JPH1090569A - Optical cord type cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical cord type cable having an improved low-temp. characteristic. SOLUTION: Optical cords 1 are housed into slots 7 of a slot member 5 having a tension member 9. Wrapping tapes 8 are applied thereon and are coated thereon with a sheath 9. The depth of the slots 7 is smaller than the average outside diameter of the optical cords 1. Then, the optical cords 1 are higher by (h) than the outside surface of the slot member 5 when the optical cords 1 are housed in the slits 7. The wrapping tapes 8 are applied thereon and the sheath 9 is applied thereon from above, by which the optical cords 1 are pressed into the slots 7 and the optical cords 1 are integrated with the slot member 5. The shrinkage of the optical cords at a low temp. is thus suppressed and the increase of the loss is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical cord type cable using an optical cord in which a tensile strength fiber is provided around an optical fiber and a plastic coating is applied to the outside.

[0002]

2. Description of the Related Art A slot type cable in which an optical fiber is loosely stored in a slot of a slot member has an advantage in that even if an external force such as bending or tension is applied to the cable, the effect on the optical fiber is small. However, since it is necessary to reinforce the drawn optical fiber at the cable end,
There is a problem that terminal processing becomes complicated. In order to attach the connector to facilitate the connection operation, an aramid fiber (registered trademark “Kevlar”) 12 is attached around the nylon tube 11 and the outer side thereof is attached as shown in FIG. A reinforcing member 14 prepared by extruding and covering PVC to form a sheath 13 is prepared, and as shown in FIG. 4B, the optical fiber 2 is inserted into the nylon tube 11 to reinforce the optical fiber 2, and a connector is attached thereto. Is used. This method not only has a problem in that the reinforcing member 14 is used, but also ensures that when a tensile force is applied to the reinforcing member 14, no tension is applied to the optical fiber in a portion not reinforced by the reinforcing member. It is necessary to consider how to make.

On the other hand, when an optical fiber of the optical cord type is used, there is an advantage that a reinforcing body used for attaching a connector is not required, and strength against a tensile force can be secured. However, the optical cord alone has a problem that the jacket shrinks at a low temperature, a compressive force acts on the optical fiber, and transmission loss increases.

[0004] Some optical cords are not used alone, but are inserted into the slots of the slot member, and have the advantage of high strength against lateral pressure. However, they are loosely housed in the slots, and are resistant to shrinkage. No consideration is given, and it cannot prevent an increase in transmission loss at low temperatures.

FIG. 5 is a sectional view of a conventional layered cable. An optical cord 16 is twisted around a strength member 15, and a sheath 17 is extruded and coated thereon. In this layered cable, the optical cord 16 is made of the tensile member 1.
5 is advantageous in that it is less susceptible to shrinkage at low temperatures and can prevent an increase in transmission loss at low temperatures, but has the problem of being vulnerable to lateral pressure.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an optical cord type cable having improved low-temperature characteristics.

[0007]

According to a first aspect of the present invention, there is provided an optical cord type cable in which an optical cord formed by attaching a tensile strength fiber around an optical fiber and applying a plastic coating to the outside is accommodated in a slot of a slot member. Wherein the optical cord is housed in the slot so that relative movement with respect to the slot is suppressed.

According to a second aspect of the present invention, in the optical cord type cable according to the first aspect, a tensile member is provided in the slot member.

According to a third aspect of the present invention, in the optical cord type cable according to the first or second aspect, the depth of the slot is not more than the average outer diameter of the optical cord. .

According to a fourth aspect of the present invention, in the optical cord type cable according to any one of the first to third aspects, the optical cord accommodated in the slot is intermittently formed of an adhesive resin. Characterized in that it is adhered to.

According to a fifth aspect of the present invention, there is provided the optical cord type cable according to any one of the first to third aspects, wherein the hold-down winding of the slot accommodating the optical cord is roughly wound. It is characterized by being subjected to extrusion coating.

