JP4139953B2 - Optical fiber manufacturing method and optical fiber manufacturing apparatus used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing an optical fiber, and more particularly to forming an ultraviolet curable resin coating on an optical fiber.
[0002]
[Prior art]
In recent years, GI (Graded-Index) fibers and FBG (Fiber Bragg Grating) fibers have been widely used. For GI fiber, FIG. 6 shows its general refractive index profile and germanium dioxide (GeO) in silica glass fiber.₂) As the concentration distribution shows, GeO₂The concentration is high. FIG. 7 shows that the cladding used for the FBG fiber is GeO.₂Added optical fiber (GeO for FBG₂Refractive index distribution and GeO₂The concentration distribution is shown. In this optical fiber, GeO₂Although the concentration itself is lower than that of GI fiber, GeO reaches the cladding region.₂The high density area is larger.
[0003]
In such an optical fiber manufacturing method, an optical fiber preform is usually drawn to form a glass fiber, and a coating material is coated on the outer periphery of the glass fiber, and then the coating material is cured by ultraviolet irradiation. And configured to wind up.
[0004]
[Problems to be solved by the invention]
In this method, at the start of drawing, one end of the optical fiber preform is melted and pulled, and during the lead-out operation that goes to the production line, the resin hardens in a part of the die that is a resin reservoir through which the glass fiber passes. There was a problem of clogging.
[0005]
When completely clogged, disconnection occurred, and even if clogged completely, uneven thickness of the resin sometimes occurred.
[0006]
Such curing of the resin in the die is considered to be caused by the following causes. GeO₂Additive quartz glass (GeO₂-SiO₂) Is irradiated with ultraviolet light, it produces luminescence, which propagates along the fiber and is considered to cure the resin in the die. FIG. 8 shows GeO₂It is a figure which shows the absorption wavelength of addition quartz glass, and the light emission wavelength by luminescence. Here, the solid line is the absorption wavelength, and it can be seen that there is a peak in the vicinity of 240 nm. The dotted line is the emission wavelength by luminescence.
[0007]
In other words, the luminescence light generated by the ultraviolet rays applied to the glass propagates through the optical fiber and spreads in the longitudinal direction of the optical fiber, and the luminescence light leaking in the vicinity of the die cures the coating resin in the die. was there.
This phenomenon is especially true for GeO.₂This was conspicuous when the optical fiber with a large amount of addition was irradiated with ultraviolet rays.
[0008]
In this case, in particular, the interruption of the drawing due to the deterioration of the uneven thickness of the resin or the disconnection as described above means that the drawing speed is stabilized again from the lead-out operation requiring the drawing at a low speed. It is necessary to redo the process up to the point of time, and further time and materials are required, which is a big problem that reduces productivity.
[0009]
Therefore, in the optical fiber drawing / coating process, no interruption is a major factor for improving productivity.
In addition, when an ultraviolet curable resin is used as a glass fiber coating material, it is necessary to keep the periphery of the glass fiber in a nitrogen atmosphere in order to eliminate the inhibition of curing by oxygen. For this reason, the ultraviolet irradiation region for resin curing is covered with a quartz tube, and ultraviolet irradiation is performed while flowing a nitrogen gas into the quartz tube. The quartz tube has a small diameter so as to reduce the amount of nitrogen supplied. For this reason, there was a risk of contact and disconnection when removing the jig.
[0010]
Under such circumstances, prevention of die clogging has been a very important problem in the optical fiber manufacturing process.
[0011]
The present invention has been made in view of the above circumstances, and GeO₂An object of the present invention is to provide a highly reliable resin coating while preventing the occurrence of resin clogging while maintaining a sufficient degree of curing of the coating resin even for an optical fiber with a large amount of addition.
Another object of the present invention is to form optical fiber strands with good controllability and continuously with good controllability through coating and curing from lead-out and wire drawing.
