JP2539953B2 - Optical fiber clamp - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber clamp used in an apparatus for manufacturing an optical fiber coupler used in a communication system or a sensor system.

[0002]

2. Description of the Related Art In constructing an optical communication system or an optical data link network, an optical splitter that distributes an optical signal emitted from a light source at a desired ratio is important as a component. There is an optical fiber coupler as one of the optical branching devices. This optical fiber coupler is usually made by heating and melting a plurality of optical fiber couplers and stretching the fused parts under a constant tension. It is a thing. When fusing, it is necessary to closely align the glass parts of the optical fiber in parallel and perform alignment, and a clamp mechanism is used for that purpose, but the accuracy of the alignment of the clamp is largely dependent on the characteristics of the manufactured optical fiber. Influence.

Conventionally used clamps are disclosed in
As described in Japanese Patent Application Laid-Open No. 3-118705, the optical fiber is pressed from two directions. Figure 10
FIG. 3 is a perspective view of the clamp described in the above publication, in which two optical fibers 3 and 4 are pressed from the vertical direction by a clamp 28, and the aligned optical fibers are pressed from the side by a horizontal position adjusting device 24 to try to align them. It is a thing.

In such a conventional clamp, since it is pressed from two orthogonal directions at a position shifted in the axial direction, the clamp is often twisted and clamped. In addition, if the groove of the clamper 28 is deeper than the diameter of the optical fibers 3 and 4, FIG.
And it is difficult to align horizontally.

As shown in FIG. 12, it is conceivable to use two position adjusting devices, a vertical position adjusting device 23 and a horizontal position adjusting device 24, as a clamper mechanism. As shown in FIG. 1, if the horizontal position adjusting device 24 is used first,
It is much more likely that the result will be as shown in FIG. 3B than that as shown in FIG.

After that, even if the vertical position adjusting device 23 is used, the horizontal position adjusting device 24, as shown in FIG.
In the vertical position adjusting device 23, it becomes as shown in FIG.
The two optical fibers 3, 4 remain axially displaced. The same applies even if the vertical position adjusting device 23 is used first.

Therefore, in the conventional method of separately sandwiching from two directions at a right angle, there is a problem that a good clamp cannot be expected.

The optical fiber fixing device described in Japanese Utility Model Laid-Open Publication No. 1-94904 uses a pair of optical fiber clamps having a thickness and a step smaller than the diameter of the optical fiber and larger than the radius. However, workability is poor,
There is a problem that it is difficult to use.

In the optical fiber coupler manufacturing apparatus described in Japanese Patent Application Laid-Open No. 64-80913, two V-grooved blocks are used, and one optical fiber is placed in each V-groove. Two optical fibers are pressed from both sides by the groove wall so as to be tightly clamped.

As described above, when the V-groove is used, the size of the V-groove is such that the two optical fibers 3 and 4 are in contact with each other as shown in FIG. 14A. It cannot be bigger than it touches.

In the state of FIG. 14 (A), as shown in FIG. 14 (B), when the angle of the V groove is 90 degrees and the radius of the optical fiber is r, the width M of the opening of the V groove is M. Is M = 2 (1 + 2 ^1/2 ) r, the maximum possible value of the width D of the opening of the V groove is the same as that shown in FIG. Become. When the diameter 2r of the optical fiber is 125 μm, M is 600 μm.
m.

Therefore, in practice, the opening width D of the V groove is D.
Is about 200 to 300 μm, which is very small. Therefore, the operation of inserting an optical fiber into this V-groove requires a microscope.

Further, it is rare that the two optical fibers are completely parallel to the V-groove due to winding habits or the like, and it is normal that the two optical fibers are slightly shifted. Therefore, in the method as described in Japanese Patent Laid-Open No. 64-80913, it is necessary to confirm that the optical fiber is completely inserted in the V groove, and this work is also done by a microscope. It's hard to think of tiredness.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an optical fiber clamp having good workability and capable of holding an optical fiber in parallel easily and securely. It was done for the purpose of doing.

