JP3031479B2 - Manufacturing method of metal fiber optical fiber core - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a metal pipe optical fiber core.

[Prior Art] First, a metal pipe optical fiber core will be described, particularly the extra length of an optical fiber.

As shown in FIG. 8, a metal pipe optical fiber core wire 10 accommodates an optical fiber 12 in a metal pipe 14 and has a consistency of 200 to 400.
Jerry 16 is filled.

The metal pipe optical fiber core can be reduced in thickness and has excellent mechanical strength.

Regarding extra length of optical fiber: From the viewpoint of long-term reliability (lifetime) of the optical fiber, it is desirable that the optical fiber 12 is loosely accommodated in the metal pipe 14 without application of elongation stress.

However, if the optical fiber 12 is too long (if the surplus length is too large) with respect to the metal pipe 14, the optical fiber 12 meanders in the metal pipe 14, causing transmission loss to deteriorate.

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

FIG. 1 shows the relationship between the excess length ratio and the transmission loss for the samples shown in Table 1 below.

(1) All mounting fibers are 250μm SM UV strands. (2)
The area ratio is the area inside the metal pipe / the area occupied by the optical fiber.

From FIG. 1, it can be seen that, except for the sample C, when the surplus ratio exceeds 0.6%, the transmission loss sharply increases.

The surplus length ratio of 0.0% is when the optical fiber and the metal pipe are equal in length, and it is understood that such a case is also effective.

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

From the above, if the value of the surplus length ratio is in the range of 0.0 to 0.6%, it is possible to manufacture without deteriorating transmission loss and to perform stable transmission over a wide temperature range. I understand.

[Conventional Manufacturing Method] A metal pipe optical fiber core was manufactured as follows (FIG. 9 (a)).

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

Continuously, the metal tape 13 is rolled by the roll forming machine 24 while the optical fiber 12 is wrapped with the tape 13, and at the same time, the jelly 16 is filled therein by the pump 26.

Then, it is made into a pipe 14 by a welding machine 28, passed through a drawer 30 and wound around a take-up capstan 32, and is strongly taken into a metal pipe optical fiber core wire 10 having a predetermined outer diameter, which is wound around a roll 34. take.

Problems to be Solved by the Invention When the above-mentioned metal pipe optical fiber core wire 10 is wound around the take-up capstan 32, as shown in FIG. 9 (b), the optical fiber 12 is moved by the back tension f. , Sinks and contacts the inside of the metal pipe 14.

That is, since the optical fiber 12 is wound inside the neutral portion 36 of the metal pipe 14, the length of the optical fiber 12 is shorter than the length of the metal pipe 14. That is, the extra length ratio is negative.

Therefore, when the wire is extended, tension is applied to the optical fiber 12, and the life thereof is extremely shortened.

As described above, the surplus rate needs to be in the range of 0.0% to 0.6%. However, at present, a method of controlling the surplus rate in the metal pipe optical fiber core has not been established.

[Means for Solving the Problems] (1) First, as shown in FIG. 4, a pipe 14 'which is equivalent to the metal pipe 14 of the above-mentioned metal pipe optical fiber core 10, and in which the jerry 16 and the light With respect to the one containing the jelly 16 'and the optical fiber 12' equivalent to the fiber 12, the longest length (hereinafter referred to as a "pull-out length") capable of pulling out the optical fiber 12 'with the same force as the back tension f is determined in advance. And set it to L.

(2) Debiting machine 30 and pick-up capstan in Fig. 3
The distance x between the distance L and the distance 32 is equal to or longer than the length L.

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

[Operation] (1) Distance x between the withdrawal machine 30 and the take-up capstan 32
However, if the drawing length L is greater than or equal to the drawing length L, the backtension applied to the optical fiber 12 is zero at the point where the metal pipe optical fiber core wire 10 is wound around the take-up capstan 32.

Therefore, the optical fiber 12 does not sink inside the metal pipe 14 when being wound.

