JP2010120811A - Method and apparatus for producing optical fiber strand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus capable of producing an optical fiber strand with small loss of transmitted light. <P>SOLUTION: The method for producing an optical fiber strand 10 includes a drawing step of drawing molten glass 11 from an optical fiber preform 1, a cooling step of cooling and solidifying the molten glass 11 by a cooling device 30 to form an optical fiber 12, a coating step of applying a resin to the optical fiber 12 by a coating apparatus 40 and curing the applied resin to coat the optical fiber 12 with a resin layer to form the optical fiber strand 10. The oscillation frequencies of the molten glass 11 in the drawing step and the optical fiber 12 in the coating step are 10 Hz or more and 200 Hz or less. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical fiber manufacturing method and an optical fiber manufacturing apparatus.

  In some cases, an optical fiber is coated with a resin layer to prevent scratches on the surface and used as an optical fiber. In the production of such an optical fiber, the optical fiber preform is melted and the molten glass is drawn into a yarn shape in a spinning furnace provided at the upper part of the drawing tower, and the drawn yarn-like molten glass is cooled. Solidified into an optical fiber. Thereafter, the optical fiber is coated with a resin layer to form an optical fiber, whereby the optical fiber is manufactured.

  Such an optical fiber has a problem that the loss of light propagated by the optical fiber increases when the diameter of the optical fiber and the thickness of the resin layer are not constant. As one of the reasons why the diameter of the optical fiber and the layer thickness of the resin layer are not constant, it is known that the drawn molten glass or the optical fiber vibrates during the manufacturing process of the optical fiber. Yes. For this reason, when manufacturing an optical fiber, an attempt has been made to suppress the vibration applied to the optical fiber and make the optical fiber diameter, the thickness of the resin layer, and the like constant.

The following patent document 1 describes an optical fiber drawing device that prevents the deterioration of the quality of the optical fiber by suppressing the vibration of the drawing tower, and the following patent document 2 describes the vibration of the optical fiber preform. An optical fiber drawing device is described that prevents deterioration of the quality of the optical fiber by suppressing the above.
Japanese Patent Laid-Open No. 10-1324 JP 2004-161499 A

  Such an optical fiber drawing device described in Patent Document 1 is used for vibration isolation of the drawing tower, and an optical fiber drawing device described in Patent Document 2 is used for vibration isolation of the optical fiber preform. Even in such a case, the molten glass drawn from the optical fiber and the optical fiber preform may still vibrate. Although this is effective in suppressing the vibration of a very low vibration frequency (for example, about several Hz), the optical fiber drawing apparatus of the said patent documents 1 and 2 is a cooling device which cools molten glass It is effective for vibrations with a high vibration frequency (for example, 100 to 500 Hz) due to the gas flow used for the gas and the gas flow used in the curing device for curing the resin when the optical fiber is coated with the resin layer. This is because there is not much.

  For this reason, even when an optical fiber is manufactured by the optical fiber drawing device described in Patent Documents 1 and 2, when the variation in the diameter of the optical fiber is large or the variation in the thickness of the resin layer is large Therefore, there is a problem that the loss of propagated light increases.

  Then, an object of this invention is to provide the manufacturing method and optical fiber strand manufacturing apparatus of an optical fiber strand which can implement | achieve manufacture of the optical fiber strand with a small loss of the light to propagate.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, the frequency at which the glass drawn from the optical fiber preform and the optical fiber in which the drawn glass is solid vibrates are all frequencies. It is not necessary to be suppressed over, and if the frequency is in a certain range, it is found that fluctuations in the diameter of the optical fiber and fluctuations in the thickness of the resin layer covering the optical fiber are suppressed, It came to make this invention.

  That is, the optical fiber manufacturing method of the present invention includes a drawing step of drawing molten glass from an optical fiber preform, and an optical fiber by cooling and solidifying the molten glass, and the optical fiber is cooled by a cooling device. An optical fiber comprising: a cooling process; and a coating process in which a resin is applied to the optical fiber by a coating apparatus, and the applied resin is cured to coat the optical fiber with a resin layer to form an optical fiber strand. The vibration frequency of the molten glass in the drawing step and the optical fiber in the coating step is 10 Hz or more and 200 Hz or less.

