JPH0450904A - Metal pipe covered optical fiber and production thereof - Google Patents

Abstract

PURPOSE:To improve transmission characteristics and reliability by specifying the range of the surplus length rate of the optical fiber. CONSTITUTION:The value of the ratio between the inside sectional area of a metallic pipe 14 and the occupying area of the optical fiber 12 is about 4 to 20 and the consistency of jelly is about 200 to 400. The range of the surplus length rate of the optical fiber 12 is specified to 0.0 to 0.6%. The optical fiber 12 is preferably loosely housed in the metallic pipe 14 without being impressed with an elongation stress in the pipe in terms of the long-term reliability (life). On the other hand, the optical fiber 12 meanders in the metallic pipe 14 if the length of the optical fiber 12 is too long (the surplus length is too long) with respect to the metallic pipe 14. The surplus length rate of the optical fiber 12 is needed, therefore, to be within the correct range. The production without entailing the deterioration of the transmission loss is possible in this way and the stable transmission in a wide temp. range is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a metal pipe optical fiber core and a manufacturing method thereof.

In the order of explanation, the purpose, structure, and effects of the metal pipe optical fiber core wire of the first invention (specific invention) will be described first, and then the manufacturing method of the second invention will be similarly described.

First invention: Metal pipe optical fiber core wire [Problem Ml (1) to be solved by the prior art and the first invention
) Regarding plastic pipe optical fiber core: Conventional pipe-type optical fiber cores are generally made by extruding thermoplastic resin (nylon, PBT resin, etc.) around the optical fiber.

Such a core wire has the advantage that it is possible to obtain an extra length of optical fiber in the pipe by utilizing the contraction of the resin during extrusion processing.

However, from the viewpoint of mechanical strength, it is necessary to increase the wall thickness, which has the disadvantage of increasing the outer diameter of the core wire.

(2) Regarding the metal pipe optical fiber core wire: As shown in FIG. 8, the metal pipe optical fiber core wire 10 is
The optical fiber 12 is housed in the inside of the optical fiber 4, and the jelly 16 is filled in the optical fiber 12.

・Kuberi A It can be made thinner and has excellent mechanical strength.

From the viewpoint of long-term reliability of the single-point optical fiber, it is desirable that the optical fiber 12 be housed loosely in the metal pipe 14 without applying any elongation stress.

However, the optical fiber 12 is
If the length of the optical fiber 12 becomes too long (if the extra length is too large), the optical fiber 12
The wires meander inside the metal pipe 14, causing deterioration of transmission loss.

Therefore, the remaining length ratio of the optical fiber must be within an appropriate range.

[Means for Solving the Problem] The ratio between the inner area of the metal pipe and the area occupied by the optical fiber is about 4 to 20, and the jelly has a degree of about 200 to 20.
In a metal pipe optical fiber core wire having a diameter of about 400, the range of the surplus length ratio of the optical fiber core wire is 0.0 to 0.6%.

[Reasons for numerical limitations] (1) Regarding the ratio between the inner area of the metal pipe and the area occupied by the optical fiber, from a manufacturing standpoint, the ratio between the inner area of the metal pipe 14 and the area occupied by the optical fiber 12 therein The ratio to the area (or the sum of the areas in the case of multiple cores) is considered to be approximately 4 to 20.

(2) Concerning the preparation of jelly, jelly is filled to prevent water supply, but the preparation should be within the optimum range from the viewpoint of being movable within the metal pipe 14 and not flowing out from the end of the metal pipe 14. is naturally about 200 to 400.

(3) Regarding the surplus length ratio: The samples shown in Table 1 below have a ratio of ■inner area of metal pipe 14:occupied area of optical fiber 12 of 4:1, as described above.
~ About 20:1, ■ Jerry's preparation is 200-400
It is a metal pipe optical fiber core wire.

FIG. 1 shows the relationship between the surplus length ratio and transmission loss.

Table 1 (1) All mounted fibers are 250μisM UV wires.

(2) Area ratio is metal pipe internal area/optical fiber occupied area.

