JPS63205615A - Optical fiber coupler and method and apparatus for producing such coupler - Google Patents

Abstract

PURPOSE:To improve productivity by bringing two optical fiber groups which are collectively positioned in parallel on the same plane into contact with each other and subjecting these optical fibers collectively to heating, fusing and stretching. CONSTITUTION:Optical fiber strands 22a-22e are so positioned that the strands are positioned at equal intervals with each other with respect to the optical fibers 22 and in succession thereof, the optical fibers 21 are superposed on the optical fibers 22 and are so positioned that the optical fiber strands 21a-21e are positioned at the equal intervals with each other. The respectively corresponding exposed optical fiber strands 21a-21e, 22a-22e of the optical fiber groups 21, 22 are brought into tight contact with each other and are heated. The respective optical fiber strands 21a-22a-21e-22e of the fibers 21, 22 are respectively fused and stretched in a fusing and stretching part 30, by which the plural optical fiber couplers are simultaneously formed. The productivity is thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a novel optical fiber coupler and its manufacturing method and manufacturing apparatus. More specifically, the optical fiber coupler according to the present invention relates to an optical fiber coupler with uniform characteristics that can be obtained by manufacturing a plurality of optical fiber couplers at once, and a method and apparatus for manufacturing the same.

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

Tape-shaped multicore optical fibers are one example of high-density signal transmission that has been put into practical use in recent years. As shown in the cross-sectional view of FIG. 7, this tape-shaped multicore optical fiber consists of a plurality of optical fibers each consisting of a core 71, a cladding 72, and a protective coating 73 formed coaxially on one arrangement plane. The rhinoceroses are arranged in parallel and are further surrounded by a covering layer 74 to form an integrated structure. Such a tape-shaped multi-core optical fiber is intended to physically increase the transmission path density per unit cross-sectional area of light within an optical fiber cable, thereby physically improving the transmission density of optical signals.

By the way, when optical fibers are used as signal transmission members, they can be used to branch an optical signal propagating through one transmission path into multiple transmission paths, or to split two or more types of light propagating from multiple transmission paths. An optical coupler that combines signals within a single transmission path is essential. Optical couplers having such functions are very frequently used members and at the same time extremely important members in constructing various optical systems that utilize optical signals. In particular, optical fiber couplers using optical fibers are easy to couple with optical fibers that are widely used as optical transmission lines, and their use is rapidly increasing with the development of various optical transmission systems.

Typical optical fiber couplers include Bee, Nis, Kawasaki, and Goo. Oh.

Hill and G, U%:/(B, S, Kawasa
ki, K, 0゜Hill and RoG, Lamo
“Optical Communication” Volume 6 (1981) by
Opt, Lett, Vol. 6.1981), a biconical single mode fiber coupler (
Biconical-Taper Single-Mo
de FiberCoupler).

FIGS. 8(a) to 8(C) are diagrams illustrating the structure and manufacturing method of this conventionally well-known optical fiber coupler. This optical fiber coupler is manufactured as follows.

That is, as shown in FIG. 8(a), two optical fibers 81 and 82 whose protective coatings have been removed to leave only a core 84 and a cladding 85 are placed in close contact with each other in parallel.

Subsequently, as shown in FIG. 8Q)), the optical fiber 81.
The central portion 83a of 82 is heated to fuse the two at this position. Further, when tension is applied to the optical fibers 81 and 82 while heating the welded portion so that the optical fibers maintain a softened state, the optical fibers 81 and 82 are heated at the welded portion 83b.
2 extends, the cores 84 approach each other, and propagating light leaks between them. In this way, the welding/stretching part 83b is used as a light mixing/branching part, as shown in FIG.
) An optical fiber coupler as shown in FIG.

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

This device is a device for manufacturing an optical fiber coupler by fusing and stretching two optical fibers at the center, and includes 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 stretching tables 95a that have the function of positioning the fusion/stretching part of the optical fibers and applying tension to the optical fibers near the center of the optical fibers 91 and 92 fixed by these. 1,95b.

