JP7188932B2 - Optical fiber tape core wire, optical fiber cable, and fusion splicing method for optical fiber tape core wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to optical fiber ribbons, optical fiber cables, and fusion splicing methods for optical fiber ribbons.

2. Description of the Related Art Conventionally, an optical fiber ribbon as shown in Patent Document 1 below has been known. This optical fiber ribbon has slits intermittently provided in a coating portion that collectively coats a plurality of optical fiber strands.
Such an optical fiber ribbon is housed in a sheath and used as an optical fiber cable.

JP 2009-163045 A

In recent years, in order to accommodate more optical fiber strands without increasing the outer diameter of the optical fiber cable, it is desired to reduce the outer diameter of the optical fiber strands. For example, conventionally, an optical fiber strand having an outer diameter of 250 μm has been widely used. However, in recent years, for example, the outer diameter of the bare optical fiber is required to be approximately 80 μm, and the outer diameter of the coated layer such as the colored layer is required to be approximately 170 μm.
Here, when the optical fiber ribbon is composed of optical fiber strands with a small outer diameter, the optical fiber ribbon has a small rigidity, so there is a problem that the optical fiber ribbon is excessively bent in the cable. be. Excessive bending of the optical fiber ribbon leads to large macrobend loss.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical fiber ribbon with increased rigidity.

In order to solve the above problems, the optical fiber tape core wire according to the first aspect of the present invention is a first unit having at least three optical fiber strands and a coating section for coating the optical fiber strands. and a second unit, and a plurality of connecting portions for connecting the first unit and the second unit, wherein the direction in which the optical fiber strand extends is set as a longitudinal direction, and the first unit and When the direction in which the second unit faces each other across the connecting portion is defined as the connecting direction, and the direction perpendicular to both the longitudinal direction and the connecting direction is defined as the orthogonal direction, the plurality of connecting portions are arranged in the longitudinal direction. At least two of the optical fiber strands intermittently arranged in the first unit are arranged at positions shifted from each other in the orthogonal direction.

According to the above aspect of the present invention, it is possible to provide an optical fiber ribbon with increased rigidity.

The perspective view which showed the shape of the cross section of the optical fiber tape core wire which concerns on this embodiment. 2 is a cross-sectional view of an optical fiber cable provided with the optical fiber ribbon of FIG. 1; FIG. FIG. 2 is a diagram showing how the first unit of FIG. 1 is deployed; It is the figure which showed a mode that the optical fiber tape core wire of FIG. 1 was developed. (a) to (d) are diagrams showing modifications of the optical fiber ribbon according to the present embodiment. (a) to (c) are diagrams showing other modifications of the optical fiber ribbon according to the present embodiment.

The optical fiber ribbon according to this embodiment will be described below with reference to the drawings.
As shown in FIG. 1, the optical fiber ribbon 20 includes a first unit 1A, a second unit 1B, a third unit 1C, a fourth unit 1D, a plurality of connecting portions 2, It has A plurality of connecting portions 2 connect the units 1A to 1D together. Each of the units 1A-1D has three optical fiber strands 3A-3C.

(direction definition)
In this embodiment, an XYZ orthogonal coordinate system is set and the positional relationship of each component will be described. The direction along the X-axis is the direction in which the optical fiber wires 3A to 3C extend (hereinafter referred to as longitudinal direction X). The direction along the Y axis is the direction in which the first unit 1A and the second unit 1B face each other with the connecting portion 2 interposed therebetween (hereinafter referred to as the connecting direction Y). The direction along the Z-axis is a direction orthogonal to both the longitudinal direction X and the connecting direction Y (hereinafter referred to as orthogonal direction Z).
A cross section orthogonal to the longitudinal direction X is called a cross section. FIG. 1 is a perspective view showing the cross-sectional shape of the optical fiber ribbon 20. FIG.

(optical fiber cable)
The optical fiber tape core wire 20 is used by being housed in an optical fiber cable 50 as shown in FIG. 2, for example. In addition, in FIG. 2, the shape of the optical fiber tape cable core 20 is simplified and displayed.