It can be seen that, except for sample C, when the surplus length ratio exceeds 0.6%, the transmission loss increases rapidly.

It should be noted that the surplus length ratio of 0.0% applies when the lengths of the optical fiber and the metal pipe are equal, and it can be seen that this is also effective in such a case.

Further, FIG. 2 shows the relationship between temperature and transmission loss when the remaining length ratio is 0.6% for the same sample.

From the above, if the value of the surplus length ratio is within the range of 0.0 to 0.6%, manufacturing is possible without deteriorating transmission loss, and stable transmission can be achieved over a wide temperature range. It turns out that it is possible.

[Effects of the first invention] The value of the ratio between the inner area of the metal pipe and the occupied area of the optical fiber is about 4 to 20, and the degree of jelly is about 200 to 40.
Since the surplus length ratio is set to 0.0 to 0.6% in the metal pipe optical fiber core wire, which is about 0%, the transmission characteristics and 1M reliability are improved as described above.

Second invention: Manufacturing method [Prior art] A metal pipe optical fiber core was manufactured as follows (FIG. 9(a)).

The optical fiber 12 is continuously fed out from the bobbin 20, and at the same time, the metal tape 13 (for example, made of sUs) is fed out from the bobbin 22.
Send continuously from

Continuously wrapping the optical fiber 12 with the tape 13, the metal tape 13 is rolled up using a roll forming machine 24, and at the same time, the jelly 16 is filled therein using a pump 26.

Then, it is made into a pipe 14 by a welding machine 28, passed through a draw-down machine 30, wrapped around a take-up capstan 32, and pulled strongly to make a metal pipe optical fiber core wire 10 having a predetermined outer diameter, which is then wound onto a roll 34. take.

[Vau to be solved by the second invention] When the above metal pipe optical fiber core wire 10 is wound around the take-up capstan 32 and taken out, the optical fiber 12 has a back tension f as shown in FIG. 9(b). Because of this, it sinks into the metal pipe 14 and comes into contact with it.

That is, the optical fiber 12 connects to the neutral portion 3 of the metal pipe 14.
6, the length of the optical fiber 12 becomes shorter than the length of the metal pipe 14. In other words, the remaining length ratio is negative.

Therefore, when the optical fiber 12 is stretched, tension is applied to the optical fiber 12, extremely shortening its lifespan.

As mentioned above, the surplus length ratio must be in the range of 0.0% to 0.6%, but at present, there is no established method for controlling the surplus length ratio in metal pipe optical fiber cores. It has not been.

[Means for Solving Problem 81] (1) First, as shown in FIG. For a jelly 16' equivalent to the optical fiber 12 and an optical fiber 12' housed therein, the maximum length (
(hereinafter referred to as the pull-out length) is determined in advance and is designated as L.

(2) The distance X between the withdrawal machine 30 and the take-up capstan 32 in FIG. 3 is set to be equal to or longer than the above-mentioned length.

(3) The elongation strain that occurs when the metal pipe is pulled down is 0.0 to 0.6%.

[Function] (1) If the distance X between the drawing machine 30 and the take-off capstan 32 is equal to or greater than the above-mentioned drawing length, at the point where the metal pipe optical fiber core wire 10 is wound around the take-off capstan 32, The back tension applied to the optical fiber 12 is zero.

Therefore, the optical fiber 12 does not sink into the metal pipe 14 when it is wound.

(2) Distance 1 between the withdrawal machine 30 and the withdrawal capstan 32
When 11tX exceeds the above-mentioned drawing length, the back tension applied to the optical fiber 12 becomes zero as described above, so the tension applied for drawing causes the tension between the drawing machine 30 and the drawing capstan 32 to , even if the metal pipe 14 is stretched, the optical fiber 12 is not stretched.

Therefore, the elongation strain of the metal pipe 14 directly becomes the remaining length ratio of the optical fiber 12.

These points will be explained later.