That is, the fixing devices 93a-93b, 94a-94b are
By gripping the optical fibers 91 and 92, respectively, it is possible to apply tension using stretching tables 95a and 95b, which will be described later.

The stretching tables 95a and 95b are each equipped with two pins 96a and 96b provided at a distance such that the optical fibers 91 and 92 are brought into close contact with each other at the center.
．． horizontal position adjustment device 97 movable in a horizontal direction perpendicular to 92;
a, 97b, a vertical position adjusting device 98a198b that grips the optical fiber 91.92 and is movable in a vertical direction perpendicular to the optical fiber 91.92, and an optical fiber temporary fixing device 99.
a and 99b are provided respectively.

In this device, first, two optical fibers 91 and 92 whose coatings have been removed for a predetermined length are each fixed to optical fiber fixing devices 93a-93b and 94a-94b with relatively weak tension. The optical fibers 91,92 are further held by a stretching table 95a195b near the middle of the fixing devices 93a-93b, 94a-94b. That is, the horizontal position adjustment devices 97a and 97b control the stretching tables 95a and 97b.
are in close contact with each other in the same plane as the surface of 95b, and further,
The vertical positioning devices 98a, 98b position the optical fibers 91, 92 so that they are not twisted or the like. The optical fibers 91 and 92 are fixed in this position by temporary fixing devices 99a and 99b, and in this state, the optical fibers 9L and 92 are fixed by a heating device (not shown).
Weld the center part of the Subsequently, while heating is continued to such an extent that the optical fibers 91 and 92 are maintained in a softened state, stretching is performed by separating the stretching tables 95a and 95b from each other and applying tension.

In this way, an 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 maximum force applied to an optical fiber for fixing or stretching is several grams per fiber, and the length of the fused portion of the optical fiber is several millimeters.
That's about it. Furthermore, factors such as twist of each optical fiber also affect the characteristics as an optical fiber coupler. This level of load or accuracy is at a level that easily changes due to the friction of each member constituting the device, and therefore, various adjustments to each optical fiber are extremely delicate. It is virtually impossible to make such adjustments only by operating the equipment; in reality, a predetermined amount of light is injected from one end of the optical fiber being fabricated, and the light is monitored at the other end while being fused or stretched. By doing this, we are able to match the characteristics of our products.

However, as mentioned above, constructing an optical system requires a huge number of optical fiber couplers, and performing the above operations on each one of them reduces the productivity of the optical fiber couplers. was making it extremely bad.

In addition, it goes without saying that it is extremely disadvantageous in terms of cost, and it significantly impairs the practicality of optical fibers, which should eventually replace metal cables.

These problems are particularly noticeable when devices such as the tape-shaped multicore optical fiber mentioned above are used, and not only are the productivity of optical fiber couplers low, but they are also extremely inconvenient to use. be. In other words, when trying to apply an optical fiber coupler to a system using tape-shaped multi-core optical fibers, the process of first repeating the production of as many optical fiber couplers as the number of optical fibers to be coupled, then It is necessary to couple both ends of the optical fiber to each core of the tape-shaped multi-core optical fiber. Furthermore, due to the extra length of optical fiber required for the coupling process and the fact that each optical fiber coupler is equipped with a package,
An extremely large volume is required to accommodate tape-shaped multicore optical fibers coupled by optical fiber couplers.

As described above, conventional optical fiber couplers have extremely poor productivity and operability, and have greatly hindered the practical use of optical fibers.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a novel optical fiber coupler that can easily produce a plurality of optical fiber couplers with uniform characteristics;
An object of the present invention is to provide a method and apparatus for manufacturing the optical fiber coupler.

Means for Solving the Problems According to the present invention, a plurality of optical fibers whose protective coatings have been removed in a predetermined section at the same longitudinal position to expose the optical fiber strands are connected to the exposed optical fibers. A first optical fiber group is formed by arranging the strands so that they are parallel to each other on the same plane, and the first optical fiber is arranged on a predetermined plane parallel to the arrangement plane of the first optical fiber group. A plurality of optical fibers each having a predetermined section of protective coating removed to expose the optical fiber strands at the same longitudinal position as the fiber group, each exposed optical fiber strand being connected to the first optical fiber group. forming a second group of optical fibers by arranging them in parallel with the exposed portions of the optical fiber strands and at the same pitch; After heating the optical fiber groups together in a state in which the optical fibers are in close contact with each other to fuse the corresponding optical fibers of the first right and second optical fiber groups, stretching is performed. Provided is a method for manufacturing an optical fiber coupler, characterized in that a plurality of optical fiber couplers are formed simultaneously.