[0015]

According to a first aspect of the present invention, there is provided an optical fiber groove portion into which an optical fiber is inserted, and an optical fiber introducing portion which expands outward from the optical fiber groove portion. In an optical fiber clamp having a grooved member having and a pushing member movably arranged so as to push the optical fiber from the optical fiber introduction part toward the optical fiber groove part, the grooved member is the optical fiber. The pressing member has an opening on the side of the optical introduction portion, a bottom surface on the side of the groove portion for the optical fiber, and a groove portion for a pressing member formed so as to intersect with the longitudinal direction of the groove portion for the optical fiber. 3. The invention according to claim 2, wherein the optical fiber introducing portion has a width larger than the opening width of the optical fiber introducing portion, and is formed so as to be fitted in the groove portion for the pressing member. To A grooved member having an optical fiber groove portion for inserting an optical fiber and an optical fiber introducing portion expanding outward from the optical fiber groove portion, and from the optical fiber introducing portion toward the optical fiber groove portion In an optical fiber clamp having a pressing member movably arranged to press the optical fiber, the pressing member has a width larger than an opening width of the optical fiber introducing portion, and
It is characterized in that it is formed so as to be in contact with the end face of the grooved member. The invention according to claim 3 is
In the optical fiber clamp according to claim 1 or 2, the pushing member and / or the grooved member is supported by an air levitation bearing, and in the invention according to claim 4, The optical fiber clamp according to claim 3 is characterized in that the position of the pressing member and / or the grooved member is secured by stopping the air supplied to the air floating bearing.

The grooved member and the pushing member may be supported by the same movement guide shaft.

The grooved member may push the optical fiber by the thickness of the coating of the optical fiber.

The pushing member may be moved by a weight or an electromagnet.

[0019]

As shown in FIG. 2, the clamp according to the present invention comprises a grooved member having an optical fiber groove for inserting an optical fiber, an optical fiber introduction portion expanding outward from the optical fiber groove, and an optical fiber. Using a pushing member having a width larger than the opening width of the fiber introduction portion, in a state where the grooved member and the pushing member are separated from each other, the optical fiber is positioned at the optical fiber introduction portion of the grooved member, and the pushing member is turned on. By moving the optical fiber from the fiber introduction section toward the optical fiber groove, the optical fiber can be inserted into the groove and clamped. When an optical fiber is clamped in an optical fiber groove using a grooved member having an optical fiber introducing portion, for example, as described in JP-A-2-242208, a width narrower than the opening width of the optical fiber introducing portion. When the pushing member 2 of No. 2 is used, as shown in FIG.
May be pinched, and the optical fiber 3 cannot be inserted into the optical fiber groove 1a. In the present invention, since the pressing member 2 having a width larger than the opening width of the optical fiber introducing portion is used, the optical fiber 3 is moved along the optical fiber introducing portion by the pressing member 2 as shown in FIG. Therefore, it can be reliably moved to the optical fiber groove portion 1a. When the width of the pushing member is larger than the opening width of the optical fiber introduction portion, the pushing member cannot enter the optical fiber introduction portion. However, in the present invention, the grooved member is provided with a pushing member groove, or the pushing member is provided. Is brought into contact with the end surface of the grooved member, the optical fiber can be clamped by the pressing member even though the width of the pressing member is larger than the opening width of the optical fiber introduction portion.

By supporting the pushing member and / or the grooved member with an air floating bearing, the pushing member and / or the grooved member can be moved with a low friction force, and the air supplied to the air floating bearing can be moved. The position of the pushing member and / or the grooved member can be secured by stopping the.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of an optical fiber coupler manufacturing apparatus for explaining one embodiment of the present invention. In the figure, 1 is a grooved member, 2 is a pressing member, 3 and 4 are glass portions of optical fibers, 5 is an optical fiber coating portion, 6 is a heat fusion portion, 7 is a burner, 8 is a flame, and 9 is a coating portion. Clamp for
Reference numeral 10 is a stretching stage, 11 is a slider, 12 is a stand, and 13 is a guide shaft. Slider 11 and guide shaft 1
3 and 3 form a linear bearing.

