JPH01200311A - Optical fiber tape aggregation type optical fiber cable - Google Patents

Abstract

PURPOSE:To enable taking out of an arbitrary number of optical fibers in an intermediate part by laminating tapes which are arranged with the covered optical fibers and are packed with plastic having a specific Young's modulus between the respective optical fibers to join the fibers into the plural spirally disposed grooves of a spacer on a circular cylinder. CONSTITUTION:The optical fiber tapes 1 each constituted by arraying a required number of the coated optical fibers 3, and packing the plastic 6 having <=50kg/mm<2> Young's modulus between the coated optical fibers thereby joining the fibers to each other are laminated into the plural grooves 12 spirally disposed on the same circumference in the longitudinal direction of the circular cylindrical spacer 11 made of plastic. Since the optical fiber tapes 1 are housed into the grooves 12 opened to the outside, the optical fiber tapes can be easily taken out of the cable inside and an arbitrary number of the optical fibers are thus taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an optical fiber tape assembly type optical fiber cable in which an optical fiber tape is accommodated in a groove provided on the surface of a plastic spacer.

Prior Art and Problems to be Solved by the Invention The structure (cross-sectional structure) of a conventional optical fiber tape is shown in FIG. 1 is an optical fiber tape, 2 is an optical fiber, 3 is a coated optical fiber, 4 is an optical fiber coating, 5 is a tape coating, and 6 is a joining member.

FIG. 6(a) is an example of a conventional optical fiber tape, in which an optical fiber coating 4 is applied concentrically around an optical fiber 2 to constitute a coated optical fiber 3, and a plurality of fibers (as shown in FIG. In the example, four (4) coated optical fibers 3 were arranged closely and parallel to each other, and a tape coating 5 was applied to the outside thereof. The optical fiber coating 4 and the tape coating 5 are generally made of plastic, and ultraviolet curing resin is widely used.

Optical fiber tape has a structure that allows high-density accommodation of optical fibers within an optical fiber cable without impairing the transmission characteristics and mechanical properties of the optical fibers. However, in optical fiber cables used for telecommunications, it is necessary to take out a required number of optical fibers in the vicinity of the location where the demand occurs, depending on the demand for communication services. Therefore, it is necessary to have the ability to take out any number of optical fibers at any point in the longitudinal direction of the cable. In this case, since optical transmission systems in which optical signals are transmitted using separate upstream and downstream optical fibers are widely used, it is appropriate to take out one or two optical fibers as a unit for taking out the optical fiber. In the structure shown in FIG. 6G), the adhesion between the optical fiber coating 8 and the tape coating 5 is generally strong;
It is difficult to separate the coated optical fiber 3 from the optical fiber tape 1, and it is difficult to separate the coated optical fiber 3 from the optical fiber tape 1.
It was not possible to extract and handle it with two cores or any number of cores. Therefore, as a method of imparting separability to the coated optical fiber 3, a peeling layer is provided between the optical fiber coating 8 and the tape coating 5, and a structure is adopted in which the adhesion between the optical fiber coating 3 and the tape coating 5 is reduced. was devised. However, the decrease in adhesion between the optical fiber coating 3 and the tape coating 5
When force is applied to the tape, the coated optical fibers 3 separate from the tape sheath 5 within the tape and the arrangement of the coated optical fibers 8 becomes disordered, which causes deterioration of transmission characteristics. In addition, even if the adhesion between the optical fiber coating 8 and the tape coating 5 is reduced, from the middle part of the optical fiber tape 1,
In order to destroy only the tape coating 5 and take out the coated optical fiber 3 without damaging the optical fiber coating 4 or breaking the optical fiber 2, advanced techniques such as using a special tool were required. .

FIG. 6(b) is another example of a conventional optical fiber tape.
The coated optical fibers 3 are arranged closely and parallel to each other, and the grooves created by the close contact of the coated optical fibers 3 are filled with a bonding member 6 to connect the optical fibers 3 to each other. The conventional optical fiber tape 1 having this structure was devised for the purpose of separating the coated optical fibers 8, but it was developed with the premise of application to a conventional cable having a cross-sectional structure as shown in FIG. Therefore, the joining member 6 is made strong so that the coated optical fiber 8 does not separate due to bending or twisting. That is, in the cable shown in FIG. 7, the optical fiber tape 1 is housed in a cavity 7 formed by a cable sheath 8 so that it can move relatively freely, and can be bent by bending the cable. , the optical fiber tape 1 freely bends and twists when subjected to torsional force. Moreover, in this cable structure, in order to ensure the flexibility of the cable, the optical fiber tape 1 is twisted in the longitudinal direction as one group, and the optical fiber tape 1 is already twisted when the cable is formed. be. Therefore, due to the strength of the joining member 6, there was a drawback that sufficient separability could not be obtained.

