JPH06107439A - Method and device for producing optical fiber for optical fiber coil - Google Patents

Abstract

PURPOSE:To reduce the variation in the outer diameter of the coating resin layer of an optical fiber. CONSTITUTION:An uncoated optical fiber is passed through a coating resin coater contg. a coating resin soln. to form a coating resin layer on the uncoated optical fiber, and an optical fiber is produced. In this case, the surface temp. of the uncoated optical fiber 13 is fixed immediately before the uncoated optical fiber is passed through the coater 9. Consequently, the optical fiber is orderly and closely coated without generating the disturbance of aligned close winding, and the optical fiber is smoothly drawn out of the optical fiber coil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an optical fiber wire for an optical fiber coil for mobile communication, which is used while drawing out an optical fiber wire from a winding part wound in a coil shape.

[0002]

2. Description of the Related Art Conventionally, in an optical fiber coil for mobile communication, an optical fiber wire of several kilometers to several tens of kilometers is wound around a metallic reel in a coil shape, and several turns of the outermost layer are coated and hardened with an adhesive. The optical fiber wires can be unwound one by one by pulling out with a force stronger than the adhesive force. In such an optical fiber coil, it is preferable that the optical fiber wires are in an aligned close-wound state in order to smoothly perform the operation of pulling out the optical fiber wires, but when the optical fiber wires are wound on the reel, When the variation of the outer diameter of the coating resin layer of the optical fiber strand exceeds the range of ± 3 μm, a gap is generated between the optical fiber strand wound around the lower layer and the optical fiber strand,
A drop phenomenon occurs in which the aligned close-wound state is disturbed.
Therefore, the winding state of the optical fiber wire in the optical fiber coil depends on the uniform outer diameter of the coating resin layer of the optical fiber wire.

In the case of manufacturing such an optical fiber element wire for an optical fiber coil, conventionally, a coating resin liquid is stored while melt-spinning an optical fiber preform in a spinning furnace to draw an optical fiber bare wire. The coating resin coater was inserted to form a coating resin layer on the outer circumference of the bare optical fiber, and the coating resin layer was wound in a coil shape. However, in the conventional method for producing an optical fiber element wire for an optical fiber coil, in order to keep the outer diameter of the bare optical fiber drawn from the spinning furnace constant, if the outer diameter fluctuates, the drawing speed is reduced. To change,
For this reason, the insertion speed of the coating resin coater also changes, and the outer diameter of the coating resin layer of the optical fiber element wire inevitably fluctuates by about ± 5 μm.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for manufacturing an optical fiber wire for an optical fiber coil, which can reduce the fluctuation of the outer diameter of the coating resin layer of the optical fiber wire. To provide.

[0005]

A method for manufacturing an optical fiber element wire for an optical fiber coil according to a first aspect of the present invention is characterized in that the surface temperature of the bare optical fiber is made constant just before the insertion into the coating resin coater. To do. Further, in the apparatus for manufacturing an optical fiber bare wire for an optical fiber coil according to a second aspect of the invention, there is provided a cooling cylinder for inserting the bare optical fiber in front of the coating resin coater and a bare optical fiber led out from the cooling barrel. A non-contact type heat balance type radiation thermometer for measuring the surface temperature and a controller for changing the flow rate of the cooling gas flowing in the cooling cylinder based on the measurement result of the non-contact type heat balance type radiation thermometer were provided. It is characterized by

[0006]

According to the method for manufacturing an optical fiber bare wire for an optical fiber coil of the present invention, the bare optical fiber is coated with the coating resin by making the surface temperature of the bare optical fiber constant just before it is inserted into the coating resin coater. When inserted into the coater,
The amount of the coating resin liquid adhering to the outer circumference of the bare optical fiber is controlled, and it is possible to reduce the fluctuation of the outer diameter of the coating resin layer of the optical fiber element wire.

[0007]

Embodiments of the method of manufacturing an optical fiber element wire for an optical fiber coil according to the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a manufacturing apparatus preferably used for the method of manufacturing an optical fiber element wire for an optical fiber coil according to the present invention. This manufacturing apparatus includes a spinning furnace 1, a cooling cylinder 5 provided below the spinning furnace 1, and a cooling cylinder 5.
Non-contact type thermal equilibrium radiation thermometer 7 installed below
And a coating resin coater 9 provided below the non-contact type heat balance type radiation thermometer 7. The spinning furnace 1 is for producing a bare optical fiber 13 by melt-spinning the fiber preform 11.

