JPH0862465A - Optical fiber cable - Google Patents

Abstract

PURPOSE: To embody the structure of optical fibers which can be densely packaged. CONSTITUTION: H-type group units 70 (optical fibers tapes 16 are set in multi- layers in two helical grooves 76, 76 formed in H-group units 72 which are mated with each other in a back-to-back relation) are twisted and bundled around a slot-type unit 60. The diameter of a cable having a 4000 core structure using 16 core optical fiber tapes is 45mm. This is smaller than an H-group type unit two-layer cable, having a size substantially equal to that of a U-group type cable. Moreover, it can be easily manufactured in comparison with the U-group type cable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable, and more particularly to improving the packaging density of the optical fiber and finishing the multi-core cable to a smaller diameter.

[0002]

2. Description of the Related Art The conventional multi-core optical cable is most commonly the multi-slot type shown in FIG. In the figure, 12 is a slot. The optical fiber tape 1 is placed in the spiral groove 14.
6 are stacked and stored, and the presser winding 18 is applied to form a slot type unit 20. The slot type unit 20 is twisted and assembled around the central tension member 22, and the sheath 24 is applied to form a multi-slot type cable 26.

In recent years, the U-groove type cable of FIG. 3 has been studied with the aim of further increasing the number of cores and increasing the density.
In the figure, 28 is a U groove. The optical fiber tape 16 is stacked and stored in the U-groove type unit 30.
And The U-groove type unit 30 is twisted and assembled around the central tension member 32, and the sheath 34 is applied to form a U-groove type cable 36.

The H-groove type cable of FIG. 4 has also been proposed. FIG. 10A is a side view of the H groove 38, and an enlarged cross section of the B is shown in FIG. H groove 3
8 is attached to an elongated rod-shaped main body 39 (generally having a circular cross section).
The two back-to-back grooves 40, 40 are provided spirally, and the cross-sectional shape at right angles to the longitudinal direction is substantially H-shaped.
The optical fiber tape 16 is stacked and stored in the groove 40 of the H groove 38, and the press winding 42 is applied to form an H groove type unit 44 (c). The H-groove type unit 44 is twisted and assembled around the central tension member 46, and the sheath 48 is applied to form an H-groove type cable 50 (d).

[0005]

Considering a 4000-fiber structure using a 16-fiber optical fiber tape having a width of 3.3 mm and a thickness of 0.25 mm for each of the above cables, the cable outer diameter is as follows. <Cable structure><Cable outer diameter> ・ Multi-slot type (Fig. 2) 50mm ・ U groove type (Fig. 3) 44mm ・ H groove type (Fig. 4) 48mm As shown in the above table, the cable outer diameter is U groove The smallest type. This is the most advantageous for achieving high density.

However, with this U-groove type cable,
The following points become a problem. That is, when manufacturing this cable, a large number of U-grooves 28 and optical fiber tapes 16 must be assembled around the central tension member 32 at a time. The groove of the U groove 28 is straight and not spiral. U-groove type unit 3 in advance
Only 0 is manufactured and it is used as the center tension member 32.
When the upper layer is twisted, the outer layer tape is subjected to a strong tensile stress due to the difference in the twisted diameter (spiral diameter) between the inner layer and the outer layer of the tape in the U groove 28, which causes the inner layer tape to move in the groove. Since the transmission loss is likely to occur due to being strongly pressed against the bottom surface, the outer layer must be made longer, but it is impossible to store the tape in such a state. Therefore, the manufacturing and the assembly of the U groove type unit 30 cannot be performed in separate steps.
Inevitably, the U groove 2 is placed on the center tension member 32.
It is necessary to collect the optical fibers 8 and to store the optical fiber tape 16 immediately after that. The first layer is also difficult, but the number of U grooves 28 is particularly large in the second layer. A large number of U-grooves 28 and the optical fiber tape 16 are congested in the narrow space. For this reason, the manufacturing equipment becomes complicated and the manufacturing work becomes difficult, so that it is almost impossible to obtain a multi-core cable of a certain level or more. An object of the present invention is to provide a high-density multi-fiber optical fiber cable that solves such a problem.

