JPH0782136B2 - Optical fiber cutler, its manufacturing method and manufacturing apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optical fiber coupler and a manufacturing method and manufacturing apparatus thereof. More specifically, the optical fiber coupler according to the present invention relates to an optical fiber coupler having uniform characteristics obtained by collectively producing a plurality of optical fiber couplers, and a method and apparatus for producing the same.

2. Description of the Related Art With the recent progress in optical signal transmission technology, many types of optical communication systems or optical systems such as optical sensor systems have been proposed and put into practical use. As a general subject of signal transmission technology, approaches to high-density and high-speed signal transmission, stabilization of characteristics of various elements, and cost reduction are always required in optical systems.

A tape-shaped multicore optical fiber has been practically used in recent years as one implementation of high-density signal transmission. As shown in the sectional view of FIG. 7, this tape-shaped multi-core optical fiber has a plurality of optical fiber element wires, each of which includes a core 71, a clad 72, and a protective coating 73 formed coaxially, on one array plane. They are arranged in parallel with each other and are surrounded by a covering layer 74 to be integrally formed. Such a tape-shaped multicore optical fiber is intended to physically increase the transmission line density per unit cross-sectional area in the optical fiber cable and physically improve the transmission density of the optical signal.

By the way, when an optical fiber is used as a member for signal transmission, an optical signal propagating in one transmission path is branched into a plurality of transmission paths, or two or more kinds of light propagated from a plurality of transmission paths. An optical coupler that superimposes signals in one transmission line is essential. The optical coupler having such a function is a member that is very frequently used in constructing various optical systems using optical signals, and is also an extremely important member. In particular, an optical fiber coupler using an optical fiber can be easily coupled with an optical fiber widely used as an optical transmission line, and its frequency of use is rapidly increasing with the development of various optoelectronic transmission systems.

Bee. S. Kawasaki, K. Oh. Hill and Gee. Ramon (BSKawasaki, KOHill and RGLamont)
Opt.Lett., Vol. 6, "Optical Communication", 1981.
Biconical-Taper Single-Mode Fiber disclosed in Vol.6, 1981).
ber Coupler).

FIGS. 8 (a) to 8 (c) are views for explaining the configuration and manufacturing method of this conventionally known optical fiber coupler. This optical fiber coupler is manufactured as follows.

That is, as shown in FIG. 8 (a), first, the protective coating is removed to form two optical fibers 81 having only the core 84 and the clad 85.
Place 82 in parallel with each other. Subsequently, as shown in FIG. 8 (b), the central portions 83a of the optical fibers 81 and 82 are heated, and both are fused at this position. Further, when tension is applied to the optical fibers 81 and 82 while heating the fusion-bonded portion so that the optical fiber maintains the softened state, the optical fibers 81 and 82 are stretched at the welded portion 83b, and the core 84 approaches each other. Then, the propagating light leaks between them. In this way, an optical fiber coupler as shown in FIG. 8 (c) can be obtained in which the welding / extending part 83b is the light mixing / branching part.

FIG. 9 is a diagram schematically showing the structure of an apparatus disclosed in Japanese Patent Application No. 59-88168 as an apparatus for producing the above-mentioned optical fiber coupler.

This device is a device for producing an optical fiber coupler by fusing and extending two optical fibers at the center, and a pair of fixing devices 93a for fixing each optical fiber 91 and a predetermined section of 91. -93b, 94a-94b, and a pair of optical fibers 91, 92 fixed by these, near the center of the optical fiber 91, 92 to position the fusion / stretched portion of the optical fiber and at the same time to have a function of applying tension to the optical fiber. Extender 95a, 95b
Is equipped with.

That is, the fixing devices 93a-93b and 94a-94b hold the optical fibers 91 and 92, respectively, so that tension can be applied by the stretching tables 95a and 95b described later. The extension tables 95a and 95b are provided with two pins 96a and 96b provided at intervals such that the optical fibers 91 and 92 are closely attached to each other in the central portion.
Horizontal position adjustment device 97a, 97b movable in the horizontal direction perpendicular to 92
And vertical position adjusting devices 98a and 98b capable of gripping the optical fibers 91 and 92 and movable in a vertical direction perpendicular to the optical fibers 91 and 92, and temporary fixing devices 99a and 99b of the optical fibers. .