The optical fiber cable 50 has a core 52 and a sheath 54 covering the core 52 . The core 52 includes a plurality of optical fiber tape core wires 20 and a pressing winding 53 (wrapping tube) that covers the plurality of optical fiber tape core wires 20 .
Each optical fiber tape core wire 20 is housed inside a pressure winding 54 in a state of being bundled with a binding material 51 . In addition, although one binding material 51 is wound around two optical fiber tape core wires 20 in FIG. Also, the binding material 51 may be omitted. A plurality of optical fiber tape core wires 20 are accommodated in the sheath 54 while being twisted together in an SZ shape, spiral shape, or the like.

The binding material 51 is wound around the optical fiber ribbon 20 in an SZ shape, spiral shape, or the like. By coloring the binding material 51, the distinguishability between the optical fiber ribbons 20 may be improved. As the binding material 51, for example, a combination of a plurality of fibers made of a high melting point material such as polyethylene terephthalate (PET) and a low melting point material such as polypropylene (PP) can be used. Note that the configuration and material of the binding material 51 are not limited to those described above, and can be changed as appropriate.

A pair of tension members 56 and a pair of tear cords 57 are embedded inside the sheath 54 . A pair of tear strings 57 are embedded in the sheath 54 at a position close to the inner peripheral surface. Marker protrusions 58 are provided on the outer peripheral surface of the sheath 54 outside the positions where the pair of tear strings 57 are arranged. A marker projection 58 is formed along the tearing string 57 and guides the embedding position of the tearing string 57 .

Note that the optical fiber cable 50 may not include the pressure wrap 54 , the tension member 56 , the tear string 57 and the marker protrusion 58 .

(optical fiber ribbon)
As shown in FIG. 1, the units 1A to 1D in the optical fiber ribbon 20 each include three optical fiber strands 3A to 3C, a coating section 10 for coating these optical fiber strands 3A to 3C, have. Each of the optical fiber wires 3A to 3C has an optical fiber bare wire B and a coating layer C covering the optical fiber bare wire B. FIG. The coat layer C may be one layer, or may be composed of two or more layers. That is, the optical fiber strands 3A to 3C may have only the primary layer, or may have secondary layers, colored layers, and the like. In addition, when the coat layer C is only one layer (primary layer), the Young's modulus of the outer covering portions 11 and 12 (described later) of the covering portion 10 is the same as the Young's modulus of a general secondary layer (700 to 1400 MPa). It may be a degree.

The number of units 1A to 1D included in the optical fiber ribbon 20 may be appropriately changed as long as the number is two or more. That is, the optical fiber ribbon 20 has at least the first unit 1A and the second unit 1B. The number of optical fiber strands 3A-3C included in each unit 1A-1D may be changed appropriately as long as it is three or more. That is, each unit 1A-1D has at least three optical fiber strands 3A-3C.

A plurality of connecting portions 2 connecting the first unit 1A and the second unit 1B are provided at intervals in the longitudinal direction X. As shown in FIG. That is, the units 1A and 1B are intermittently fixed. Similarly, the second unit 1B and the third unit 1C, and the third unit 1C and the fourth unit 1D are intermittently fixed by a plurality of connecting portions 2. As shown in FIG.
The connecting portion 2 that connects the units 1A and 1B to each other and the connecting portion 2 that connects the units 1B and 1C to each other are arranged at positions shifted in the longitudinal direction X. As shown in FIG. Thus, the plurality of connecting portions 2 of the optical fiber ribbon 20 are arranged in a zigzag pattern. Note that the arrangement of the connecting portion 2 may be changed as appropriate. Also, the strength of connection between the units 1A to 1D by the connecting portion 2 can be adjusted as appropriate.

In cross-sectional view, each of the units 1A to 1D is formed in a substantially polygonal shape (substantially triangular shape in this embodiment). The connecting portion 2 is arranged to connect the corners of the units 1A to 1D adjacent in the connecting direction Y. As shown in FIG.

In cross-sectional view, the three optical fiber strands 3A-3C included in each unit 1A-1D are arranged in a triangular shape. More specifically, the optical fiber wires 3A and 3B are arranged side by side in the connection direction Y. As shown in FIG. The optical fiber strand 3C is arranged at a position shifted in the orthogonal direction Z with respect to the two optical fiber strands 3A and 3B. In the connection direction Y, the central axis of the optical fiber wire 3C is located between the central axes of the optical fiber wires 3A and 3B.