The clamp composed of the grooved member 1 and the pushing member 2 has a groove into which the glass portions 3 and 4 (two in this figure) of the optical fiber whose coating has been removed are inserted. It will be described later. After the glass portion of the optical fiber is fixed by this clamp, the outside thereof is clamped by the coating clamp 9. The coating clamp 9 is placed on a stretching stage 10 for axially stretching the optical fiber,
The covering portions 5 of the two optical fibers arranged side by side are clamped from the lateral direction. The heat fusion portion 6 at the center of the glass portions 3 and 4 of the optical fibers aligned in parallel by the grooved member 1 and the pressing member 2 is heated by the flame 8 of the burner 7 and is fused.

Thereafter, the grooved member 1 and the pushing member 2 are separated from each other, and the heated and fused portion 6 is tensioned by the stretching stage 10 on which the coating clamp 9 to which the optical fiber coating portion 5 is fixed is placed while being heated by the flame 8. Has been added. The heat-fused portion 6 is stretched by this tension, and when a predetermined branching ratio is obtained, the stretching is stopped, and an optical fiber coupler is manufactured.

FIG. 2 is an explanatory view of one embodiment of the optical fiber clamp of the present invention. In the figure, 1 is a grooved member, 1a
Is a groove for an optical fiber, 1b is an optical fiber introduction portion, 1c is a groove for a pushing member into which a pushing member is inserted, and 2 is a pushing member. As shown in the perspective view of FIG. 2 (A), this clamp is such that the pressing member 2 presses the optical fiber and clamps it in a state where the optical fiber is inserted into the optical fiber groove 1a of the grooved member 1. It was done. The pressing member 2
The width of the grooved member 1 is set so as to enter the groove 1c for the pressing member.

Since the optical fibers are inserted side by side in the optical fiber groove portion 1a of the grooved member 1 and pressed by the pushing member 2 from the outside, the height of the optical fiber groove portion 1a is the minimum of the optical fiber. About 1.5 times is required. If it is larger than that, there is no problem because the optical fiber can be sufficiently housed in the optical fiber groove portion 1a, but as shown in FIG. 2B, the bottom of the pushing member groove portion 1c is the optical fiber groove portion. When it is higher than the bottom of the optical fiber 1a, the difference h between the bottom of the optical fiber groove 1a and the bottom of the pressing member groove 1c needs to be about 1.5 times the minimum of the optical fiber. In this case, the optical fiber groove 1a is also provided to extend at the bottom of the pressing member groove 1c. The bottom of the pressing member groove 1c may be lower than the bottom of the optical fiber groove 1a. However, the pushing member groove 1
If the bottom of c is higher than the bottom of the optical fiber groove 1a,
There is an advantage that the force exerted by the pushing member 2 on the optical fiber is dispersed evenly.

The groove width is, for example, the diameter 125 of the optical fiber.
In the case of μm, it is better to be 130 μm, which is slightly larger than that. If the precision of the diameter of the optical fiber and the processing precision are good, the groove width can be approached to 125 μm. As described above, the depth of the groove may be 125 μm × 1.5 = 187.5 μm or more, which is 250 times twice the diameter of the optical fiber.
It is also possible to make it deeper than μm. There is no problem if h described in FIG. 2B is not less than 187.5 μm and not more than 250 μm.

Referring to FIG. 3, the clamp explained in FIG.
A state where two optical fibers are clamped will be described. In the figure, the same parts as those in FIG. Reference numerals 3 and 4 denote glass portions of the optical fiber.