  According to such a method for manufacturing an optical fiber, molten glass is drawn in a drawing process. At this time, since the vibration frequency of the molten glass is 10 Hz or more, fluctuations in the diameter of the optical fiber in which the molten glass is cooled and solidified are suppressed. Although the reason for this is not clear, the present inventors have found that since the vibration frequency of the molten glass is 10 Hz or more, the neck-down shape immediately after the molten glass is drawn out from the optical fiber preform is a gentle shape of the molten glass. It is considered that the periodic fluctuation of the optical fiber in the pass line, which occurs when the axis of the molten glass deviates from the center axis of the spinning furnace due to vibration, is suppressed and stable.

  Furthermore, since the vibration frequency of the cooled and solidified optical fiber is set to 200 Hz or less in the coating process, fluctuations in the layer thickness of the resin layer covering the optical fiber are suppressed. The present inventors consider that this is because when the resin is applied to the optical fiber and the applied resin is cured, the axis of the optical fiber is stabilized. In other words, it is considered that the optical fiber having a high vibration frequency suppresses the disturbance of the thickness of the resin layer without stabilizing the surface tension at the interface between the optical fiber and the resin covering the optical fiber. Yes.

  In the optical fiber manufactured by such a manufacturing method, fluctuations in the diameter of the optical fiber and fluctuations in the layer thickness of the resin layer covering the optical fiber are suppressed, so that the loss of transmitted light is reduced. can do.

  In the method for manufacturing an optical fiber, the molten glass and the optical fiber are not in contact with the cooling device and the coating device, and the direction changer is in contact with the optical fiber. It is preferable that a direction changing step for changing the direction of the line is further provided after the covering step, and the vibration frequency of the molten glass and the optical fiber is controlled by the direction changing device. According to such a configuration, when the optical fiber strand comes into contact with the direction changing device and is changed in direction, the vibration of the optical fiber strand is controlled by the direction changing device. Since the molten glass and the optical fiber are not in contact with the cooling device and the coating device until the molten glass is drawn from the molten fiber from the optical fiber preform, the control of the optical fiber strand is It is transmitted to optical fiber and molten glass. Therefore, the vibration of the molten glass and the optical fiber can be controlled through the optical fiber. Therefore, it is possible to control the vibration frequency of the optical fiber in the manufacturing process with higher accuracy. Therefore, the fluctuation | variation of the diameter of an optical fiber and the fluctuation | variation of the layer thickness of a resin layer can be suppressed more.

  The optical fiber manufacturing apparatus of the present invention includes a spinning furnace for heating and melting an optical fiber preform, a cooling device for cooling an optical fiber in which molten glass drawn from the optical fiber preform is cooled and solidified, and A coating device that coats the optical fiber with a resin layer to apply the resin to the optical fiber and cures the applied resin, and changes the direction of the optical fiber. The cooling device and the coating device are in non-contact with the molten glass and the optical fiber, and the direction changing device is a turn pulley on which the optical fiber is laid, the molten glass and the It has a vibration control unit for controlling the turn pulley so that the vibration frequency of the optical fiber is 10 Hz or more and 200 Hz or less.

  According to such an optical fiber manufacturing apparatus, fluctuations in the diameter of the optical fiber are suppressed, and fluctuations in the layer thickness of the resin layer covering the optical fiber are suppressed. Therefore, the optical fiber manufactured by such a manufacturing apparatus can reduce the loss of the propagated light.

  According to the method for manufacturing an optical fiber and the optical fiber manufacturing apparatus according to the present invention, it is possible to manufacture an optical fiber with a small loss of propagated light.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an optical fiber manufacturing method and an optical fiber manufacturing apparatus according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described in detail with reference to FIGS.

(Optical fiber)
First, an optical fiber manufactured by the method for manufacturing an optical fiber according to the present invention will be described. FIG. 1 is a cross-sectional view showing an optical fiber manufactured by the method for manufacturing an optical fiber according to the present invention.

  As shown in FIG. 1, the optical fiber 10 includes an optical fiber 12 and a resin layer 13 that covers the optical fiber 12.

The diameter of the optical fiber 12 is not particularly limited, but is 125 μm, for example. Although not shown, the optical fiber 12 has a core part and a cladding part, and the refractive index of the core part is higher than the refractive index of the cladding part. The material of the core part and the clad part is composed mainly of, for example, silica glass (SiO ₂ ), and a dopant for adjusting the refractive index is added to at least one of the core part and the clad part. For example, the core part is made of silica glass to which GeO ₂ is added, and the cladding part is made of pure silica glass or silica glass to which F is added.