[0012]
[Means for Solving the Problems]
  Accordingly, the optical fiber manufacturing method of the present invention includes a step of drawing an optical fiber preform and forming a glass fiber, and applying an ultraviolet curable resin while transporting the drawn glass fiber toward a winding unit. And an optical fiber manufacturing method comprising: a coating step of curing by ultraviolet irradiation to form an optical fiber strand; and a winding step of winding the optical fiber strand on which the ultraviolet curable resin is formed at a winding portion InThe optical fiber is 4.2 × 10 6 per 1 m of a glass fiber having a diameter of 125 μm. ^-7 containing more than mol germanium dioxide,The coating step includesThe light source on the downstream side is turned on first, and the number of lighting light sources is sequentially increased,The method includes a step of adjusting the lighting time and the number of lighting of a plurality of light sources based on the linear velocity so as to obtain a necessary amount of light.
[0013]
According to such a configuration, since a plurality of light sources are used and the lighting time and the number of lighting are adjusted based on the linear speed so that a plurality of required light amounts can be obtained, a wide range of light amounts Adjustment is easily possible. In addition, since the lighting of the light source is adjusted in accordance with the linear velocity, it is not necessary to adjust the linear velocity in the curing process, and the resin coating can be performed while winding in accordance with the linear drawing speed. Further, since there is no need to remove the jig as in the case of the conventional apparatus, there is no danger of the jig contacting the optical fiber and disconnecting at the time of removal.
[0014]
Desirably, the number of lighting of the light source is reduced at the time of extraction, and the number of lighting of the light source is increased at the time of normal manufacturing, that is, for the optical fiber after the resin curing is completed in a sufficient area. It is possible to perform highly reliable coating with high controllability and high reliability.
[0015]
Desirably, when the ultraviolet curable resin has a two-layer structure made of the first and second ultraviolet curable resins, only one of the first ultraviolet curable resin and the second ultraviolet curable resin is produced at the start of manufacture. Applying and curing, then applying and curing both UV curable resins, the amount of UV light when curing only one UV curable resin, the amount of UV light per resin when curing both UV curable resins An adjustment step of adjusting the lighting time and the number of lighting of a plurality of light sources so as to reduce the number of light sources.
[0016]
According to such a configuration, in order to reduce the ultraviolet rays reaching the core layer, a predetermined time is passed at the start of passage of the optical fiber strand before coating and the optical fiber strand coated with only one ultraviolet curable resin layer. The number of lighting of the plurality of light sources is reduced, and the amount of ultraviolet rays reaching the optical fiber can be easily controlled with good controllability, so that the luminescence phenomenon is suppressed and the resin at the die portion is suppressed. It is possible to prevent clogging of the resin due to curing. Since only the lighting control of the light source is required, the switching time is short and the controllability is good. Moreover, in this hardening process, since it can adjust by lighting control of a light source, it is not necessary to adjust a drawing speed and a winding speed.
[0017]
This is based on the following experiment.
That is, the present inventors reduced the amount of ultraviolet light irradiation within the range necessary for resin curing, and repeated various experiments. As a result, the following was found about die clogging and irradiation conditions.
[0018]
First, this phenomenon does not occur even when two layers are applied and irradiated with ultraviolet light of normal power.
When the normal power ultraviolet light was irradiated in a state where only one of the resins was applied, die clogging occurred with a probability of 50%. In particular, in the case of the tandem coating method in which coating and curing are performed for each layer, when coating is applied from the second layer, die clogging occurs with a probability of almost 100% when the UV irradiation furnace for curing the second layer is normal power. To do.
[0019]
Therefore, for an optical fiber that passes through an ultraviolet curing device with at least one of the resin layers applied, the number of light sources to be turned on is reduced as compared with the case where two layers of resin are applied, and ultraviolet light is transmitted. By reducing, it is thought that luminescence can be suppressed and clogging of the resin can be prevented. Again, the number of lighting is adjusted in accordance with the drawing speed of the optical fiber, luminescence can be suppressed without adjusting the drawing speed, and clogging of resin can be reduced without reducing productivity. It becomes possible.
[0020]
Preferably, in the covering step, the light amount of the light source is increased so as to increase the light amount of the irradiated ultraviolet light so that the light amount is sufficient to cure the first and second ultraviolet curable resins after suppressing the light amount of the ultraviolet light. By including the step of adjusting the lighting, the resin is prevented from being insufficiently cured and the reliability is improved.
