JPH01224707A - Fusion splicing method for optical fiber - Google Patents

Abstract

PURPOSE:To simplify the fiber connection work and to shorten the connection time with a low-cost device by allowing a part of each optical fiber to face a guide groove of a supporting base and applying an oscillation force to both optical fibers at the time of positioning. CONSTITUTION:Parts of two optical fibers 7, 8 whose terminals are preliminarily formed are allowed to face guide grooves 3 and 4 of a supporting base 1, and they are pressed in the direction perpendicular to axial lines to position them on the supporting base 1, and thereafter, terminal faces of optical fibers 7 and 8 are butted and they are melt-fixed by heating. Since the oscillation force is applied at the time of pressing both optical fibers 7 and 8 in this case, both optical fibers 7, 8 are surely guided to bottoms of guide grooves 3 and 4. Thus, the fiber connection work is simplified in case of connection of multicore optical fibers because the occurrence of axial deviation is reduced at the time of positioning of optical fibers 7, 8. In case of connection of single core optical fibers, fibers are connected with a low-cost device and the fiber connection time is shortened because a driving device, etc., which is required in a conventional method is unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for fusion splicing optical fibers in which the fibers are spliced by, for example, discharge heating.

[Conventional technology]

Conventionally, this type of optical fiber fusion splicing method has been carried out using an optical fiber fusion splicing apparatus shown in FIG. This optical fiber fusion splicing device will be explained based on the same figure. In the figure, the reference numeral 1 denotes a support base having a groove 2 opening upward in the center, and 3 and 4 refer to this support base 1. A guide groove with a V-shaped cross section extending on both sides of the concave groove, 5
and 6 are multi-core (4-core) optical fiber core wires having strands 7° 8, a portion of which faces into the id grooves 3 and 4, and whose end faces 7a and 8a face each other; and 9 and 10 A pair of clamps 11 and 1 press and hold the strands 7.8 of both multi-core optical fibers 5 and 6 on the support base 1.
Reference numeral 2 denotes a pair of electrodes which are provided between the two clamps 9 and 10 and which face each other via the connecting portions of the two strands 7 and 8. Note that 13 and 14 are covering portions from which the terminal portions of the two core wires 5 and 6 have been removed.

Next, a method for fusion splicing optical fibers using the splicing device configured as described above will be described.

First, the terminal coating portions of both optical fiber cores 5.6 are removed, and the bare fibers vA7, 8 are cut to form the pre-terminated 2.
Parts of the strands 7 and 8 of the two optical fibers are placed in the guide grooves 3 and 4 of the support base 1, respectively. Next, clamp these 9
．． 10 in a direction perpendicular to the axis of the optical fiber core 5.6 to position it on the support base 1. Thereafter, the terminal surfaces 7a and 8a of both the wires 7 and 8 are brought into contact with each other, and then the image electrodes 11 and 12 are heated and fused by causing an electric discharge between them.

In this way, two optical fibers can be connected.

By the way, in this lightning fiber fusion splicing method, there are cases in which the fibers of multi-core optical fiber tape are connected together, and cases in which the fibers of single-core optical fibers are connected together. It is known that if this is done in a misaligned state, a connection loss will occur which is proportional to the square of the amount of axis misalignment, as shown in FIG. In this case, as shown in Figure 5, the amount of axis misalignment is quite large at maximum 6 μm (and the connection loss is 0.2 μm).
The result is more than dB.

Therefore, when connecting optical fibers, it is necessary to prevent axial misalignment as much as possible since it is a major cause of connection loss.

[Problem to be solved by the invention]

However, in the conventional optical fiber fusion splicing method, the clamps 9 and 10 press and hold the optical fiber strands 7 and 8 on the support stand 1 at once, so the former (multi-core optical fiber connection) ), the axis misalignment detection device (
When axis misalignment is detected as shown in FIG. 6 by the method (not shown), it becomes necessary to bring each of the optical fiber strands 7 and 8 back into the guide grooves 3 and 4, which complicates the fiber connection work. There was a problem.

On the other hand, for the latter (single-core optical fiber connection), two support stands (not shown) on which both strands 7 and 8 are placed are prepared, and each support stand (not shown) is connected to a drive device. (not shown) to eliminate axis misalignment, but in this case, not only is the equipment expensive, but the drive device (not shown) is operated after detecting axis misalignment, making it difficult to connect fibers. This had the disadvantage of consuming a large amount of time.

The present invention was made in view of the above circumstances, and provides a method for fusion splicing of optical fibers, which enables fiber splicing using low-cost equipment, simplifies fiber splicing work, and shortens fiber splicing time. It provides a connection method.