Further, the optical fiber strand 3A is in contact with both the optical fiber strands 3B and 3C, and the optical fiber strand 3B is in contact with both the optical fiber strands 3A and 3C. That is, the optical fiber strands 3A to 3C in one unit are in contact with each other. In this manner, the optical fiber strands 3A to 3C are arranged in a close-packed manner.

With the above configuration, at least two of the optical fiber wires 3A to 3C included in one unit are arranged at positions shifted in the orthogonal direction Z from each other. For example, in the first unit 1A shown in FIG. 1, the optical fiber 3C is arranged at a position shifted in the orthogonal direction Z with respect to the optical fiber 3A. Therefore, the rigidity against bending in the orthogonal direction Z of the first unit 1A is enhanced.

Moreover, at least two of the optical fiber wires 3A to 3C included in one unit are arranged at positions shifted in the connecting direction Y from each other. For example, in the first unit 1A, the optical fiber wire 3B is arranged at a position shifted in the connecting direction Y with respect to the optical fiber wire 3A. Therefore, the rigidity against bending in the connection direction Y of the first unit 1A is enhanced.

In this embodiment, the coating section 10 collectively coats the optical fiber wires 3A to 3C. Each of the units 1A to 1D has a covering portion 10, which has outer covering portions 11 and 12 positioned on the outer periphery and an inner covering portion 13 positioned on the inside. The first outer covering portion 11 and the second outer covering portion 12 have different adhesion strengths to the optical fiber strands 3A to 3C. The adhesion force of the second outer coating portion ₁₂ to the optical fiber strand (hereinafter referred to as adhesion force F12) is higher than the adhesion force of the first outer coating portion ₁₁ to the optical fiber strand (hereinafter referred to as adhesion force F11). small. That is, F ₁₂ <F ₁₁ .
Therefore, when the outer coatings 11 and 12 are to be stripped from the optical fibers 3A to 3C, the second outer coating 12 is preferentially stripped from the optical fibers 3A to 3C.

In addition, in this embodiment, an inner coating portion 13 is formed in a portion surrounded by the optical fiber wires 3A to 3C. However, the inner coating portion 13 may not be formed, and the space surrounded by the optical fiber wires 3A to 3C may be used as the gap.
When the inner covering portion 13 is formed, it is preferable that the adhesion force between the inner covering portion 13 and the optical fiber wires 3A to 3C (hereinafter referred to as adhesion force F ₁₃ ) is smaller than the adhesion force F ₁₁ . That is, it is preferable to set F ₁₃ <F ₁₁ . Moreover, it is preferable that the adhesion force F ₁₃ is equal to the adhesion force F ₁₂ . That is, it is preferable to satisfy F ₁₂ ≈F ₁₃ <F ₁₁ . Further, by using the same material as the second outer covering portion 12 for the inner covering portion 13, F ₁₂ ≈F ₁₃ may be satisfied.

The adhesion forces F ₁₁ to F ₁₃ change depending on the difference in the material forming the part. Further, when the covering portion 10 is formed of, for example, an ultraviolet curable resin, it is possible to increase or decrease the adhesive strength of the portion by partially varying the degree of curing. Therefore, F ₁₁ to F ₁₃ can be appropriately set depending on the material, degree of hardening, and the like.

For example, when the coating portion 10 is an ultraviolet curable resin, the amount of ultraviolet irradiation (intensity x time) to the portion to be the second outer coating portion 12 is equal to the amount of ultraviolet irradiation to the portion to be the first outer coating portion 11. It can be smaller than the quantity. In this case, since the degree of curing is small in portions where the amount of ultraviolet irradiation is small, the adhesion to the optical fiber strands is reduced. In other words, a difference in adhesion between the first outer covering portion 11 and the second outer covering portion 12 can be provided by the difference in the amount of ultraviolet irradiation.
Also, for example, the contact area of the second outer covering portion 12 with respect to the optical fiber strands 3A to 3C may be reduced to make a difference between F ₁₁ and F ₁₂ . Specifically, the second outer covering portion 12 may be intermittently formed along the longitudinal direction X, and the first outer covering portion 11 may be formed continuously along the longitudinal direction X. Alternatively, a plurality of through holes, perforations, slits, or the like may be formed in the second outer covering portion 12 .