In this device, first, the two optical fibers 91 and 92 from which the coating of the predetermined length is removed are fixed to the optical fiber fixing devices 93a-93b and 94a-94b with relatively weak tension. The optical fibers 91, 92 are further gripped by the extension tables 95a, 95b near the middle of the fixing devices 93a-93b, 94a-94b. That is, the horizontal position adjusting devices 97a and 97b are in close contact with each other in the same plane as the surfaces of the drawing tables 95a and 95b, and the vertical position adjusting devices 98a and 98b do not twist the optical fibers 91 and 92. Is positioned as. The optical fibers 91 and 92 are fixed by temporary fixing devices 99a and 99b so as to maintain this position, and in this state, the central portions of the optical fibers 91 and 92 are fused by a heating device (not shown). Then, the optical fiber 9
While continuing the heating to such an extent that the softened state of 1 and 92 is maintained, the stretching tables 95a and 95b are separated from each other and tension is applied to perform stretching.

Thus, the optical fiber coupler as shown in FIG. 8 (c) is manufactured.

Problems to be Solved by the Invention The manufacturing operation of the conventional optical fiber coupler as described above is an extremely precise operation. That is, for example, the force applied to the optical fiber for fixing or stretching is about several g at the maximum, and the length of the fused portion of the optical fiber is also about several mm. Furthermore, factors such as the twist of each optical fiber also affect the characteristics of the optical fiber coupler. The load or accuracy to this extent is a level that easily changes due to the friction of each member constituting the apparatus, and therefore various adjustments to each optical fiber are extremely delicate. It is virtually impossible to make such adjustments only by operating the device.In practice, predetermined light is injected from one end of the optical fiber being manufactured, and fusion or drawing is performed while monitoring this at the other end. By doing, the characteristics of the product are made uniform.

However, as mentioned above, an enormous number of optical fiber couplers are required to build an optical system, and performing the above-mentioned operations on each of these optical fiber couplers increases the productivity of the optical fiber couplers. Was extremely bad.
Further, it goes without saying that it is also extremely disadvantageous in terms of cost, and eventually, the practicality of the optical fiber that should replace the metal cable has been significantly impaired.

Such a problem is particularly remarkable when a device such as the above-mentioned tape-shaped multi-core optical fiber is used, and not only the productivity of the optical fiber coupler is low, but also its use is extremely inconvenient. That is, when applying an optical fiber coupler to a system using a tape-shaped multi-core optical fiber, first, the work of producing optical fiber couplers by the number of optical fiber strands to be coupled is repeated, and further, the optical fiber coupler is It is necessary to connect both ends of each to each core of the tape-shaped multi-fiber optical fiber. Furthermore, since the extra length of the optical fiber required for the coupling work and the package of each optical fiber coupler are provided, it is extremely difficult to accommodate the tape-shaped multi-core optical fiber coupled by the optical fiber coupler. A large volume was needed.

As described above, the conventional optical fiber coupler is extremely poor in productivity and operability, and greatly impedes practical use of the optical fiber.

Therefore, an object of the present invention is to provide a novel optical fiber coupler capable of easily producing a plurality of ones having uniform characteristics,
It is to provide a manufacturing method and a manufacturing apparatus for the optical fiber coupler.

Means for Solving the Problems That is, according to the present invention, a plurality of optical fibers whose protective fiber is exposed in a predetermined section at the same position in the longitudinal direction to expose the optical fiber strand are provided. The first optical fiber group is formed by arranging the portions of the strands so as to be parallel to each other on the same plane, and the first optical fiber is placed on a predetermined plane parallel to the arrangement surface of the first optical fiber group. A plurality of optical fibers in which the protective coating in a predetermined section is removed at the same position in the longitudinal direction as the fiber group to expose the optical fiber element wire, and the exposed optical fiber element wire portions are the first optical fiber group. Of the exposed optical fiber strands are arranged in parallel and aligned at the same pitch to form a second optical fiber group, and the corresponding exposure of each of the first and second optical fiber groups is performed. The adhered optical fiber strands In this state, the optical fiber strands are collectively heated to fuse the corresponding optical fiber strands of the first and second optical fiber groups, and then stretched to simultaneously form a plurality of optical fiber couplers. A method for manufacturing an optical fiber coupler is provided which is characterized in that the optical fiber coupler is formed.

According to the manufacturing method of the present invention, a plurality of optical fibers each having a core and a clad are integrally formed with a protective coating so that a pair of tape-shaped multi-core optical fibers are fused together and stretched to form an optical fiber. It can be suitably applied to manufacture a coupler.

Further according to the present invention, arranged in parallel on the same plane,
A first optical fiber group formed by removing a protective coating of a predetermined section at the same position as the adjacent optical fibers, and the first optical fiber group on a predetermined plane parallel to the array surface of the first optical fiber group. A second optical fiber group which is arranged in parallel with the optical fiber group at the same pitch, and which is the same as the first optical fiber group and has the protective coating of a predetermined section removed at the same position as the adjacent optical fibers; In the predetermined section where the protective coating is removed, the first
Provided is an optical fiber coupler, wherein the optical fibers of the optical fiber group and the second optical fiber group are fused and stretched by corresponding optical fibers to form respective light mixing / branching portions. To be done.