Cooling gas 6 is circulated inside cooling tube 5, and bare optical fiber 13 is cooled by inserting bare optical fiber 13 on the central axis thereof. A supply pipe 5a for supplying the cooling gas 6 into the cooling cylinder 5 is provided below the cooling cylinder 5, and an exhaust pipe for discharging the cooling gas 6 supplied into the cooling cylinder 5 is provided above the cooling pipe 5. 5b are respectively connected. As the cooling gas 6, nitrogen gas for cooling is preferably used.

The non-contact type heat balance type radiation thermometer 7 measures the relative change of the surface temperature along the length direction of the bare optical fiber 13 led out from the cooling tube 5 in a non-contact manner. A measurement point is provided below the cooling cylinder 5 on the traveling path of the bare optical fiber 13.

The supply pipe 5a of the cooling cylinder 5 and the non-contact type heat balance type radiation thermometer 7 are connected via a controller 15 and a mass flow controller 17, and the non-contact type heat balance type radiation thermometer 7 is provided. The measured value of the surface temperature of the bare optical fiber 13 is sent to the controller 15, which feeds it back to the mass flow controller 17 to change the flow rate of the cooling gas flowing in the supply pipe 19.

The coating resin coater 9 has a coating resin liquid stored therein. By inserting the bare optical fiber 13, the coating resin liquid adheres to the outer periphery of the bare optical fiber 13 to form a coating resin layer. To be formed. An ultraviolet curable resin is preferably used as the coating resin liquid, and for example, a urethane acrylate-based resin, an epoxy acrylate-based resin, a butadiene acrylate-based resin, a silicon acrylate-based resin, or the like is preferable.

The following steps are used to manufacture an optical fiber element wire for an optical fiber coil by using the manufacturing apparatus as shown in FIG. First, the optical fiber preform 11 is prepared, placed in the spinning furnace 1, and melt-spun at 100 to 600 m / min to obtain the bare optical fiber 13. Then, the bare optical fiber 13 is inserted into the cooling tube 5. In the cooling cylinder 5, the bare optical fiber 13 is cooled by the cooling gas to keep the surface temperature constant.

After this, the bare optical fiber 13 is sent to a non-contact type heat balance type radiation thermometer 7 for measuring the relative change of the surface temperature along the lengthwise direction, and the surface temperature is measured. Here, since the surface temperature along the length direction of the bare optical fiber 13 changes depending on the spinning linear velocity, it is possible to set the fluctuation of the outer diameter of the coating resin layer of the optical fiber element wire within a range of ± 3 μm in advance. The controller 15 stores a preferable surface temperature range of the bare bare optical fiber 13. And
The controller 15 compares the preferable surface temperature range with the value measured by the non-contact type thermal equilibrium radiation thermometer 7 and sends a control signal to the mass flow controller 17. The mass flow controller 17 then uses the control signal to cool the cooling cylinder. The flow rate of the cooling gas supplied into 5 is changed.

A control signal is sent to the mass flow controller 17 when the linear velocity of the bare optical fiber 13 increases and the surface temperature starts to rise above the above-mentioned preferable surface temperature range. Then, the mass flow controller 17 increases the flow rate of the cooling gas supplied into the cooling cylinder 5, so that the bare optical fiber 13 is cooled to a preferable surface temperature range. Further, when the linear velocity of the bare optical fiber 13 becomes slow and the surface temperature starts to fall below the preferable surface temperature range, a control signal is sent to the mass flow controller 17. Then, the mass flow controller 17 reduces the flow rate of the cooling gas supplied into the cooling cylinder 5, so that the cooling of the bare optical fiber 13 is suppressed and the preferable surface temperature range is set.

Finally, when the bare optical fiber 13 having the above preferable surface temperature range is inserted into the coating resin coater 9, the optical fiber bare wire 21 in which the variation of the outer diameter of the coating resin layer is within ± 3 μm is obtained. The obtained optical fiber strand 21
Is wound on a bobbin (not shown) to form an optical fiber coil.

In the method of manufacturing an optical fiber bare wire for an optical fiber coil according to the embodiment, the bare optical fiber 13 is cooled so that the surface temperature of the bare optical fiber 13 is kept constant just before it is inserted into the coating resin coater 9. While introducing the gas into the cooling cylinder, the relative change of the surface temperature along the length direction of the bare optical fiber 13 led out from the cooling cylinder 5 was measured, and based on this measured value, the cooling cylinder was measured. Since the flow rate of the cooling gas 6 supplied to the inside of the optical fiber 5 is changed, when the bare optical fiber 13 is inserted into the coated resin coater 9, the amount of the coated resin liquid attached to the outer periphery of the bare optical fiber 13 is controlled. The fluctuation of the outer diameter of the coating resin layer of the optical fiber wire 21 is
It becomes possible to make it within 3 μm. Therefore, in the optical fiber coil using the optical fiber wire 21 obtained by the present invention, the drop phenomenon that disturbs the aligned dense winding state of the optical fiber wire 21 does not occur, and the optical fiber wire 21 is pulled out from the optical fiber coil. Work on the occasion proceeds smoothly.

