JPH0475008A - high density fiber optic cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application in M Business) The present invention relates to a high-density optical fiber cable using a thin optical fiber core having a core diameter of 200 μm or less.

(Prior Art) FIG. 4 and FIG. 5 are both cross-sectional views of structural examples of conventional tape fiber assembly type optical fiber cables. Also the 6th
The figure is a cross-sectional view of an example of an optical fiber ribbon used in the above-mentioned cable.

Figure 4 shows a slot-type optical fiber cable with multiple throwers (102a) formed on the outer periphery and a tensile strength member (102a) in the center.
The optical fiber ribbon (10
A laminate made by laminating a plurality of sheets of 1) is stored. The slot rod (+02) is made of plastic material, and the slot rod (102a) has a rectangular cross section in order to store the laminate of the optical fiber tape (+01) at high density without any disorder. , and extends in the length direction in the shape of a spiral cane or Sz.

A pressure wrapping tape (+04) is applied on the outer periphery of the slot rod (+02), and an outer covering layer (105) formed by extrusion molding of a plastic material such as polyethylene is further provided on the outside thereof.

Figure 5 shows a composite pipe (LAP pipe) (+06) formed by laminating aluminum and polyethylene.
A plurality of LAP pipe units (+10) containing a plurality of optical fiber tape cores (+01) are twisted around a tensilon member (+07) in which a plastic layer (+07b) is provided on a tensile member (+07a). It is constructed by applying a pressing layer (+04) and an outer covering layer (+05) thereon.

The optical fiber tape (101) used in these cables has an outer diameter of +2511 as shown in Figure 6.
Soft lining (+12) on intestinal fibers (Ill)
A plurality of coated optical fibers each having an outer diameter (d') of 250+l+ and having a hard outer layer (+13) formed thereon are arranged in parallel and integrated with tape resin (+14). In the case of the 8-fiber ribbon shown in the figure, this dimension is the thickness (t
' ) = 0.41111 width (v' ) = 2. Imm.

(Problems to be Solved) Currently, there is a growing demand for multi-core and high-density optical fiber cables, and reducing the diameter of optical fiber cores is an extremely important issue.

However, in the conventional tape fiber assembly type optical fiber cable described above, the optical fiber tape cores are directly housed in the slot or LAP pipe. For this reason, the optical fiber ribbon and the inner wall of the slot or the inner wall of the LAP vibe come into direct contact and force is applied to the optical fiber ribbon, so the optical fiber used is required to have lateral pressure resistance characteristics. It has been difficult to reduce the diameter of the fiber core.

(Means for Solving the Problems) The present invention provides a high-density optical fiber cable that solves the above-mentioned problems. The structure consists of a high-density tape core unit in which a plurality of fiber tape cores are laminated and a buffer layer and a protective layer are sequentially provided on the outside thereof.

(Example) Figure 1 is a cross-sectional view of an example of the high-density optical fiber cable of the present invention, Figure 2 (A) is a cross-sectional view of an example of the optical fiber ribbon used therein, and Figure 2 (B) is a cross-sectional view of an example of the optical fiber ribbon used therein. 1 is a cross-sectional view of an example of a high-density tape core unit.

In this embodiment, as shown in FIG. 2(A), 12
511 optical fiber (12) with soft inner layer (+3)
and an outer diameter (d) of 0.
18 ■Thickness (t) of 8 thin optical fiber cores (11) of diameter φ arranged in parallel and integrated with thin tape material (15)
A thin tape core wire (1) having a width (v) of approximately 0.18 mm and a width (v) of 1.4 mm was used. This thin tape core wire (1) is 8
A high-density tape core unit (2) is formed by laminating the sheets, applying a soft cushioning layer (21) on the outside, and applying a hard protective layer (22) on top of it. It consists of At this time, the laminate of the thin ribbon core wires (1) may or may not be twisted.

The material for the buffer layer (21) is an ultraviolet curing resin (U
V resin), thermosetting type/recon resin, etc. can be considered, but Young's modulus of 0.5 kg/
It is desirable that the thickness be less than m2. Various materials such as UV resin, nylon, polyethylene, vinyl chloride, etc. can be used as the material for the protective layer (22), but Young's modulus of 20 is suitable for the protective layer (22).
Kg/mm2 or more is desirable.

As shown in FIG. 1, a plurality of the high-density tape fiber units (2) are twisted around a tension member (3) provided with a plastic layer (32) on the outer periphery of a tensile strength member (31). A pressing tape (4) is applied thereon, and an outer covering layer (5) formed by extrusion molding of a plastic material such as polyethylene is further provided on the outside thereof. The high-density tape fiber unit (2) may be twisted in the same direction or may be twisted in Sz.

FIG. 3 is a cross-sectional view of another embodiment of the high-density optical fiber cable of the present invention. As shown in the drawing, in the slot (6a) of a slotted rod (6) made of plastic, for example, which has a tensile strength member (7) in the center and has a plurality of slots (6a) having a fan-shaped cross section on the outer periphery, Figure 2 (b)
A plurality of high-density tape fiber units (2) shown in the figure are housed in each case. A pressure tape (4) is applied on the outer periphery of the slot rod (6), and an outer coating layer (5) is further provided on top of the tape (4).