[0021]
Desirably, the coating process includes an adjustment process that adjusts the lighting time and the number of lights according to the linear speed at the start of application and at the time of high-speed manufacturing, so that the light quantity for curing is reliably guaranteed. In addition, since high-speed drawing can be continued continuously, productivity is improved.
[0022]
Preferably, in the coating step, after the light amount is reduced at the start of application, the number of light sources that are sequentially turned on is increased so that the light amount is sufficient for curing the first and second ultraviolet curable resins, and the ultraviolet rays that are irradiated are irradiated. By including the step of increasing the amount of light, it is possible to prevent the resin from reaching the resin reservoir (dies), the resin is sufficiently cured, and when the coating is sufficiently applied so that the ultraviolet rays do not reach the glass fiber. The light source on the side can be turned on to increase the amount of ultraviolet light.
[0023]
Desirably, in the covering step, the light source on the downstream side is first turned on at the time of extraction, and the light source lighting position at the time of extraction is kept away from the resin coating part, so that the luminescence light propagates in the optical fiber. Then, when the resin is sufficiently cured and the glass fiber is sufficiently coated so that the ultraviolet rays do not reach, the upstream light source is turned on to increase the amount of ultraviolet rays. Thus, it is possible to perform sufficient curing. In this way, it is possible to perform stable and quick light amount adjustment.
[0024]
Preferably, in the covering step, after the light source on the downstream side is turned on first, the light source close to the application part is turned on, so that the section where the resin is uncured is shortened when the distance from the die is short. Thus, it is possible to suppress the generation of waviness on the fiber surface due to the adhesion of dust in the atmosphere and the line blurring.
[0025]
In particular, 4.2 × 10 4 per 1 m of glass fiber having a diameter of 125 μm.^-7More than mol GeO₂In the case of quartz glass containing luminescence, this method is particularly effective because luminescence is particularly likely to occur.
[0026]
For GI fiber, GeO₂This method is particularly effective because of the large amount of addition of benzene, and particularly luminescence is likely to occur.
Also, GeO is used for the core and cladding.₂In the case of FBG fiber doped with₂This method is particularly effective because of the large amount of addition of benzene, and particularly luminescence is likely to occur.
[0027]
Preferably, the coating step includes a first application step of applying the first ultraviolet curable resin, and a first ultraviolet irradiation that irradiates the ultraviolet rays with a plurality of light sources so as to cure the first ultraviolet curable resin. A second application step of applying a second ultraviolet curable resin to an upper layer of the first ultraviolet curable resin, and a second light irradiation with a plurality of light sources so as to cure the second ultraviolet curable resin. 2 in the first ultraviolet irradiation step, and the lighting energy is configured to be smaller than that in the second ultraviolet irradiation step.
In particular, in the case of a so-called tandem coating method in which curing is performed each time a coating film is formed, in the first ultraviolet irradiation process, the light quantity is reduced by adjusting the number of lighting of the light source and the like, thereby more reliably preventing clogging. be able to.
[0028]
The die for applying the first ultraviolet curable resin includes both ultraviolet rays (first ultraviolet rays) irradiated to the first ultraviolet curable resin and ultraviolet rays (second ultraviolet rays) irradiated to the second ultraviolet curable resin. Therefore, the number of light sources to be lit may be adjusted so that the amount of the first ultraviolet light is small. Since the first ultraviolet curable resin is cured by the second ultraviolet ray, there is no problem even if the amount of light is reduced. Both the first ultraviolet ray and the second ultraviolet ray are formed by a plurality of light sources, but it is desirable to turn on the side farther from the dice, that is, the downstream side first among the constituent light sources of the first ultraviolet ray.