Means for Solving the Problems The present invention provides a method for arranging a required number of coated optical fibers in such a manner that the coated optical fibers are in contact with each other in substantially one direction within a cross section. , the Young's modulus of the groove formed between the coated optical fibers is 5 Q k1j
A plurality of optical fiber tapes, each of which is filled with a plastic of less than /ai+'' and formed by joining the coated optical fibers together, are disposed in a plurality of helical shapes on the same circumference in the longitudinal direction of a cylindrical spacer made of plastic. The spacer is stacked and housed in the groove so that the spacer does not move in the radial direction.Furthermore, a plastic coating is further applied to the outside of the two coated optical fibers to form a tape-like structure. A required number of twin-core optical fiber tapes formed in It is constructed by joining two optical fiber tapes together.

Effect of the Invention The present invention has the above-mentioned configuration, so that even if the optical fiber tape is housed in a high density, the optical fiber will not be subjected to uneven force against external forces such as bending or pulling under the actual cable usage environment, and the optical fiber tape will coated optical fibers can be separated naturally, thereby preventing deterioration of transmission characteristics.

In the present invention, since the optical fiber tape is housed in the groove open to the outside, the optical fiber tape can be easily taken out from inside the cable after the cable jacket is removed.

Therefore, at any position in the longitudinal direction of the cable,
You can take out any number of optical fiber tapes from inside the cable, and since it contains high-density optical fiber tape, you can take out any number of optical fibers from the removed optical fiber tape. .

Therefore, for communication demand that occurs at any point,
Communication lines can be easily provided using optical fibers.

Embodiment FIG. 1 is a sectional view of a first embodiment of the optical fiber cable of the present invention, and FIG. 2 is a sectional view of the first embodiment of the optical fiber tape 1 used in the optical fiber cable of the present invention. .

In the figure, the same reference numerals as in FIGS. 6 and 7 indicate the same parts.

In the figure, 9 is an optical fiber cable, 10 is a tensile strength member, 11 is a cylindrical spacer, and 12 is a groove.

As shown in Figure 2, the optical fiber tape l is the optical fiber 2
Coated optical fibers 3 formed by coating with plastic such as ultraviolet curable resin are arranged closely and parallel to each other,
The grooves formed between the coated optical fibers 8 are filled with a bonding member 6 such as a plastic such as an ultraviolet curable resin or an adhesive. Because of this structure, by reducing the Young's modulus of the joining member 6, if force is applied to the optical fiber tape 1 from outside with a human finger, the joining member 6 itself will be destroyed, and the optical fiber It becomes possible to easily separate the coated optical fiber 3 from the tape 1. The Young's modulus of the bonding member 6 must be smaller than the Young's modulus near the surface of the optical fiber coating 4 so that the optical fiber coating 4 of the coated optical fiber 3 is not damaged when external force is applied. be.

On the other hand, as for the optical fiber cable 9, as shown in FIG. 1, a tensile strength member 10 is arranged at the center of the spacer 11, and a required number of grooves 12 are formed spirally in the longitudinal direction on the surface. ing. The spacer 11 itself is made of plastic such as polyethylene. The tensile strength body 10 is made of a single steel wire, a steel stranded wire made by twisting multiple (7 is common) copper wires, or reinforced plastic (FRP).
) etc. are used. The optical fiber tape 1 is housed in the groove 12, and as a feature of the present invention, one side of the optical fiber tape 1 is placed closely to the bottom of the groove 12 as shown in the figure, and the other side of the optical fiber tape 1 is One side of another optical fiber tape 1 is placed closely on the surface of the optical fiber tape 1, and the optical fiber tapes 1 are stacked one after another in close contact with each other. In this case, the bottom of the groove 12, the optical fiber tape 1, and the optical fiber tapes 1 are not fixed to each other, but the optical fiber tape 1 is arranged so as not to move in the radial direction of the optical fiber cable 9. For this purpose, put plastic tape IIA around the outer circumference of spacer 11.
Measures are taken to suppress the degree of freedom of the optical fiber tape 1 by applying pressure winding such as the following. The groove portion 12 is designed according to the width of the optical fiber tape 1, and is designed to prevent the stack of optical fiber tapes 1 from collapsing.

