JPH0534531A - Method of splicing for assembled fibers - Google Patents

Abstract

PURPOSE:To provide the method of splicing assembled coated optical fibers to splice plural single optical fibers in one action by aligning both optical fibers laid horizontally to fix the aligned state of assembled fibers, and facilitates reassembling. CONSTITUTION:When plural coated optical fibers W1, W2,... are spliced at least the tip parts of the fibers W<1>, W2,... are coated with a soln. of a thermosetting resin adhesive soluble in an org. solvent, especially 10-20% soln. of polyvinyl butyral in ethanol and the fibers are assembled spliced. Reassembling is facilitated and the spliced coated optical fibers are made almost free from misalignment of the axes and connection loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collectively adhering optical fiber single-core wires, and more specifically to aligning a plurality of optical fiber single-core wires side by side, both optical fiber single-core wires being connected side by side. The present invention relates to a method of adhering to a group for assembling and fixing the aligned and assembled state.

[0002]

2. Description of the Related Art In the case of collectively connecting a plurality of optical fiber single-core wires (including tape core wires separated into single cores), a collective jig 1 (slide collective section 11 and cores) as shown in FIG. (Consisting of the wire guide portion 12), a plurality of optical fiber single-core wires (W _1, W _2, ...) On both sides of the connection are arranged side by side by arranging the core wire numbers, and the aligned and assembled state is fixed. Then, the procedure is to set the fiber holder jig for connection (not shown). In order to fix this aligned and assembled state, conventionally, (1) fixing is simply performed by using a metal clip such as a clip, and (2) an instant adhesive made of an organic polymer material as shown by reference numeral 2 in FIG. Collective adhesion methods such as applying and fixing in a tape form, and (3) similarly fixing in a tape form using a paste adhesive made of an inorganic material are used.

[0003]

However, each of the above-mentioned conventional methods for collectively adhering optical fiber single-core wires has its own drawbacks. That is, in the case of the mechanical collective fixing method of (1), the connecting work after the collective fixing (removal of coating, end face preparation, connection, reinforcement)
If you fail to open the fiber holder or if you accidentally open the fiber holder during the work, you may have to re-align, set, and fix it again. Deflection occurs in each optical fiber single-core wire when moving it, and the core wires easily cross in the reinforcing sleeve.If the reinforcement work is continued in this state and the operation is finished, loss of the connection part will occur if the outside temperature fluctuates. Tends to increase.

In the method (2) using the instant adhesive,
If the optical fiber single-strand wires are separated for some reason, they must be re-bonded, but at this time the instantaneous adhesive cures too quickly to reassemble the single-strand wires that have been separated. If the alignment is easy to collapse and the reassembly fails like this, it is necessary to separate the core wires again and repeat the assembly, but the instantaneous adhesive has too strong adhesive force to cover the core wires. It has the drawback of being damaged. In addition, since the instant adhesive has a low viscosity, it has a drawback that it may be adhered to other parts or parts which do not need to be applied with the adhesive along the gap between the core wires.

The difficulty of re-assembling is the same in the method (3). In particular, the paste-like adhesive easily enters between the single-core wires during application, and this causes the gap between the single-core wires of each optical fiber to be widened, and the misalignment of the axes is likely to occur during connection. Also, in the case of containing a large amount of inorganic materials such as calcium oxide and calcium carbonate, many residues remain on the clad surface even after wiping after removing the coating, and this residue abnormally burns due to electrical discharge for connection and deforms the core. Therefore, there is a drawback that the connection loss is increased. Further, the pasty adhesive generally has a weak adhesive force, and there is a disadvantage that it is easily separated when a twisting force is applied to the assembled single-core wires.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in fusion-splicing a plurality of optical fiber single-core wires together, these optical fiber single-core wires are to be connected. Is a method of assembling and adhering an optical fiber single-core wire, characterized in that a thermoplastic adhesive that can be dissolved by an organic solvent is applied to the aligned assembly of at least the tip portions of the. Further, the present invention is the method for collectively adhering optical fiber single-core wires, characterized in that polyvinyl butyral (PVB) is particularly used as the thermoplastic adhesive.

[0007]

[Function] A thermoplastic adhesive which can be dissolved by an organic solvent,
In particular, polyvinyl butyral obtains flow adhesiveness by being dissolved by an organic solvent to give an adhesive force to the surface of the optical fiber single core wire, and is rapidly cured by evaporation of this organic solvent so that two things intervening between themselves are mutually Let it adhere. Due to this property, the re-bonding and fixing of the single-core optical fiber is easy, the curing time is appropriate, and the assembly work is easy.