In the manufacturing method of the present invention, optical fibers of a pair of tape-shaped multicore optical fibers, each of which is formed integrally with a plurality of optical fibers each having a core and a cladding by a protective coating, are fused together and stretched to form an optical fiber. It can be suitably applied to manufacturing couplers.

Furthermore, according to the present invention, arranged in parallel on the same plane,
a first group of optical fibers each having a predetermined section of its protective coating removed at the same position as the adjacent optical fibers; a second group of optical fibers arranged in parallel at the same pitch as the group of optical fibers, the same as the first group of optical fibers, and having a predetermined section of the protective coating removed from the adjacent optical fibers at the same position; In the predetermined section where the protective coating is removed, the first
Each of the optical fibers of the optical fiber group and the second optical fiber group is fused and drawn between corresponding optical fibers to form each optical fiber.
An optical fiber coupler is provided, which is characterized in that it forms an optical mixing/branching section.

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

Furthermore, according to the present invention, the protective coatings of the respective optical fibers of the first optical fiber group and the second optical fiber group are removed and the exposed portions of the optical fibers are joined to form a plurality of optical fiber couplers. a first holding means for holding the exposed optical fiber strands of the first optical fiber group parallel to each other on one plane at a predetermined pitch; a second holding means for holding the exposed optical fiber strands of the group so as to be aligned parallel to and at the same pitch as 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 means for bringing the respective exposed optical fiber strands of the first and second optical fiber groups into close contact with each other. comprising means for heating and fusing, and means for drawing the fused optical fiber,
An apparatus for manufacturing an optical fiber coupler is provided, which is characterized by simultaneously forming a plurality of optical fiber couplers.

According to a preferred embodiment of the invention, the first and second holding means each have flat upper surfaces located on the same plane supporting the group of optical fibers thereon, and the first and second holding means each have a flat upper surface located on the same plane supporting the group of optical fibers thereon, and It includes a pair of frames that are movable relative to each other.

Further, according to a preferred aspect of the present invention, the first and second holding means are comprised of means for cooperating with the pair of pedestals to fix a portion of the optical fiber group onto the pedestals,
Further, the close contact means includes means for pressing down and holding the optical fiber group onto the upper surface of each of the pair of mounts.

Further, according to a preferred embodiment of the present invention, the heating and fusing means is disposed at an intermediate position between the pair of pedestals, parallel to the arrangement plane of the optical fiber group held on the pedestal, and parallel to the arrangement surface of the optical fiber group held on the pedestal. The heating means extends in a direction perpendicular to the axial direction and simultaneously heats the same longitudinal position of the group of optical fibers held on the pedestal.

Further, according to a preferred aspect of the present invention, means for holding the optical fibers 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 pedestals.

Further, according to a preferred aspect of the present invention, the stretching means each includes a flat upper surface located on the same plane supporting the first or second group of optical fibers thereon, and the stretching means has an axis of the group of optical fibers to be supported. 1 movable relative to each other in the direction
A pair of pedestals and means for fixing the fused first and second optical fiber groups onto the pair of pedestals are provided.

According to the present invention, a plurality of optical fiber couplers having uniform characteristics can be simultaneously produced by manipulating and producing a plurality of optical fibers at once. In other words,
The optical fiber coupler manufactured according to the present invention can be manufactured into a plurality of products with uniform characteristics by simple operations as described below.

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

In addition, since the fusing and stretching processes, which are the most time-consuming processes in the production of optical fiber couplers, are performed all at once, the time required to produce multiple optical fiber couplers is greatly reduced, making it possible to achieve high productivity. .