[0029]
  In the apparatus of the present invention, a drawing means for drawing an optical fiber preform to form a glass fiber, and an ultraviolet curable resin is applied while the drawn glass fiber is conveyed toward a winding unit, and ultraviolet irradiation is performed. In the optical fiber manufacturing apparatus, comprising: coating means for curing by an optical fiber, and winding means for winding the optical fiber strand on which the ultraviolet curable resin is formed in a winding section. The means comprises an application part for applying an ultraviolet curable resin to a glass fiber, and an ultraviolet irradiation part comprising a plurality of light sources for irradiating the ultraviolet ray to cure these ultraviolet curable resins,The optical fiber is 4.2 × 10 6 per 1 m of a glass fiber having a diameter of 125 μm. ^-7 containing more than mol germanium dioxide,The ultraviolet irradiation unit isThe downstream light source is turned on first, and the number of light sources to be turned on is sequentially increased, and the lighting time and the number of lights of a plurality of light sources are set based on the linear speed so that the required light quantity can be obtained. AdjustControl means for controlling the amount of ultraviolet irradiation light is provided.
  According to such a configuration, the number of lighting of the light source and the lighting time can be easily controlled by the control means, and die clogging can be prevented.
  Preferably, the coating means includes a first application unit that applies a first ultraviolet curable resin to a glass fiber, a first ultraviolet irradiation unit that irradiates and cures the first ultraviolet curable resin with ultraviolet rays, and A second application part for applying the second ultraviolet curable resin to the upper layer of the first ultraviolet curable resin, and a second ultraviolet irradiation part for irradiating the second ultraviolet curable resin with ultraviolet rays to cure the second ultraviolet curable resin, At least the second ultraviolet irradiation unit includes a plurality of light sources, and includes control means for controlling the number of lighting times and the lighting time of the light sources according to the linear velocity and controlling the amount of ultraviolet irradiation light.
  According to such a configuration, die clogging can be prevented in the tandem coating method.
[0030]
In this way, by preventing clogging of the dies, not only can maintenance be reduced, but it can be performed continuously without stopping the drawing process, greatly improving productivity. Can be achieved.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First embodiment
An optical fiber manufacturing apparatus used in the manufacturing method of the embodiment of the present invention is shown in FIG. In this manufacturing apparatus, the first and second curing devices 181 and 182 that are the first and second ultraviolet irradiation units of the resin coating unit 160 are respectively used as the first to sixth ultraviolet lamps 181a, 181b, 181c, and 182a. , 182b, 182c, and the on / off of these six lamps is controlled by the control device 190.
[0032]
The sixth ultraviolet lamp 182c, the start of application, the fourth ultraviolet lamp 182a, the fifth ultraviolet lamp 182b, the third ultraviolet lamp 181c, the first ultraviolet lamp 181a, and the second ultraviolet lamp 181b are sequentially timed. By adjusting the irradiation light amount by shifting lighting, a change in the irradiation light amount to the optical fiber as shown in FIG. 2 can be obtained. Here, an example of suppressing the amount of ultraviolet light reaching the optical fiber at the start of passage of the optical fiber covered with only one second ultraviolet curable resin layer is shown. Here, the vertical axis represents the amount of light, and the horizontal axis represents time. This suppresses the luminescence phenomenon and prevents resin clogging due to curing of the resin at the die portion.
[0033]
This apparatus is equipped with an optical fiber preform 100, the lower end of the optical fiber preform is heated and softened, and a drawing furnace 110 for obtaining an optical fiber, and a laser outside for measuring the outer diameter of the optical fiber. Diameter measuring device 140, a drawing controller 150 for controlling drawing conditions based on the output of the laser outer diameter measuring device 140, a resin coating unit 160, a guide roller 210, a capstan 220, and a winding drum 240 Is an apparatus for forming an optical fiber by continuously drawing and coating.
[0034]
In this apparatus, the coating unit 160 includes a first resin coating die 161 filled with a liquid resin 171 and first to third ultraviolet lamps 181a, 181b, 181c for curing the applied resin. A second curing unit 181, a second resin coating die 162 filled with a liquid resin 172, and a second to sixth ultraviolet lamps 182 a, 182 b and 182 c for curing the applied resin. The first and second curing devices 181 and 182 are each composed of three ultraviolet lamps that can be controlled on and off independently by the control device 190 as described above. ing. Here, the first resin coating die 161 supplies an ultraviolet curable resin having a particularly high sensitivity to 240 nm and 400 nm light called R1055. On the other hand, the second resin coating die 162 supplies an ultraviolet curable resin having a particularly high sensitivity to 300 nm light called R3061B.