[0008]

EXAMPLE One example of the present invention will be described. For adhesion, polyvinyl butyral (PVB) is a solution of ethyl alcohol when applied. Solution concentration is 10-20%
Is appropriate. When applied to a single optical fiber, a minute amount is sufficient, and it cures in a few seconds. If the concentration exceeds 20%, the curing time will be delayed to 10 to 10 seconds. Also, the concentration is 1
If it is less than 0%, the adhesiveness will decrease. The state after curing becomes an extremely thin film, and even if they are applied repeatedly, the presence thereof does not change the distance between the cores, and does not cause axis deviation after connection. Even if it is once hardened, its flowability is restored by containing ethyl alcohol, so that reassembling work can be performed immediately when the ordered assembly is not perfect. Ethyl alcohol, which is the solvent for polyvinyl butyral, is convenient because the same one is used for wiping off the coating.

Polyvinyl butyral (PVB) of the present invention
Fig. 3 (in the case of PVB), when examining the frequency distribution regarding the axis deviation at the time of connection in the two cases of collective adhesion using and the conventional pasty adhesive As shown, when PVB is used, the axis deviation does not exceed 2.5 μm at the maximum, and the sampled values are concentrated around the average value of 1.3 μm. However, in the case of the conventional pasty adhesive, as shown in FIG. 4, a large amount of misalignment reaches 5 .mu.m, and the misalignment of the misalignment value is great.

Since PVB has very fine particles, even if it remains adhered to the clad surface of the optical fiber after the coating is removed, it can be easily wiped off with ethyl alcohol. Therefore, the occurrence of core deformation due to abnormal combustion of the residue is suppressed,
Connection loss is kept low. As for the connection loss, when a comparison was made using a histogram with the case of using the pasty adhesive as before, when using PVB, as shown in Fig. 5, the numerical values of all the samples did not exceed 0.1 dB at the maximum. Is less than this. On the other hand, in the case of the paste adhesive, as shown in FIG.
A connection loss of 7 dB was observed, and other poor connection such as 1.8 dB was found in some of the 40 samples, which is a poor result.

Next, another embodiment of the present invention will be described. Among the thermoplastic resins, vinyl-based ones are easy to use and can be reassembled according to the PVB described above. For example, vinyl acetal, vinyl acetate, vinyl acetate copolymer and the like. Both are used as an ethyl alcohol solution like PVB.

As another group of thermoplastic resins, acrylic resins have relatively good results. Examples thereof include ethyl acrylate, butyl methacrylate, isobutyl methacrylate and the like. However, for these acrylic compounds, ethyl alcohol is not suitable as a solvent, and esters or ketones are preferred.

[0013]

According to the present invention, a thermoplastic adhesive which can be dissolved in an organic solvent, particularly polyvinyl butyral, has a flow adhesive property by being dissolved in an organic solvent to give an adhesive force to the surface of an optical fiber single core. , The organic solvent is rapidly hardened by evaporation and has the effect of adhering the optical fiber single-core wires interposing each other to each other. Further, due to this property, there is an advantage that the single-core optical fiber can be easily reassembled, adhered and fixed, the curing time is appropriate, and the assembly work is easy.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a collecting jig used for carrying out the method of the present invention.

FIG. 2 is a perspective view showing a state in which end portions of single-core optical fibers are collectively bonded.

FIG. 3 is a histogram showing a frequency distribution of axis deviation values after connection of optical fiber single-core wires assembled using PVB.

FIG. 4 is a histogram showing a frequency distribution of axis deviation values after connection of optical fiber single-core wires assembled using a conventional paste adhesive.

FIG. 5 is a histogram showing a frequency distribution of splice loss values for optical fiber single-core wires assembled by using PVB.

FIG. 6 is a histogram showing a frequency distribution of splice loss values for an optical fiber single-core wire assembled using a conventional paste adhesive.

[Explanation of symbols]

W _1, W ₂ single optical fiber

Claims (2)

[Claims] 1. A plurality of optical fiber single-core wires (W _1, W _2, ...)
In fusing and splicing all of them together, a thermoplastic adhesive that can be dissolved by an organic solvent is applied to an aligned assembly of at least the tip end portions of these optical fiber single-core wires (W _1, W _2, ...). Method for collectively adhering single-core optical fiber. 2. A polyvinyl butyral (PVB) is used as the thermoplastic adhesive.
A method for collectively adhering a single optical fiber according to the description.