[More Detailed Description of Manufacturing Method] FIG. 3(a) is an explanatory diagram of the manufacturing method, which is the same as FIG. 9(a) above. However, the distance X between the withdrawal machine 30 and the withdrawal capstan 32 is larger than in the conventional case.

Part B of the figure is enlarged and shown in (b).

The length of X is determined based on the drawing length described below.

[About pull-out length] In order to determine the pull-out length, the following experiment is conducted in advance.

The metal pipe 114' in FIG. 4 is a pipe equivalent to the metal pipe 14 of the metal pipe optical fiber core wire 10. However, to be precise, the inner diameters only need to be equal.

An optical fiber 12' equivalent to the optical fiber 12 is housed therein, and a jelly 16° equivalent to the jelly 16 is housed therein.
is filled.

The optical fiber 12' is pulled with the same force as the back tension f. As shown in FIG. 4A, when the metal bi 114° is short, the optical fiber 12' is easily pulled out.

However, as the length of the metal pipe 14' gradually increases, the resistance force generated due to the viscosity of the jelly 16' also gradually increases, and when it finally becomes equal to f, it becomes impossible to pull out the optical fiber 12''. Become.

The length of the metal bi 114' at this time is the pull-out length (FIG. 2b).

In this way, if it is impossible to pull out the optical fiber 12' from the metal pipe 14', when the metal pipe 14'' is moved, the optical fiber 12' will be pulled out even if back tension is applied to it. metal pipe 14'
move as one.

Therefore, when manufacturing the metal pipe optical fiber core 1s10 (FIG. 3), if the distance When the optical fiber 12 is wound around the stun 32, the optical fiber 12 moves together with the metal pipe 14.

Even when the optical fiber 12 is wound around the take-up capstan 32, the optical fiber 12 remains on the neutral portion 36 (FIG. 3b), and does not sink inside the metal pipe 14 as in the conventional case.

E Regarding control of surplus length ratio] FIG. 5(a) shows the withdrawal machine 30 and the withdrawal capstan 3.
2 schematically shows a metal pipe optical fiber core 10 between the two.

At this time, the metal pipe 14 is stretched and stretched for drawing down.

Therefore, when the tension is removed, it returns to its original length (
Figure b).

If the length of the metal pipe 14 when it is being stretched is X, and the elongation at that time is ΔX, then the elongation strain a=Δx/(x−ΔX).

On the other hand, even while the metal pipe 14 collapses and returns to its original length, the length of the optical fiber 12 remains unchanged.

Therefore, in the state shown in FIG. 5B when manufacturing is completed, the length of the optical fiber 12 is X, the length of the metal pipe 14 is (X - ΔX), and the remaining length of the optical fiber 12 is ΔX.
It is.

Therefore, the surplus length ratio α=ΔX/(X−ΔX),
This is the same as the elongation strain a mentioned above.

Taking all the above into consideration, in order to obtain the desired surplus length ratio α, ■ the distance between the withdrawal machine 30 and the take-up capstan 32 is 11[
x is set to be longer than the pulling length so that the optical fiber 12 or the metal pipe 14 can move together with the force of the jelly 16.

(2) When drawing down the metal pipe 14, adjust the drawing rate and tension appropriately so that the elongation strain a of the metal pipe 14 becomes α%.

In the above manner, a metal pipe optical fiber core wire 10 having a surplus length ratio α is obtained.

[Example] Inner/outer diameter = 1. A single optical fiber of 250 μι UV cable was mounted on a metal pipe of O/1.2m+*φ, 5US304, and a test was conducted on the metal pipe optical fiber core filled with jelly having a consistency of 300.

First, the relationship between the pulling force (corresponding to back tension) and the pulling length of the optical fiber 12' was determined for the metal pipe 14' in the same state as the metal pipe optical fiber core wire 10. The results are shown in FIG.

Note that, for manufacturing reasons, the appropriate back tension is 20 to 150 g per core.

This is because if it is less than that, it is difficult to control the back tension, and if it is more than that, it may cause breakage or strength deterioration of the optical fiber.