(2) Distance x between withdrawing machine 30 and take-up capstan 32
However, when the drawing length L or more, the back tension applied to the optical fiber 12 becomes zero as described above,
Even if the metal pipe 14 extends between the drawer 30 and the take-up capstan 32, the optical fiber 12 does not expand due to the tension applied for the drawdown.

Therefore, the elongation strain of the metal pipe 14 becomes the extra length of the optical fiber 12 as it is.

 These points will be described later.

[Detailed Description of Manufacturing Method] FIG. 3A is an explanatory diagram of the manufacturing method, which is the same as FIG. 9A described above. However, the distance x between the withdrawing machine 30 and the take-off capstan 32 is larger than in the conventional case.

 The portion B in the same figure is enlarged and shown in FIG.

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

[About Drawing Length] In order to obtain the drawing length L, the following experiment is performed in advance.

The metal pipe 14 'in FIG. 4 is a pipe equivalent to the metal pipe 14 of the metal pipe optical fiber core 10. However, it is sufficient that the inner diameters are exactly the same.

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

The optical fiber 12 'is pulled with the same force as the back tension f. When the metal pipe 14 'is short as shown in FIG. 9A, the optical fiber 12' can be easily pulled out.

However, as the length of the metal pipe 14 'increases, the resistance generated by the viscosity of the jelly 16' also increases, and when it becomes equal to f, the optical fiber 12 'cannot be pulled out. .

The length of the metal pipe 14 'at that time is the drawing length L (b in the drawing).

As described above, when it becomes impossible to pull out the optical fiber 12 'from the metal pipe 14',
When the 14 'is moved, the optical fiber 12' moves integrally with the metal pipe 14 ', even if back tension is applied thereto.

Therefore, when the metal pipe optical fiber core 10 is manufactured (FIG. 3), if the distance x between the drawing-out machine 30 and the take-up capstan 32 is set to be equal to or greater than the drawing length L, the metal pipe optical fiber core 10 is formed. The optical fiber 12 moves integrally with the metal pipe 14 when it is wound on the take-up capstan 32.

Even when the optical fiber 12 is wound on the take-up capstan 32, the optical fiber 12 is on the neutral portion 36 (FIG. 2B), and does not sink inside the metal pipe 14 as in the conventional case.

[Regarding control of extra length ratio] FIG. 5 (a) shows a drawing machine 30 and a take-up capstan 32.
1 schematically shows a metal fiber optical fiber core wire 10 located between the optical fiber core fiber 10 and the metal pipe 10.

At this time, the metal pipe 14 is stretched by being pulled down.

Therefore, when the tension is lost, the length returns to the original length again (b in the figure).

Assuming that the length of the metal pipe 14 when being pulled is x and the elongation at that time is Δx, the elongation strain a = Δx / (x−Δx).

On the other hand, the length of the optical fiber 12 does not change while the metal pipe 14 extends or returns to its original length.

Accordingly, in the state shown in FIG. 2B, 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. is there.

Therefore, the extra length ratio α = Δx / (x−Δx), which is the same as the above-mentioned elongation strain a.

In view of the above, in order to obtain a desired extra length α, the distance x between the drawing machine 30 and the take-up capstan 32 should be longer than the drawing length L, and the optical fiber should be driven by the force of the jerry 16.
12 can be moved integrally with the metal pipe 14.

When the metal pipe 14 is pulled down, the elongation strain a of the metal pipe 14 is set to α% by appropriately setting the pulling rate and the tension.

As described above, the metal pipe optical fiber core wire 10 having the extra length α is obtained.

[Example] Inner / outer diameter = 1.0 / 1.2mmφ, SUS304 metal pipe, 250
For a metal pipe optical fiber core with a μm UV bare fiber and a jelly of 300 consistency,
The test was performed.

First, the relationship between the drawing force (corresponding to the back tension) of the optical fiber 12 ′ and the drawing length L was determined for the metal pipe 14 ′ in the same state as the metal fiber core 10. The result is shown in FIG.

The size of the back tension is suitably 20 to 150 g per core for reasons of manufacturing. 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 of the optical fiber and deterioration of the strength.