[0007]

As illustrated in FIG. 1,
A cable structure is provided in which a layer of the H groove type unit 70 is provided on the slot type unit 60.

The slot type unit 60 has a slot 62.
The optical fiber tapes 16 are stacked and housed in the spiral groove 64. Reference numeral 66 is a tension member, and 68 is a presser winding. This is the slot type unit 20 of FIG.
It has the same structure as. However, the number of grooves 64 is large. Also,
The H-groove type unit 70 has the same structure as the H-groove type unit 44 of FIG. 4, and has two back-to-back spiral grooves 76, 76 provided in an elongated rod-shaped main body 74 of the H-groove 72.
The optical fiber tape 16 is stacked and stored in the inside, and a press winding 78 is applied.

The term "H-groove type unit 70" in the claims means that an optical fiber tape is provided in the groove of the above-mentioned "H-groove in which two back-to-back spiral grooves are provided in a slender rod-shaped body. It means that they are stacked and stored.

The H-groove type unit 70 can be manufactured in a separate process in advance. These are twisted and assembled on the slot type unit 60, and the presser winding 80 and the sheath 82 are
To form an H groove + slot type cable 84.
Further, the H-groove type unit 70 can have two or more layers as required.

[0011]

[Work]

(1) When a cable structure is provided in which the layer of the H groove type unit 70 is provided on the slot type unit 60, the cable outer diameter can be reduced as compared with the H groove type two-layer structure, as described later. (2) Since the H-groove type unit 70 has the spiral groove, it can be manufactured in advance and assembled later (the difference in length between the inner layer tape and the outer layer tape in the groove 76 is not accumulated).

[0012]

[Examples] Same as above, 16 mm wide and 0.25 mm thick
In the case of a 4000-core structure using a core optical fiber tape, the outer diameter of the H groove + slot type cable of the present invention is
It will be 45 mm. The above data is reprinted for reference. <Cable structure><Cable outer diameter> -U groove type 44mm-H groove type 2 layers 48mm This reduces the cable outer diameter from the H groove type 2 layers, and it is possible to achieve the same level as the U groove type. I understand.

[0013]

Since the H-groove type unit layer is provided on the slot type unit, the following effects can be achieved. (1) As described above, the outer diameter of the cable can be reduced to the same level as that of the U-groove type cable. (2) Further, compared to the U-groove type cable, there is no manufacturing problem when the number of cores is increased, so that the cable can be manufactured relatively easily. (3) In order to further increase the density, even when a large number of tapes with a thin coating layer and high density are stored, they are stored by dividing them into two spiral grooves that are back-to-back, thus reducing transmission loss. Unlikely to occur. Therefore, a high-density multi-core cable can be easily obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an example of a conventional high-density optical cable.

FIG. 3 is an explanatory view of another example of the conventional high-density optical cable.

FIG. 4 is an explanatory view of still another example of the conventional high-density optical cable.

[Explanation of symbols]

 12,62 Slot 14,40,64,76 Groove 16 Optical fiber tape 18,42,68,78,80 Holding roll 20,60 Slot type unit 22,32,46 Center tension member 24,34,48,82 Sheath 26 Multi-slot type cable 28 U groove 30 U groove type unit 36 U groove type cable 38,72 H groove 39,74 Main body 44,70 H groove type unit 50 H groove type cable 60 Slot type unit 66 Tension member 84 H groove + slot Type cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Suehiro Miyamoto Inventor, 1440 Rokuzaki, Sakura City, Chiba Fujikura Co., Ltd. Sakura Factory (72) Inventor Hideyuki Iwata 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph Telephone Within the corporation

Claims (1)

[Claims] 1. An optical fiber cable in which a layer of an H groove type unit is provided on a slot type unit in which an optical fiber core wire is housed in a groove of a slot.