JP2872095B2 - Resin-filled optical fiber unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin-filled optical fiber unit used in the field of optical communication and the like.

[0002]

2. Description of the Related Art In the field of optical communication and the like, a resin-filled optical fiber unit is used in which a plurality of optical fiber cores are assembled and integrated using a resin. This resin-filled optical fiber unit has the configuration shown in FIG. The resin-filled optical fiber unit 1 includes a tensile strength line 2 located at the center of the unit, an optical fiber core 3 disposed around the tensile strength line 2, and an inner layer for fixing the tensile strength line 2 and the optical fiber core 3. Unit enrichment 4 and outer unit enrichment 5 coated on inner layer enrichment 4
It is composed of This optical fiber unit 1
They are further assembled to form a submarine optical fiber cable or the like.

In this optical fiber unit 1, the outer layer unit enrichment material 5 is made of a relatively hard resin, for example, an ultraviolet curable resin (hereinafter abbreviated as UV resin). To protect. Also, since the inner layer unit enrichment material 4 is made of a relatively soft resin, for example, a UV resin, it protects the optical fiber core wire 2 by relaxing external force. Generally, UV resin is used as a solid material for each optical fiber unit because it cures quickly and has good productivity.

As the resin constituting the outer layer unit enrichment material 5, a resin having a large tear elongation is preferable in order to prevent the optical fiber unit from being broken by an external force. Therefore, a relatively large resin having a tear elongation of about 7% is conventionally used as the resin for the outer layer unit enrichment material.

On the other hand, this type of optical fiber unit is required to process its terminal, take out the optical fiber core, and connect it to the optical fiber core of another optical fiber unit. Wire to fiber optic unit,
Specifically, it is desirable to be able to separate from various solid materials constituting the optical fiber unit.

In the terminal processing of the optical fiber unit 1, as shown in FIGS. 7A to 7C, the terminal of the optical fiber unit 1 is connected to a divided optical fiber including optical fiber cores 3a and 3b. The optical fiber is divided into two units: a unit 1a and a divided optical fiber unit 1b including optical fiber cores 3c and 3d. Here, FIG. 7A is a side view showing a case where the terminal processing is performed on the optical fiber unit 1, FIG. 7B is a cross-sectional view of the split optical fiber unit 1a, and FIG. It is sectional drawing of the optical fiber unit 1b.

[0007]

As described above, when the optical fiber unit 1 is divided into two parts, the inner layer unit enrichment material 4
And the outer layer unit enrichment material 5 are not equally divided. That is, when the section of the optical fiber unit 1 is divided, for example, when the divided optical fiber unit 1a has a substantially circular shape as shown in FIG. 7B, the divided optical fiber unit 1b becomes as shown in FIG. 7C. Has a concave portion corresponding to the split optical fiber unit 1a and has a claw-shaped end C. Therefore, in the terminal processing, the optical fiber unit 1
Is divided into two, the divided optical fiber units 1a, 1
b, the split optical fiber unit 1a
Is caught on the end C of the split optical fiber unit 1b. As a result, if the optical fiber units 1a and 1b are forcibly pulled apart in this state, the optical fiber cores 3a and 3b are disconnected. Further, when taking out the optical fiber cores 3c and 3d from the split optical fiber unit 1b, the optical fiber cores 3c and 3d are also connected to the optical fiber unit 1b.
The optical fiber core wires 3c and 3d are caught on the end C of the wire b. As described above, the conventional resin-filled optical fiber unit has a problem that the terminal processing cannot be performed satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a resin-filled optical fiber unit which can sufficiently protect against external force and can perform a good terminal treatment.

[0009]

According to the present invention, there is provided an inner layer unit filling material for interposing a plurality of optical fibers, and an outer layer unit filling material formed outside the inner layer unit filling material. The resin constituting the solid material is 3.0 to
Provided is a resin-filled optical fiber unit having a tear elongation of 4.5%.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical fiber unit according to the present invention comprises:
A resin comprising an inner layer unit enrichment material for interpolating a plurality of optical fiber cores and an outer layer unit enrichment material formed outside the inner layer unit enrichment material, wherein the resin constituting the outer layer unit enrichment material is 3.0 to 4 It has a tear elongation of 0.5%. In particular, the resin constituting the outer layer unit enrichment material preferably has a tear elongation of about 3.5%.