At least a part of the first optical fiber group and / or the second optical fiber group is a tape-shaped multicore optical fiber in which a plurality of optical fibers each having a core and a clad are integrally formed by a protective coating. Alternatively, the first optical fiber group and / or the second optical fiber group may be a part of a tape-shaped multicore optical fiber in which a plurality of optical fibers each having a core and a clad are integrally formed by a protective coating. May be

Furthermore, according to the present invention, the protective coatings of the optical fibers corresponding to the first optical fiber group and the second optical fiber group are removed, and the exposed portions of the optical fiber element wires are joined to form a plurality of optical fiber couplers. And a second holding means for holding the exposed portions of the optical fiber wires of the first optical fiber group at a predetermined pitch and parallel to each other on one plane. Second holding means for holding the exposed optical fiber strand portions of the group so as to be aligned in parallel and at the same pitch as the corresponding exposed optical fiber strand portions of the first optical fiber group. And means for bringing the corresponding exposed optical fiber strands of the first and second optical fiber groups into close contact with each other, and the optical fiber elements of the first and second optical fiber groups brought into close contact with each other. A means for heating and fusing the wires together, and a means for stretching the fused optical fiber element wire,
Provided is an apparatus for manufacturing an optical fiber coupler, which is characterized by simultaneously forming a plurality of optical fiber couplers.

According to a preferred aspect of the present invention, each of the first and second holding means includes a flat upper surface located on the same plane for supporting the optical fiber group thereon, and is provided in an axial direction of the optical fiber group to be supported. It is equipped with a pair of mounts that can move relative to each other.

Further in accordance with a preferred aspect of the present invention, the first and second holding means comprise means for cooperating with the pair of mounts to fix a part of the optical fiber group on the mounts.
Further, the contact means comprises means for pushing down and holding the optical fiber group on the upper surface of each of the pair of mounts.

Further in accordance with a preferred aspect of the present invention, the heating and fusing means is disposed at an intermediate position between the pair of mounts and is parallel to the array surface of the optical fiber groups held on the mounts and The heating means extends in a direction perpendicular to the axial direction and simultaneously heats the same longitudinal position of the optical fiber group held on the frame.

Further in accordance with a preferred aspect of the present invention, means for holding the optical fiber strands of the first and second optical fiber groups at a predetermined distance from each other is provided on the upper surface of each of the pair of mounts.

Further in accordance with a preferred aspect of the present invention, said stretching means each comprises a flat upper surface located on the same plane for supporting said first or second optical fiber group,
The optical fiber group includes a pair of pedestals that can move relative to each other in the axial direction, and means for fixing the fused first and second optical fiber groups on the pair of pedestals.

Operation According to the present invention, a plurality of optical fibers having uniform characteristics can be manufactured at the same time by operating and manufacturing a plurality of optical fibers at the same time. In other words,
The optical fiber coupler manufactured according to the present invention becomes a plurality of products having uniform characteristics by a simple operation as described later.

That is, according to the method for manufacturing an optical fiber coupler of the present invention, two optical fiber groups positioned in parallel on the same plane are brought into contact with each other, and they are collectively heated and fused / stretched. Therefore, various elements related to these operations, that is, variations in lateral pressure or tension with respect to the optical fibers are uniformly applied to all the optical fibers to be alleviated, and the characteristics of the manufactured optical fiber coupler become substantially uniform. .

In addition, since the most time-consuming fusion-bonding / stretching process is collectively performed in the production of optical fiber couplers, the time required to produce a plurality of optical fiber couplers is greatly reduced, and high productivity can be realized. .

Further, it is also possible to use the above-mentioned tape-shaped multicore optical fiber as the material of the optical fiber coupler. In this case, the characteristics of the plurality of optical fiber couplers manufactured at the same time become more uniform. The reason is that the tape-shaped multi-core optical fiber is an integrated structure of a plurality of optical fiber strands having originally uniform characteristics. Furthermore, regarding the problem such as twisting of each optical fiber in the welded portion, This is because it has already been solved when the above is manufactured as a tape-shaped multicore optical fiber. Further, the optical fiber coupler manufactured by using the tape-shaped multi-core optical fiber is a novel element that can collectively combine a plurality of strands of the tape-shaped multi-core optical fiber, and the conventional optical fiber described above. The tape-shaped multicore optical fiber, which could not be achieved by the coupler, can be easily coupled.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the drawings, but the examples disclosed below are merely examples of the present invention and do not limit the technical scope of the present invention. .

