JPH07128553A - Optical cable - Google Patents

Abstract

PURPOSE:To provide the optical cable having a high degree of freedom in addition and change of size reducing cables without the used for connection to numerous fiber optical cables at the time of size reducing. CONSTITUTION:Three pieces of the multiple optical cable 1 and three piece of the few fiber optical cables 2 are twisted around a tension member 3 and are provided with a covering 10. Coated fiber ribbons 6 are housed in the grooves of the rods 4 of the numerous fiber optical cables 1 and the are provided with retaining windings 8. The optical units 7 of a small number of fibers are housed in the grooves of the rods 6 of the few fiber optical cables 2 and are provided with retaining windings 8. The numerous fiber optical cables 1 are used for integral connecting and the few fiber optical cables 2 are used for intermediate post branching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cable suitable for constructing an optical subscriber wiring system for distributing an optical communication network to each subscriber.

[0002]

2. Description of the Related Art Various methods have been proposed for constructing an optical communication network. Among them, it is considered to construct an optical subscriber wiring system by distributing an optical communication network from a station to each subscriber like a conventional telephone.

FIG. 6 is a schematic diagram of an example thereof. In the figure,
31 is a station, 32 is an underground cable, 33, 34 and 35 are utility poles, 36 is a connection box, 37 is a wiring cable, 38 is a connection box, 39 and 40 are wiring cables, 41, 42 and 43 are connection boxes, 44, Reference numeral 45 is an optical drop line, and 46 and 47 are subscribers. The wiring cable 37 connected from the station 31 through the underground cable 32 by the connection box 36 is connected to the pole-mounted type connection box 38 installed on the utility pole 33. From the connection box 38, the wiring cables 39 and 40 are sequentially connected to the utility pole 3
After 4,35, it is wired to the area where the subscriber is. The wiring cables 39 and 40 are supported by a support wire stretched between the electric poles.
1 connected to each other. The subscriber 46 in demand is withdrawn from the connection box 41 by the optical withdrawal line 44. The withdrawal to the subscriber may be withdrawn from the connection box provided near the telephone pole, or may be withdrawn from the connection box 43 provided between the telephone poles 34 and 35, like the subscriber 47. Of course, it is not necessary to provide a connection box for each electric pole, and an electric pole that only holds the electric pole may be arranged.

As described above, the optical fiber in the wiring cable is dropped to the subscriber in response to the demand. Conventionally, an optical cable used for an optical subscriber wiring system is disclosed in, for example, Japanese Patent Laid-Open No. 4-372917. A multi-fiber optical cable as described is used. FIG. 7 is a sectional view thereof. In the figure, 51 is a tape core wire, 52 is a U-shaped spacer, 53 is a fitting spacer, 54 is a press winding, and 5
5 is a tension member, and 56 is a sheath. The spacer 52 is made of plastic and has a substantially U-shaped cross section.
It is formed to have a shape, and accommodates a plurality of tape core wires 51 therein. The tape core wire 51 is, for example,
Five optical fibers are arranged side by side and integrated with an ultraviolet curable resin or the like. The spacers 52 are assembled such that the bottoms thereof are twisted so as to face the tension members 55 arranged in the center of the optical cable, or arranged in parallel. The adjacent wall surfaces of the adjacent spacers are engaged with each other at the edge portions of both ends of the fitting spacer 53 to be connected and integrated with each other, and then the press winding 54 and the sheath 56 are provided. Since the adjacent U-shaped spacers 52 are integrated by the fitting spacer 53,
As a whole, the U-shaped spacer 52 has the tension member 5
5 is integrally fixed to the periphery of 5, and a single multi-core optical cable having a sturdy structure is formed.

On the other hand, as a so-called optical drop line for connecting an optical fiber in a wiring cable to extend an optical line to a subscriber and connecting it to a subscriber terminal, an optical cable with a small number of fibers containing one or two optical cables. It has been known. Therefore, the optical subscriber system is constructed by pulling down the optical fiber of a small number of optical fibers, which is connected in series with the optical fibers in the optical fiber of the multi-core described above, to the subscriber's house.

