JP2001290058A - Optical fiber cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical fiber cord for mobile communication having high breaking strength and improved water pressure characteristics. SOLUTION: The optical fiber cord 6 constituted by winding tension fiber around a coated optical fiber 3 to form a flat tension layer 4 and disposing a cord coating layer thereon is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cord with improved breaking strength used for communication control of a high-speed moving body or the like.

[0002]

2. Description of the Related Art Hitherto, a moving body such as a moving body moving at a high speed or a moving body moving in the sea, and a device for controlling these moving bodies have been connected to each other, and an optical communication code for controlling the moving bodies has been used. Fiber cords are used. As an optical fiber cord used for communication of such a mobile body, a coating layer made of an ultraviolet curing resin is formed on a bare optical fiber having an outer diameter of 125 μm to form an optical fiber core. A structure is used in which a tensile member made of aramid fiber, glass fiber, or the like is vertically attached around a wire, and a cord coating layer made of nylon or the like is provided on the tensile member.

[0003] Such an optical fiber cord is
It is housed in an optical fiber cord spool 8 as shown in FIG. In the figure, reference numeral 6 denotes an optical fiber cord. The optical fiber cord 6 is wound around a cylindrical bobbin 7 in multiple layers (hereinafter referred to as a coil) and housed in an optical fiber cord spool 8. Is done. When the optical fiber cord spool 8 is used, the optical fiber cord spool 8 is attached to a moving body or a control device.
The optical fiber cord 6 is paid out from the optical fiber cord spool 8 and used.

[0004]

However, in the optical fiber cord having such a structure, since the tensile members are vertically attached, it is difficult to arrange the tensile members evenly on the optical fiber core. . Therefore, when such an optical fiber cord is used for communication of a mobile object, the optical fiber cord may be coiled when housed in the optical fiber cord spool 8 or pulled out from the optical fiber cord spool 8 due to tensile force. There was a problem that it was easily buckled. In addition, when an optical fiber cord having such a structure is used in water, there is a problem that the water pressure characteristics are poor and the loss of the optical fiber cord increases due to the received water pressure.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical fiber cord for mobile communication having excellent flexibility and improved hydraulic characteristics.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical fiber comprising winding a tensile strength fiber around an optical fiber, forming a flat tensile strength layer, and providing a cord coating layer thereon. Solved by fiber cord. At this time, it is preferable that the tensile strength layer is formed by winding 5 to 7 aramid fibers of 170 to 230 denier.
With such an optical fiber cord, the strength members can be evenly arranged and provided around the optical fiber core wire, so that it is excellent in flexibility and hardly buckled. Therefore, loss at the time of coiling or extension can be reduced. Further, since it has excellent water pressure characteristics, it can be suitably used as an optical fiber cord for mobile communication.

[0007]

FIG. 1 shows an example of an optical fiber cord according to the present invention. In the figure, reference numeral 1 denotes a bare optical fiber. The bare optical fiber 1 has an outer diameter of 125 μm, but is not limited to this. On the bare optical fiber 1, a coating layer 2 formed by applying and curing an ultraviolet curable resin or the like is provided to form an optical fiber core 3. The outer diameter of the optical fiber core wire 3 is about 250 to 400 μm.

[0008] On the outer periphery of the optical fiber core wire 3, a tensile strength fiber is wound horizontally to form a tensile strength layer 4. Fibers such as aramid fibers and carbon fibers are examples of the tensile strength fibers. Among them, aramid fiber can provide sufficient strength to the optical fiber cord 6 and can be easily wound around the optical fiber core wire 3, so that it is suitably used as a tensile strength fiber. At this time, the thickness of the tensile strength fiber is preferably 170 to 230 denier. If it is less than 170 denier, sufficient strength cannot be given to the optical fiber cord 6, and if it exceeds 230 denier, it becomes difficult to wind it on the optical fiber core wire 3.

When the tensile strength layer 4 is formed by the tensile strength fibers, the tensile strength fibers having such a thickness are formed in a thickness of 5 to 7 mm.
It is preferable to use six, preferably six. When the number of the tensile strength fibers is four or less, the tensile strength fibers cannot be evenly arranged on the optical fiber 3 when the tensile strength layer 4 is formed by being wound horizontally. As described above, when the tensile strength layer 4 is uneven, the optical fiber cord 6 is
Cannot be absorbed, and the loss particularly when the optical fiber cord 6 receives a high water pressure increases. If the number is eight or more, the transverse winding of the tensile strength fiber becomes difficult, and the proportion of the tensile strength layer 4 in the optical fiber cord 6 increases, so that the handleability of the optical fiber cord 6 deteriorates. In addition, the horizontal winding pitch of these tensile strength fibers is 150 to 250 m.
The range of m is preferred. Within this range, the tensile strength fibers can be evenly arranged on the optical fiber core wire 3, the tensile strength layer 4 can be flattened, and the breaking strength of the optical fiber cord 6 can be improved.

On such a tensile strength layer 4, nylon 1
2. A cord coating layer 5 is provided by coating with a polyamide resin such as nylon 11. The Young's modulus of the resin forming the cord coating layer 5 is desirably about 100 to 200 kg / mm ² . The thickness of the cord covering layer 5 is 100 to 150 μm, and the outer diameter of the optical fiber cord is 800 to 900 μm.