  The resin layer 13 includes a first resin layer 13a that covers the optical fiber 12, and a second resin layer 13b that covers the first resin layer 13a. The first resin layer 13a is a relatively soft resin layer, and the second resin layer 13b is a relatively hard resin layer. The thicknesses of the first resin layer 13a and the second resin layer 13b are not particularly limited, but may be 25 to 40 μm and 15 to 35 μm, respectively. Furthermore, the resin layer 13 thickness, which is the sum of the thickness of the first resin layer 13a and the thickness of the second resin layer 13b, may be 55 to 65 μm. Examples of the resin of the first resin layer 13a and the second resin layer 13b include urethane (meth) acrylate-based, epoxy (meth) acrylate-based, and polyester (meth) acrylate-based ultraviolet curable resin compositions. .

(Manufacturing method of optical fiber)
Next, an optical fiber manufacturing method and an optical fiber manufacturing apparatus according to the present invention will be described. FIG. 2 is a diagram showing an optical fiber manufacturing apparatus for carrying out the manufacturing method of the optical fiber 10.

  As shown in FIG. 2, an optical fiber manufacturing apparatus 100 includes a spinning furnace 20 that melts an optical fiber preform 1, and an optical fiber 12 that is obtained by cooling and solidifying molten glass 11 drawn from the molten optical fiber preform 1. Main components are a cooling device 30 that cools the optical fiber 12, a coating device 40 that coats the optical fiber 12 with a resin layer to form the optical fiber strand 10, and a direction changing device 50 that changes the direction of the optical fiber strand 10. Prepare as.

(Drawing process)
First, the optical fiber preform 1 made of quartz glass is installed in the spinning furnace 20 of the optical fiber manufacturing apparatus 100. And the heating part 21 of the spinning furnace 20 generates heat, and the optical fiber preform 1 is heated. At this time, the lower end of the optical fiber preform 1 is heated to, for example, 2000 ° C. and is in a molten state. Then, the molten glass 11 is drawn from the optical fiber preform 1. The molten glass 11 drawn at this time becomes a neck-down shape immediately after being drawn. The neck-down shape is a shape in which the diameter of the molten glass 11 drawn from the optical fiber preform 1 is large in the vicinity of the optical fiber preform 1 and decreases as the distance from the optical fiber preform 1 increases. For this reason, the neck-down shape has a tapered side surface. At this time, the vibration frequency of the molten glass 11 is 10 Hz or more and 200 Hz or less. Therefore, the neck-down shape is not uneven in the axial direction of the molten glass 11, and the shape is stable.

(Cooling process)
Next, when the drawn molten glass 11 comes out of the spinning furnace 20, the temperature is lowered due to the temperature outside the spinning furnace 20 and solidifies to become the optical fiber 12. Thereafter, the optical fiber 12 passes through the cooling device 30 and is cooled. When entering the cooling device 30, the temperature of the optical fiber 12 is about 1800 ° C., but when leaving the cooling device 30, the temperature of the optical fiber 12 is 40 ° C. to 50 ° C.

(Coating process)
Next, the optical fiber 12 is coated with the resin layer 13 by the coating device 40. The coating apparatus 40 is supplied with a first coating apparatus 41 to which an ultraviolet curable resin to be the first resin layer 13a is supplied, a first ultraviolet irradiation apparatus 42, and an ultraviolet curable resin to be the second resin layer 13b. The second coating device 45 and the second ultraviolet irradiation device 46 are provided.

  First, the optical fiber 12 passes through the first coating device 41 containing the ultraviolet curable resin that becomes the first resin layer 13a, and is coated with the ultraviolet curable resin. Furthermore, the 1st resin layer 13a is formed by passing the 1st ultraviolet irradiation device 42 and irradiating an ultraviolet-ray. At this time, the optical fiber 12 is not in contact with the first coating device 41 and the first ultraviolet irradiation device 42.

  FIG. 3 is a cross-sectional view showing the main part of the first coating apparatus 41. The first coating apparatus 41 includes a nipple 41a and a die 41b. The nipple 41a and the die 41b are provided with a through hole 41h through which the optical fiber 12 passes. Then, an ultraviolet curable resin 13r serving as the first resin layer 13a is supplied from between the nipple 41a and the die 41b, and the resin 13r flows out to the through hole 41h.