Example 1 FIGS. 1 (a) and 1 (b) are diagrams showing the configuration of an optical fiber coupler manufacturing apparatus according to the present invention, and FIG.
Is a plan view of the apparatus seen from above, and FIG. 1 (b) is a side view. The following example is an apparatus for producing an element equipped with five optical fiber couplers by using two 5-core tape-shaped multi-core optical fibers, and FIGS. 1 (a) and 1 (b) show It is shown in a state where a 5-core tape-shaped multi-core optical fiber is attached to the apparatus.

This apparatus comprises a pair of stretching tables 11A and 11B and a heating means 12
It is mainly composed of A and 12B.

The drawing tables 11A and 11B are a pair of fixing means 111A and 111B for fixing a tape-shaped multi-core optical fiber, which will be described later, including an external coating, and a pair of optical fibers each having the coating removed in the horizontal direction. Pin group 112A-113A, 112B-113
B, means for moving each optical fiber element in the vertical direction for vertical positioning, that is, means for closely adhering the optical fiber element 11
Each has 4A and 114B. In addition, the stretching table 11A, 11B
Although the driving means is not shown, this pair of extension tables
The guide members 120A and 120B are configured to be movable in a direction in which they are separated from each other by a uniform driving force. Further, rolls 13A, 13B, 13C, and 13D are provided on one outside of these drawing bases, and the tape-shaped optical fiber core wire, which will be described later, is on the outside of this roll and is not shown. Tension is applied by the traction means.

As the pin groups 112A-113A and 112B-113B, a piano wire having an outer diameter of 123 μm and a length of 2 mm fixed perpendicularly to the surfaces of the stretching tables 11A and 11B was used, and the arrangement interval was 250 μm. Further, the fixing means 111A, 111B and the contact means 114A, 114B are
It is configured such that one plate is pressed against a plurality of optical fiber strands via elastic means to fix or closely attach the strands to the surfaces of the drawing bases 11A and 11B. This is as described below
This is a consideration so that a uniform load is applied to a plurality of optical fiber strands.

Now, the tape-shaped multi-core optical fiber used as the material in this embodiment has a core diameter of 6.5 μm and a cladding outer diameter of 125 μm.
m, a 1.3 μm band single mode optical fiber with a cut-off wavelength of 1.1 μm, coated with urethane or acrylic UV-curable resin to have an outer diameter of 250 μm. , Which is made of urethane or acrylic UV curable resin and has a thickness of about 75 μm.

The operation of producing an optical member having five sets of optical fiber couplers from this tape-shaped terminal optical fiber using the above-mentioned apparatus will be described below.

First, each of the five optical fiber strands 21a, 21b, 21
A pair of 5-core tape-shaped optical fibers 21 and 22 formed of c, 21d, 21e or 22a, 22b, 22c, 22d, 22e and having a length corresponding to XX in FIG. Was removed with polyethylene glycol as well as sulfuric acid.

Subsequently, first, the tape-shaped optical fiber 22 was positioned by the pins 112A-113A, 112B-113B so that the optical fiber element wires 22a, 22b, 22c, 22d, 22e were positioned at equal intervals. Then, the tape-shaped optical fiber 21 is overlaid on the tape-shaped optical fiber 22, and the optical fiber strands 21a, 21b, 21
Pins 112A-113A and 112B-113B were also positioned so that c, 21d and 21e were located at equal intervals.
Due to the pin arrangement described above, the optical fiber strands are separated from each other by approximately 125 μm, and the overall width of the tape-shaped optical fiber is approximately 1.2 mm.

Subsequently, on the side of the stretching table 11A, the tape-shaped optical fibers 21 and 22 are collectively fixed by the fixing means 111A, and the tape-shaped optical fibers 21 and 22 are approximately fixed to the tape-shaped optical fibers 21 and 22 via the roll groups 13A, 13B, 13C, and 13D. A tension of 50 g is applied, and while maintaining this state, the tape-shaped optical fibers 21 and 22 are fixed by the fixing means 111B on the drawing table 11B side. That is, the tape-shaped optical fiber is fixed between the drawing stands 11A and 11B while maintaining a tension of about 50 g. During these operations, the stretching table
11A and 11B are fixed so as not to move.