[0035]
Here, the drawing furnace 110 includes a heater 120 for heating and softening the lower end of the optical fiber preform 100, and performs drawing at, for example, a drawing speed of 100 m / min while heating and softening.
[0036]
Then, the outer diameter of the drawn glass fiber 130 is measured by a laser outer diameter measuring device 140, and this measurement result is input to the drawing controller 150 and the heating temperature of the heater 120 is set so that the outer diameter is normally 125 microns. The base material feeding speed, the take-up speed by the capstan 220 and the drawing speed are controlled.
Further, the coating unit 160 is configured to guide the coated optical fiber 200 to the guide roller 210, the capstan 220, and the take-up drum 240.
[0037]
Next, an optical fiber manufacturing process using this apparatus will be described.
First, when the optical fiber preform 100 having an outer diameter of 50 mm is mounted in the drawing furnace 110, the lower end of the optical fiber preform 100 is heated to about 2000 ° C. by the heater 120 and softened by heating to start drawing. Then gradually increase the linear velocity. Simultaneously with the start of the drawing, the sixth ultraviolet lamp 182c of the second curing device 182 is turned on by controlling the voltage so that the amount of light becomes 50%, and ultraviolet irradiation is started.
[0038]
At this time, although an optical fiber not coated with resin passes through first, only the sixth ultraviolet lamp 182c located at the most downstream of the light sources in the curing device is lit, so this ultraviolet light is the first light. And it takes time to reach the second die, and even if luminescence occurs, it hardly reaches the die.
[0039]
Then, the heating temperature, the base material feeding speed, the take-up speed and the drawing speed by the capstan 220 are measured, and while stabilizing the fiber diameter, the irradiation light quantity to the resin is made constant according to this value. The UV light 182c, the start of application, the fourth UV lamp 182a, and the fifth UV lamp 182b are turned on sequentially in order to adjust the amount of light applied to the optical fiber passing therethrough (see FIG. 2). . Here, after turning on the sixth ultraviolet lamp 182c by half (50%), the gate (not shown) of the second resin coating die 162 filled with the liquid resin 172 is opened, and the optical fiber passing therethrough is opened. The second layer resin is applied to a desired thickness, and ultraviolet irradiation is performed by a second curing device 182 for curing the applied resin. The fourth ultraviolet lamp 182a is turned on 100%, and after the first layer application is started, the third ultraviolet lamp 181c is turned on 50%, the first ultraviolet lamp 181a is turned on, and finally the second ultraviolet lamp 181b, The fifth ultraviolet lamp 182b is turned on to enter a steady state, and the lights are sequentially turned on.
[0040]
After starting the coating of the second layer resin in this way, next, the gate (not shown) of the first resin coating die 161 filled with the liquid resin 171 is opened, and the first optical fiber is passed through the first optical fiber. The third ultraviolet lamp 181c and the first ultraviolet lamp are provided so that the layer resin is applied to a desired thickness (for example, 30 to 40 μm), and the light quantity adjusted to a level at which the die is not clogged is obtained. The resin is cured by irradiating ultraviolet light from the first curing device 181 while sequentially shifting the timings of the 181a and the second ultraviolet lamp 181b.
[0041]
In a steady state, the entire amount of ultraviolet light is applied to the optical fiber that passes therethrough. At this time, the first curing device is configured so that the amount of light is smaller than that of the second curing device as long as the total curing is not insufficient. In the tandem method, it is desirable to reduce the irradiation amount of the ultraviolet light to the first layer resin even in the steady drawing process after the linear velocity is increased.
[0042]
In this manner, the optical fiber strand 200 is formed by coating the surface of the glass fiber 130 with the resin coating 190 made of two layers of resin.