  The optical fiber 12 is covered with a resin 13r that flows out between the nipple 41a and the die 41b when passing through the through hole 41h. At this time, the vibration frequency of the optical fiber 12 is 10 Hz or more and 200 Hz or less. For this reason, the axis of the optical fiber 12 is stable. That is, it is considered that the optical fiber 12 having a high vibration frequency suppresses the occurrence of disturbance in the layer thickness of the resin layer without stabilizing the surface tension at the interface between the optical fiber 12 and the resin covering the optical fiber 12. .

  Next, the optical fiber 12 covered with the first resin layer 13a passes through the second coating device 45 containing the ultraviolet curable resin to be the second resin layer 13b, and is covered with this resin. At this time, the vibration frequency of the optical fiber 12 covered with the first resin layer 13a is 10 Hz or more and 200 Hz or less. For this reason, the axis of the optical fiber 12 covered with the first resin layer 13a is stabilized. Next, the second resin layer 13b is formed by passing through the second ultraviolet irradiation device 46 and being irradiated with ultraviolet rays. At this time, the optical fiber 12 covered with the first resin layer 13 a is not in contact with the second coating device 45 and the second ultraviolet irradiation device 46. The configuration of the second coating apparatus 45 is the same as that of the first coating apparatus 41.

  In this way, the optical fiber 10 is manufactured.

(Direction change process)
Next, the direction of the manufactured optical fiber 10 is changed by the direction changing device 50.

  The direction changing device 50 includes a turn pulley 51 having an outer peripheral groove on which the optical fiber 10 is bridged, an arm 53 that rotatably supports the turn pulley 51, and a vibration frequency of the molten glass 11 and the optical fiber 12 of 10 Hz to 200 Hz. And a vibration control unit 52 that controls the turn pulley 51 via the arm 53.

  The direction of the optical fiber 10 that is hung on the turn pulley 51 is changed along the outer circumferential groove of the turn pulley 51.

  The vibration control unit 52 has a plurality of springs (not shown) having a plurality of different natural frequencies, and this spring transmits a vibration frequency lower than 10 Hz of the optical fiber 10 transmitted from the turn pulley 51 via the arm 53. And vibrations with vibration frequencies higher than 200 Hz are absorbed. For this reason, the vibration frequency of the vibration of the optical fiber 12 and the vibration of the molten glass 11 is limited to 10 Hz or more and 200 Hz or less.

  The optical fiber 10 whose direction is changed by the direction changing device 50 is wound up by the winder 60.

  According to such a method for manufacturing an optical fiber and an apparatus for manufacturing an optical fiber, the vibration frequency of the molten glass 11 is 10 Hz to 200 Hz. Therefore, the optical fiber 12 obtained by the solidification of the molten glass 11 is suppressed in variation in diameter. The reason for this is not clear, but the present inventors believe that this is because the neck-down shape of the molten glass 11 immediately after being drawn from the optical fiber preform 1 is stabilized.

  Further, when the optical fiber 12 passes through the coating apparatus 40, the vibration frequency of the optical fiber 12 is set to 10 Hz or more and 200 Hz or less. Therefore, fluctuations in the layer thickness of the resin layer are suppressed. Therefore, the fluctuation | variation of the diameter of the optical fiber strand 10 is suppressed.

  As described above, the vibration frequency of the molten glass 11 and the optical fiber 12 is set to 10 Hz or more and 200 Hz, so that the variation in the diameter of the optical fiber 12 and the variation in the thickness of the resin layer are suppressed, and the loss of the propagated light. Is produced.

  Further, in the cooling step and the covering step, the molten glass 11 and the optical fiber 12 are not in contact with the cooling device 30 and the covering device 40, and the optical fiber is laid on a turn pulley of the direction changing device. The direction is changed in contact with the direction changing device. At this time, the direction changing device controls the optical fiber so that the vibration frequency of the molten glass 11 and the optical fiber 12 is 10 Hz or more and 200 Hz or less. As described above, the cooling device 30 and the coating device 40 are not in contact with the molten glass 11 and the optical fiber 12, and the vibration changing frequency of the molten glass 11 and the optical fiber 12 is changed by the direction changing device that contacts the optical fiber strand 10. Since it is controlled, the vibration frequency of the molten glass 11 and the optical fiber 12 can be controlled with higher accuracy. Therefore, the fluctuation | variation of the diameter of the optical fiber 12 and the fluctuation | variation of the layer thickness of a resin layer can be suppressed more.

(Second Embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to FIG. In addition, about the component same or equivalent to 1st Embodiment, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted. FIG. 4 is a diagram showing an optical fiber manufacturing apparatus according to the second embodiment of the present invention.

