other optical fiber 11' has an outer diameter of 124 μm.
If it were 126 μm, the center would be shifted by approximately 2 μm. If the optical fiber to be connected is a GI type fiber with a core diameter of about 50 μm, the above-mentioned results can be achieved by using the refractive index matching agent.
Even if there is a deviation of about 2 μm, the connection loss is reduced to 0.1 dB.
You can stop below. However, when the object to be connected is a single mode fiber with a core diameter of about 10 μm, the connection loss reaches as much as 0.5 dB due to the above-mentioned 2 μm deviation.

Recently, single-mode fibers are entering the stage of full-scale practical use for long-distance, high-capacity transmission, but the above-mentioned loss of 0.5 dB in such single-mode fibers is equivalent to an optical fiber length of 1 km.
This corresponds to a transmission loss of 100%, which significantly impairs the inherent long-distance transmission characteristics of single-mode fiber.

The above example explained the case where the fiber outer diameter difference = 2 μm, but the outer diameter tolerance of today's normal fibers is set at 125 ± 3 μm, and it is necessary to consider the maximum outer diameter difference of 6 μm. In this case, it is inevitable that the connection loss will be extremely large, and a situation may occur where the V-groove connector becomes unusable.

[Purpose of the invention] The present invention eliminates the drawbacks of the conventional technology as described above, and even if there is a difference in the outer diameter of the optical fibers to be connected, the difference in outer diameter is absorbed and the occurrence of axis misalignment is prevented. However, it is an object of the present invention to provide a new optical fiber connector that can always achieve a good connection.

[Summary of the invention] That is, the gist of the invention is that the V-groove portion for receiving the optical fiber and the inner surface of the holding plate are made of an elastic material such as rubber or plastic, and each V-groove is made independent. Therefore, when optical fibers with different outer diameters are held down by the holding plate, the fiber with the larger outer diameter sinks into the groove structure due to elastic deformation of the groove and the inner surface of the holding plate. This makes it possible to minimize the displacement of the center of abutment and the occurrence of connection loss.

[Examples] The present invention will be described below based on Examples.

FIG. 1 shows that an optical fiber 11 with a small outer diameter and an optical fiber 1 with a large outer diameter are connected by a connector according to the present invention.
FIG. 1 is an explanatory cross-sectional view showing a state in which they are butt-connected. In the present invention, the V-groove 2 is not made of metal as in the conventional example, but is made of an elastic body 2a made of urethane rubber or the like provided on the base body 1. The V-groove surface side of the holding plate 3 is also made of the same elastic material 3a having the same degree of deformation.

As described above, the inner surfaces of the V-groove 2 and the holding plate 3 are made of elastic bodies 2a and 3a, and as shown in FIG.
When pressed from above the abutting portion of 11', the elastic body 2a or 3 made of the optical fiber 11 with a small outer diameter
There is almost no deformation of a. However, on the side of the optical fiber 11' having the larger outer diameter, the elastic bodies 2a and 3a are deformed by being pressed by the excessively contoured portion of the optical fiber 11', as shown in a typical embodiment in FIG. In other words, the excess outer diameter of the optical fiber 11' sinks into these elastic bodies 2a and 3a and is absorbed. Due to this absorption effect,
The state is equivalent to when optical fibers of the same diameter are butted together, and the misalignment between the centers of optical fibers 11 and 11' is absorbed.
The occurrence of axis misalignment due to the difference in outer diameter as shown in FIG. 6 can be sufficiently eliminated.

In this way, the inner surface of the presser plate 3 is also covered with the elastic body 3a.
With this configuration, it is possible to suppress the occurrence of axis misalignment even when the difference in the outer diameter of the optical fibers is large. Therefore, when both the V-groove 2 side and the holding plate 3 side are made of an elastic body as described above, it is desirable to use the same elastic body material for both sides to ensure the same degree of deformation.

On the other hand, regarding the material of the elastic body itself,
If it is too soft, there will be no pressing effect, and if it is too hard, on the other hand, the absorption deformability will be small and there will be no sufficient absorption effect. According to experiments, Young's modulus is 5
It has been found that using a rubber or plastic elastic body of about 150 kg/mm ² is suitable for the intended purpose.