[0012]

FIG. 1 is an explanatory diagram of an optical cord used in the present invention. In the figure, 1 is an optical cord, 2 is an optical fiber, 3 is a tensile fiber, and 4 is a sheath. The optical fiber 2 is a single layer or 2 layers on the drawn glass fiber.
0.25mm outside diameter coated with UV curable resin
Something was used. A tensile fiber is added around the optical fiber 2, and PVC is extruded and coated to a thickness of, for example, about 0.3 mm on the optical fiber 2 to form a sheath 4. The outer diameter is about 2 mm in this example. . However, the dimensions of each part and the material of the resin are not limited to this example, but can be appropriately selected. As the tensile strength fiber, an appropriate tensile strength fiber such as an aramid fiber is used.

FIG. 2 is a view for explaining a first embodiment of the optical cord type cable according to the present invention. FIG. 2 (A) is a perspective view for explaining the internal structure, and FIG. 2) is a sectional view, and FIG. 2C is an enlarged sectional view near the slot.
In the figure, 1 is an optical cord, 5 is a slot member, 6 is a tensile member, 7 is a slot, 8 is a presser winding, and 9 is a sheath. In FIG. 2A, illustration of the optical cord stored in the slot 7 is omitted for easy viewing.

The slot member 5 is made of, for example, polyethylene and is provided with a tensile member 6. Sheath 9 is L
AP (Laminated Aluminum Pol)
(ethylene) was used. However, the material is not limited to this example, and an appropriate material can be selected. In an example of the dimensional relationship, the outer diameter of the tensile member is 1.6 mm, the outer diameter of the slot member 5 is 7 mm, and the outer diameter of the sheath 9 is 11 mm.

In this embodiment, the depth of the slot 7 is smaller than the average outer diameter of the optical cord 1. Therefore, when the optical code 1 is stored in the slot 7, in FIG.
Although not shown in detail, the optical cord 1 is the same height as the outer surface of the slot member 5, or as shown in FIG. 2C, the optical cord 1 is higher than the outer surface of the slot member 5 by h. ing. That is, h ≧ 0. As shown in FIGS. 2A and 2B, the optical cord 1 is pressed against the slot 7 by applying a presser winding 8 and applying a sheath 9 thereon. It is integrated with the member 5. Note that even if h = 0,
The pressing force works, and the optical cord 1 and the slot member 5 can be integrated, but the greater the h, the greater the integration force. However, if h is too large, the loss increases with respect to the lateral pressure. Therefore, h should be determined in consideration of these conditions.

In FIG. 2B, the slot member 5 is formed with four slots, and the optical cord 1
Although the optical cord 1 is stored in two of the slots, the optical cord 1 may be stored in all the slots, or may be stored in some of the slots. Further, the number of slots is not limited to four. Although the wrap winding was used for the holding roll, it may be vertically attached. In addition, if the material of the slot member 5 has sufficient tensile strength, the tensile strength member 6 is not always necessary.

The width of the slot 7 in this embodiment is preferably equal to or slightly smaller than the average outer diameter of the optical cord 1. The adhesion between the optical cord 1 and the inner wall of the slot 7 is improved, and the optical cord 1 and the slot member 5 are more firmly attached.
And can be integrated.

As described above, the optical cord 1 is connected to the slot member 5.
By integrating the optical cord, the shrinkage of the coating of the optical cord 1 at a low temperature can be suppressed, and the low-temperature characteristics of the optical cord can be improved. Also, the side pressure can be absorbed by the tensile strength fiber of the optical cord 1 and the slot member 5, and the side pressure applied to the optical fiber can be sufficiently reduced.