A concave portion 14 (groove portion) is formed in the first outer covering portion 11 so as to be concave toward the inside of each of the units 1A to 1D and extend in the longitudinal direction Z. As shown in FIG. Two recesses 14 are formed in each of the units 1A to 1D. For example, with respect to the first unit 1A, there are two concave portions in the outer covering portion 11, a portion covering between the optical fiber wires 3A and 3C and a portion covering between the optical fiber wires 3B and 3C. 14 are provided. In this embodiment, the second outer covering portion 12 is not formed with the concave portion, but the second outer covering portion 12 may be formed with the concave portion 14 as necessary.

As described above, the optical fiber ribbon 20 of this embodiment includes the first unit 1A, the second unit 1B, and a plurality of connecting portions 2 that intermittently connect the units 1A and 1B. there is Each of the units 1A and 1B has at least three optical fiber wires 3A to 3C and a coating section 10 for collectively coating the optical fiber wires 3A to 3C. At least two of the optical fiber strands 3A to 3C included in the first unit 1A are arranged at positions shifted in the orthogonal direction Z from each other. Also, when viewed from the orthogonal direction Z, at least two of the optical fiber wires 3A to 3C included in the first unit 1A overlap each other.

With this configuration, the rigidity of the first unit 1A in the orthogonal direction Z is increased, and excessive bending of the optical fiber wires 3A to 3C included in the first unit 1A is suppressed. Therefore, it is possible to suppress an increase in the macro-bend loss of the optical fiber strands 3A to 3C. Since the other units 1B to 1D also have the same configuration, similar effects can be obtained.

Furthermore, the units 1A to 1D are intermittently connected by a connecting portion 2. As shown in FIG. Therefore, when accommodated in the optical fiber cable 50, the units 1A to 1D can move relatively easily around the connecting portion 2. FIG. That is, while the rigidity of the units 1A to 1D is enhanced, the flexibility of the optical fiber ribbon 20 as a whole is ensured. Therefore, a plurality of optical fiber tape core wires 20 can be easily twisted and housed in the optical fiber cable 50, and untwisting is less likely to occur.

Also, at least two of the optical fiber wires 3A to 3C included in the first unit 1A are arranged at positions shifted in the connecting direction Y from each other. Also, when viewed from the connecting direction Y, at least two of the optical fiber wires 3A to 3C included in the first unit 1A overlap each other. Therefore, the rigidity in the connecting direction Y of the first unit 1A is enhanced, and excessive bending of the optical fiber wires 3A to 3C can be suppressed more reliably. Since the other units 1B to 1D also have the same configuration, similar effects can be obtained.

Also, the three optical fiber strands 3A to 3C included in the first unit 1A are in contact with each other and are arranged in a close-packed manner. As a result, the cross-sectional area of the first unit 1A is reduced, and the optical fiber cables 50 can be packed with higher density.

Further, the units 1A to 1D are formed in a substantially polygonal shape (substantially triangular shape) in a cross-sectional view, and the connecting portion 2 connects the corners of the units 1A to 1D. Therefore, each unit 1A to 1D can be easily moved around the connecting portion 2, and the flexibility of the optical fiber ribbon 20 as a whole is enhanced.
Note that the first outer covering portion 11 and the second outer covering portion 12 may have different colors. In this case, each unit 1A to 1D can be distinguished from each other by a combination of colors of the outer covering portions 11 and 12. FIG.

(fusion splicing method)
Next, a fusion splicing method for the optical fiber ribbon 20 of this embodiment will be described. The object to be connected may be a ribbon ribbon similar to the optical fiber ribbon ribbon 20 of the present embodiment, or may be a ribbon ribbon in another form. Alternatively, a plurality of uncoated (single) optical fiber core wires or optical fiber bare wires arranged in a row may be connected.