Since the optical fiber cable 9 has such a structure, even if the optical fiber cable 9 is bent or expanded/contracted when the optical fiber cable 9 is actually used, the optical fiber tape 1 will remain at the bottom of the groove 12. Although the cable may move in the longitudinal direction between the cable and the optical fiber tape 1 or between the optical fiber tapes 1, it does not move in the radial direction of the cable.

Furthermore, the stacked state of the optical fiber tape 1 does not collapse. Furthermore, since the optical fiber tape 1 is accommodated along the groove 12 spirally provided in the longitudinal direction of the cable, and the optical fiber tape 1 cannot move freely in the radial direction of the cable as described above, the optical Even if the fiber cable 9 is bent under normal usage conditions, the optical fiber tape 1 accommodated within the optical fiber cable 9 will not be excessively bent. Therefore, uneven forces such as bending with a small radius of curvature or twisting of the optical fiber tape 1 do not act on the optical fiber tape 1 . Because this cable structure has such characteristics, even if the optical fiber tape l shown in FIG. 2 is accommodated, the optical fiber cable 9 will not bend or expand or contract during actual use. Even when the optical fiber tube is housed inside, no uneven force acts on the optical fiber tube. Therefore, even if the Young's modulus of the bonding material joining the coated optical fibers 8 constituting the optical fiber tape 1 is small, the coated optical fibers 3 will not separate spontaneously. Thereby, it is possible to realize an optical fiber cable that has stable transmission characteristics during actual use of the cable. Moreover, since the Young's modulus of the bonding material used to bond the coated optical fibers 8 constituting the optical fiber tape 1 can be reduced, the coated optical fibers 8 can be easily separated from the optical fiber tape 1, and the optical fibers can be easily separated from each other. It becomes possible to take out any number of coated optical fibers 3 from the middle part of the tape 1.

As an example of the constituent materials of the optical fiber tape 1 shown in FIG.
As the joining member 6, an ultraviolet curable resin is used, and a two-layer structure with different Young's modulus (a structure having an inner layer with a small Young's modulus and an outer layer with a large Young's modulus) is used. The Young's modulus of the optical fiber coating 4 and the bonding/member 6 is 0.0 for the inner layer of the optical fiber coating 4.
1~10ky/lAm: 80~150゜kt/outer layer
It is effective to select xm"z joining member 6 to be 0.1 to 50)/lightning". In this case, the structure of optical fiber coating 4 should be It is necessary to design the optical fiber 2 by taking into consideration the longitudinal force applied to the optical fiber 2 by the contraction force sometimes generated in the optical fiber coating 4.In other words, regarding the lateral pressure, it is necessary to suppress the occurrence of micro-bending of the optical fiber 2 due to the lateral pressure. It is necessary to design Young's modulus and coating thickness to create a structure that suppresses the increase in optical loss caused by microbending.

Regarding the shrinkage force at low temperatures, the shrinkage force of the optical fiber sheath 4 is reduced at low temperatures so that the optical fiber 2 does not buckle due to the shrinkage force of the optical fiber sheath 4 and increase optical loss. It is necessary to design the ratio and coating thickness.

FIG. 8 is a sectional view of a second embodiment of the optical fiber tape used in the optical fiber cable of the present invention. Joining member 6
In this case, coated optical fibers 8 are arranged and coated on one side, and the same effect as shown in FIG. 2 is obtained.

FIG. 4 is a sectional view of another embodiment of the optical fiber cable of the present invention. This optical fiber cable 9A has a tensile strength member 10A arranged in the center, and around it, as shown in FIG. 2 or 3.
Spacer 1 containing the optical fiber tape f′ shown in the figure
A plurality of cables 1 are twisted together and assembled, and a cable jacket 8 is coated on the outside. In this structure, as in FIG. 1, the optical fiber tape 1 is placed so that one side thereof is in close contact with the bottom of the groove 12 provided spirally in the longitudinal direction of the spacer 11, and the optical fiber tape 1 is further placed on top of the groove 12. 1 are closely arranged and housed in a stacked manner. Although the optical fiber tape °1 can be moved in the longitudinal direction, the spacer 11
The outer periphery of the spacer 11 is wrapped so that it cannot move freely in the radial direction of the optical fiber cable 9A or in the radial direction of the optical fiber cable 9A. Therefore, even if the optical fiber cable 9A with this structure is bent or expanded/contracted during actual use, the optical fiber tape 1 inside the optical fiber cable 9A will not be excessively bent or twisted, and the optical fiber tape 1 will not be damaged. Uniform force is not applied. For this reason, even if the optical fiber tape 1 in which the Young's modulus of the bonding member 6 as shown in FIG. 2 or FIG. The coated optical fiber 3 does not naturally separate from the optical fiber tape 1 due to bending during actual use, and an optical fiber cable having stable transmission characteristics can be realized.