As described above, when the tear elongation of the outer layer unit enriched material is in the range of 3.0 to 4.5%, even if the optical fiber unit is divided at the time of terminal processing of the optical fiber unit, the end shape thereof is not changed. Since the divided optical fiber unit and the optical fiber core are not caught at the end, the problem of disconnection of the optical fiber core does not occur, and the optical fiber unit is not broken by an external force. In addition, the tearing property is better as the tear elongation is smaller, but if the tear elongation is less than 3.0%, plastic deformation occurs when an external force is applied, and the fiber cannot be used as an optical fiber unit. On the other hand, when the tear elongation exceeds 4.5%, the tearability is deteriorated, so that the terminal treatment cannot be performed well.

In the present invention, UV resin, thermosetting resin, electron beam curable resin and the like can be used as the resin constituting the outer layer unit enrichment material. In particular, in the case of a UV resin, a urethane acrylate resin is preferable. Further, as the material constituting the inner layer unit enrichment material, the UV resin, the thermosetting resin, the electron beam curable resin, or the like can be used. In consideration of workability, it is preferable to use a UV resin. In consideration of the shell effect, it is preferable that the resin forming the outer layer unit filling material and the resin forming the inner layer unit filling material be different.

In the present specification, the tear elongation is defined as
It refers to a value determined from the tear elongation obtained by a test based on JIS K6301 (1975). Specifically, a test piece (B type) is prepared from a sheet having a thickness of 70 μm, the tear elongation is measured at a tear speed of 1 mm / min, and the tear elongation rate is calculated from the measured value. However, the tear elongation shall be determined by dividing the distance between the marked lines on the test specimen before the tear fracture by the distance between the marked lines on the test specimen after the tear fracture. When the resin forming the outer layer unit enrichment material is a curable resin, a test piece is prepared from a sheet obtained by curing the resin in advance. For example, in the case of a UV resin, a test piece is prepared from a sheet previously irradiated with ultraviolet rays (UV light) of about 1000 J / cm ² by a metal halide lamp.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the optical fiber unit of the present invention. The optical fiber unit 11 includes a tensile wire (tension member) 12 having an overcoat layer 12 a on the outer periphery and four optical fiber core wires 13 spirally arranged around the tensile wire 12.
And an inner layer unit enrichment material 14 formed so as to embed and fix the tensile wire 12 and the optical fiber core wire 13, and an outer layer unit enrichment material 15 provided on the outer periphery of the inner layer unit enrichment material 14. ing.

The tensile strength wire 12 is arranged at the center of the optical fiber unit section in order to prevent an unnecessary tension from being applied to the optical fiber, and a steel wire, a piano wire or the like can be used. The outer diameter of the tensile strength wire 12 depends on the outer diameter of the optical fiber unit, but is preferably about 0.3 to 1.2 mm in consideration of the space factor. When a steel wire is used as the tensile wire 12,
The surface may be subjected to surface treatment such as plating.

As a material of the overcoat layer 12a,
Examples thereof include a UV resin, a thermosetting resin, and an electron beam curable resin. Further, the thickness of the overcoat layer is preferably about 0.02 to 0.2 mm in consideration of the space factor.

The optical fiber cores 13 may be arranged in four cores as shown in FIG. 1, and as shown in FIGS. 3 and 4,
They may be arranged with 6 cores and 8 cores, respectively. In addition, the optical fiber core 13 is usually formed around the tensile strength wire 12 and the tensile strength wire 1.
2 are arranged along the longitudinal direction.

The outer diameter of the inner layer unit enrichment material 14 is 1.6
The outer diameter of the outer layer unit enrichment material is preferably about 2.0 to 3.0 mm.