Next, each of the optical fiber strands of the tape-shaped optical fibers 21 and 22 is closely contacted so that the respective corresponding optical fiber strands, that is, in the present embodiment, the respective optical fiber strands respectively corresponding to the vertical direction are closely attached. The means 114A and 114B are operated.
That is, by pressing down the contact means 114A and 114B downward, the respective optical fiber wires corresponding to the top and bottom are 21a-22a, 21b-22b, 21c-22c, 21d-22d, 21 which are in close contact with each other.
Create a set of e-22e. In FIG. 1, a part of 114A is cut out to show the state of the optical fiber.

In this way, at the substantially intermediate position between the tape-shaped optical fiber drawing bases 11A and 11B where the array ends and the strands are in close contact,
By the pair of heating torches 12A and 12B arranged above and below, the optical fiber strands 21a-22a, 21b-22b, 21c-22c, 21d-22
d, 21e-22e are heated and fused to each other.

If fusion of each optical fiber strand is confirmed, the output of the heating torches 12A, 12B is reduced, while maintaining a state in which the optical fiber strands can be softened and stretched, the stretching table 11A, 1
Both 1Bs move at a substantially equal speed so as to move away from each other. As will be described later in detail, five sets of optical fiber couplers are produced by simultaneously operating five sets of optical fiber strands in this manner.

During this operation, the emitted light of the semiconductor laser is injected from one end of the optical fiber element wire 21a, while the other end of the optical fiber element wire 21a and the end portion of the optical fiber element wire 21a forming a pair 22a. The characteristics of the optical fiber coupler formed by coupling the light receiving elements 23 and 24 together with the drawing operation were monitored.

That is, at the beginning of the operation, the light receiving element 24 has no output, and the extension length is
Only when the distance becomes 5 mm to 30 mm, the branching action occurs and the light receiving element 24
Appears in the output. Therefore, when the output light intensities of the light receiving elements 24 and 23 are monitored and the stretching / heating is stopped when the desired value is obtained, the optical fiber coupler having the desired characteristics is completed.

FIGS. 2 (a) to 2 (c) show a member in which the five optical fiber couplers completed as described above are integrated, and FIG. 2 (a) is a plan view. 2 (b) is a side view and FIG. 2 (c) is a sectional view taken along line MM. That is, the tape-shaped multicore optical fibers 21, 22
Each optical fiber strand 21a-22a, 21b-22b, 21c-22c, 21
Each of d-22d and 21e-22e forms an optical fiber coupler in the fusion / stretching section 30. It goes without saying that this optical fiber coupler is formed so as to be connected to the tape-shaped optical fiber core wire and is extremely easy to handle. In the actual use, the optical fiber coupler group is reinforced so that external force is not applied to the fusion splicing section 30 and is housed in the container.

FIG. 3 is a graph showing the characteristics of the above-mentioned optical fiber coupler, and shows the coupling rate wavelength characteristics of the optical fiber coupler that mixes or demultiplexes the light of wavelength 1.3 μm and the light of wavelength 1.55 μm. .

It should be noted that this graph is obtained by measuring the above-mentioned optical fiber wires 21a and 22a using the light receiving elements 23 and 24. As can be seen from FIG. 3, this optical fiber coupler has a wavelength
The coupling rate at 1.3 μm is 0.007 and the coupling rate at wavelength 1.55 μm is 0.997, which shows that it has a function of separating or multiplexing light of wavelengths 1.3 μm and 1.55 μm.

Also, when the same characteristics were measured for the other four optical fiber couplers, the coupling rate at the wavelength of 1.3 μm was
0.006 ± 0.001, coupling rate at wavelength 1.55μm is 0.997 ±
In the range of 0.001, it was found that these five optical fiber couplers had uniform characteristics. That is, the slight temperature distribution inevitably generated when the five optical fiber strands are heated and drawn did not actually cause a problem.

As described above, according to the manufacturing method of the present invention, when five sets of optical fiber couplers are manufactured, online measurement of the degree of coupling is performed on any one of the optical fiber couplers. Has the same characteristics.

Regarding the heating method of the coupling portion of the primary side and secondary side optical fiber groups, in the embodiment of FIG. 1, heating from two directions, up and down, was mentioned, but this direction is not particularly limited to up and down. Instead, it is possible in a horizontal direction or in a state where an arbitrary angle is given. On the other hand, as shown in FIG. 1, a fixing method for collectively fixing two pairs of optical fiber strands, which are paired together, is a conventional method even when a single optical fiber coupler of one pair is prepared. Is superior to the device. That is, in such a fixing method, the load is evenly applied to the two optical fiber strands, so that the characteristics of the respective waveguides become uniform, especially when an element that performs 50% branching is manufactured. .

In this embodiment, the movement of the part of the tape-shaped multi-core optical fiber from which the coating is removed in the optical fiber alignment direction (x-axis direction) is fixed using the positioning pin. As long as it has a function of substantially preserving the axial distance between the optical fibers and suppressing the movement of the optical fibers in the x-axis direction, it can be used for manufacturing the optical fiber coupler of the present invention as in the case of the present embodiment. Is.