The above concept was known from NTT Research Practical Report Vol. 33, No. 3, No. 3 (1984), pp. 116-129, etc., but conventionally, the development of optical terminals was not sufficient. Due to the fact that the price was high, the actual use of the optical subscriber system was extremely limited. For this reason, the work of connecting an optical cable from a multi-core optical cable to a small-core optical cable is a special construction with a low frequency, and workability and economic efficiency have not been a problem.

However, with the progress of the advanced information society in recent years, the optical subscriber system is nearing the time of realization, and the optical subscriber wiring system is required to be economical, workable, and expandable. Is becoming more common.

That is, as the number of optical subscriber systems expands, the number of installations increases significantly, and it is necessary to simplify the work and save labor, and at the same time, add a connection point with an optical drop line according to fluctuations in demand trends. There is also a strong need for freedom of change.

A big problem here is a method of connecting an optical fiber from a multi-core optical cable to a small-core optical cable, and development of a technique for extracting a necessary optical fiber from a sturdy cable. Was desired.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is not necessary to take out or connect a large number of optical fiber core wires in a wiring cable at the time of withdrawal. It is an object of the present invention to provide an optical cable that has a high degree of freedom in adding or changing a location where a light drop line is drawn, that is, an intermediate branch point.

[0011]

According to a first aspect of the present invention, there is provided an optical cable having a multi-core structure in which a tape core wire is housed in a groove of a rod having a single groove including a center of the rod. An optical cable and an optical cable in which a small number of optical fibers are accommodated in the groove of a rod having a single groove including the center of the rod are twisted around a tension member and coated. Is.

According to the invention of claim 2, in the optical cable of claim 1, the optical cable is SZ.
It is arranged so as to be twisted. In the invention according to claim 3, in the optical cable according to claim 1 or 2, the groove of the rod is formed in a spiral shape in one direction. According to the invention of claim 4, in the optical cable according to any one of claims 1 to 3, the optical fiber having a small number of fibers is a tear cord. It is configured as an optical unit provided with the optical cable according to any one of claims 1 to 4 in the optical cable according to any one of claims 1 to 4. The fiber is characterized by being separable into the same number of cores as the optical drop line.

According to a sixth aspect of the invention, in an optical cable, a multi-core loose tube unit in which a tape core wire is housed in a tube and a small core in which a small number of optical fibers are housed in a tube. The loose tube unit is twisted around the tension member and coated.

According to a seventh aspect of the present invention, in the optical cable according to the sixth aspect, the loose tube unit is arranged so as to be SZ twisted. In the invention of
In the optical cable according to claim 6 or 7, the optical fiber having a small number of fibers is configured as an optical unit including a tear cord, and in the invention according to claim 9, The optical cable according to any one of claims 6 to 8 is characterized in that the optical fiber having a small number of fibers can be separated into a fiber having the same number of fibers as the optical drop line.

[0015]

When the need for intermediate drawing occurs on a series of cables between connecting boxes, in order to cope with this, the necessary one is taken out of the laminated optical fiber cores, for example, the tape cores. The processing must be done without changing the cable length, which is very difficult.

According to the optical cable of the present invention, the optical fiber core wire can be taken out from the optical fiber cable having a small number of fibers and the loose tube unit having a small number of fibers, so that the intermediate post branching is easy. . Also, the majority of optical fibers that do not require intermediate branching are stored in a multi-core optical cable or a multi-core loose tube unit,
Since the tape core wire is used, a connector for collective connection can be used and the connection work is simple. Since the multi-core optical cable and the low-core optical cable, or the multi-core loose tube unit and the low-core loose tube unit are twisted together, they can be separated during the post branch work, and the core of the rod that does not branch back can be separated. Does not affect the line.

Further, by making the optical cable or loose tube unit the SZ twist in which the twisting direction is alternately continuous in the left rotation direction and the right rotation direction, it is easy to take out, and the extra connection length when the twist is restored. Can be taken. Furthermore, by using an optical unit provided with a tear cord, the coating can be easily torn and the optical fiber core wire can be easily taken out.

Further, since the optical fiber core wire in the small number optical fiber cable or the small core loose tube unit accommodating the small number of optical fibers is accommodated as the core wire having the same number of cores as the optical drop line, At the time of withdrawing to the subscriber, it is easy to perform fusion splicing for each core wire or to connect core wires using a connector without separating the core wire into single cores or two cores. Become.