Ideally or theoretically, if the two optical fibers are well aligned in the covering clamp 9 described in FIG. 1, the glass portions 3 and 4 are separated from each other as shown in FIG. ), The optical fiber itself is twisted or bent, or the clamp 9 for the covering portion is used.
It is difficult to completely align the coating 27 due to
As shown in (A), the reality is that the two optical fibers are separated from each other and their positions are also irregular.

Now, as shown in FIG. 3 (A), the grooved member 1 is attached to the glass parts 3 and 4 of the optical fiber by the arrow 26.
Proceed in the direction of. If it goes well, the glass parts 3 and 4 fit into the optical fiber groove 1a as shown in FIG. 3B, but if not, one glass part 4 becomes light as shown in FIG. As shown in FIG. 3D, both the glass portions 3 and 4 stop at the entrance of the optical fiber groove 1a and do not enter the fiber groove 1a. Sometimes. In either state, as shown in FIG. 7E, the pushing member 2 is fitted into the pushing member groove of the grooved member 1 and pushes the glass 3 and 4 portions of the optical fiber into the optical fiber groove 1a. Thus, the two optical fibers can be completely aligned.

FIG. 4 is an explanatory diagram of a process of clamping two optical fibers in the optical fiber coupler manufacturing apparatus described in FIG. In the figure, 1, 1 ′ is a grooved member,
2'is a pressing member, 3 and 4 are glass portions of the optical fiber, 5
5 is a covering part.

Before clamping, as shown in FIG. 3A, the grooved members 1, 1 'and the pushing members 2, 2' are located at positions separated from each other. Before entering the fusing step, the grooved members 1, 1 '
And the pushing members 2 and 2 'are moved, and the pushing members 2 and 2' are fitted into the pushing member grooves of the grooved members 1 and 1 ', and the glass portions 3 and 4 of the optical fiber are moved in FIG. Clamp as described. In this case, it is important that the glass parts 3 and 4 of the two optical fibers are clamped symmetrically as shown in FIG. Therefore, it is important that the grooved members 1 and 1 'and the pressing members 2 and 2' press the glass portions 3 and 4 by the thickness of the coating of the optical fiber, respectively.
In order to be able to set as such, it is necessary to consider the position regulation of both, and how to apply a pressing force.

FIG. 6 is a schematic view of a clamp mechanism in an optical fiber coupler manufacturing apparatus for explaining an embodiment in which a clamp is driven by using a weight. In the figure, 1 is a grooved member, 2 is a pressing member, 3 and 4 are glass parts of an optical fiber, 1
1a and 11b are sliders, 13a and 13b are guide shafts,
14a and 14b are air cylinders, 15 is a stopper, 1
Reference numeral 6 is a thread fixing portion, 17 is a thread, 18 is a roller, 19 is a weight, 20a and 20b are air supply pipes, and 21a and 21b are air sources. Air sliders are used as the sliders 11a and 11b.

An example of the air slider is shown in FIG. A gap is provided between the guide shaft 13 and the slider 11. A plurality of injection holes 29 are provided around the guide shaft 13 and communicate with an air supply pipe 20 attached to one end of the guide shaft 13. Guide shaft 13 from air supply pipe 20
When the compressed air is introduced into the inside, the slider 11 can be floated with respect to the guide shaft 13 by the pressure of the air flowing out from the injection hole 29. Since it is floated by air, the slider 11 can be moved with extremely low friction, and the clamp attached to this can be moved with a small force.

The operation of the clamp mechanism shown in FIG. 6 will be described. At the time of non-clamping, as shown in the figure, the grooved member 1 and the pushing member 2 are separated from each other, and the glass parts 3 and 4 of the optical fiber are set therebetween. The grooved member 1 is provided with an air cylinder 14a.
To move the glass parts 3 and 4 so as to be accommodated in the grooves. The stop position of the movement of the grooved member 1 is controlled by the stopper 15. The pushing member 2 is moved by applying a force to the thread fixing portion 16 by the weight 19, the roller 18, and the thread 17. Prior to the movement, the pressing force on the slider 11b by the air cylinder 14b is released. The force of the weight 19 causes the glass portions 3 and 4 of the optical fiber.
Is pressed.