When connecting optical fiber ribbons to objects to be connected, generally, a plurality of optical fiber strands are arranged in a line and then collectively spliced with a fusion splicer. Therefore, by unfolding the optical fiber ribbon 20 of the present embodiment in a straight line according to the following procedure, the connection work can be performed using a general-purpose fusion splicer.

First, as shown in FIGS. 3A and 3B, the second outer covering portion 12 of the first unit 1A is removed (removal step). At this time, since F ₁₂ <F ₁₁ , it is possible to easily remove the second outer covering portion 12 while leaving the first outer covering portion 11 .
Moreover, when the inner covering portion 13 is formed, the inner covering portion 13 is removed. At this time, since F ₁₃ <F ₁₁ , the inner covering portion 13 can be easily removed while the first outer covering portion 11 remains. In addition, when removing the inner covering part 13, the first outer covering part 11 may be deformed so that the recess 14 is closed. As a result, the space between the optical fiber wires 3A and 3B is widened, and the inner coating portion 13 can be taken out from the space.

Next, as shown in FIG. 3(c), the optical fiber wires 3A and 3B are rotated around the optical fiber wire 3C. As a result, the three optical fiber strands 3A to 3C are arranged in a straight line. At this time, the first outer covering portion 11 remains, but the formation of the concave portion 14 facilitates deformation of the first outer covering portion 11 . Therefore, the work of straightening the optical fiber strands 3A to 3C is facilitated.

By performing the above-described operations for the other units 1B to 1D, as shown in FIG. 4, the optical fiber strands included in the optical fiber ribbon 20 are arranged in a straight line (parallel process). At this time, the units 1A to 1D may be connected by the connecting portion 2. FIG. Alternatively, the connecting portion 2 may be broken.
Then, using a fusion splicer or the like, the linearly arranged optical fiber wires are fusion-spliced to the object to be spliced (splicing step).
Through the steps described above, the optical fiber ribbon 20 of the present embodiment can be fusion-spliced to the object to be spliced.

As described above, the optical fiber ribbon fusion splicing method of the present embodiment includes a removal step of removing a part (second outer coating portion) of the coating portion 10 of the units 1A to 1D, and an optical fiber element It includes a paralleling step of rotating the wires relative to each other and arranging them in a straight line, and a connecting step of fusion splicing the optical fiber bare wires arranged in a straight line to an object to be spliced. As a result, the optical fiber ribbons 20 can be collectively fusion-spliced using a general-purpose fusion splicer.

Further, the adhesion force F12 of the second outer covering portion ₁₂ to the optical fiber wire is smaller than the adhesion force F11 of the first outer covering portion ₁₁ to the optical fiber wire. This makes it possible to easily perform the removing process.

In addition, recesses 14 extending in the longitudinal direction X and recessed toward the inside of the units 1A to 1D are formed in the covering portion 10. As shown in FIG. This makes it possible to easily perform parallel processes.

Further, as shown in FIG. 4, when the second outer covering portion 12 and the connecting portion 2 are removed, the units 1A to 1D are connected to each other by the connecting portion 2. All the optical fiber strands included in 1A to 1D are arranged in positions where they can be developed in a straight line. In other words, when the units 1A to 1D are laid out in a plane, the connecting part 2 connects the ends of the rows of the optical fiber strands 3A to 3D in each of the units 1A to 1D. As a result, the optical fiber wires can be arranged in a straight line while the units are connected by the connecting portion 2, and the parallel process can be performed more easily.

The above embodiments will be described below using specific examples. In addition, the present invention is not limited to the following examples.
Table 1 lists each numerical value of Example, Comparative Example 1, and Comparative Example 2.

(Example)
In this example, an optical fiber ribbon 20 as shown in FIG. 1 was prepared. The number of units included in one optical fiber ribbon 20 was four, and each unit contained three optical fiber strands. That is, the optical fiber ribbon 20 of this embodiment has a total of 12 optical fiber strands. Moreover, the cross-sectional shape of each unit is substantially triangular. As the optical fiber wire, an optical fiber wire in which a primary layer, a secondary layer, and a colored layer were formed on the optical fiber bare wire B was used. That is, the coat layer C has a three-layer structure. The outer diameter of the bare optical fiber B was set to 80 μm, the outer diameter of the secondary layer was set to 160 μm, and the outer diameter of the colored layer (wire diameter, outer diameter of the coating layer C) was set to 170 μm. The width (tape width) of the optical fiber ribbon 20 in the connecting direction Y was 1.25 mm, and the thickness (tape thickness) in the orthogonal direction Z was 0.33 mm.