  As shown in FIG. 4, the optical fiber manufacturing apparatus 110 includes a first detection unit 71 that detects vibration immediately after the molten glass 11 comes out of the spinning furnace 20, and the optical fiber 12 that enters the first coating apparatus 41. A second detection unit 72 that detects vibration, and the first detection unit 71 and the second detection unit 72 are connected to the vibration control unit 56 of the direction changing device 55.

  The 1st detection part 71 and the 2nd detection part 72 are comprised by the laser type displacement measuring device and the photocoupler, for example. Then, a signal indicating the detected vibration frequency of the molten glass 11 and the optical fiber 12 is sent into the vibration control unit 56.

  The vibration control unit 56 receives the signals of the first detection unit 71 and the second detection unit 72, and moves the arm 53 so that the vibration frequency of the molten glass 11 and the optical fiber 12 becomes 10 Hz or more and 200 Hz or less by a servo (not shown). The turn pulley 51 is controlled via this. Due to the controlled operation of the turn pulley, the vibration frequency of the molten glass 11 and the optical fiber 12 is set to 10 Hz to 200 Hz.

  According to the optical fiber manufacturing method and the optical fiber manufacturing apparatus of the present embodiment, the direction changing device 55 actively controls so that the vibration of the molten glass 11 and the optical fiber 12 is 10 Hz or more and 200 Hz or less. Therefore, the vibration of the molten glass 11 and the optical fiber 12 can be controlled with higher accuracy.

  Although the present invention has been described with reference to the first and second embodiments, the present invention is not limited to these.

  For example, in the first embodiment, a plurality of springs having different natural frequencies of the vibration control unit 52 are transmitted from the turn pulley 51 via the arm 53 with vibrations having a vibration frequency lower than 10 Hz. Suppose that it absorbs vibrations with a vibration frequency higher than 200 Hz. However, the present invention is not limited to this. For example, instead of a plurality of springs having different natural frequencies, an anti-vibration rubber that absorbs vibrations of 10 Hz or less and an anti-vibration rubber that absorbs vibrations of 200 Hz or more may be used.

  In the second embodiment, a third detector that detects the vibration of the optical fiber 12 entering the second coating device 45 may be further provided.

  Moreover, in 1st Embodiment and 2nd Embodiment, although the resin layer 13 of the optical fiber strand 10 is comprised from the 1st resin layer 13a and the 2nd resin layer 13b, one resin layer 13a and the 1st resin layer 13a You may be comprised only from either one of the 2 resin layers 13b. In this case, the second coating device 45 and the second ultraviolet irradiation device 46 are not necessary.

  Hereinafter, although the content of this invention is demonstrated more concretely, giving an experiment example, this invention is not limited to the following experiment examples.

(Experimental example 1)
In the optical fiber manufacturing apparatus shown in FIG. 2, the optical fiber preform was heated to 2000 ° C. to draw the molten glass. The drawing speed at this time was 1000 m / min. And the molten glass was cooled in the cooling device, and the optical fiber whose diameter was 125 micrometers was manufactured. An ultraviolet curable resin was applied to the optical fiber with a first coating device so that the layer thickness was 33 μm, and cured with the first ultraviolet curing device to form a first resin layer. Further, an ultraviolet curable resin was applied on the first resin layer by the second coating apparatus so as to have a layer thickness of 30 μm by the second coating apparatus, and cured by the second ultraviolet curing apparatus to form a second resin layer.

  At this time, the vibration frequency of the molten glass was changed to 5 Hz, 10 Hz, 50 Hz, 100 Hz, 200 Hz, and 300 Hz by changing the spring of the vibration control unit. And the fluctuation | variation of the diameter of the optical fiber manufactured at each frequency was measured. The result is shown in FIG. As shown in FIG. 5, when the vibration frequency of the molten glass is 10 Hz or more, the variation in the diameter of the optical fiber is small, but when the vibration frequency of the molten glass is less than 10 Hz, the variation in the diameter of the optical fiber is 0. The result is that the diameter of the fiber is remarkably increased by 5 μm or more.

(Experimental Examples 2 to 4)
Except that the drawing speed was set to the value shown in FIG. The result is shown in FIG. As shown in FIG. 6, even if the drawing speed changes, if the vibration frequency of the molten glass is 10 Hz or more, the variation in the diameter of the optical fiber is small, but if the vibration frequency of the molten glass is less than 10 Hz, As a result, the fluctuation of the diameter of the optical fiber was remarkably increased.

