JP7663018B2 - Optical fiber processing device and processing method - Google Patents

Description

This disclosure relates to an optical fiber processing device and processing method.

Patent Document 1 discloses a method for treating optical fiber in which a reaction vessel that contains a bobbin around which optical fiber is wound is decompressed, and a deuterium (D2)-containing gas is introduced into the reaction vessel to expose the optical fiber to the deuterium-containing gas. This treatment method further involves recovering the deuterium-containing gas in the reaction vessel and storing it in a storage vessel, thereby recovering and supplying the deuterium-containing gas.

Patent Document 2 discloses an optical fiber processing device that reduces the pressure in a reaction vessel that contains a bobbin around which an optical fiber is wound, and introduces a deuterium-containing gas into the reaction vessel to expose the optical fiber to the deuterium-containing gas. This processing device further includes a storage vessel that collects and stores the deuterium-containing gas in the reaction vessel, and uses a suction pump to collect and supply the deuterium-containing gas.

Patent Document 3 and Patent Document 4 disclose a method for treating an optical fiber in which an optical fiber wound on a bobbin is placed in a sealed container, deuterium gas is supplied to replace the gas in the sealed container with a deuterium-containing gas, and the optical fiber in the sealed container is exposed to the deuterium-containing gas.

International Publication No. WO 2005/062088 JP 2005-301118 A JP 2019-127412 A JP 2005-292465 A

The present disclosure aims to provide an optical fiber processing device and processing method that can recover and reuse deuterium-containing gas while minimizing the size of the device.

The optical fiber processing device of the present disclosure comprises:
a treatment tank for accommodating the optical fiber therein;
a gas supply device for supplying a deuterium-containing gas to the treatment tank;
a pump that draws in the deuterium-containing gas from within the treatment tank;
a pressure increasing unit for increasing the pressure of the deuterium-containing gas discharged from the pump;
a pipe for supplying the deuterium-containing gas pressurized by the pressure boosting unit to the treatment tank;
Equipped with
The pressure increasing unit is connected between the pump and the piping,
The deuterium-containing gas is pressurized and stored in the pipe without a dedicated gas tank .

The method of the present disclosure for treating an optical fiber includes:
A first step of placing an optical fiber in a treatment bath;
a second step of supplying a deuterium-containing gas into the treatment tank through a pipe after the first step;
a third step of exposing the optical fiber accommodated in the treatment tank to an atmosphere of the deuterium-containing gas after the second step;
a fourth step of, after the third step, aspirating the deuterium-containing gas in the processing tank with a pump , pressurizing the aspirated deuterium-containing gas with a pressure increasing unit , and returning the gas to the piping;
It has
The pressure increasing unit is connected between the pump and the piping,
There is no dedicated gas tank, and the pressurized deuterium-containing gas is stored in the piping .

The present disclosure makes it possible to provide an optical fiber processing device and processing method that can recover and reuse deuterium-containing gas while minimizing the size of the device.

FIG. 1 is a conceptual diagram showing the configuration of an optical fiber processing apparatus according to an embodiment. FIG. 2 is a diagram showing a process flow in the method for processing an optical fiber according to an embodiment.

[Description of the embodiments of the present disclosure]
First, the contents of the embodiments of the present disclosure will be listed and described.
The optical fiber processing device of the present disclosure comprises:
(1) a treatment tank for accommodating an optical fiber therein;
a gas supply device for supplying a deuterium-containing gas to the treatment tank;
a pump that draws in the deuterium-containing gas from within the treatment tank;
a pressure increasing unit for increasing the pressure of the deuterium-containing gas discharged from the pump;
a pipe for supplying the deuterium-containing gas pressurized by the pressure boosting unit to the treatment tank;
Equipped with
The pressure increasing unit is connected between the pump and the piping,
The deuterium-containing gas is pressurized and stored in the pipe without a dedicated gas tank .