Twelve optical fiber ribbons 20 were bundled with a binding material 51 (see FIG. 2) to form one bundle. Twelve of these bundles were prepared and housed in a sheath 54 in an SZ-twisted state to prepare an optical fiber cable 50 . That is, the optical fiber cable 50 of this embodiment has a total of 12×12×12=1728 optical fiber strands. The outer diameter (cable outer diameter) of this optical fiber cable 50 was 18.2 mm, and the mounting density was 21.8 cables/mm ² . Note that the packaging density is a value obtained by dividing the number of optical fiber strands included in the optical fiber cable 50 (1728 in this embodiment) by the cross-sectional area inside the sheath 54 .

(Comparative example 1)
As Comparative Example 1, a conventionally used optical fiber ribbon was prepared. In the optical fiber ribbon of Comparative Example 1, 12 fiber strands are arranged in a straight line and intermittently fixed by connecting portions. The outer diameter of the optical fiber strand of Comparative Example 1 is 250 μm. Other conditions were the same as in the example. The tape width of the optical fiber ribbon of Comparative Example 1 was 3.12 mm, and the tape thickness was 0.27 mm.

Using this optical fiber ribbon, an optical fiber cable having 1728 optical fiber strands was produced. The conditions (kind of binding material, thickness of sheath, etc.) for preparing the cable are the same as in the example.
The optical fiber cable of Comparative Example 1 had an outer diameter of 22.0 mm and a mounting density of 10.3 cables/mm ² .

As is clear from the comparison between the example and comparative example 1, by using the optical fiber ribbon 20 of the present example, the mounting density is approximately doubled compared to the conventional optical fiber ribbon. I was able to

(Low temperature loss test)
Next, for the optical fiber cables of Example and Comparative Example 2, the results of confirming an increase in transmission loss under a low-temperature environment will be described. Here, according to the standard of IEC60794-1-22, Method F1, the increment of the transmission loss in the low temperature environment with respect to the value of the transmission loss in the normal temperature environment was measured. "Low temperature loss test results" in Table 1 shows the measurement results of the transmission loss. More specifically, when the maximum increase in transmission loss at the measurement wavelength of 1.55 μm is 0.15 dB/km or less, the result is good (OK), and when it exceeds 0.15 dB/km, the result is bad. (NG).

(Comparative example 2)
As Comparative Example 2, a conventionally used optical fiber ribbon was prepared. In the optical fiber ribbon of Comparative Example 2, 12 fiber strands are arranged in a straight line and intermittently fixed by connecting portions. The outer diameter of the optical fiber strand of Comparative Example 1 is 170 μm. Other conditions were the same as in the example. The tape width of the optical fiber ribbon of Comparative Example 2 was 2.18 mm, and the tape thickness was 0.17 mm.

Using this optical fiber ribbon, an optical fiber cable having 1728 optical fiber strands was produced. The conditions (kind of binding material, thickness of sheath, etc.) for preparing the cable are the same as in the example.

As shown in Table 1, the optical fiber cable of Example had good low temperature loss test results, and the optical fiber cable of Comparative Example 2 had poor low temperature loss test results. Consider this result.
In a low-temperature environment, the sheath thermally shrinks, so the optical fiber strands housed inside the sheath are compressed. At this time, the optical fiber is excessively bent, and the transmission loss may increase locally. This phenomenon is called macrobend loss.

It is considered that the magnitude of macrobend loss depends on the rigidity of the optical fiber ribbon. In other words, if the rigidity of the optical fiber tape core wire is low, the optical fiber tape core wire compressed by the sheath is excessively bent, resulting in an increase in macrobend loss. On the other hand, if the rigidity of the optical fiber ribbon is high, the deformation of the optical fiber ribbon can be suppressed against the compression by the sheath. Therefore, an increase in macrobend loss can be suppressed.