(Function) Since an optical fiber ribbon in which optical fibers are arranged in parallel is vulnerable to external forces such as lateral pressure, the outer diameter of a conventional optical fiber ribbon was 0.25 mmφ. For example, when the same external force is applied to an optical fiber core wire of 0.25 mmφ and O, 1115 mφ in the above example, the stress generated in the optical fiber is:
In the case of 0.18mmφ, it is about 5 ~ compared to 0.25mmφ.
IO times larger. For this reason, it was extremely difficult to apply the thin ribbon ribbon using the thin optical fiber according to the present invention to the cables shown in FIGS. 4 and 5.

The present invention solves this problem by attaching shoes/I! to the outside of a laminate of thin tape core wires. By constructing a high-density tape fiber unit by providing a buffer layer with a strong resistance and a protective layer with a protective effect on top of the buffer layer, the lateral pressure property is improved and the density of the optical fiber is increased. be. In the above-mentioned unit, since the laminate of the thin tape core wires is integrated, arrangement disorder does not occur, and no clearance is required for the tape core wires to move.

The high-density thin-diameter tape core unit has a problem in that it is difficult to take out the tape core because the thin-diameter tape core is integrated into a laminate. For this purpose, a release agent such as silicone or oil is applied to the surface of the tape core wire, or a notch (23) is formed in the protective layer (22) in a straight or spiral shape as shown in Figure 2 (b). or tear string (2
4) can be easily resolved by taking measures such as having one or more people in attendance.

Note that the units can be easily identified by coloring the surface of the protective layer of the unit or by coloring the protective layer itself. Furthermore, since the thin-diameter tape fiber laminate is twisted, and the high-density thin-diameter tape fiber unit is further twisted, the stress applied to the optical fiber may increase. For this reason, it is desirable to use a carbon-coated optical fiber in which a carbon foot is provided on the surface of the optical fiber. This carbon-coated optical fiber has a fatigue coefficient n value of about five times that of a normal optical fiber, and is excellent in that even if stress is applied to the optical fiber, there is little deterioration in life.

(Example of Prototype Production) A prototype cable was produced using the cable shown in Figure 1, with only one unit having a high-density tape core unit, and the other units using dummy polyethylene strings.

Because it is a small-diameter optical fiber core, the loss value of the optical fiber was high due to lateral pressure in the bobbin-wound state after drawing and in the bobbin-wound state after making tape, but when the sample was gripped and there was no lateral pressure, it was After confirming the optical fiber loss value, we proceeded to the unitization process. The optical fiber used was a 1.3 .mu.Ge-5N carbon-coated optical fiber with a core diameter of 0.18 .phi..

There were no particular problems in unitizing it, and it was possible to manufacture it. In this prototype, the tape core wire laminate was not twisted, so a unit winding bobbin with a body diameter of 1100 h was used to reduce the difference in tape core length due to bobbin winding. The loss value of the optical fiber after unitization was good, and it was confirmed that this structure is effective in improving the lateral pressure characteristics of the small-diameter ribbon core.

The high-density tape core unit and the dummy polyethylene string were twisted together on the outer periphery of the polyethylene-coated steel wire, a pressing tape was applied thereon, and an outer coating layer was further applied thereon. There was no change at all between the processes of twisting and outer coating of the unit, indicating good manufacturability. We checked the mechanical and temperature characteristics of the prototype cable, but the temperature characteristics were -
It shows good characteristics except for a slight increase in loss at 40°C.
It was confirmed that there were no problems in practical use.

(Effects of the Invention) As explained above, according to the high-density optical fiber cable of the present invention, for example, in the case of the cable shown in FIG. 1, the outer diameter is 400 fibers! In the case of the conventional cable shown in Fig. 4,
In the case of 2001C1, IS■厘φ, and the cable shown in Figure 5,
21 mm≠ for 200 fibers, and the cable structure of the present invention can achieve extremely high density compared to the conventional structure.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an embodiment of the high-density optical fiber cable of the present invention, Fig. 2 (a) is a cross-sectional view of the optical fiber tape used therein, and Fig. FIG. 3 is a cross-sectional view of the line unit. FIG. 3 is a cross-sectional view of another embodiment of the high-density optical fiber cable of the present invention. Figures 4 and 5 are both cross-sectional views of a structural example of a conventional optical fiber tape assembly type optical fiber cable;
The figure is a cross-sectional view of the optical fiber ribbon used therein. DESCRIPTION OF SYMBOLS 1...Small diameter tape coated wire, 11...Optical fiber tape coated wire, 2...High density tape coated wire unit, 21...
buffer layer, 22... protective layer, 23... notch, 24...
... Tear string, 3... Tennyon member, 4 river pressing tape, 5... External covering layer.

Claims (5)

[Claims] (1) Constituent element is a high-density tape core unit in which a plurality of optical fiber tape cores made of thin optical fiber cores with an outer diameter of 200 μm or less are laminated, and a buffer layer and a protective layer are successively provided on the outside. A high-density optical fiber cable characterized by: (2) The high-density optical fiber cable according to claim (1), wherein the laminate of optical fiber ribbons is twisted. (3) The high-density optical fiber cable according to claim 1 or 2, wherein the optical fiber of the thin optical fiber core wire is a carbon coated optical fiber. (4) Claims (1)-(
3) High-density optical fiber cable as described. (5) The high-density optical fiber cable according to any one of claims (1) to (4), characterized in that a tearing string is embedded in the high-density tape core unit.