At the start of coating, the application of the second layer resin as the hard layer is started first, and then the gate of the die is opened so as to start the application of the first layer resin as the soft layer. This is because the first layer resin usually has adhesiveness and is easily entangled with a roller or the like.
[0043]
At this time, the outer diameter of the optical fiber 200 after coating is, for example, 250 microns.
Next, the optical fiber 200 is sequentially guided by the guide roller 210 and wound around the drum 240.
[0044]
In this way, after the light quantity is adjusted according to the lighting timing of the light source and the drawing speed is stabilized, the drawing is continuously performed while controlling the lighting of a plurality of light sources so as to adjust the light quantity corresponding to the speed. To form an optical fiber. A cross-sectional view of this optical fiber is shown in FIG. In this optical fiber, a glass fiber 130 made of a core layer and a clad layer is formed with a resin film made of a first layer resin 191 and a second layer resin 192 concentrically, and there is no uneven thickness.
[0045]
According to this method, there is no clogging of the dies, and the light quantity is adjusted by adjusting on / off of a plurality of ultraviolet lamps without adjusting the linear speed, and the linear speed remains constant. In particular, the optical fiber could be formed with high productivity.
[0046]
In addition, since the light source close to the application part is turned on after the light source on the downstream side is turned on first, the section where the resin is uncured because the lamp at a short distance from the die is turned on early. And the generation of undulations on the fiber surface due to the adhering of dust and wire shake in the atmosphere can be suppressed.
[0047]
In this example, the light amount adjustment is performed by sequentially shifting the on / off timing of the ultraviolet lamp, but the amount of ultraviolet light irradiated may be changed by a method such as changing the voltage applied to the curing device. .
[0048]
Second embodiment
Next, a second embodiment of the present invention will be described.
In the first embodiment of the present invention, the tandem-coating optical fiber drawing / coating method in which the first layer resin and the second layer resin are respectively applied and cured has been described. In this example, the first layer A method for drawing and coating a dual coating type optical fiber in which the resin and the second layer resin are continuously applied on the same die and cured at once will be described.
[0049]
In the apparatus used for drawing and covering the optical fiber of this dual coating system, as shown in FIG. 4, the resin coating unit 260 supplies the first supply port 261 for supplying the first layer resin and the second layer resin. A second supply port 262 and a curing device 281 that is an ultraviolet irradiation unit formed on the downstream side of the second supply port 262 are provided, so that the amount of ultraviolet rays irradiated to the curing device 281 can be adjusted. The first to third ultraviolet lamps 281a to 281c are configured. Also here, the second supply port 262 is configured to be opened slightly earlier than the first supply port 261, and the application start point of the second layer resin is slightly ahead.
[0050]
Then, as shown in FIG. 5, the amount of light emitted from the curing device 281 is adjusted so that the amount of light is increased only after the first layer resin and the second layer resin are formed. Features.
Other parts other than the coating part are formed in the same manner as in the first embodiment, and the same parts are denoted by the same reference numerals. Here, as in FIG. 2, the supply voltage is adjusted so that 50% and 100% are 50% and 100%, respectively.
[0051]
According to such a configuration, since the amount of light is reduced at the start of drawing and coating, the luminescence phenomenon can be suppressed, and the resin clogging due to the resin curing at the die portion can be prevented, and the resin clogging occurs. Therefore, the optical fiber can be drawn and coated efficiently.
In the first embodiment of the present invention, the example in which the first layer is started after the second layer is applied in the case of tandem coating has been described. Application of the layer may be started. An example of lighting control of the ultraviolet lamp in this case is shown in FIG.
Even with such control, it becomes possible to easily draw and coat the optical fiber with good controllability without clogging of the resin.
[0052]
【The invention's effect】
As described above, according to the method of the present invention, by using a plurality of light sources and adjusting the lighting timing without changing the drawing speed, there is no resin clogging and the optical fiber drawing / It is possible to perform coating.
[Brief description of the drawings]
FIG. 1 is a diagram showing an optical fiber manufacturing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a change in the amount of light applied to the optical fiber according to the first embodiment of the present invention.