As shown in FIG. 1, the optical fiber ribbon 20 of the embodiment is arranged in a state in which the optical fiber strands included in each unit are arranged at positions shifted in the orthogonal direction Z and the connecting direction Y, and the coated portion 10 are collectively covered. Therefore, the rigidity of the unit itself is enhanced.
On the other hand, in the optical fiber ribbon of Comparative Example 2, the optical fiber strands are not arranged at positions shifted in the orthogonal direction Z. FIG. Therefore, the rigidity against bending in the orthogonal direction Z is smaller than that of the optical fiber ribbon 20 of the embodiment. As a result, transmission loss increased due to macro-bend loss, and the low-temperature loss test result was considered to be unsatisfactory.

As described above, according to the optical fiber ribbon 20 of the present embodiment, the mounting density of the optical fiber cable 50 is increased, and the rigidity of the units 1A to 1D is increased, thereby suppressing an increase in macrobend loss. It is possible.

The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

(Modification)
For example, as shown in FIGS. 5(a) to 5(d), the shape of the units 1A to 1D or the position of the connecting portion 2 may be changed as appropriate.
In the example of FIG. 5(a), by removing the second outer coating portion 12 and rotating each optical fiber strand, the units 1A to 1D are connected to each other by the connecting portion 2, and along the dashed line L It is possible to develop the optical fiber strands in a straight line.

5(b) to 5(d), for example, by breaking the connecting portion 2 at the time of fusion splicing, batch fusion splicing can be performed on the object to be spliced. .
In the examples of FIGS. 5(b) and 5(d), the second outer covering portion 12 is arranged at the portion connected by the connecting portion 2. As shown in FIG. For this reason, for example, by pulling the adjacent units 1A to 1D so as to separate them in the connection direction Y, it is possible to remove the second outer covering portion 12 together with the connection portion 2 while breaking the connection portion 2. Therefore, work efficiency is improved when deploying one unit.

In the example of FIG. 5(c), when viewed from the longitudinal direction X, some recesses 14 and connecting portions 2 are located at the same position, but the positions of the recesses 14 and connecting portions 2 in the longitudinal direction X may be different. It is also possible to have such an arrangement. In this case, a plurality of recesses 14 may be intermittently formed in the longitudinal direction X.

(Other modifications)
Also, as shown in FIGS. 6(a) to 6(c), the number of optical fiber strands included in the units 1A to 1D may be changed.
In the examples of FIGS. 6A and 6B, the second outer coating portions 12 are removed, and the optical fiber wires are rotated so that the recesses 14 are closed, thereby forming the optical fiber wires in a straight line. can be arranged. At this time, the optical fiber ribbon is developed along the broken line L.
In the example of FIG. 6(c), the third unit 1C is connected to the second unit 1B in the orthogonal direction Z for the units 1A and 1B. In the example of FIG. 6(c) as well, the optical fiber ribbon can be developed linearly along the dashed line L.

Further, the coating portion 10 may not cover the optical fiber wires 3A to 3C all at once, and the optical fiber wires 3A to 3C may be partly exposed from the coating portion 10. FIG. Also, the coating portion 10 may intermittently fix the optical fiber strands 3A to 3C. In other words, the covering portion 10 only needs to cover at least part of the optical fiber strands 3A to 3C.

In addition, it is possible to appropriately replace the components in the above-described embodiment with known components without departing from the scope of the present invention, and the above-described embodiments and modifications may be combined as appropriate.

DESCRIPTION OF SYMBOLS 1A... 1st unit 1B... 2nd unit 2... Connection part 3A-3C... Optical fiber bare wire 10... Coating part 11... First outer coating part 12... Second outer coating part 14... Recess 20... Optical fiber tape Core wire 50 Optical fiber cable 54 Sheath X Longitudinal direction Y Connection direction Z Orthogonal direction