Furthermore, it is also possible to use the tape-shaped multicore optical fiber described above as the material of the optical fiber coupler. In this case, the characteristics of the plurality of optical fiber couplers produced at the same time become even more uniform. This is because a tape-shaped multi-core optical fiber is originally composed of multiple optical fiber strands with uniform characteristics, and furthermore, problems such as twisting of each optical fiber at the welded part can be avoided. This is because this problem has already been solved when producing a tape-shaped multi-core fiber. In addition, an optical fiber coupler fabricated using a tape-shaped multicore optical fiber is a new element that can collectively couple multiple strands of a tape-shaped multicore optical fiber, and it is a new device that can combine multiple strands of a tape-shaped multicore optical fiber at once. It becomes possible to easily couple tape-shaped multicore optical fibers, which could not be achieved with couplers.

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

Embodiment 1 FIGS. 1(a) and 1) are diagrams showing the configuration of an optical fiber coupler manufacturing apparatus according to the present invention, and FIG. 1(a) is a plan view of the apparatus viewed from above. Figure 3) is a side view. The following example is an apparatus for producing an element equipped with five optical fiber couplers using two five-core tape-shaped multicore optical fibers, and is shown in FIGS. 1(a) and 1(a).
1 shows a state in which a five-core tape-shaped multicore optical fiber is attached to the device.

This apparatus mainly consists of a pair of stretching tables 11A and 11B and heating means 12A and 12B.

The stretching tables 11A and 11B have fixing means 111A and 111 for fixing the tape-shaped multicore optical fiber including the outer coating, which will be described later.
11B, and a pair of pin groups 112A each for horizontally positioning a single uncoated optical fiber strand.
-113A, 112B-1138, and means 114A, 114B for moving each optical fiber in the vertical direction for vertical positioning, that is, for bringing the optical fibers into close contact with each other. Although driving means for the stretching tables 11A and 11B are not shown, the pair of stretching tables are configured to be movable in directions away from each other with equal driving force along the guide members 12OA and 120B.

Further, on the outside of one of these stretching tables, a roll 13A,
13B, 13C, and 130 are provided, and as will be described later, tension is applied to the tape-shaped optical fiber core by a pulling means (not shown) located further outside the roll.

In addition, the aforementioned pin groups 112A-113A, 112B-1
As the wire 13B, 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. Furthermore, the fixing means 111
A, 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 bring the strands into close contact with the surfaces of the drawing tables 11A and 11B. This is a consideration to ensure that a uniform load is applied to the plurality of optical fiber strands, as will be described later.

Now, the tape-shaped multicore optical fiber used as a material in this example has a core diameter of 6.5 μm, a cladding outer diameter of 1
25 μm single mode optical fiber for the 1.3 μm band with a cutoff wavelength of 1.1 μm coated with urethane or acrylic ultraviolet curable resin to have an outer diameter of 250 μm, arranged in 5 horizontal parallels on a plane. and about 75μ
It is integrally bound with urethane or acrylic ultraviolet curing resin to a thickness of m.

Hereinafter, the operation of producing an optical member equipped with five sets of optical fiber couplers from this tape-shaped terminal optical fiber using the above-mentioned apparatus will be described.

First, each has five optical fiber strands 21a and 21b.
, 21C, 21d, 21e or 22a, 22
b, 22C, 22d.

A pair of 5-core tape-shaped optical fibers 2 formed from 22e
For Samples No. 1 and No. 22, the coating layer having a length corresponding to the line xx in FIG. 1 was removed using polyethylene glycol and sulfuric acid.

Next, first, regarding the tape-shaped optical fiber 22, the optical fiber strands 22a, 22b, 22c, 22
d, pins 112A-113A such that 22e are equally spaced from each other.

112B-1138. continue,
Tape-shaped optical fiber 21 is placed on tape-shaped optical fiber 22.
The optical fibers 21a, 21b, 21
c, 21d.

21e are equally spaced from each other.
Positioning was performed by 12A-113A and 112B-113B.