On the pushing member 2 side, the force for pushing the optical fiber is only required to continue. Therefore, when an air slider is used on the pushing member 2 side, after contacting the optical fiber,
Even if the supply of air is stopped, there is no problem because the optical fiber is held down. Not only does it save air, but it does not matter if it shakes.

In using the clamp of the present invention,
Care should be taken to reduce the force with which the pushing member pushes the optical fiber to prevent the occurrence of scratches on the optical fiber. From this viewpoint, it is considered that an air floating type bearing is suitable for the pressing member side.

FIG. 7A is a schematic view of a clamp mechanism in an optical fiber coupler manufacturing apparatus for explaining another embodiment of the clamp drive mechanism. In the figure, parts similar to those in FIG. 6 are designated by the same reference numerals, and description thereof will be omitted. 22 is a magnet mechanism, and 25 is a motorized stage. Grooved member 1
Has an important meaning for positioning, so the motorized stage 2
5 can be used. The pushing member 2 side has an electromagnet 22.
There is no problem even if driven by.

FIG. 7B is a schematic view of the clamp mechanism in the optical fiber coupler manufacturing apparatus for explaining another embodiment of the clamp drive mechanism. In the figure, parts similar to those in FIG. 6 are designated by the same reference numerals, and description thereof will be omitted. In this embodiment, the same guide shaft 13 is used instead of the two guide shafts 13a and 13b described in FIG. Therefore, it is easy to align the grooved member 1 and the pressing member 2.

The method of moving the clamp is not limited to the above embodiment. Although a well-known linear bearing can be used, the use of a moving mechanism having a large radius is not limited to a linear bearing.

Further, the grooved members 1, 1'and the pushing member 2,
As shown in FIG. 9, the 2'is displaced from the position shown in FIG. 4 in the axial direction of the optical fiber so that the pushing members 2, 2'are in contact with the end faces of the grooved members 1, 1 '. The optical fiber may be clamped. However, since the shearing force applied to the optical fiber is increased, the optical fiber is likely to be broken. Therefore, it is necessary to pay sufficient attention to how to apply the pressing force.

Next, the results of experiments conducted using the mechanism described in FIG. 6 will be shown. As a comparative example, the clamp mechanism described in FIG. 12 was used. The prototype has a cladding diameter of 125
A normal single mode optical fiber for ± 1.3 μm band of ± 1.5 μm, MFD of 9.5 ± 1 μm, and cut-off wavelength of 1.2 μm, using an ultraviolet curable resin, has an outer diameter of 0.25 m
An optical fiber finished to m was used. L of wavelength 1.3μm
The D light source was introduced into one optical fiber, and the output light of each optical fiber was detected from the opposite side with a power meter and stretched while monitoring the branching ratio. When the branched state reached 50%, the burner was moved away from the fiber and the drawing was stopped. An optical fiber coupler was prototyped to evaluate the excess loss, with the aim of keeping the branching ratio within 50 ± 3%. The length of the exposed glass portion from which the coating was removed was about 30 mm, and acetylene and an oxygen burner were used for heat fusion. The fusion was performed by heating the optical fiber at 1400 ° C. for 5 minutes with a radiation thermometer, and then stretching the film with a weight of 3 g for applying a stretching tension.

30 couplers prototyped by the conventional technique and 30 couplers prototyped by the apparatus of the present invention were tested. The average value of excess loss of the coupler manufactured according to the comparative example was 0.29 dB, and the maximum value was 0.6 dB.
The average value of excess loss of the coupler manufactured according to the example was 0.18 dB, and the maximum value was as good as 0.46 dB.