According to the above configuration, the deuterium-containing gas supplied to the processing tank can be recovered and reused. In addition, when the deuterium-containing gas to be reused is stored under atmospheric pressure, a dedicated large gas tank is required. However, since the deuterium-containing gas recovered from the processing tank is pressurized, the volume of the container for storing the deuterium-containing gas can be reduced. This eliminates the need for a dedicated large gas tank, and for example, the pressurized deuterium-containing gas can be stored in a pipe that supplies the deuterium-containing gas to the processing tank. In addition, since the pressurized deuterium-containing gas is supplied to the processing tank, a pump used to supply the deuterium-containing gas to the processing tank is not required. Therefore, it is possible to provide an optical fiber processing device that can recover and reuse the deuterium-containing gas while suppressing the increase in size of the device.

(2) The optical fiber processing device may further include a filter unit provided in the piping.

The above configuration allows the removal of dust and dirt contained in the collected gas, thereby preventing dust and dirt from adhering to the optical fiber exposed to the atmosphere of the reused deuterium-containing gas in the treatment tank.

(3) The optical fiber processing device may include a plurality of the processing tanks.

With the above configuration, deuterium treatment is performed on multiple optical fibers simultaneously, improving optical fiber productivity.

The method of the present disclosure for treating an optical fiber includes:
(4) a first step of placing the optical fiber in a treatment bath;
a second step of supplying a deuterium-containing gas into the treatment tank through a pipe after the first step;
a third step of exposing the optical fiber accommodated in the treatment tank to an atmosphere of the deuterium-containing gas after the second step;
a fourth step of, after the third step, aspirating the deuterium-containing gas in the processing tank with a pump , pressurizing the aspirated deuterium-containing gas with a pressure increasing unit , and returning the gas to the piping;
It has
The pressure increasing unit is connected between the pump and the piping,
There is no dedicated gas tank, and the pressurized deuterium-containing gas is stored in the piping .

According to the above method, the deuterium-containing gas supplied to the processing tank can be recovered and reused. In addition, when the deuterium-containing gas to be reused is stored under atmospheric pressure, a dedicated large gas tank is required. However, since the deuterium-containing gas recovered from the processing tank is pressurized, the volume of the container for storing the deuterium-containing gas can be reduced. This eliminates the need for a dedicated large gas tank, and for example, the pressurized deuterium-containing gas can be stored in a pipe that supplies the deuterium-containing gas to the processing tank. In addition, since the pressurized deuterium-containing gas is supplied to the processing tank, a pump used to supply the deuterium-containing gas to the processing tank is not required. Therefore, it is possible to provide a method for processing optical fiber that can recover and reuse the deuterium-containing gas while suppressing the increase in size of the device.

(5) The second step may include blowing the deuterium-containing gas into the treatment tank at atmospheric pressure.

According to the above configuration, when air remains in the treatment tank at atmospheric pressure, the blowing process can replace the air remaining in the treatment tank with deuterium-containing gas. In addition, since the recovered deuterium-containing gas is pressurized, deuterium-containing gas can be supplied to the treatment tank at atmospheric pressure without using a pump.

(6) The optical fiber processing method may include a fifth step, after the first step and before the second step, of depressurizing the processing tank so that the pressure in the processing tank is in the range of 20 kPa or more and 90 kPa or less in absolute pressure.

According to the above configuration, the treatment tank is depressurized, so that, for example, when an optical fiber is wound around a fiber bobbin, the deuterium-containing gas can be distributed up to the vicinity of the winding core of the bobbin. In addition, since the amount of depressurization is small, the treatment tank can be depressurized in a short time. Furthermore, if the pressure difference between when the treatment tank is depressurized and when it is at normal pressure is too large, for example, there is a risk that the optical fiber may become loose around the fiber bobbin. However, since the amount of depressurization is small, it is possible to prevent the optical fiber from becoming loose around the fiber bobbin.

(7) In the fourth step, the deuterium-containing gas in the treatment tank may be aspirated so that the pressure in the treatment tank is in the range of 20 kPa or more and 90 kPa or less in absolute pressure.