(Example) An apparatus for manufacturing an optical fiber element wire for an optical fiber coil as shown in FIG. 1 was prepared, and 40 ± 3 ° C. was stored in the controller 15 as a preferable surface temperature range in advance. Then, the optical fiber preform 11 is installed in the spinning furnace 1, melt-spun at 100 to 600 m / min, and the bare optical fiber 13 is cooled by a cooling cylinder 5 through which nitrogen gas for cooling flows.
Inserted inside. Along with this, the relative change of the surface temperature along the length direction of the bare optical fiber 13 led out from the cooling cylinder 5 is measured by a non-contact type heat balance type radiation thermometer (manufactured by Tokyo Seiko).
TH-B) 7 and the cooling cylinder 5 based on this measurement value.
The flow rate of the cooling gas 6 supplied to the inside is 10 to 20 liters /
The surface temperature of the bare optical fiber 13 was made constant by changing the temperature within the range of minutes. Next, the optical fiber 13 is covered with a coating resin coater 9 in which a urethane acrylate resin liquid is stored.
Then, the optical fiber strand 21 was obtained.

Comparative Example An optical fiber element wire 21 was obtained in the same manner as in Example except that the bare optical fiber 13 was not inserted into the cooling tube 5.

Then, with respect to the optical fiber strands 21 obtained in the examples and the comparative examples, the relationship between the drawing line length (km) and the fluctuation of the outer diameter of the coating resin layer (μm) was examined. Here, for the variation of the outer diameter, a laser transmission outer diameter measuring device was used. The results are shown in Figure 2. In FIG. 2, a curved line shows an optical fiber element wire obtained in the example, and a curve shows an optical fiber element wire obtained in the comparative example.

As is clear from the results shown in FIG. 2, the fluctuation of the outer diameter of the coating resin layer of the optical fiber element wire obtained in the comparative example was about ± 5 μm. In comparison with this, the variation of the outer diameter of the coating resin layer of the optical fiber element wire obtained in the example is ± 1 μm.
m is within the range of m, and when this optical fiber wire is used for an optical fiber coil, the drop phenomenon that disturbs the aligned close-wound state is less likely to occur, and the optical fiber coil is used for the optical fiber wire 2
The work for pulling out 1 will proceed smoothly.

[0021]

As described above, according to the present invention,
By keeping the surface temperature of the bare optical fiber constant just before it is inserted into the coating resin coater, the amount of coating resin liquid that adheres to the outer circumference of the bare optical fiber when the bare optical fiber is inserted into the coating resin coater Is controlled, and the fluctuation of the outer diameter of the coating resin layer of the optical fiber strand can be reduced. Therefore, the optical fiber coil using the optical fiber wire obtained according to the present invention does not cause a sagging phenomenon in which the aligned dense winding state of the optical fiber wire is disturbed, and work for drawing out the optical fiber wire from the optical fiber coil. Progresses smoothly.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a manufacturing apparatus preferably used for a method of manufacturing an optical fiber element wire for an optical fiber coil according to an embodiment.

FIG. 2 is a drawing line length (km) of optical fiber strands obtained in Examples and Comparative Examples and a variation (μ in outer diameter of a coating resin layer).
It is a graph which shows the relationship with m).

[Explanation of symbols]

5 ... Cooling cylinder, 6 ... Cooling gas, 7 ... Non-contact type heat balance type radiation thermometer, 8 ... Coating resin coater, 13 ... Bare optical fiber, 15 ... Controller, 17 ... Mass flow controller, 21 ... Optical fiber strand

Claims (2)

[Claims] 1. A method of manufacturing an optical fiber element wire for an optical fiber coil, wherein a bare optical fiber is inserted through a coating resin coater in which a coating resin liquid is stored to form a coating resin layer on the outer periphery of the bare optical fiber. A method for manufacturing an optical fiber bare wire for an optical fiber coil, wherein the surface temperature of the bare optical fiber is made constant just before the insertion into the coating resin coater. 2. An apparatus for producing an optical fiber bare wire for an optical fiber coil, wherein a bare optical fiber is inserted through a coating resin coater in which a coating resin liquid is stored to form a coating resin layer on the outer circumference of the bare optical fiber. In front of the coating resin coater, a cooling cylinder for inserting the bare optical fiber, a non-contact type thermal equilibrium radiation thermometer for measuring the surface temperature of the bare optical fiber drawn from the cooling barrel, and the non-contact And a controller for changing the flow rate of the cooling gas flowing through the cooling cylinder based on the measurement result of the heat balance type radiation thermometer.