[Means to solve the problem]

The method for fusion splicing optical fibers according to the present invention involves exposing parts of two pre-terminated optical fibers into a guide groove of a support, and then pressing them in a direction perpendicular to the axis. This is a method of connecting both optical fibers by positioning them on a support stand, then butting the end surfaces of these two strands together, and then heating and fusing them, and applying vibration force when pressing both strands. It is something.

[For production]

In the present invention, both strands of optical fiber are guided to the groove bottom of the guide groove by applying a vibration force to both strands of optical fiber during positioning.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the structure etc. of this invention will be explained in detail by the Example shown in the figure.

FIG. 1 is a perspective view showing an optical fiber fusion splicing apparatus used in the method according to the present invention. In this figure, the same members as in FIG. In the figure, reference numerals 21 and 22 indicate a pair of clamps that press and hold the wire 7.8 on the support base 1, each of which is a laminated piezoelectric clamp that expands and contracts depending on the polarity of the applied voltage. It is composed of actuators, each of which is configured to vibrate upon application of an alternating current voltage. Note that 23 is the piezoelectric actuator 21.22.
It is an AC power supply that applies voltage to the

Next, a method for fusion splicing optical fibers using the splicing device configured as described above will be described.

First, the terminal coating portions of both optical fiber cores 5.6 are removed, and the strands 7 and 8 are cut, and a part of the strands 7.8 of the two optical fibers whose terminals have been formed in advance are placed on the support stand 1. Guide groove 3
, 4 respectively. Next, these are clamped 21
．． 22 in a direction perpendicular to the axis of the optical fiber core 5.6 to position it on the support base 1. At this time, both the optical fiber strands 7, 8 are guided to the groove bottoms of the guide grooves 3, 4 by applying vibration force to both the optical fiber strands 7, 8 by the clamps 21, 22. Thereafter, the terminal surfaces 7a and 8a of both the wires 7 and 8 are brought into contact with each other, and then the image electrodes 11 and 12 are heated and fused by causing an electric discharge between them.

In this way, two optical fibers can be connected.

Therefore, in the present invention, the optical fiber wires 7, 8
Since the occurrence of axis misalignment during positioning can be reduced, the connection loss of the optical fiber can be significantly reduced.

This can be understood from the histograms of the amount of axis deviation shown in FIGS. 2(a) and 2(b).

In other words, by guiding the strands 7 and 8 to the groove bottoms of the guides a3 and 4 using the vibrations from the clamps 21 and 22 during fiber positioning, the amount of axis misalignment, which was 2.7 μm on average, becomes smaller on average after applying the vibration. The amount of axis misalignment, which was at most 5.4 μm, has increased to 3.6 μm, which is an improvement of 1.8 μm, which translates to a connection loss of 0.07 dB compared to 0.17 dB. It corresponds to becoming. Here, (a) and (b) of the same figure show the experimental results when the number of core wires is 80, and show the cases where vibration force is applied and the case where no vibration force is applied, respectively. 50 Hz) for 5 seconds.

Although this embodiment shows an example in which optical fibers are fusion spliced by electric discharge, the present invention is not limited to this, and other heat sources such as a laser or gas may also be used. .

〔Effect of the invention〕

As explained above, according to the present invention, parts of two pre-terminated optical fibers are exposed into the guide groove of the support base, and then they are supported by pressing them in a direction perpendicular to the axis. This is a method of connecting both optical fibers by positioning them on a table, then butting the end surfaces of both strands together, and then heating and fusing them, and applying vibration force when pressing both strands. Both optical fiber strands can be reliably guided to the bottom of the guide groove. Therefore, it is possible to reduce the occurrence of axis misalignment during positioning of the optical fiber strands, so that in the case of multi-core optical fiber connection, the fiber connection work can be simplified. Also,
In the case of single-core optical fiber connection, since the driving device and the like that were conventionally required are not required, the fiber connection can be performed using a low-cost device, and the fiber connection time can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an optical fiber fusion splicing device used in the method according to the present invention, and FIG. FIG. 3 is a perspective view showing an optical fiber fusion splicing apparatus used in the conventional method, and FIG. 4 is a diagram showing the relationship between the amount of axial deviation before fiber fusion and the splice loss after fiber fusion,
FIG. 5 is a histogram of the amount of axis misalignment according to the conventional method, and FIG. 6 is a diagram showing the state of occurrence of axis misalignment in a pair of optical fibers. 1... Support stand, 3.4... Guide groove, 5.6...
...core wire, 7,8... bare wire? a. 8a...terminal surface, 11.12...electrode, 13.
14... Covering part, 21.22... Clamp. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] Parts of the two optical fibers whose terminals have been formed in advance are exposed in the guide groove of the support base, and then positioned on the support base by pressing them in a direction perpendicular to the axis,
A method of connecting both optical fibers by then butting the end faces of these two strands together and then heating and fusing them, the method comprising: applying a vibrating force when pressing the two strands. fusion splicing method.