[0019]

1 is a sectional view of an embodiment of the optical cable of the present invention. In the figure, 1 is a multi-core optical cable, 2 is a small-core optical cable, 3 is a tension member, 4 and 5 are rods,
Reference numeral 6 is a tape core wire, 7 is an optical unit, 8 and 9 are press windings, and 10 is a coating. In the optical cable of this embodiment, three multi-core optical cables 1 and three multi-core optical cables 2 are twisted around a tension member 3 and a coating 10 is applied. The twisting is preferably SZ twisting.

The multi-core optical cable 1 uses a rod in which a groove for accommodating an optical fiber is formed. The groove is formed in a spiral shape so as to include the center of the rod 4. The tape core wire 6 is accommodated and the press winding 8 is applied.
Since the groove is formed so as to include the center of the rod 4, the tape core wire 6 can be located near the center of the rod 4, and when the multi-core optical cable 1 is bent, the tape core wire 6 is bent. The line 1 is prevented from being given a large compressive force or a stretching force. In one embodiment, rod 4
Is made of synthetic resin and has a diameter of 6 mm.
Using a four-core tape core wire having a thickness of 0.4 mm and a width of 1.1 mm, five grooves are accommodated in each groove, and a press winding 8 made of a synthetic resin tape is applied.

The optical fiber 2 having a small number of fibers, like the optical cable 1 having a small number of fibers, is a rod 5 in which a groove for accommodating an optical fiber is formed, and a press winding 9 is applied to the outer periphery of the rod 5. The groove includes the center of the rod. As described above, it is formed in a spiral shape and accommodates a plurality of optical units 7 having a small number of cores.

An example of the optical unit 7 is shown in FIG.
In the figure, 11 is a tension member, 12 is an optical fiber, 1
3 is a tear string, and 14 is a coating. Optical fiber 12
In this embodiment, an ultraviolet-curing resin coating having a diameter of 0.25 mm is used, and five of them are twisted together with the tearing string 13 around the tension member 11 and the coating 14 is formed thereon. Is applied. When the coating 14 is torn by the tear string, the optical fiber 1
Two are separated one by one.

However, the optical fiber accommodated in the optical cable 2 does not need to be configured as an optical unit, and the optical fiber shown in FIG.
As shown in (B), the coating 16 is applied to the single-core optical fiber 15.
May be provided, and a plurality of them may be accommodated in the groove of the rod 5 in a separated state.

FIG. 3 is a sectional view of an example of the rod. In the embodiment of FIG. 1, in the optical cables 1 and 2, the outer periphery of the rod 5 or 6 is coated with 9 or 10. However, as shown in FIG. 3 may be used, or alternatively, as shown in FIG.
You may use the rod 17 which has arrange | positioned 8. Reference numeral 19 is a coating. The tear string is not limited to a fibrous one, and a metal wire or a plastic wire can be used. The placement of the tear cord has the advantage that no special tools are required to remove the coating in the post-branch operation.

FIG. 4 is a sectional view of another embodiment of the optical cable of the present invention. In the figure, the same parts as those in FIG. 21 is a multi-core loose tube unit, 22 is a low-core loose tube unit, 2
3 and 24 are tubes. In the optical cable of this embodiment, three loose core tube units 21 and three loose core tube units 22 are twisted around the tension member 3 or arranged in parallel, and the coating 10 Is applied. When twisting, SZ twisting is preferable.

The tubes 23 and 24 are made of synthetic resin, for example, PBT (polybutadiene terephthalate), and can accommodate appropriate optical fiber cores such as tape cores and UV-curable resin-coated single core optical fibers. it can. Jelly compound may be filled.

In this embodiment, the tape core wire 7 and the optical unit 8 are the same as those in the embodiment of FIG. The loose tube unit 21 corresponds to the multi-core optical cable 1,
The loose tube unit 22 with a small number of cores corresponds to the optical cable 2 with a small number of cores.