[0043]

As is apparent from the above description, according to the optical fiber clamp of the present invention, the optical fiber is reliably pushed into the groove portion during fusion in the optical fiber coupler manufacturing process, so that the optical fiber The optical fibers for use can be reliably aligned every time, and it has become possible to manufacture an optical fiber coupler with good reproducibility.

As can be confirmed from the experimental results, the variation of the excess loss of the manufactured optical fiber coupler can be reduced, which is effective in improving the yield.

Further, since the clamp can be automatically opened and closed, it is effective in saving labor.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of an optical fiber coupler manufacturing apparatus of the present invention.

FIG. 2 is an explanatory view of an embodiment of the optical fiber clamp of the present invention.

FIG. 3 is an explanatory diagram of an operation state of the clamp described in FIG. 2;

FIG. 4 is an explanatory diagram of a process of clamping two optical fibers in the optical fiber coupler manufacturing apparatus.

FIG. 5 is an explanatory diagram of a positional relationship of glass portions of an optical fiber.

FIG. 6 is an explanatory diagram of an embodiment of a drive mechanism for an optical fiber clamp according to the present invention.

FIG. 7 is an explanatory view of another embodiment of the drive mechanism of the optical fiber clamp of the present invention.

FIG. 8 is an explanatory diagram of an example of an air slider.

FIG. 9 is a schematic view of another embodiment of the optical fiber clamp of the present invention.

FIG. 10 is a perspective view of a conventional clamp.

11 is an explanatory diagram of an operating state of the clamp shown in FIG.

FIG. 12 is a perspective view of another conventional clamp.

13 is an explanatory diagram of an operating state of the clamp shown in FIG.

FIG. 14 is an explanatory diagram of another conventional example.

FIG. 15 is an explanatory diagram of an operation.

[Explanation of Codes] 1 ... Grooved member, 1a ... Optical fiber groove portion, 1b ... Optical fiber introduction portion, 1c ... Push member groove portion, 2 ... Push member,
3, 4 ... Glass part of optical fiber, 5 ... Optical fiber coating part, 6 ... Heat fusion part, 7 ... Burner, 9 ... Clamp for coating part, 10 ... Stretching stage, 11 ... Slider, 12 ... Stand, 13 ... Guide axis.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junichi Yoshikawa 1-chome, Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Kazuhiko Arimoto 7-31, Omorinishi 7-chome, Ota-ku, Tokyo No. Sumiden Opcom Co., Ltd. (56) References JP-A-2-242208 (JP, A)

Claims (4)

(57) [Claims] 1. An optical fiber groove portion into which an optical fiber is inserted, a grooved member having an optical fiber introducing portion that expands outward from the optical fiber groove portion, and the optical fiber introducing portion to the optical fiber groove portion. In an optical fiber clamp having a pushing member movably arranged so as to push the optical fiber toward, the grooved member has an opening on the optical fiber introducing portion side and a bottom surface on the optical fiber groove portion side. Having, and having a pressing member groove formed so as to intersect the optical fiber groove in the longitudinal direction, the pressing member has a width larger than the opening width of the optical fiber introducing portion, and An optical fiber clamp is formed so as to be fitted in the groove for the pushing member. 2. An optical fiber groove portion into which an optical fiber is inserted, a grooved member having an optical fiber introducing portion that expands outward from the optical fiber groove portion, and the optical fiber introducing portion to the optical fiber groove portion. In an optical fiber clamp having a pushing member movably arranged to push the optical fiber toward, the pushing member has a width larger than the opening width of the optical fiber introducing portion, and An optical fiber clamp, which is formed so as to contact an end face. 3. The optical fiber clamp according to claim 1, wherein the pushing member and / or the grooved member is supported by an air floating bearing. 4. The optical fiber clamp according to claim 3, wherein the position of the pressing member and / or the grooved member is secured by stopping the air supplied to the air floating bearing.