As described above, in the case of the optical fiber cord 6 in which the tensile strength fiber is wound horizontally on the optical fiber core wire 3 to form the tensile strength layer 4, the tensile strength fiber is vertically attached to the optical fiber core wire 3. The flexibility can be improved as compared with the optical fiber cord provided in the above manner. Therefore, the optical fiber cord 6 does not buckle due to a tensile force applied when the optical fiber cord 6 is formed into a coil or when the optical fiber cord 6 is extended from the optical fiber cord spool 8. Further, in the optical fiber cord 6, since the tensile strength fibers are uniformly distributed around the optical fiber core wire 3, the thickness of the tensile strength layer 4 can be kept constant, and the optical fiber cord can be formed flat. The cross-sectional shape of No. 6 can be set to a state close to a perfect circle without irregularities. Therefore, when such an optical fiber cord 6 is used in water, especially in a place where the water pressure is high such as on the sea floor, even if it is subjected to a high water pressure, the tensile strength layer 4 is uniformly pressed and the pressure is increased. Is absorbed by the tensile strength layer 4, so that the pressure applied to the bare optical fiber 1 inside is reduced, and the optical fiber cord 6
Loss can be reduced.

With such an optical fiber cord 6 having excellent flexibility and excellent water pressure characteristics, for example, a communication code for a mobile body such as a mobile body moving on the seabed or a mobile body moving at a high speed. Can be suitably used.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. (Example 1) An ultraviolet curable resin was applied to an optical fiber bare wire having a diameter of 125 µm and cured to obtain an optical fiber core wire having a diameter of 400 µm. As the tensile strength fibers, 200 ± 5 denier (d) aramid fiber yarns were used, and six of them were wound around the optical fiber core wire so as to have a pitch of 200 mm. Next, the tensile strength layer was coated with nylon 12 to provide a cord coating layer having a diameter of 850 μm.
m optical fiber cords were manufactured.

Comparative Example 1 Diameter 400 used in Example 1
μm optical fiber, 200 ±
Four yarns of aramid fiber of 5 denier (d) were longitudinally added, and nylon 12 was further coated thereon to provide a cord coating layer, thereby producing an optical fiber cord of Comparative Example 1. (Comparative Example 2) An optical fiber cord of Comparative Example 2 was manufactured in the same manner as in Example 1 except that four aramid fibers were used.

With respect to the optical fiber cords of Example 1 and Comparative Examples 1 and 2, buckling properties, water pressure characteristics, and an increase in loss during feeding were examined. Table 1 shows the results. (Bullability) The optical fiber cord was bent, and the bending radius (mm) when the optical fiber cord was buckled was measured.

(Hydraulic pressure test) The above optical fiber cord 100
0 m was placed in a hydraulic test container, and the container was forcibly filled with water so that a water pressure of 100 atm was applied to the optical fiber cord. At this time, the loss at a wavelength λ of 1.55 μm was measured. .

(Increase in Loss at the Time of Feeding Out) The 10 km of the optical fiber cord of Example 1 and Comparative Examples 1 and 2 is applied to the bobbin 7 having an outer diameter of 10 cm of the optical fiber cord spool 8 having the structure shown in FIG. Then, the optical fiber cord was pulled out of the optical fiber cord spool 8 with a pulling force of 1 to 3 kg, and the light receiving power level at a wavelength of 1.55 μm was measured. Then, the maximum value (P _max ) of the level fluctuation at this time and the light receiving power level (P ₀ ) at the wavelength λ1.55 μm of the optical fiber cord before being fed are obtained, and the difference (P ₀ −P _max ) between these values is obtained. ) Was calculated.

[0018]

[Table 1]

From the results shown in Table 1, it can be seen that the optical fiber cord of the present invention has excellent flexibility, excellent water pressure characteristics, and a small increase in loss even when the cord is pulled out from the optical fiber cord spool.

[0020]

As described above, according to the optical fiber cord of the present invention, since the tensile strength layer is formed by flatly winding the tensile strength fiber in a horizontal winding, it has excellent flexibility. Even when a tensile force is applied to the optical fiber cord at the time of winding around the optical fiber cord spool or unreeling from the optical fiber cord spool, the optical fiber cord does not buckle.
Further, this optical fiber cord has excellent water pressure characteristics, and the increase in loss is small even under high water pressure. Therefore, it can be suitably used as an optical fiber cord for communication of a moving body such as a moving body moving in the sea or a moving body moving at a high speed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an optical fiber cord of the present invention.

FIG. 2 is a sectional view showing an example of a conventional optical fiber cord for mobile communication.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bare optical fiber 3 core optical fiber 4 tensile strength layer 5 cord coating layer 6 optical fiber cord 7 bobbin 8 optical fiber cord spool

Claims (2)

[Claims] 1. An optical fiber cord comprising a tensile strength fiber wound around an optical fiber core wire to form a flat tensile strength layer, and a cord coating layer provided thereon. 2. The optical fiber cord according to claim 1, wherein the tensile strength layer is formed by winding 5 to 7 aramid fibers of 170 to 230 denier.