Therefore, the same optical fiber 12 and metal pipe 1 as above
4, When manufacturing the metal pipe optical fiber core wire 10 having the jelly 16, the distance x between the draw-off machine 30 and the take-up capstan 32 is required to be at least 3 m or more, and as the back tension and the number of core wires increase, It needs to be longer.

-Control of excess length-Outer diameter of take-off capstan: 600mm-Back tension of optical fiber: 50g-Deduction rate after welding metal pipe: about 20%-Pull-down tension: 15kg-Metal by pull-down tension The relationship between the distance x between the draw-off machine 30 and the take-up capstan 32 and the extra length α was obtained under the condition of elongation strain of pipe: 0.2% or more. The result is the seventh
Shown in the figure.

 The following can be seen from FIGS. 6 and 7.

When the back tension of the optical fiber 12 is 50 g, the drawing length L is about 5 m (FIG. 6), and the distance x between the draw-down machine 30 and the take-up capstan 32 needs to be 5 m or more.

Also, from FIG. 7, when x becomes 5 m or more, the excess length ratio becomes 0.00.
% Or more.

The excess length is saturated at 0.2%, which is the same as the elongation strain of the metal pipe 14 due to the pull-down tension.

Effects of the Invention Since the drawing length L is obtained, the distance x between the drawing machine 30 and the drawing capstan 32 is determined, and the elongation strain generated when the metal pipe is drawn down is set to 0.0 to 0.6%. In addition, it becomes possible to select a desired value within the range of 0.0 to 0.6%.

[Brief description of the drawings]

FIGS. 1 to 7 relate to the present invention. FIG. 1 is a diagram showing a relationship between extra length ratio of optical fiber in a metal pipe and transmission loss, and FIG. 2 shows a relationship between temperature and transmission loss. FIG. 3 (a) is an explanatory view of a manufacturing method, FIG. 3 (b) is an enlarged explanatory view of a main part, FIGS. 4 (a) and 4 (b) are explanatory views of a method of obtaining a drawing length L. 5 (a) and 5 (b) are explanatory diagrams showing the relationship between the elongation strain of the metal pipe 14 and the extra length of the optical fiber, FIG. 6 is a diagram showing the relationship between the drawing length and the drawing force, and FIG. FIG. 8 is a diagram showing the relationship between the distance x between the draw-off machine and the take-up capstan and the extra length ratio, FIG. 8 is a cross-sectional view of a metal pipe optical fiber core common to the present invention and the prior art, and FIG. (A) is explanatory drawing of the manufacturing method of the conventional metal pipe optical fiber core wire, (b) is explanatory drawing of a winding state. 10: Metal pipe optical fiber core wire 12: Optical fiber 13: Metal tape 14: Metal pipe 16: Jerry 24: Roll forming machine 26: Jerry pump 28: Welding machine 30: Dropping machine 32: Take-off capstan 36: Neutral

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideo Suzuki 1440 Mutsuzaki, Sakura City, Chiba Pref. Fujikura Electric Wire Co., Ltd. Sakura Plant 112111 (JP, A) JP-A-60-39610 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 6/44

Claims (1)

(57) [Claims] 1. A state in which a back-tensioned optical fiber and jelly are present in a metal pipe, and the metal pipe having a predetermined outer diameter is continuously drawn down. When manufacturing a metal pipe optical fiber core by using a pipe optical fiber core and winding and winding the metal pipe optical fiber as described above continuously around a roller, (a) the metal pipe optical fiber core A pipe equivalent to a metal pipe of wire and containing therein a jelly and an optical fiber equivalent to the jelly and the optical fiber; the longest length capable of extracting the optical fiber with a force equal to the back tension (A) The position where the metal pipe is pulled down and the optical fiber core of the metal pipe are applied to the roller. The distance between the point where you want trees,
(C) a range of elongational strain generated when the metal pipe is pulled down is set to 0.0 to 0.6%, and a method of manufacturing a metal pipe optical fiber core.