(Experimental example 5)
Except that the vibration frequency of the optical fiber was changed to 5 Hz, 10 Hz, 150 Hz, 180 Hz, 200 Hz, and 210 Hz by replacing the spring of the vibration control unit, the same procedure as in Experimental Example 1 was performed, and the diameter of the optical fiber strand The variation of was measured. The result is shown in FIG. As shown in FIG. 7, when the vibration frequency of the optical fiber is 200 Hz or less, the fluctuation of the diameter of the optical fiber is small. However, when the vibration frequency of the optical fiber exceeds 200 Hz, the fluctuation of the diameter of the optical fiber is changed. As a result, the variation of the diameter of the optical fiber was significantly increased.

(Experimental Examples 6 to 8)
Except that the drawing speed was set to the value shown in FIG. The result is shown in FIG. As shown in FIG. 8, even when the drawing speed changes, the fluctuation of the diameter of the optical fiber is small when the vibration frequency of the optical fiber is 200 Hz or less, but suddenly when the vibration frequency of the optical fiber exceeds 200 Hz. As a result, the fluctuation of the diameter of the optical fiber was significantly increased.

  As described above, in the method of manufacturing an optical fiber, it is possible to manufacture an optical fiber with a small loss of light to be propagated by setting the vibration frequency of the molten glass and the optical fiber to 10 Hz to 200 Hz. it is conceivable that.

It is sectional drawing which shows the optical fiber strand manufactured by the manufacturing method of the optical fiber strand of this invention. It is a figure which shows the optical fiber strand manufacturing apparatus for enforcing the manufacturing method of the optical fiber strand which concerns on 1st Embodiment of this invention. It is a figure which shows the principal part of the 1st coating apparatus 41 of FIG. It is a figure which shows the optical fiber strand manufacturing apparatus for enforcing the manufacturing method of the optical fiber strand which concerns on 2nd Embodiment of this invention. It is a figure which shows the result of Experimental example 1. FIG. It is a figure which shows the result of Experimental example 2-4. It is a figure which shows the result of Experimental example 5. FIG. It is a figure which shows the result of Experimental Examples 6-8.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical fiber base material 10 ... Optical fiber strand 11 ... Molten glass 12 ... Optical fiber 13 ... Resin layer 20 ... Spinning furnace 21 ... Heating part 30 ... Cooling device 40 ... coating device 41 ... first coating device 42 ... first ultraviolet irradiation device 45 ... second coating device 46 ... second ultraviolet irradiation device 50, 55 ... direction change Device 51: Turn pulley 52, 56 ... Vibration control unit 53 ... Arm 60 ... Winding machine 71 ... First vibration detection unit 72 ... Second vibration detection unit 100, 110 ..Optical fiber manufacturing equipment

Claims (3)

A drawing process for drawing molten glass from an optical fiber preform;
An optical fiber by cooling and solidifying the molten glass, and a cooling step of cooling the optical fiber by a cooling device;
By a coating device, a resin is applied to the optical fiber, and the applied resin is cured, so that the optical fiber is coated with a resin layer to form an optical fiber strand; and
An optical fiber manufacturing method comprising:
The method for manufacturing an optical fiber, wherein a vibration frequency of the molten glass in the drawing step and an optical fiber in the covering step is 10 Hz or more and 200 Hz or less. The molten glass and the optical fiber are not in contact with the cooling device and the coating device,
A direction changing step of changing the direction of the optical fiber strand by a direction changing device in contact with the optical fiber strand is further provided after the covering step,
The method for manufacturing an optical fiber according to claim 1, wherein the vibration frequency of the molten glass and the optical fiber is controlled by the direction changing device. A spinning furnace for heating and melting the optical fiber preform;
A cooling device for cooling the optical fiber in which the molten glass drawn from the optical fiber preform is cooled and solidified, and
A coating device that applies a resin to the optical fiber and cures the applied resin, thereby coating the optical fiber with a resin layer to form an optical fiber strand;
A direction changing device for changing the direction of the optical fiber,
The cooling device and the coating device are not in contact with the molten glass and the optical fiber,
The direction changing device includes a turn pulley on which the optical fiber is laid, and a vibration control unit that controls the turn pulley so that vibration frequencies of the molten glass and the optical fiber are 10 Hz to 200 Hz. An optical fiber manufacturing apparatus characterized by comprising:

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