JPH07261051A - Simultaneous fusion-splicing method of multicore optical fiber - Google Patents

Abstract

PURPOSE:To surely and simultaneously fusion-splice plural optical fibers to each other with a low loss by subjecting all of the respective plural optical fibers of the multicore optical fiber to be connected to each other to uniform heating, thereby uniformly fusing these fibers. CONSTITUTION:The respective front ends of the bare optical fibers 11 to 14 are melted by heating and are eventually deformed into a round shape by the effect of surface tension. The front end positions retract from the original front end positions but distances d1 to d4 are thereafter measured and a fusion- splicing device is so adjusted that these distances are equaled. The front ends of the bare optical fibers 11 to 14 and the front ends of the other bare optical fibers to be arranged opposite thereto are then simultaneously heated and thereafter, the front ends of the bare optical fibers on both sides to be arranged opposite to each other are pushed in a direction where these front ends but against each other, thereby, the optical fibers are simultaneously fusion-spliced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fusion splicing optical fibers, and more particularly to a method for collectively splicing multi-core optical fibers.

[0002]

2. Description of the Related Art In a fusion splicing method for optical fibers, the tips of two optical fibers to be spliced to each other are heated and melted together, and when they are melted, they are pushed in a direction in which they are abutted to each other for fusion splicing. In such a fusion splicing method, it is important to know exactly how much heat is actually applied.

Particularly, in the case of connecting multi-core optical fibers together, it is important to uniformly heat these many optical fibers in order to ensure reliable connection and reduce the connection loss. It is desirable to accurately measure uniformity.

Therefore, conventionally, when atmospheric pressure discharge is used as a heat source, for example, the light generated by the discharge during discharge is transmitted to the TV.
It has been attempted to measure the heating intensity from the brightness distribution obtained by imaging with a camera or the like.

[0005]

However, in the method of measuring the heating intensity from the brightness distribution of the image of the light generated by the discharge with the TV camera or the like, the amount of heat actually applied to the optical fiber is directly measured. However, it is merely an analogy of this from the heat of the heat source itself, which is captured from the brightness, and can be said to be indirect and qualitative. Therefore, it is not possible to secure the heating uniformity during the fusion splicing of the multi-core optical fibers.

Further, since the luminance distribution is analyzed from the image of the discharge light taken by a TV camera or the like, a storage device or an image processing device for storing one image of the image is required, and the entire device becomes large in scale. There are problems such as taking time.

The present invention ensures uniform heating of a large number of optical fibers in the case of fusion-splicing multi-core optical fibers together, and ensures reliable and loss-free for all of the large number of optical fibers. It is an object of the present invention to provide a collective fusion splicing method for multi-core optical fibers, which enables collective splicing with less number of fibers.

[0008]

In order to achieve the above object, in the method for collectively splicing multi-core optical fibers according to the present invention, the amount of receding due to heating of the tips of the optical fibers of the multi-core optical fibers is equal. After heating and melting each of these optical fibers at once, press the tips of the optical fibers of both multi-core optical fibers that should be connected to each other in the direction in which they abut, and perform fusion splicing. Is a feature.

[0009]

Operation When heat is applied to the end of the optical fiber, the tip of the optical fiber melts and becomes round due to surface tension. Therefore, the tip position retracts from the original position before heating by the amount of this rounding.

Since this amount of receding corresponds to the amount of melting of the tip, that is, the amount of heat actually applied to the tip, if the tips of a plurality of optical fibers are collectively heated so that the amounts of receding are equal. The amount of heat actually applied to the plurality of optical fibers can be exactly and quantitatively matched.

Therefore, by collectively connecting the plurality of optical fibers so that the amounts of receding due to the heating of the tips of the plurality of optical fibers become equal, all the plurality of optical fibers can be uniformly heated and uniformly melted. Thus, the plurality of optical fibers can be reliably and collectively fused and spliced with low loss.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a multi-core optical fiber 1 is formed in a tape shape, and core wires are arranged in parallel. The coating 15 is peeled off at the end, and the bare optical fibers 11 to 11
14 is exposed. The bare optical fibers 11 to 14 are cut into the same length, and the tip positions of the bare optical fibers 11 to 14 are arranged in a straight line.

In this embodiment, in the batch fusion splicing apparatus for multi-core optical fibers, the tips of these bare optical fibers 11 to 14 are collectively heated by atmospheric pressure discharge by a pair of electrodes 2, 2.