Note that due to the arrangement of the pins 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 stretching table 11A side, the tape-shaped optical fibers 21 and 22 are collectively fixed by the fixing means 111A, and the roll groups 13A, 13B, 13C, 1
Approximately 50 g of tension is applied to the tape-shaped optical fibers 21 and 22 through the 3D, and further, while maintaining this state, the tape-shaped optical fibers 21 and 22 are fixed by the fixing means 111B on the stretching table 11B side. That is, the tape-shaped optical fiber is fixed between the stretching table 11A and IIB while maintaining a tension of about 50 g. Note that during these operations, the stretching tables 11A and IIB are fixed so as not to move.

Next, each optical fiber strand of the tape-shaped optical fiber 2L 22 is brought into close contact with the corresponding optical fiber strand, that is, in this embodiment, the optical fiber strands corresponding to each other in the vertical direction are brought into close contact with each other. 114A, 114B
operate. That is, by pushing down the adhesion means 114A and 114B, the optical fiber strands 21a-22a, 2 corresponding to the upper and lower parts are brought into close contact with each other.
1b-22b, 21cm22c, 21d-22
d, create a set of 21e-226. In FIG. 1, a part of the optical fiber 114A is cut away to show the state of the optical fiber.

A pair of heating torches 12A are arranged above and below at approximately the midpoint between the tape-shaped optical fiber drawing tables 11A and 11B, where the strands are in close contact with each other after the arrangement is completed.
12B, optical fiber strands 21a-22a.

21b-22b, 21cm22c, 21d-2
2d, 21e-22e are heated to fuse them together.

Once it is confirmed that each optical fiber has been fused, the output of the heating torches 12A and 12B is reduced, and the drawing tables 11A and IIB are maintained while the optical fiber is softened and can be drawn. both move at approximately the same speed so as to move away from each other. As will be described in detail later, five sets of optical fiber couplers are produced by simultaneously operating five sets of optical fiber strands in this way.

In this operation, the output light of the semiconductor laser is injected from one end of the optical fiber 21a, while the other end of the optical fiber 21a and the end of the optical fiber 22a paired with the optical fiber 21a are injected. The light receiving elements 23 and 24 were coupled together and the characteristics of the optical fiber coupler formed during the drawing operation were monitored.

That is, at the beginning of the operation, there is no output in the light receiving element 24, and only when the extended portion reaches 5 mm to 30+ nm does the branching operation occur and an output appears in the light receiving element 24. Therefore, by monitoring the output light intensity of the light receiving elements 24 and 23 and stopping the stretching and heating when the desired value is obtained, an optical fiber coupler with desired characteristics is completed.

Figures 2(a) to (C) depict a member in which the five optical fiber couplers completed as described above are integrated, and Figure 2(a) is a plan view, and 2) shows a side view, and FIG. 2(C) shows a sectional view taken along line M-M. That is, the tape-shaped multicore optical fiber 21.2
2 each of the optical 7 fiber wires 21a-22a, 21b-2
2b, 21cm22c, 21d-22d,
21e to 22e form optical fiber couplers in the fusion/stretching section 30, respectively. It goes without saying that this optical fiber coupler is formed while being coupled to a tape-shaped optical fiber core wire, and is extremely easy to handle. In actual use, this optical fiber coupler group is housed in a container with reinforcement so that no external force is applied to the fusion-stretching section 30.

Figure 3 is a graph showing the characteristics of the optical fiber coupler as described above, showing the characteristics of light with a wavelength of 1.3 μm and light with a wavelength of 1.55 μm.
It shows the coupling rate wavelength characteristics of an optical fiber coupler that mixes or demultiplexes m light.

Incidentally, this graph shows the above-mentioned optical fibers 21a and 22.
A was measured using light receiving elements 23 and 24. As can be seen from Fig. 3, this optical fiber coupler has a coupling ratio of 0.007 at a wavelength of 1.3 μm and a coupling ratio of 0.997 at a wavelength of 1.55 μm, so that light at wavelengths of 1.3 μm and 1.55 μm It can be seen that it has the function of separating and combining.

In addition, when similar characteristics were measured for the other four optical fiber couplers, the coupling rate at a wavelength of 1.3 μm was 0.006±o, ooi, and the coupling rate at a wavelength of 1.55 μm was 0.997±o, It was found that these five optical fiber couplers had uniform characteristics. That is, the slight temperature distribution that inevitably occurs when heating and drawing five optical fiber strands did not actually pose a problem.