FIG. 3 is a sectional view showing an optical fiber formed by the method according to the first embodiment of the present invention.
FIG. 4 is a diagram showing an optical fiber manufacturing apparatus according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a change in the amount of light applied to an optical fiber according to a second embodiment of the present invention.
FIG. 6: GI fiber refractive index and GeO₂The figure which shows the relationship between a density | concentration and its diameter.
FIG. 7 GeO for FBG₂Refractive index and GeO of doped clad fiber₂The figure which shows the relationship between a density | concentration and its diameter.
FIG. 8 is a diagram showing an absorption wavelength of an optical fiber and a wavelength of luminescence light in the embodiment of the present invention.
FIG. 9 is a diagram showing a change in the amount of light applied to an optical fiber according to another embodiment of the present invention.
[Explanation of symbols]
160 Resin coating part
181 First curing device
181a First UV lamp
181b Second UV lamp
181c Third UV lamp
182a Fourth UV lamp
182b Fifth UV lamp
182c Sixth ultraviolet lamp 182 Second curing device
260 Resin coating part
261 First supply port
262 Second supply port

Claims (7)

Drawing an optical fiber preform to form a glass fiber;
A coating step of forming an optical fiber by applying an ultraviolet curable resin while conveying the drawn glass fiber toward the winding unit and curing it by ultraviolet irradiation,
In the method of manufacturing an optical fiber, including a winding step of winding the optical fiber formed with the ultraviolet curable resin in a winding unit,
The optical fiber includes 4.2 × 10 ⁻⁷ mol or more of germanium dioxide per 1 m of glass fiber having a diameter of 125 μm ,
In the covering step, the light sources on the downstream side are turned on first, and the number of light sources to be turned on is sequentially increased, and a plurality of light sources are turned on based on the linear velocity so that the required light quantity can be obtained. The manufacturing method of the optical fiber characterized by including the process of adjusting time and the number of lighting.   The coating step comprises a step of applying and curing only one of the first ultraviolet curable resin and the second ultraviolet curable resin at the start of production, and thereafter applying and curing both the ultraviolet curable resins. Adjustment that adjusts the lighting time and number of lights of the light sources so that the amount of UV light when curing UV curable resin is less than the amount of UV light per resin when curing both UV curable resins The method for manufacturing an optical fiber according to claim 1, further comprising a step. In the coating step, after the amount of light is reduced at the start of application, the number of light sources that are sequentially turned on is increased so that the amount of light is sufficient to cure the first and second ultraviolet curable resins, and the amount of ultraviolet light that is irradiated. The method of manufacturing an optical fiber according to claim 1 or 2 , further comprising a step of increasing The optical fiber manufacturing method according to claim 3 , wherein the covering step is configured to turn on a light source close to a coating portion after first turning on a light source on a downstream side. The optical fiber manufacturing method according to claim 4 , wherein the optical fiber is a GI fiber. The optical fiber preform according to claim 4 , wherein germanium dioxide is added to the core and the clad of the optical fiber preform. A drawing means for drawing an optical fiber preform to form a glass fiber;
A coating means for forming an optical fiber strand by applying an ultraviolet curable resin while transporting the drawn glass fiber toward the winding unit, and curing it by ultraviolet irradiation.
In an optical fiber manufacturing apparatus including a winding means for winding the optical fiber formed with the ultraviolet curable resin in a winding unit,
The coating means comprises an application part for applying an ultraviolet curable resin to a glass fiber, and an ultraviolet irradiation part comprising a plurality of light sources for irradiating ultraviolet rays to cure the ultraviolet curable resin,
The optical fiber includes 4.2 × 10 ⁻⁷ mol or more of germanium dioxide per 1 m of glass fiber having a diameter of 125 μm ,
The ultraviolet irradiation unit is configured to first turn on the downstream light source and sequentially increase the number of light sources to be turned on, and to obtain a necessary light amount, a plurality of light sources based on the linear velocity. An apparatus for manufacturing an optical fiber, characterized by comprising control means for adjusting the lighting time and the number of lights and controlling the amount of ultraviolet irradiation light.

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