If the pressure difference between the reduced pressure and normal pressure in the processing tank is too large, for example, there is a risk that the optical fiber may become loose around the fiber bobbin. However, with the above configuration, the amount of reduced pressure is small, so that the optical fiber can be prevented from becoming loose around the fiber bobbin.

[Details of the embodiment of the present disclosure]
Specific examples of optical fiber processing devices and processing methods according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope of the claims as set forth in the claims. In addition, the scale of each drawing used in the following description has been appropriately changed so that each component can be recognized.

(Optical fiber processing device)
1 is a schematic diagram showing the configuration of an optical fiber processing apparatus 1 according to an embodiment. The optical fiber processing apparatus 1 is configured to perform deuterium processing on an optical fiber 10 produced by drawing, and to diffuse deuterium molecules into the optical fiber 10.

The optical fiber 10 is manufactured by coating the outer periphery of a glass fiber produced by drawing an optical fiber preform with a resin. The optical fiber preform is drawn so that the outer diameter of the glass fiber is, for example, 125 μm. The glass fiber has, for example, a core portion made of silica glass doped with germanium or a compound containing germanium (e.g., GeO ₂ ), and a cladding portion made of high-purity silica glass (an example of pure silica glass) provided on the outer periphery of the core portion. The optical fiber with the resin coated around the glass fiber is wound around a fiber bobbin 11.

It is known that optical fibers made of quartz glass (silica glass) transmit light with wavelengths in the infrared band, and that the transmission loss increases when hydrogen ( _H2 ) gas diffuses into the quartz glass. The main cause of this increase in transmission loss is the absorption of the transmitted light by the reaction product (Si-OH) between _H2 molecules diffused into the glass and lattice defects (Si-O.) present in the quartz glass.

In the deuterium treatment, the optical fiber 10 wound around the fiber bobbin 11 is exposed to an atmosphere of deuterium-containing gas, which fills the Si-O bond defects with deuterium, thereby suppressing the increase in transmission loss caused by the Si-O bond defects.

As shown in FIG. 1, the optical fiber processing device 1 includes a processing tank 2, a gas supply device 3, a vacuum pump 4, a pressure boosting unit 5, and a gas flow path 6. The vacuum pump 4 is an example of a pump.

The treatment tank 2 has a space 2A for accommodating the optical fiber 10, and is configured to be able to keep the space 2A sealed. In this example, the optical fiber treatment device 1 has two treatment tanks 2. The optical fiber 10 is placed in the treatment tank 2 while being wound around a fiber bobbin 11. The treatment tank 2 may be fitted with an instrument such as a pressure gauge for measuring the internal pressure.

The gas supply device 3 supplies deuterium-containing gas to the processing tank 2. The deuterium-containing gas may be a mixed gas containing deuterium gas, or deuterium gas alone. The gas supply device 3 is connected to a deuterium gas supply unit that stores deuterium gas and a dilution gas supply unit that stores dilution gas, not shown. The gas supply device 3 mixes deuterium gas and dilution gas to generate deuterium-containing gas, and supplies the deuterium-containing gas to the processing tank 2. The gas supply device 3 controls the mixing ratio of deuterium gas and dilution gas so that the concentration of deuterium gas (deuterium concentration) in the deuterium-containing gas supplied to the processing tank 2 is, for example, 2%.

The vacuum pump 4 sucks the gas in the processing tank 2. For example, before the deuterium-containing gas is supplied into the processing tank 2, the vacuum pump 4 sucks the air in the processing tank 2 to reduce the pressure in the processing tank 2. In addition, the vacuum pump 4 sucks the deuterium-containing gas in the processing tank 2 after the optical fiber 10 in the processing tank 2 is exposed to the deuterium-containing gas.

The pressure boosting unit 5 boosts the pressure of the deuterium-containing gas discharged from the vacuum pump 4. The pressure boosting unit 5 boosts the pressure of the deuterium-containing gas, for example, to atmospheric pressure or higher.