As described above, according to the manufacturing method of the present invention, when manufacturing five sets of optical fiber couplers, if online measurement of the degree of coupling is performed on any one of them, the five optical fiber couplers manufactured at the same time will approximately have the same characteristics.

Regarding the method of heating the joint portion of the primary and secondary optical fiber groups, in the embodiment shown in FIG. It is also possible to move it horizontally or at any angle. On the other hand, as shown in Figure 1, the fixing method of fixing two groups of optical fibers in pairs is also conventional when producing a single optical fiber coupler of one water pair. It is superior to other devices. In other words, with this fixing method, the load is applied equally to the two optical fibers, so the characteristics of each waveguide will be uniform, especially when creating an element that performs 50% branching. .

In this example, positioning pins were used to fix the movement of the uncoated portion of the tape-shaped multicore optical fiber in the optical fiber arrangement direction (X-axis direction). Of course, any function that can suppress the movement of the optical fibers in the X-axis direction by almost preserving the axial spacing between the optical fibers can be used in the production of the optical fiber coupler of the present invention in the same manner as in this example. It is.

In the above explanation, tape-shaped multicore optical fibers were used as the primary and secondary optical fiber groups, but as both the primary and secondary optical fiber groups, or either one of the optical fiber groups, Even if a plurality of coated single-core optical fibers are lined up, a plurality of optical fiber couplers with uniform characteristics can be produced using the same manufacturing method and equipment as in the above 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 were basically the same as in Example 1, and only the drawing operation was different.

That is, as in Example 1, as one of the five sets of optical fibers, the optical fiber 21a (with wavelength 1
．． A 3 μm semiconductor laser beam is injected into the optical fiber 2.
The other end of the optical fiber 1a and the end of the optical fiber 22a 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 optical fiber couplers in the optical fiber coupler group completed in this way was within 50% ± 1%, and the insertion loss was in the range of 0.05 ± 0.02 dB, with extremely small variations in characteristics. Ta.

Example 3 FIGS. 4(a) and 4(b) show another example of manufacturing an optical fiber coupler according to the present invention, FIG. 4(a) is a plan view, and FIG. 4(c) is a N-N FIG. In this example, only three of the five optical fiber strands of the tape-shaped multicore optical fiber were coupled together using an optical fiber coupler.

That is, a pair of five-core tape-shaped optical fibers 41, 42 are used, and the optical fibers 41a, 41b, 41c are arranged to form a pair with the optical fibers 42cs, 42ds, 42e, respectively, and these optical fibers are Wire 41a
-e and 42a-e were heated and stretched all at once.

At this time, in addition to the stretched portion 43 that forms the optical fiber coupler, the optical fiber strand 41d that is not coupled with other optical concentrators
, 41e as well as 42a and 42b are also stretched, but the loss due to this is extremely small and can be considered to have virtually no effect on the optical transmission characteristics.

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

That is, FIGS. 5(a) and 5(b) respectively show another embodiment of the optical fiber coupler according to the present invention in a plan view and an O-0 sectional view, in which a tape-shaped optical fiber 51 with an IO core is shown. and five-core tape-shaped optical fibers 52 and 53.
It is made by combining.

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

It goes without saying that combinations of types of optical fibers constituting the optical fiber coupler of the present invention are possible for tape-shaped multicore optical fibers having any number of optical fiber strands. Of course, a single-core optical fiber may also be used. Therefore, the type of optical fiber to be fused and stretched may be appropriately selected depending on the application.

Effects of the Invention As detailed above, the optical fiber coupler according to the present invention can be manufactured by manipulating a plurality of optical fibers at once, thereby making it possible to simultaneously manufacture a plurality of optical fiber couplers with uniform characteristics. .

In other words, the optical fiber coupler manufactured according to the present invention can be manufactured into a plurality of products with uniform characteristics by a simple operation as described below.