Claims (10)

a first unit and a second unit each having at least three optical fiber strands and a coating section for collectively and directly coating the optical fiber strands;
a plurality of connecting parts that connect the first unit and the second unit,
The direction in which the optical fiber strand extends is defined as the longitudinal direction, and the direction in which the first unit and the second unit face each other with the connecting portion interposed therebetween is defined as the connecting direction, and both the longitudinal direction and the connecting direction are perpendicular to each other. When the direction of
The plurality of connecting portions are arranged intermittently in the longitudinal direction,
at least two of the optical fiber strands included in the first unit are arranged at positions offset from each other in the orthogonal direction ;
The first unit and the second unit are formed in a substantially polygonal shape in a cross-sectional view orthogonal to the longitudinal direction,
The optical fiber ribbon , wherein the plurality of connecting portions connect corners of the first unit and the second unit . a first unit and a second unit each having at least three optical fiber strands and a coating section for coating the optical fiber strands;
a plurality of connecting parts that connect the first unit and the second unit,
The direction in which the optical fiber strand extends is defined as the longitudinal direction, and the direction in which the first unit and the second unit face each other with the connecting portion interposed therebetween is defined as the connecting direction, and both the longitudinal direction and the connecting direction are perpendicular to each other. When the direction of
The plurality of connecting portions are arranged intermittently in the longitudinal direction,
at least two of the optical fiber strands included in the first unit are arranged at positions offset from each other in the orthogonal direction;
A first outer covering portion and a second outer covering portion are formed in a portion of the covering portion of the first unit located on the outer periphery of the first unit,
The optical fiber ribbon, wherein the adhesive strength of the second outer covering portion to the optical fiber strand is smaller than the adhesion strength of the first outer covering portion to the optical fiber strand. 3. The optical fiber ribbon according to claim 1, wherein at least two of the optical fiber strands included in said first unit overlap when viewed from said orthogonal direction. 4. The optical fiber tape core according to any one of claims 1 to 3, wherein at least two of the optical fiber strands included in the first unit are arranged at positions shifted from each other in the connecting direction. line. The optical fiber ribbon according to any one of claims 1 to 4, wherein the three optical fiber strands included in the first unit are in contact with each other. A first outer covering portion and a second outer covering portion are formed in a portion of the covering portion of the second unit located on the outer periphery of the second unit,
When the second outer covering portion of the first unit and the second outer covering portion of the second unit are removed and the first unit and the second unit are spread out in a plane, the connecting portion is 3. The optical fiber tape core according to claim 2, which couples an end portion of the row of the optical fiber strands in the first unit and an end portion of the row of the optical fiber strands in the second unit. line. 7. The covering portion of the first unit is formed with a concave portion that is concave toward the inside of the first unit and extends in the longitudinal direction. Optical fiber tape cord. A first outer covering portion and a second outer covering portion are formed in a portion of the covering portion of the first unit located on the outer periphery of the first unit,
The optical fiber ribbon according to any one of claims 1 to 7 , wherein the first outer covering portion and the second outer covering portion have different colors. an optical fiber tape core wire;
An optical fiber cable comprising a sheath covering the optical fiber tape core wire,
The optical fiber ribbon is
a first unit and a second unit each having at least three optical fiber strands and a coating section for coating the optical fiber strands;
a plurality of connecting portions that connect the first unit and the second unit;
The direction in which the optical fiber strand extends is defined as the longitudinal direction, and the direction in which the first unit and the second unit face each other with the connecting portion interposed therebetween is defined as the connecting direction, and both the longitudinal direction and the connecting direction are perpendicular to each other. When the direction of
The plurality of connecting portions are arranged intermittently in the longitudinal direction,
at least two of the optical fiber strands included in the first unit are arranged at positions offset from each other in the orthogonal direction ;
The first unit and the second unit are formed in a substantially polygonal shape in a cross-sectional view orthogonal to the longitudinal direction,
The plurality of connecting portions are optical fiber cables connecting corner portions of the first unit and the second unit . An optical fiber tape cable comprising three or more optical fiber strands, a plurality of units having a coating portion for collectively coating the optical fiber strands, and a plurality of coupling portions for coupling the units to each other. A fusion splicing method for optical fiber tape core wires, wherein
a removing step of removing a portion of the covering portion of the unit;
a parallel step of relatively rotating the optical fiber strands included in the single unit and arranging the plurality of optical fiber strands in a straight line;
a connecting step of fusion splicing the plurality of optical fiber strands arranged in a straight line to the connection object;
A fusion splicing method for optical fiber ribbons.

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