The gas flow path 6 includes a first flow path 61 and a second flow path 62. The first flow path 61 and the second flow path 62 are an example of piping. The gas supply device 3 is connected to the treatment tank 2 via the first flow path 61. The pressure boosting unit 5 is connected to the treatment tank 2 via the second flow path 62 and the first flow path 61. The first flow path 61 is provided with an on/off valve 71 that switches the first flow path 61 between open and closed. The second flow path 62 is provided with an on/off valve 72 that switches the second flow path 62 between open and closed.

The gas flow path 6 further includes a third flow path 63 and a fourth flow path 64. The vacuum pump 4 is connected to the treatment tank 2 via the third flow path 63. The pressure increase unit 5 is connected to the vacuum pump 4 via the fourth flow path 64. The third flow path 63 is provided with an on/off valve 73 that switches the third flow path 63 between open and closed. The fourth flow path 64 is provided with a three-way valve 74, and the three-way valve 74 is connected to a gas exhaust path 65. The three-way valve 74 is a valve that switches between a state in which the vacuum pump 4 is connected to the pressure increase unit 5 and a state in which the vacuum pump 4 is connected to the gas exhaust path 65.

(Method of Processing Optical Fiber)
Next, an optical fiber processing method for performing deuterium treatment on an optical fiber using the optical fiber processing device 1 will be described with reference to Fig. 2. Fig. 2 is a diagram showing a process flow in the optical fiber processing method according to one embodiment.

First, a fiber bobbin 11 around which an optical fiber 10 is wound is placed in the treatment tank 2 (step S1), and the space 2A of the treatment tank 2 is sealed.

Then, the treatment tank 2 is depressurized by the vacuum pump 4 (step S2). Specifically, the on-off valves 71, 72, and 73 are operated to close the first flow path 61 and the second flow path 62 and open the third flow path 63. The three-way valve 74 is operated to connect the vacuum pump 4 to the gas exhaust path 65. The air in the treatment tank 2 is then sucked by the vacuum pump 4 through the third flow path 63 and released to the atmosphere through the gas exhaust path 65. For example, the treatment tank 2 is depressurized so that the pressure in the treatment tank 2 is in the range of 20 kPa to 90 kPa absolute pressure.

Then, the gas supply device 3 supplies deuterium-containing gas into the treatment tank 2 (step S3). Specifically, the on/off valves 71 and 73 are operated to open the first flow path 61 and close the third flow path 63. Then, the gas supply device 3 supplies deuterium-containing gas into the treatment tank 2 through the first flow path 61. The gas supply device 3 controls the mixing ratio of deuterium gas and dilution gas so that the concentration of deuterium gas (deuterium concentration) in the deuterium-containing gas supplied to the treatment tank 2 is, for example, 2%. As the deuterium-containing gas is supplied, the inside of the treatment tank 2 becomes atmospheric pressure.

Then, the optical fiber 10 contained in the treatment tank 2 is exposed to an atmosphere of deuterium-containing gas (step S4). Specifically, the on-off valve 71 is operated to close the first flow path 61. The optical fiber 10 contained in the treatment tank 2 is then exposed to an atmosphere of deuterium-containing gas with a deuterium concentration of, for example, 2% for a predetermined period of time. In other words, the optical fiber 10 is subjected to deuterium treatment.

When the deuterium treatment of the optical fiber 10 is completed, the deuterium-containing gas in the treatment tank 2 is sucked in by the vacuum pump 4. Specifically, the on-off valve 73 is operated to open the third flow path 63. Then, the deuterium-containing gas in the treatment tank 2 is sucked in by the vacuum pump 4 through the third flow path 63 (step S5).

The deuterium-containing gas sucked by the vacuum pump 4 is pressurized by the pressure boosting unit 5 (step S6). Specifically, the three-way valve 74 is operated to connect the vacuum pump 4 to the pressure boosting unit 5. The deuterium-containing gas sucked by the vacuum pump 4 is then transported to the pressure boosting unit 5, where it is pressurized, for example, to atmospheric pressure or higher. The pressurized deuterium-containing gas is stored, for example, in the second flow path 62.