Although not shown in the figure, a multi-core optical fiber similar to this multi-core optical fiber 1 is placed on the lower left side of FIG. 1, and these bare optical fibers are the above-mentioned bare optical fibers 1.
1 to 14 are arranged to face each other. The plurality of bare optical fibers of the omitted multi-core optical fiber are also cut into the same length, and the respective tip positions are arranged in a straight line. As described above, the two rows of the bare optical fibers are collectively heated by the atmospheric pressure discharge by the electrodes 2 and 2 with their tips facing each other.

When actually heated, the tips of the bare optical fibers 11 to 14 are melted by the heat and deformed into a round shape as shown in FIG. 2 by the action of surface tension. Then, the tip position retreats from the tip position shown by the original dotted line by the amount of the deformation to the round shape. This retreat distance d1,
d2, d3 and d4 are measured respectively. Then, the larger the amount of heat actually applied to the tips of the bare optical fibers 11 to 14 is, the larger the amount of melting is and the larger the amount of retreat is. Therefore, the retreat distances d1, d2, d3 and d4 are It is considered to correspond to the amount of heat actually applied to the tips of 11 to 14.

Therefore, the retreat distances d1, d2, d
If 3, d4 are equal, the amount of heat actually applied to the tips of the bare optical fibers 11 to 14 is equal. Therefore,
When the plurality of bare optical fibers 11 to 14 are collectively heated, the fusion splicing device is adjusted so that the receding distances d1, d2, d3, d4 of their tips become equal. The adjustment so that the receding distances are equal to each other is performed not only for one row of the bare optical fibers of the multi-fiber optical fibers on one side to be fusion-spliced but also for the one row of the multi-fiber optical fibers on the other side. Do this for bare optical fiber.

The retreat distances d1, d2, d of this tip position
3 and d4 are visually observed with a microscope and measured with a visual field scale, or with a small TV camera and a monitor device, on a monitor screen,
Furthermore, it is also possible to process the leading edge image captured by the TV camera by the image processing device and perform automatic measurement. Even when the image is processed by the image processing device and automatically measured, the device can be configured simply because it is not necessary to store the information of the entire screen by only measuring the moving distance of the tip positions of the bare optical fibers 11 to 14. It can be downsized and does not take much processing time.

As described above, the receding distance d from the position before heating of the tips of the bare optical fibers 11 to 14 after heating.
Measuring 1, d2, d3, d4 means measuring quantitative parameters that correspond well to the amount of heat actually applied to the tips of the bare optical fibers 11-14. The fact that the receding distances d1, d2, d3 and d4 match means that
This means that the amounts of heat applied to the tips of the bare optical fibers 11 to 14 are the same.

Therefore, if the fusion splicing device is adjusted in this way to perform the fusion splicing at once, the same amount of heat is applied to a plurality of bare optical fibers, and the opposing optical fibers are abutted to each other in a molten state. Since it is possible to push in a direction to make a collective connection, it is possible to perform a reliable and low-loss collective fusion connection between the multi-core optical fibers 1.

Although the atmospheric pressure discharge was used as the heat source in the above-mentioned embodiments, the measuring method of the present invention can be applied to any one such as an oxyhydrogen flame or a carbon dioxide laser.

[0021]

As described above with reference to the embodiments, according to the batch fusion splicing method for multi-core optical fibers of the present invention, the tips of these optical fibers are bundled together so that the amount of receding due to heating is the same. After heating, they are pushed in the direction of abutting and are fused and spliced together, so uniform heating can be performed on all of the multiple optical fibers, and they can be melted uniformly. It is possible to reliably and with low loss collectively perform the fusion splicing. In order to perform uniform heating on all of the plurality of optical fibers, it is only necessary to measure the amount of recession due to heating of each optical fiber.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a change in shape of the tip of an optical fiber before and after heating.

[Explanation of symbols]

 1 multi-core optical fiber 11-14 optical fiber bare wire 15 coating 2 discharge electrode

Claims (1)

[Claims] 1. A multi-core optical fiber, which is to be connected to each other after being melted by collectively heating the respective optical fibers so that the amounts of receding due to heating of the respective optical fibers become equal. A collective fusion splicing method for multi-core optical fibers, characterized in that the tips of the respective optical fibers are pushed together in the direction in which they are abutted and fused together.