Further, according to the method for manufacturing an optical fiber coupler according to the present invention, two groups of optical fibers that are collectively positioned in parallel on the same plane are brought into contact with each other, and they are heated, fused, and stretched at once. Therefore, various factors related to these operations, such as variations in lateral pressure or tension on the optical fibers, act uniformly and dispersedly on all the optical fibers in each group, and the characteristics of the manufactured optical fiber coupler also change. Approximately average.

Furthermore, if the optical fiber coupler manufacturing apparatus according to the present invention is used, it is possible to perform the most labor-intensive fusing and stretching processes in the production of optical fiber couplers all at once. The time required for this process is greatly reduced and high productivity can be achieved.

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

According to these effects of the present invention, it is possible to realize mass production that could never be achieved with conventional optical fiber coupler manufacturing methods, and furthermore, optical fiber couplers that currently cost more than 100,000 yen per unit can be produced. The price can be reduced to several thousand yen per bottle. Furthermore, since the optical fiber coupler according to the present invention has uniform characteristics among a plurality of optical fiber couplers, its application field is extremely wide, such as as a tap for public optical communication and a monitor for a characteristic test circuit.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are schematic diagrams showing the configuration of an optical fiber coupler manufacturing apparatus constructed according to the present description, with FIG. 1(a) showing a plan view and FIGS. 2 is a diagram schematically showing the configuration of an optical fiber coupler according to the present invention manufactured by the apparatus shown in FIG. 1, and FIG. 3 is a diagram schematically showing the structure of the optical fiber coupler shown in FIG. FIG. 4, FIG. 5, and FIG. 6 are graphs showing the characteristics of optical fiber couplers according to various embodiments of the present invention, and FIG. 4(a), FIG. FIG. 4(a) is a plan view of each of these optical fiber couplers, FIG. 4(b) is a sectional view taken along N-N in FIG. 4(a), and FIG.
The O-0 sectional view of Figure (a) is shown, and Figure 6(b) is the
), FIGS. 7(a) to (C) are diagrams for explaining the configuration of a conventional optical fiber coupler and its manufacturing method, and FIG. 8 is a tape-shaped multi-core optical fiber coupler. FIG. 9 is a diagram illustrating the configuration of an optical fiber. FIG. 9 is a schematic plan view showing the configuration of a conventional optical fiber coupler manufacturing apparatus. [Main reference numbers] 11A, 11th...Stretching table 12A, 12B...Heating torch, 13A,
13B, 13C, 130...roll, 21.22
．． 41.42.51.52.53.61.62.63.
64...Tape-shaped multicore optical fiber, 21a, 21b, 21c, 21d, 21
e. 22a, 22b, 22c, 22d, 22
e... Optical fiber wire, 23.24... Light receiving element, 71... Core, 72... Clad, 73... Protective coating, 74... Coating , 81.82.91.92...Optical fiber wire, 83a
, 83b...fusion/stretching part, 93a, 93b
, 93a, 93b -- fixing device, 95a19
5b...Stretching table, 97a, 97b...Horizontal position adjustment device, 96
a, 96b...'pin,

Claims (15)