In the above description, the tape-shaped multicore optical fibers are used as the primary side and secondary side optical fiber groups, but both the primary side and the secondary side optical fiber groups, or either one of the optical fiber groups, Even if a plurality of single-core optical fibers coated with one optical fiber are arranged, a plurality of optical fiber couplers having uniform characteristics can be obtained by the same manufacturing method and apparatus as those in the above-mentioned embodiment. Of course, it can be manufactured.

Example 2 The most common 3 dB optical fiber coupler was manufactured using the 5-core tape-shaped optical fiber coupler manufacturing apparatus shown in FIG. The manufacturing operation and the form of the manufactured optical fiber coupler are basically the same as those in Example 1, except for the stretching operation. That is, as in the first embodiment, as one of the five sets of optical fiber strands, a semiconductor laser beam having a wavelength of 1.3 μm is injected into the optical fiber strand 21a to connect the other end of the optical fiber strand 21a. The optical fiber strand 22a and the end portion on the same side were heated and stretched while being monitored by the light receiving elements 23 and 24.

The branching ratio of the five sets of optical fiber couplers in the optical fiber coupler group thus completed was within 50% ± 1%, and the insertion loss was in the range of 0.05 ± 0.02 dB, and the variation in characteristics was extremely small.

Example 3 FIGS. 4 (a) and 4 (b) show another production example of the optical fiber coupler according to the present invention. FIG. 4 (a) is a plan view and FIG. 4 (b) is N-N. FIG. In this embodiment, only three of the five optical fiber strands of the tape-shaped multi-core optical fiber are coupled as an optical fiber coupler.

That is, a pair of five-core tape-shaped optical fibers 41, 42 are used, and the optical fiber strands 41a, 41b, 41c are respectively connected to the optical fiber strand 4
2c, 42d, and 42e are arranged so as to form a pair, and these optical fiber element wires 41a-e and 42a-e are collectively heated and stretched.

At this time, in addition to the extending portion 43 forming the optical fiber coupler, the optical fiber strands 41d and 41e that are not coupled to other optical strands.
Also, 42a and 42b are also stretched, but the loss for this is extremely small, and it can be considered that there is virtually no effect on the optical transmission characteristics.

Example 4 Here, a case will be described where the present invention is implemented using tape-shaped multicore optical fibers having different numbers of cores.

That is, FIG. 5 (a) and FIG. 5 (b) show another embodiment of the optical fiber coupler according to the present invention in a plan view and a sectional view taken along the line O--O, respectively.
It is manufactured by combining 51 and five-core tape-shaped optical fibers 52 and 53.

6 (a) and 6 (b) show another embodiment of the optical fiber coupler according to the present invention in a plan view and a PP sectional view, respectively, and show a 10-core tape-shaped optical fiber. 61, 62 and 5-core tape-shaped optical fibers 63 and 64
It is made by combining and.

It goes without saying that such a combination of types of optical fibers constituting the optical fiber coupler of the present invention is possible for a tape-shaped multicore optical fiber having an arbitrary number of optical fiber strands, Of course, a single-core optical fiber core wire may be used. Therefore, the type of optical fiber to be fused and drawn may be appropriately selected according to the application.

EFFECTS OF THE INVENTION As described in detail above, the optical fiber coupler according to the present invention can be manufactured by collectively operating a plurality of optical fibers to simultaneously manufacture a plurality of optical fiber couplers having uniform characteristics. . In other words, the optical fiber coupler manufactured according to the present invention becomes a plurality of products having uniform characteristics by a simple operation as described later.

Further, according to the method for manufacturing an optical fiber coupler according to the present invention, two optical fiber groups that are collectively positioned in parallel on the same plane are brought into contact with each other, and these are collectively heated and fused / stretched. Therefore, various factors related to these operations, that is, variations such as lateral pressure or tension with respect to the optical fibers, are uniformly dispersed and act on all the optical fibers in each group, and the characteristics of the optical fiber coupler manufactured also It becomes almost uniform.

Furthermore, if the optical fiber coupler manufacturing apparatus according to the present invention is used, the most troublesome fusion and stretching process in manufacturing the optical fiber coupler can be performed at once, so that a plurality of optical fiber couplers can be manufactured. The time required for is greatly reduced and high productivity can be realized.