[Example] In order to confirm the effect of the connector according to the present invention, both a connector with a V-groove and a retaining plate formed of urethane rubber having a Young's modulus of 10 kg/mm ² as shown in FIG. 1, and a conventional connector were tested. Prepare a connector made of metal, with a core diameter of 10 μm and a fiber outer diameter.
Same core diameter as 124μm single mode fiber
A single mode fiber of 10 μm and a fiber outer diameter of 127 μm was connected using a refractive index matching agent, and the connection loss of each was measured. the result,
While the connector with the conventional configuration caused a connection loss of 0.5 dB or more, the connector according to the present invention only caused a connection loss of 0.1 dB or less. It has become clear that the street has excellent effects.

FIG. 3 shows an embodiment of the connector according to the present invention, in which the V-grooves 2, 2 are made of an elastic body 2a, and there are gaps 2b, 2b between each V-groove 2, 2.
By forming the V-grooves, each V-groove is configured to be able to deform independently. By separating the V-grooves 2, 2 independently by the gaps 2b, 2b, mutual interference does not occur in the deformation of the groove inner surfaces by the optical fibers 11, 11 when the presser plate 3 is pressed, and each groove is Since it deforms freely and independently, excellent connection performance can be expected even when the outer diameter of the optical fiber varies.

The same thing applies to the elastic bodies 2a, 2a as shown in FIG.
is constructed as a separate object, and this is used as the partition wall 1 of the base 1.
This can also be said by forming independent grooves 2 and 2 by partitioning them by a and 1a, and there is no influence between adjacent grooves, and the grooves are extremely low and unaffected by environmental temperature, etc. Experiments have confirmed that a lossy connection can be achieved.

In the above, the shape of the groove is a typical V
Although the groove was explained as an example, it is not limited to a perfect V shape, but can be modified as necessary such as a U-shaped cross section or a semi-elliptical shape, and as long as the connection effect is the same, it is within the scope of the technical idea of the present invention. Needless to say, it is. Furthermore, the core wires to be connected are not limited to tape-shaped ones, and may be of other shapes such as circular ones.

[Effects of the Invention] As described above, the connector according to the present invention can exhibit the following excellent effects.

(1) Optical fibers with different outer diameters, especially single mode fibers with small core diameters, can be connected with extremely low connection loss.

(2) There is no need to prepare any special equipment for connection, and connection can be made extremely simply and quickly, resulting in significant reductions in time and cost.

(3) Since the connector itself has an automatic centering action, the connection work is easy and does not require the training of skilled workers as in the past.

(4) According to the optical fiber connector of the present invention, in which each groove provided on the base is separated from each other, the deformation of the inner surface of the groove by the optical fiber when pressing the holding plate is Since each groove is independent, mutual interference due to deformation does not occur in each groove, and a high-performance connection with little connection loss can be achieved even when the outer diameter of the optical fiber varies.

[Brief explanation of the drawing]

1 and 2 are explanatory cross-sectional views showing how optical fibers with different outer diameters are connected by the connector according to the present invention, and Figures 3 and 4 show an embodiment of the optical fiber connector according to the present invention. 5 is an explanatory diagram showing a case where a conventional connector is used to connect optical fibers, and FIG. 6 is an explanatory sectional view showing a state in which optical fibers having different outer diameters are connected by a conventional connector. 1... Base body, 1a... Partition wall, 2... V groove,
2a...Elastic body, 2b...Gap, 3...Press plate,
3a...Elastic body, 10, 10'...Tape, 11,
11'...Optical fiber.

Claims (1)

[Claims for Utility Model Registration] 1. In a connector that cuts a plurality of optical fibers at once, butts them together in a groove provided on a base body, and presses them with a holding plate from above the groove to butt and connect them all at once, An optical fiber connector characterized in that both the groove portion and the inner surface of the holding plate are made of an elastic body having an equal degree of deformation, and gaps are provided on both sides of the groove to make each groove independent. 2. In a connector that cuts a plurality of optical fibers at once, abuts them in a groove provided on a base, and presses a presser plate from above the groove to connect them all at once, the groove and the inner surface of the presser plate are An optical fiber connector characterized in that both of the grooves are made of elastic bodies having the same degree of deformation, and that partition walls are provided on both sides of the groove to make each groove independent.