[Claims] (1) A plurality of optical fibers whose protective coatings have been removed from a predetermined section at the same longitudinal position to expose the optical fibers, the exposed optical fibers are parallel to each other on the same plane. A first optical fiber group is formed by arranging the first optical fiber group, and a predetermined section is arranged at the same longitudinal position as the first optical fiber group on a predetermined plane parallel to the arrangement plane of the first optical fiber group. A plurality of optical fibers whose protective coatings have been removed to expose the optical fiber strands, each exposed optical fiber strand being the exposed optical fiber strand of the first optical fiber group. a second optical fiber group is formed by arranging the fibers parallel to each other and at the same pitch, and the corresponding exposed optical fiber strands of the first and second optical fiber groups are in close contact with each other. heating the optical fiber strands all at once to fuse the corresponding optical fiber strands of the first and second optical fiber groups, and then drawing them to form a plurality of optical fiber couplers at the same time; A method of manufacturing an optical fiber coupler characterized by: (2) In a predetermined section where either one of the first and second optical fiber groups is moved and the protective coating is removed, the corresponding exposed light of the first and second optical fiber groups is exposed. A method for manufacturing an optical fiber coupler according to claim 1, characterized in that the fiber wires are brought into close contact with each other. (3) At least a portion of the first optical fiber group and/or the second optical fiber group is a tape-shaped multicore optical fiber formed integrally with a plurality of optical fibers each having a core and a cladding with a protective coating. A method for manufacturing an optical fiber coupler according to claim 1 or 2, characterized in that: (4) The first optical fiber group and/or the second optical fiber group are part of a tape-shaped multicore optical fiber formed by integrally forming a plurality of optical fibers each having a core and a cladding with a protective coating. A method for manufacturing an optical fiber coupler according to any one of claims 1 to 3, characterized in that: (5) a first group of optical fibers arranged in parallel on the same plane, each having a predetermined section of protective coating removed at the same position as the adjacent optical fibers, and an arrangement surface of the first group of optical fibers; on a predetermined plane parallel to the first optical fiber group, arranged in parallel with the same pitch as the first optical fiber group, and having a predetermined section of protective coating on the same and adjacent optical fibers as the first optical fiber group. a second group of optical fibers from which the protective coating has been removed;
An optical fiber coupler characterized in that each of the optical fibers of the optical fiber group and the second optical fiber group are fused and drawn together to form an optical mixing/branching section. (6) At least a portion 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 cladding are integrally formed with a protective coating. The optical fiber coupler according to claim 5, characterized in that: (7) The first optical fiber group and/or the second optical fiber group are part of a tape-shaped multicore optical fiber formed by integrally forming a plurality of optical fibers each having a core and a cladding with a protective coating. The optical fiber coupler according to claim 5, characterized in that: (8) Manufacturing a plurality of optical fiber couplers 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 fibers. An apparatus comprising: a 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 exposing the second optical fiber group. a second holding means for holding the exposed optical fiber strands so as to be aligned parallel to and at the same pitch as the corresponding exposed optical fiber strands of the first optical fiber group; means for bringing exposed optical fiber strands of the first and second optical fiber groups into close contact with each other; heating and melting the closely attached optical fiber strands of the first and second optical fiber groups; and a means for drawing the fused optical fiber,
An optical fiber coupler manufacturing apparatus characterized in that a plurality of optical fiber couplers are simultaneously formed. (9) The first and second holding means each have flat upper surfaces positioned on the same plane that support the optical fiber group thereon, and are movable relative to each other in the axial direction of the optical fiber group to be supported. 9. The optical fiber coupler manufacturing apparatus according to claim 8, comprising a pair of frames. (10) The first and second holding means include means for cooperating with the pair of pedestals to fix a part of the optical fiber group onto the pedestals.
An apparatus for manufacturing an optical fiber coupler as described in 2. (11) The optical fiber according to claim 9 or 10, wherein the close contact means is constituted by means for pressing down and holding the optical fiber group on the upper surface of each of the pair of frames. Fiber coupler manufacturing equipment. (12) The heating and fusing means is arranged at an intermediate position between the pair of pedestals, and extends in a direction parallel to the arrangement plane of the optical fiber group held on the pedestal and perpendicular to the axial direction of the optical fiber group. The optical fiber according to claim 9, further comprising a heating means that extends over the optical fiber group and simultaneously heats the same longitudinal position of the group of optical fibers held on the pedestal. Coupler manufacturing equipment. (13) A patent characterized in that means is provided on the upper surface of each of the pair of mounts to hold the optical fiber strands of the first and second optical fiber groups at a predetermined distance from each other. An optical fiber coupler manufacturing apparatus according to claim 9. (14) The stretching means each has a flat upper surface located on the same plane that supports the first or second optical fiber group thereon, and is movable relative to each other in the axial direction of the supported optical fiber group. 9. The optical system according to claim 8, further comprising: a pair of pedestals; and means for fixing the fused first and second optical fiber groups onto the pair of pedestals. Fiber coupler manufacturing equipment. (15) The optical fiber coupler according to any one of claims 8 to 14, wherein each of the first and second optical fiber groups is a tape-shaped optical fiber. Manufacturing equipment.