The optical fiber coupler and the manufacturing method thereof according to the present invention are particularly advantageous when a tape-shaped multi-core optical fiber is used as a material, and the characteristics of a plurality of optical fiber couplers manufactured at the same time are more uniform. Therefore, the tape-shaped multi-core optical fiber according to the recent trend of communication technology, in which the demand for high-density transmission is increasing, can be utilized as a more practical member.

According to the effects of the present invention, it is possible to realize mass production which could never be realized by the conventional optical fiber coupler manufacturing method, and further, the optical fiber couplers each currently cost 100,000 yen or more. The price of can be reduced to several thousand yen per one. Moreover, the optical fiber coupler according to the present invention has a wide range of applications as a tap for public optical communication and a monitor for a characteristic test circuit because the characteristics of a plurality of optical fiber couplers are uniform.

[Brief description of drawings]

FIGS. 1 (a) and 1 (b) are schematic views showing the construction of an optical fiber coupler manufacturing apparatus constructed according to the present invention. FIG. 1 (a) is a plan view and FIG. 1 (b) is a schematic view. Are side views respectively, FIG. 2 is a diagram schematically showing a configuration of an optical fiber coupler according to the present invention manufactured by the apparatus of FIG. 1, and FIG. 3 is an optical fiber shown in FIG. It is a graph which shows the characteristic of a coupler, FIG. 4, FIG. 5, and FIG. 6, respectively, showing the optical fiber coupler of various aspects of this invention, FIG. 4 (a), FIG. 5 (a) and FIG. FIG. 6 (a) is a plan view of each of those optical fiber couplers, FIG. 4 (b) is a sectional view taken along line N--N of FIG. 4 (a), and FIG. Fig. 5 (a) is a sectional view taken along line O-O, and Fig. 6 (b) is Fig. 6 (a).
7 is a cross-sectional view taken along the line PP of FIG. 7, FIG. 7 is a diagram for explaining the configuration of the tape-shaped multicore optical fiber, and FIGS. 8A to 8C are diagrams showing the configuration of the optical fiber coupler of the prior art and It is a figure explaining the manufacturing method, and FIG. 9 is a schematic plan view which shows the structure of the manufacturing apparatus of the conventional optical fiber coupler. [Major reference numbers] 11A, 11B …… Drawing table 12A, 12B …… Heating torch, 13A, 13B, 13C, 13D …… Roll, 21, 22, 41, 42, 51, 52, 53, 61, 62, 63, 64 ... Tape-shaped multi-core optical fiber, 21a, 21b, 21c, 21d, 21e, 22a, 22b, 22c, 22d, 22e ...
… Optical fiber strands, 23,24 …… Light receiving element, 71 …… Core, 72 …… Clad, 73 …… Protective coating, 74 …… Coating, 81,82,91,92 …… Optical fiber strand, 83a , 83b ... fusion / extension part, 93a, 93b, 93a, 93b ... fixing device, 95a, 95b ... extension table, 97a, 97b ... horizontal position adjusting device, 96a, 96b ... pin, 111A, 111B ...... Core wire fixing device, 112A, 112B, 113A, 113B ...... Pins, 114A, 114B ...... Contact means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Souichi Noda 162 Shirahane, Shirahoji, Tokai-mura, Naka-gun, Ibaraki Prefecture In-house of Ibaraki Telecommunications Research Laboratories, Nippon Telegraph and Telephone Corporation (72) Mitsuhiro Tateda Naka-gun, Ibaraki Prefecture Tokai-mura, Oita, Shirahoji, 162, Shirane, Nippon Telegraph and Telephone Corporation, Ibaraki Telecommunications Research Laboratory

Claims (15)