Then, the on-off valve 73 is operated to close the third flow path 63. Then, air is sent into the treatment tank 2 from a flow path (not shown), and after the pressure inside the treatment tank 2 reaches atmospheric pressure, the optical fiber 10 is removed from the treatment tank 2 (step S7).

The deuterium-containing gas stored in the second flow path 62 is reused for the next deuterium treatment. That is, the deuterium-containing gas stored in the second flow path 62 is supplied to the treatment tank 2 in which a new optical fiber 10 is accommodated. Specifically, after the pressure inside the treatment tank 2 is reduced, the on-off valves 71 and 72 are operated to open the first flow path 61 and the second flow path 62. Then, the deuterium-containing gas stored in the second flow path 62 is supplied to the treatment tank 2 via the second flow path 62 and the first flow path 61.

At this time, the gas supply device 3 discharges deuterium-containing gas to the treatment tank 2 according to the measured value of the deuterium concentration of the deuterium-containing gas stored in the second flow path 62 measured by a concentration meter (not shown). The deuterium-containing gas discharged from the gas supply device 3 is mixed in the first flow path 61 with the recycled deuterium-containing gas transported from the second flow path 62 and supplied to the treatment tank 2. For example, if the deuterium concentration of the recycled deuterium-containing gas is less than 2%, the gas supply device 3 adjusts the deuterium concentration of the discharged deuterium-containing gas so that the deuterium concentration of the deuterium-containing gas supplied to the treatment tank 2 is 2%.

After the deuterium-containing gas is supplied into the treatment tank 2, the optical fiber 10 is subjected to deuterium treatment as described above.

As described above, the optical fiber processing apparatus 1 and processing method according to the embodiment of the present disclosure boosts the pressure of the deuterium-containing gas discharged from the processing tank 2 and supplies the boosted deuterium-containing gas to the processing tank 2. This allows the deuterium-containing gas supplied to the processing tank 2 to be recovered and reused. In addition, when the deuterium-containing gas to be reused is stored at atmospheric pressure, a dedicated large gas tank is required. However, since the deuterium-containing gas recovered from the processing tank 2 is boosted, the volume of the container for storing the deuterium-containing gas can be reduced. This eliminates the need for a dedicated large gas tank, and for example, the boosted deuterium-containing gas can be stored in the second flow path 62. In addition, since the boosted deuterium-containing gas is supplied to the processing tank 2, a pump used to supply the deuterium-containing gas to the processing tank 2 is not required. Therefore, it is possible to provide an optical fiber processing apparatus 1 and method capable of recovering and reusing the deuterium-containing gas while suppressing the increase in size of the apparatus.

In particular, in this embodiment, the optical fiber processing device 1 is equipped with multiple processing tanks 2. This allows deuterium processing to be performed simultaneously on multiple optical fibers 10, improving the productivity of the optical fibers 10.

In addition, in this embodiment, in step S2, the treatment tank 2 is depressurized so that the pressure inside the treatment tank 2 is in the range of 20 kPa or more and 90 kPa or less in absolute pressure. Since the treatment tank 2 is depressurized in this manner, the deuterium-containing gas can be distributed up to the vicinity of the winding core of the fiber bobbin 11. Since the amount of depressurization is small, the treatment tank can be depressurized in a short time. If the pressure difference between the depressurized state of the treatment tank 2 and the normal pressure state is too large, for example, there is a risk that the winding of the optical fiber 10 around the fiber bobbin 11 will loosen. However, since the amount of depressurization is small, it is possible to prevent the winding of the optical fiber 10 around the fiber bobbin 11 from loosening.

The optical fiber processing device 1 may further include a filter unit 8 provided between the booster unit 5 and the processing tank 2, as illustrated in FIG. 1. This makes it possible to remove dust and dirt contained in the recovered gas, thereby preventing dust and dirt from adhering to the optical fiber 10 exposed to the atmosphere of the reused deuterium-containing gas in the processing tank 2.