FIG. 5 shows a second embodiment of the optical fiber tape used in the optical fiber cable of the present invention.

This optical fiber tape IA consists of two coated optical fibers 3 shown in FIG. 6 (hereinafter referred to as a two-core optical fiber tape 2A). The two-core optical fiber tapes 2A are arranged in parallel and bonded to each other by a bonding member 6. This is because an optical transmission system in which optical signals are transmitted using separate upstream and downstream optical fibers is widely used for transmission between a terminal and a repeater, so two fibers are extremely effective as a unit for taking out optical fibers. Although FIG. 3 shows the use of two two-core optical fiber tapes 1', a multi-core optical fiber tape 1' can be constructed as required. The optical fiber tape 1' having such a structure has the function of allowing optical fibers to be easily taken out in units of 26 not only from the ends of the optical fiber tape 1' but also from the intermediate portion. By applying this optical fiber tape 1' to the optical fiber cable 9 shown in FIG. 1, it is possible to realize an optical fiber cable from which optical fibers can be easily taken out in units of 26 from the middle part of the cable.

Effect of the invention The present invention provides the following effects.

(1) It is possible to take out any number of optical fibers at the intermediate portion, and it is possible to realize an optical fiber cable that accommodates high-density optical fiber tape.

(2) The structure of the optical fiber cable of the present invention is such that even if the optical fiber tape is housed at a high density, the optical fiber is subjected to uneven force against external forces such as bending and pulling under the cable's actual usage environment. This method does not cause natural separation of the coated optical fiber from the optical fiber tape and does not cause deterioration of transmission characteristics.

(3) In the optical fiber cable of the present invention, the optical fiber tape is housed in the groove that is open to the outside, so the optical fiber tape can be easily taken out from inside the cable after removing the cable jacket. It is possible.

Therefore, any number of optical fiber tapes can be taken out from inside the cable at any position in the longitudinal direction of the cable, and at the same time, due to the effect of (1), light of any number of fibers can be extracted from the taken out optical fiber tape. The fiber can be extracted.

Thereby, it is possible to easily supply a communication line using optical fiber in response to a demand for communication that occurs at an arbitrary location.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a first embodiment of the optical fiber cable of the present invention, FIG. 2 is a cross-sectional view of the first embodiment of the optical fiber tape 1 used in the optical fiber cable of the present invention, and FIG. is a cross-sectional view of a second embodiment of the optical fiber tape 1' used in the optical fiber cable of the present invention, FIG. 4 is a cross-sectional view of another embodiment of the optical fiber cable of the present invention, and FIG. 6(a) is a sectional view of an example of a conventional optical fiber tape, and FIG. 6(b) is a sectional view of the other side of the conventional optical fiber tape. , FIG. 7 shows a cross-sectional view of a conventional optical fiber cable using a conventional optical fiber tape. 1.1' Bi-optical fiber tape 2: Optical fiber 8: Coated optical fiber 4: Optical fiber coating 6: Joining member 8: Cable jacket 9.9A: Optical fiber cable 10 of the present invention, IOA:
Tensile strength body 11 Ni spacer 12: Mizobe Patent applicant Nippon Telegraph and Telephone Corporation

Claims (2)

[Claims] (1) Arrange the required number of coated optical fibers in which the coated optical fibers are arranged in a state in which the coated optical fibers are aligned in almost one direction within the cross section and in contact with each other, and Young's modulus in the groove part is 50kg/mm^2
An optical fiber tape made by filling the following plastic and joining the coated optical fibers to each other is placed in a plurality of spiral grooves arranged on the same circumference in the longitudinal direction of a plastic cylindrical spacer. An optical fiber tape assembly type optical fiber cable, characterized in that the optical fiber tape is stacked and housed in such a way that the spacer does not move in the radial direction. (2) Arrange the required number of two-core optical fiber tapes, which are formed into a tape shape by applying a plastic coating to the outside of two coated optical fibers, with the optical fibers aligned in almost one direction within the cross section. According to claim 1, the optical fiber tape is constructed by filling the grooves formed between the two-core optical fiber tapes with plastic and joining the two-core optical fiber tapes together. The optical fiber tape assembly type optical fiber cable described above.