Next, an embodiment for clarifying the effect of the present invention will be described. In this example, several types of optical fiber units 11 were manufactured by changing the outer diameter, the number of optical fiber cores 13, and the tear elongation of the outer layer unit enrichment material 15. The optical fiber core 13 constituting the optical fiber unit 11 of the present embodiment has an outer diameter of 0.4 mm, and the tensile strength wire 12 has an outer diameter of 0.6 mm.
mm copper-plated piano wire was used. Furthermore, the overcoat layer 12a was a UV resin layer having a thickness of 0.03 mm.

The resin constituting the inner layer unit enrichment material 14 is a UV resin DIC FC-2111 (trade name, 16% tear elongation, manufactured by Dainippon Ink Co., Ltd.).
Other resins may be used as the resin constituting the outer layer unit enrichment material 15, such as a UV resin GRANDICFC-2403A.
(Dai Nippon Ink Co., Ltd., trade name, tear elongation 3.5%) and others.

In this embodiment, FIGS.
As shown in (C), the four-core optical fiber unit 11
Is divided into a split optical fiber unit 11a including the optical fiber cores 13a and 13b and a split optical fiber unit 11b including the optical fiber cores 13c and 13d. That is, the optical fiber unit 11 is divided in such a manner that the inner layer unit enrichment material 14 is almost equally divided, and becomes divided optical fiber units 11a and 11b. Here, FIG. 2A is a side view showing a case where the terminal processing is performed on the optical fiber unit 11, FIG. 2B is a cross-sectional view of the split optical fiber unit 11a, and FIG. Optical fiber unit 1
It is sectional drawing of 1b.

As a result, the torn end C of the split optical fiber unit 11b having a large cross-sectional area is the same as the torn end C of the conventional split optical fiber unit 11b shown in FIG.
Smaller than. Therefore, the optical fiber unit 1
Even if 1 is split and separated into the split optical fiber units 11a and 11b, the split optical fiber unit 11a does not catch on the torn end portion C of the split optical fiber unit 11b during the terminal processing operation. Also, when the optical fiber cores 13c and 13d are taken out from the split optical fiber unit 11b, the optical fiber cores 13c and 13d do not catch on the end C. Thereby, the terminal processing of the optical fiber unit 11 can be performed favorably. The optical fiber unit 11 can sufficiently protect the optical fiber unit from external force.

With respect to each of the optical fiber units 11 manufactured by changing the tear elongation rate, the number of optical fibers, and the unit outer diameter of the outer layer unit enrichment material 15, the terminal treatment was examined. The results are shown in Table 1 below. In addition,
As for the terminal processing property, as shown in FIG. 2 (A), the coating of one optical fiber unit was peeled off over 20 m (the inner layer unit enrichment material 14 and the outer layer unit enrichment material 15 were divided), and even one optical fiber unit was used. If the core wire is broken or the sheath of the optical fiber core is peeled off,
A case in which there was no disconnection or peeling of the coating was regarded as good.

[0024]

[Table 1]

From the results shown in Table 1, it can be seen that the terminal treatment property is the best when the tear elongation of the outer layer unit enriched material is 3.5%. Specifically, when the tear elongation rate is 3.5%, the terminal processing property is good regardless of the outer diameter of the optical fiber unit and the number of optical fiber cores. However, the tear elongation of the outer layer solid material is 5%.
%, The terminal processability was poor when the number of optical fiber cores was as small as four, and when it was 7%, the terminal processability was poor under all conditions.

Incidentally, in order to investigate the influence of the external force applied when each of the above optical fiber units is laid, the fracture resistance was examined by measuring the change in loss and the change in outer diameter in a lateral pressure test. It was able to withstand external forces. However, when the tear elongation of the outer layer unit filling material was smaller than 3%, the outer layer unit filling material was plastically deformed when an external force was applied, and could not be used as an optical fiber unit.