As described above, the optical cable of the present invention includes a multi-core optical cable or loose tube unit and a low-core optical cable or loose tube unit. The multi-core optical cable and the loose tube unit can be collectively connected using a connector for multi-core connection, which is advantageous in terms of connection work and connection loss. Further, since the optical fiber cable or loose tube unit having a small number of fibers can be used for the intermediate branch, it does not affect the optical fiber cable or the loose tube unit having a large number of fibers in the rear branch. The number of optical fibers in the optical fiber or the loose tube unit having a small number of fibers may be the same as the number of optical drop lines, or may be the same structure. That is, when the number of the light pull-down lines is one, as described with reference to FIG.
By doing so, it is possible to perform fusion splicing in units of core wires or to connect core wires to each other using a connector without pulling the core wires into single cores or two cores at the time of withdrawal. It will be easy. When the number of cores to the subscribers of the optical subscriber wiring system is mixed and used, it is preferable to accommodate the cores corresponding to the number of cores in a mixed manner.

FIG. 5 is a conceptual diagram for explaining an example of a method of using the characteristics of the optical cable of the present invention, showing the first 6 spans. In the figure, 1 is a multi-core optical cable, 1a, 1b, 1c and 1d are tape cores of the optical cable 1, 2 is a small core optical cable, S0 to S5 are spans, C0 to C5 are optical cables, and B1 to B5 are cable laying. It is the connection point of time. The multi-fiber optical cable 1 and the low-fiber optical cable 2 are illustrated one by one. In this example, the multi-core optical cable 1 accommodates four 8-fiber ribbons, and the small-fiber optical cable 2 accommodates four 2-fiber ribbons. The distance between the spans S1 to S3 is
For example, the length is about 300 m, and therefore the length of the optical cables C1 to C5 is a length corresponding to the distance.

The span S0 is a section from the base station and is wired by the optical cable C0. At the connection point B1, between the optical cables C0 and C1, the optical cable 1
The eight-core tape core wire 1a in 4 and the four two-core tape core wires in the optical cable 2 are exchanged and connected. Therefore, in the span S1, the optical fiber connected to the 8-core tape core wire 1a in the optical cable 1 at the base station can be branched in the middle.

At the connection point B2, between the optical cables C1 and C2, the 8-fiber ribbon 1 of the optical cable 1 is provided.
b and the four core ribbons of the optical cable 2 are exchanged and connected. Therefore, in the span S2, the optical fiber connected to the 8-core tape core wire 1b in the optical cable 1 at the base station is in a state of being capable of intermediate branching.

Similarly, at the connection point B3, between the cables C2 and C3, the 8-fiber ribbon core 1c in the optical cable 1 is connected.
, And the four two-fiber ribbons in the optical cable 2 are exchanged and connected. Therefore, in the span S3, the optical fiber connected to the 8-core tape core wire 1c in the optical cable 1 at the base station is in a state of being capable of intermediate branching.

Similarly, at the next connection point B4, the 8-fiber ribbon 1d and the four 2-fiber ribbons in the optical cable 2 are exchanged and connected, and the 8-fiber ribbon in the optical cable 1 is connected at the base station. The optical fiber connected to 1d is ready for intermediate branching.

After the connection point B5, the 8-fiber ribbon of the optical cable 1 and the 4-fiber ribbon of the optical cable 2 may be exchanged for connection, or 8 of other optical cables (not shown). The core tape core wire and the four two-core tape core wires in the optical cable 2 may be sequentially exchanged and connected.

Further, in the above-mentioned spans S1 to S4, it has been described that only the 8-fiber ribbon in the optical cable 1 and the 4 2-fiber ribbons in the optical cable 2 are sequentially exchanged and connected. In S1 to S4, at the same time, the 8-core tape core wire in the optical cable different from the optical cable 1 and the tape core wire of the optical cable different from the optical cable 2 accommodating the four double-core tape core wires are sequentially replaced. You may make it connect. In this case, in the next span S5, even if the same optical cable is repeated, as in the case described above, the tape cores of the other optical cables containing the 8-fiber ribbons and the 4-fiber ribbons are accommodated. The wires may be sequentially exchanged and connected.
Further, the tape cores of the optical cable accommodating the four two-core tapes may be sequentially exchanged and connected with the 8-core tapes of the other optical cables.