[Claims] 1. A plurality of optical fibers in which a protective coating in a predetermined section is removed at the same position in the longitudinal direction to expose an optical fiber element wire, and the exposed optical fiber element wire portions are on the same plane. The first optical fiber groups are arranged so as to be parallel to each other to form a first optical fiber group, and at the same longitudinal position as the first optical fiber group on a predetermined plane parallel to the array surface of the first optical fiber group. A plurality of optical fibers whose protective coatings have been removed in a predetermined section to expose the optical fiber strands, each exposed optical fiber strand being a portion of the exposed optical fiber strands of the first optical fiber group. The second optical fiber group is formed by arranging so as to be parallel to and aligned at the same pitch as the above portion, and the corresponding exposed optical fiber strands of the first and second optical fiber groups are in close contact with each other. In this condition, bundle the optical fiber strands together. A method of manufacturing an optical fiber coupler, characterized in that after heating to fuse the respective corresponding optical fiber element wires of the first and second optical fiber groups to each other, they are stretched to simultaneously form a plurality of optical fiber couplers. Method. 2. An exposed portion corresponding to each of the first and second optical fiber groups in a predetermined section where the protective coating is removed by moving one of the first and second optical fiber groups. The method for producing an optical fiber coupler according to claim 1, wherein the optical fiber strands are closely attached. 3. A tape-shaped multicore optical fiber in which at least a part of the first optical fiber group and / or the second optical fiber group is integrally formed by a protective coating with a plurality of optical fibers each having a core and a clad. It is a fiber, The manufacturing method of the optical fiber coupler of Claim 1 or 2 characterized by the above-mentioned. 4. A part of a tape-shaped multi-core optical fiber in which the first optical fiber group and / or the second optical fiber group are integrally formed by a protective coating of a plurality of optical fibers each having a core and a clad. The method for manufacturing an optical fiber coupler according to any one of claims 1 to 3, wherein: 5. A first optical fiber group, which is arranged in parallel on the same plane and has the protective coating of a predetermined section removed at the same position as adjacent optical fibers, and the first optical fiber group. The optical fibers are arranged in parallel on the predetermined plane parallel to the arrangement plane at the same pitch as the first optical fiber group, and are the same as the first optical fiber group, and the adjacent optical fibers are also protected at the same position in a predetermined section. A second optical fiber group having a coating removed, and the first optical fiber group in the predetermined section from which the protective coating has been removed.
An optical fiber coupler in which each of the optical fibers of the optical fiber group and the second optical fiber group is fused and stretched between the corresponding optical fibers to form an optical mixing / branching portion. 6. A tape-shaped multicore in which at least a part of the first optical fiber group and / or the second optical fiber group is integrally formed by a protective coating with a plurality of optical fibers each having a core and a clad. An optical fiber coupler according to claim 5, wherein the optical fiber coupler is an optical fiber. 7. A tape-shaped multicore optical fiber in which the first optical fiber group and / or the second optical fiber group are integrally formed by a protective coating of a plurality of optical fibers each having a core and a clad. The optical fiber coupler according to claim 5, wherein the optical fiber coupler is a part. 8. A plurality of optical fiber couplers are formed by removing the protective coatings of the corresponding optical fibers of the first optical fiber group and the second optical fiber group and joining the exposed portions of the optical fiber element wires. An apparatus for manufacturing, comprising: first holding means for holding the exposed optical fiber strands of the first optical fiber group at a predetermined pitch and parallel to each other on one plane; and the second optical fiber group. Second holding means for holding the exposed optical fiber strands of the first optical fiber group in parallel and aligned with the corresponding exposed optical fiber strands of the first optical fiber group. A means for bringing the corresponding exposed optical fiber strands of the first and second optical fiber groups into close contact with each other, and a means for bringing the closely contacted optical fiber strands of the first and second optical fiber groups into contact with each other. Heat, means for fusing, and means for stretching the fused optical fiber strand,
An optical fiber coupler manufacturing apparatus, wherein a plurality of optical fiber couplers are simultaneously formed. 9. The first and second holding means are respectively provided with flat upper surfaces located on the same plane for supporting the optical fiber group thereon, and relatively move relative to each other in the axial direction of the supporting optical fiber group. The apparatus for manufacturing an optical fiber coupler according to claim 8, comprising a pair of possible mounts. 10. The first and second holding means are provided with means for cooperating with the pair of mounts to fix a part of the optical fiber group on the mounts. Item 9. An optical fiber coupler manufacturing apparatus according to Item 9. 11. The method according to claim 9 or 10, wherein the contact means comprises means for pushing down and holding the optical fiber group on the upper surface of each of the pair of mounts. Optical fiber coupler manufacturing equipment. 12. The heating and fusing means is arranged at an intermediate position between the pair of mounts and is parallel to the array surface of the optical fiber groups held on the mounts and perpendicular to the axial direction of the optical fiber groups. 10. The heating means for simultaneously heating the same position in the same length direction of the optical fiber group held on the pedestal, which extends in any direction, according to claim 9, Optical fiber coupler manufacturing equipment. 13. A means for holding the optical fiber strands of the first and second optical fiber groups at a predetermined distance from each other, which is provided on the upper surface of each of the pair of mounts. The optical fiber coupler manufacturing apparatus according to claim 9. 14. The stretching means each have a flat upper surface located on the same plane for supporting the first or second optical fiber group thereon, and are relative to each other in the axial direction of the supporting optical fiber group. The pair of movable pedestals, and means for fixing the fused first and second optical fiber groups on the pair of pedestals, Claim 8. Optical fiber coupler manufacturing equipment. 15. The first and second optical fiber groups,
The optical fiber coupler manufacturing apparatus according to any one of claims 8 to 14, wherein each is a tape-shaped optical fiber.