Next, using an optical fiber unit in which the tear elongation of the enriched material of the outer layer unit is 3.5%, FIG.
An optical submarine cable shown in FIG. 5A and FIG. 5B was produced. This optical submarine cable has an outer diameter of about 22.5 mm, and as shown in FIG.
A three-piece iron piece (first metal layer) 21 provided on the outer circumference of the optical fiber unit 11, a plurality of tensile wires 22 arranged around the three-piece iron piece 21, and , A copper tube (second metal layer) 23, an insulating layer 24 provided on the copper tube 23, and a sheath layer 25 provided on the insulating layer 24.
Here, a polyolefin such as polyethylene is used as a material of the insulating layer 24, and a polyolefin such as polyethylene is used as a material of the sheath layer 25.

Also in the optical submarine cable having the above-mentioned structure, since the tear elongation rate of the outer layer unit enrichment material is 3.5% which is within the range of the present invention, it is possible to perform the terminal treatment satisfactorily and to reduce the external force. It has sufficient strength for it.

[0029]

As described above, the resin-filled optical fiber unit of the present invention comprises an inner layer unit filling material for inserting a plurality of optical fiber cores, and an outer layer unit formed outside the inner layer unit filling material. Since the resin constituting the outer layer unit enriched material has a tear elongation of 3.0 to 4.5%, it can be sufficiently protected from external force and can be subjected to favorable terminal treatment. Things.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an optical fiber unit according to the present invention.

FIG. 2A is an explanatory diagram showing a case where a terminal process is performed on an optical fiber unit, and FIG. 2B is a diagram showing IIB-IIB in FIG.
FIG. 2C is a cross-sectional view along the line, and FIG. 2C is a cross-sectional view along the IIC-IIC line in FIG.

FIG. 3 is a sectional view showing another example of the optical fiber unit of the present invention.

FIG. 4 is a sectional view showing another example of the optical fiber unit of the present invention.

5A is a sectional view showing an optical submarine cable using the optical fiber unit of the present invention, and FIG. 5B is an enlarged view of the optical fiber unit in FIG.

FIG. 6 is a sectional view showing an optical fiber unit.

7A is an explanatory diagram showing a case where a terminal process is performed on an optical fiber unit, and FIG. 7B is a diagram showing VIIB-VIIB in FIG.
Sectional drawing which follows the line, (C) is sectional drawing which follows the VIIC-VIIC line in (A).

[Explanation of symbols]

11, 11a, 11b ... optical fiber unit, 12, 2
2: strength line, 12a: overcoat layer, 13, 13
a, 13b, 13c, 13d ... optical fiber cores, 14 ...
Inner layer unit filling material, 15 ... Outer layer unit filling material, 21
… Three-piece iron pieces, 23… copper tubes, 24… insulation layers, 2
5 ... sheath layer.

Claims (5)

(57) [Claims] 1. A resin constituting an outer layer unit enrichment material, comprising: an inner layer unit enrichment material for inserting a plurality of optical fiber core wires; and an outer layer unit enrichment material formed outside the inner layer unit enrichment material. Has a tear elongation of 3.0 to 4.5%. 2. The resin-filled optical fiber unit according to claim 1, wherein the resin constituting the outer layer unit filling material is an ultraviolet curable resin. 3. A tensile strength line is inserted in the inner layer unit enrichment material so as to be located substantially at the center of the cross section of the inner layer unit enrichment material, and the optical fiber core wire is helically disposed around the tensile strength line. The resin-filled optical fiber unit according to claim 1. 4. An inner layer unit filling material for interposing a plurality of optical fiber core wires, and an outer layer formed of resin having a tear elongation of 3.0 to 4.5% formed outside the inner layer unit filling material. A resin-filled optical fiber unit composed of a unit-filling material, a tensile strength line arranged on the resin-filled optical fiber unit via a first metal layer, and a second metal layer on the tensile strength line. An optical submarine cable, comprising: an insulating layer provided through the optical submarine cable. 5. The optical submarine cable according to claim 4, wherein the resin forming the outer layer unit enrichment material is an ultraviolet curable resin.