As described above, the multi-core optical cable accommodating four 8-fiber ribbons and the small-fiber optical cable accommodating four 2-fiber ribbons are used for connecting the multi-fibers together. Then, the latter is used for intermediate branching, and as described above, by connecting and using it in advance at the connection point of the cable, it is possible to carry out withdrawal by an optical cable with a small number of fibers.

Furthermore, the multi-core optical cable and the low-core optical cable are not connected at the time of laying, and when the intermediate branch is required, the low-core optical cable in the span needs to be pulled down. The optical cable may be connected at a connection point.

The connection between the optical cable 2 and the optical drop line is carried out by removing the binding line at the intermediate branch point, separating the optical cable 2 and attaching the optical connection box.
Open and make the appropriate connections. At that time, if the optical cable is twisted in the SZ twist, there is an advantage that a necessary optical cable can be taken out easily and a connection extra length can be taken.

The numerical values and the arrangement of the optical fibers in the above-mentioned embodiments are merely examples, and it goes without saying that they can be appropriately changed.

[0040]

As is apparent from the above description, according to the present invention, a multi-fiber optical cable and a low-fiber optical cable, or a multi-fiber loose tube unit and a low-fiber loose tube unit are assembled. Therefore, the former can be used for a line that does not require an intermediate post-branch, and the latter can be used for a line that requires an intermediate post-branch, and it is possible to provide an optical cable with a high degree of freedom in adding and changing drop cables .

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an optical cable of the present invention.

FIG. 2 is a cross-sectional view of an example of the optical unit of FIG.

3 is a cross-sectional view of an example of the rod of FIG.

FIG. 4 is a cross-sectional view of another embodiment of the optical cable of the present invention.

FIG. 5 is a conceptual diagram for explaining an example of how to use the optical cable of the present invention.

FIG. 6 is a schematic diagram of an example of a conventional optical subscriber wiring system.

FIG. 7 is a cross-sectional view of an example of an optical cable used in a conventional optical subscriber wiring system.

[Explanation of symbols]

 1 Multi-core optical cable 2 Small-core optical cable 3,11 Tension member 4,5 Rod 6 Tape core wire 7 Optical unit 8,9 Holding winding 10,14 Cover 12 Optical fiber 13,16,18 Tear string 21 Multi-core loose Tube unit 22 Loose tube unit with a small number of cores 23, 24 tubes

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Saya 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Industries, Ltd. Yokohama Works (72) Inventor Shigeru Tanaka 1-tani, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Ki Industry Co., Ltd. Yokohama Works (72) Inventor Toshinobu Matsuo 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Ki Industries Co., Ltd. (72) Inventor Wataru Katsurajima 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Ki Industry Co., Ltd. Yokohama Works (72) Inventor Hiroaki Sano 1 Taya-cho, Sakae-ku, Yokohama-shi, Kanagawa Sumitomo Electric Ki Industries Co., Ltd. Yokohama Works (72) Inventor Shigeru Tomita 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (9)

[Claims] 1. A multi-core optical cable in which a tape core wire is accommodated in a groove of a rod having a single groove including a center of the rod,
An optical cable in which an optical cable in which a small number of optical fibers are accommodated in the groove of a rod having a single groove including the center of the rod is twisted around a tension member and coated. 2. The optical cable according to claim 1, wherein the optical cable is arranged so as to have an SZ twist. 3. The optical cable according to claim 1, wherein the groove of the rod is formed in a spiral shape in one direction. 4. The optical cable according to claim 1, wherein the optical fiber with a small number of fibers is configured as an optical unit including a tear cord. 5. The optical cable according to claim 1, wherein the optical fiber having a small number of fibers is separable into a fiber having the same number of fibers as the optical drop line. 6. A multi-core loose tube unit in which a tape core wire is housed in a tube and a low-core loose tube unit in which a small number of optical fibers are housed in a tube are provided around a tension member. An optical cable characterized by being twisted and covered. 7. The optical cable according to claim 6, wherein the loose tube unit is arranged so as to be SZ twisted. 8. The optical cable according to claim 6, wherein the optical fiber having a small number of fibers is configured as an optical unit including a tear cord. 9. The optical cable according to claim 6, wherein the optical fiber having a small number of fibers is separable into the optical fibers having the same number of fibers as the optical drop line.