Therefore, the same optical fiber 12. Metal pipe 14. When manufacturing the metal pipe optical fiber core wire 10 having the jelly 16, the distance jl [x] between the drawing machine 30 and the taking-off capstan 32 is required to be at least 31,
It is necessary to increase the length as the back tension and number of conductors increase.

Gorigo Nikura 11 ・Outside diameter of take-up capstan: 600+*m ・Back tension of optical fiber = 50 g ・Take-down rate after metal pipe welding: Approx. 20% ・Take-down tension crab 15 kg ・Take-down tension The relationship between the distance X between the drawer 30 and the take-up capstan 32 and the surplus length ratio α was determined under the condition that the elongation strain of the metal pipe was 0.2% or more.

The results are shown in FIG.

The following can be seen from Figures 6 and 7.

When the back tension of the optical fiber 12 is 50 g, the pulling length is approximately 5 mm (FIG. 6), and the distance Mx between the pulling device 30 and the pulling capstan 32 must also be 5 mm or more.

Also, from Fig. 7, when X becomes 5 m or more, the surplus length ratio is 0.
00% or more.

The remaining length ratio is saturated at 0.2%, which is the same as the elongation strain of the metal pipe 14 due to the pulling tension.

[Effect of the second invention] The drawing length is determined, then the distance ll1X between the drawing machine 30 and the drawing capstan 32 is determined, and the elongation strain that occurs when drawing down the metal pipe is set to 0.0 to 0.6. %
Therefore, as mentioned above, the surplus length ratio is within the range of 0.0 to 0.6%,
It becomes possible to select a desired value.

[Brief explanation of the drawing]

Figures 1 to 7 relate to the present invention; Figure 1 is a diagram showing the relationship between the surplus length ratio of optical fiber in a metal pipe and transmission loss, and Figure 2 is a diagram showing the relationship between temperature and transmission loss. Line diagram, Figure 3 (
(a) is an explanatory diagram of the manufacturing method, (b) is an enlarged explanatory diagram of the main parts, and Fig. 4 (a) and (b) are explanations of how to determine the pull-out length. Fig. 5 (a) and (b) are illustrations of metal An explanatory diagram of the relationship between the elongation strain of the pipe 14 and the residual length ratio of the optical fiber, FIG. 6 is a diagram showing the relationship between the pulling length and the pulling force, and FIG. 7 is a diagram showing the relationship between the drawing machine and the pulling capstan. A diagram showing the relationship between distance It is an explanatory diagram of the manufacturing method of a core wire, (b) is an explanatory diagram of a winding state. 10: 12: 13: 14: 16: 24: 26: 28: Metal pipe Optical fiber cored optical fiber Metal tape Metal pipe Jelly roll forming machine Jerry pump welding machine 30: Pulling machine 32: Pick-up capstan 36: neutral part

Claims (2)

[Claims] (1) A metal pipe in which an optical fiber is housed and filled with jelly; the ratio of the inner area of the metal pipe to the area occupied by the optical fiber is about 4 to 20, and the jelly is A metal pipe optical fiber coated wire having a tension of about 200 to 400, wherein the surplus length ratio of the optical fiber coated wire is in a range of 0.0 to 0.6%. (2) Continuously create a state in which back-tensioned optical fibers and jelly exist in a metal pipe, and then continuously pull down the metal pipe to create a metal pipe light with a predetermined outer diameter. When manufacturing a metal pipe optical fiber core by taking the metal pipe optical fiber core as a fiber core and continuously winding it around a roller, (a) the metal pipe optical fiber core is For a pipe equivalent to a metal pipe and containing a jelly and an optical fiber equivalent to the above-mentioned jelly and optical fiber; the longest length L that allows the optical fiber to be pulled out with a force equal to the back tension. (a) The distance between the position where the metal pipe is pulled down and the position where the metal pipe optical fiber core wire is wound around the roller is equal to or longer than the length of L, (c) The range of elongation strain that occurs when the metal pipe is pulled down is set to 0.
．． A method for manufacturing a metal pipe optical fiber core wire, characterized in that the content is 0 to 0.6%.