In the second embodiment, the optical cord stored in the slot is intermittently bonded in the longitudinal direction of the slot. By bonding the optical cord to the inner wall of the slot, the optical cord 1 and the slot member 5 can be integrated. In this case, as described in the first embodiment, the depth of the slot may be smaller than the average diameter of the optical cord.
The depth of the slot may be greater than the average diameter of the optical cord. It is advantageous for the side pressure to make the depth of the slot larger than the average diameter of the optical cord.

In a specific example, for light having a wavelength of 1.55 μm, the loss increase at −30 ° C. is 0.5% in an optical cord type cable in which an optical cord is not bonded to a slot.
In contrast to 5 dB / km, in the case of an optical cord type cable in which optical cords were bonded to slots at 1 m intervals, 0.0
It was 1 dB / km, and the increase in loss at low temperatures could be improved.

FIG. 3 is a perspective view for explaining an optical cord type cable according to a third embodiment of the present invention. In the figure,
The same parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. Also in this figure, the illustration of the optical cord stored in the slot 7 is omitted. In this embodiment, the hold-down winding 8 is coarsely wound so that the optical cord stored in the slot is partially exposed. The spiral direction of the presser winding is opposite to the spiral direction of the slot. The relationship between the cross-sectional dimension of the slot 7 and the outer diameter of the optical cord may be a dimension such that the optical cord just fits into the slot, ie, a dimension such that h = 0 in FIG. 2C. Of course, as described in the first embodiment, h ≧ 0 may be satisfied.
<0 may be used. By directly pushing out the sheath 9 from above, the material of the sheath enters the slot and the optical cord can be bonded to the slot member 5. Since the optical cord is integrated with the slot member 5 by the material of the sheath, there may be some gap between the slot 7 and the optical cord. In this embodiment, polyethylene is used as the material of the sheath 9, but other thermoplastic resins can be used in consideration of adhesiveness.

In a specific example, a 3 mm-wide presser winding was applied to a slot member having an outer diameter of 7 mm, and a sheath was extruded thereon. With respect to light having a wavelength of 1.55 μm, the increase in loss at −30 ° C. is equivalent to 0.
While it was 55dB / km, 2m
In the case where the coil was roughly wound by opening m, the loss was 0.01 dB / km, and the increase in loss at low temperature could be improved.

[0023]

As is apparent from the above description, according to the present invention, the optical cord is housed in the slot of the slot member and is integrated with the slot member.
Shrinkage of the optical cord at low temperatures can be suppressed, and increase in loss at low temperatures can be reduced. Further, by providing a tensile member in the slot member, it is possible to improve the tensile strength characteristics of the optical cord type cable.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an optical code used in the present invention.

FIGS. 2A and 2B are views for explaining a first embodiment of an optical cord type cable according to the present invention, wherein FIG. 2A is a perspective view for explaining an internal structure, and FIG. FIG. 2
(C) is an enlarged sectional view near the slot.

FIG. 3 is a perspective view illustrating an optical cord type cable according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional terminal processing technique.

FIG. 5 is a cross-sectional view of a conventional layered cable.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical cord, 2 ... Optical fiber, 3 ... Tensile fiber, 4 ...
Sheath, 5: slot member, 6: tensile strength member, 7: slot, 8: hold-down, 9: sheath.

Claims (5)

[Claims] 1. An optical cord type cable in which an optical cord formed by applying a tensile strength fiber to the periphery of an optical fiber and applying a plastic coating to the outside is accommodated in a slot of a slot member, wherein the optical cord is positioned relative to the slot. An optical cord type cable which is housed in the slot so that movement is suppressed. 2. The optical cord type cable according to claim 1, wherein a tensile member is provided in the slot member. 3. The optical cord type cable according to claim 1, wherein a depth of the slot is equal to or less than an average outer diameter of the optical cord. 4. The optical cord type according to claim 1, wherein the optical cord stored in the slot is intermittently adhered to the slot with an adhesive resin. cable. 5. The optical cord type according to claim 1, wherein a press-winding of the slot storing the optical cord is roughly wound, and a cover is extruded thereon. cable.