In addition, in the step of supplying deuterium-containing gas into the treatment tank 2 of the optical fiber treatment method, the gas in the treatment tank 2 may be replaced with the deuterium-containing gas by blowing the deuterium-containing gas into the treatment tank 2, which has been brought to atmospheric pressure.

The gas discharged from the treatment tank 2 by the blowing of the deuterium-containing gas is discharged, for example, into a gas exhaust path (not shown) and released into the atmosphere. Alternatively, the gas discharged from the treatment tank 2 may be recovered via a vacuum pump and reused as the deuterium-containing gas supplied to the treatment tank 2. The gas replacement in the treatment tank 2 is terminated, for example, when the deuterium concentration contained in the gas discharged from the treatment tank 2 becomes the same as the deuterium concentration (for example, 2%) of the deuterium-containing gas supplied into the treatment tank 2.

With this configuration, when air remains in the treatment tank 2, which is at atmospheric pressure, the air remaining in the treatment tank 2 can be replaced with deuterium-containing gas by the blowing process. In addition, since the recovered deuterium-containing gas is pressurized, deuterium-containing gas can be supplied to the treatment tank 2, which is at atmospheric pressure, without using a pump.

In addition, in the process of aspirating the deuterium-containing gas in the processing tank 2, the deuterium-containing gas in the processing tank 2 may be aspirated so that the pressure in the processing tank 2 is in the range of 20 kPa or more and 90 kPa or less in absolute pressure. If the pressure difference between the reduced pressure and normal pressure in the processing tank 2 is too large, for example, there is a risk that the winding of the optical fiber 10 around the fiber bobbin 11 will loosen. However, because the amount of reduced pressure is small, it is possible to prevent the winding of the optical fiber 10 around the fiber bobbin 11 from loosening.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the number, position, shape, etc. of the components described above are not limited to the above embodiment, and can be changed to any number, position, shape, etc. suitable for implementing the present invention.

In the above embodiment, one fiber bobbin 11 is placed in the treatment tank 2. However, multiple fiber bobbins 11 may be placed in the treatment tank 2.

In the above embodiment, the optical fiber processing device 1 is provided with two processing tanks 2. However, the optical fiber processing device 1 may be provided with one processing tank 2, or three or more processing tanks 2.

In the above embodiment, the optical fiber 10 is wound around the fiber bobbin 11 and placed in the treatment tank 2. However, the state of the optical fiber 10 placed in the treatment tank 2 is not limited to being wound around the fiber bobbin 11.

In the above embodiment, the pressurized deuterium-containing gas is stored in the second flow path 62. However, for example, a small buffer tank may be disposed between the gas supply device 3 and the processing tank 2, and the pressurized deuterium-containing gas may be stored in the buffer tank.

1: Optical fiber treatment device 2: Treatment tank 2A: Space 3: Gas supply device 4: Vacuum pump 5: Pressure boosting unit 6: Gas flow path 8: Filter unit 10: Optical fiber 11: Fiber bobbin 61: First flow path 62: Second flow path 63: Third flow path 64: Fourth flow path 65: Gas exhaust path 71, 72, 73: On/off valve 74: Three-way valve

Claims (7)

a treatment tank for accommodating the optical fiber therein;
a gas supply device for supplying a deuterium-containing gas to the treatment tank;
a pump that draws in the deuterium-containing gas from within the treatment tank;
a pressure increasing unit for increasing the pressure of the deuterium-containing gas discharged from the pump;
a pipe for supplying the deuterium-containing gas pressurized by the pressure boosting unit to the treatment tank;
Equipped with
The pressure increasing unit is connected between the pump and the piping,
The pressurized deuterium-containing gas is stored in the piping without a dedicated gas tank.
Optical fiber processing equipment. The optical fiber processing device according to claim 1, further comprising a filter unit provided in the piping. The optical fiber processing device according to claim 1 or 2, which is provided with a plurality of the processing tanks. A first step of placing an optical fiber in a treatment bath;
a second step of supplying a deuterium-containing gas into the treatment tank through a pipe after the first step;
a third step of exposing the optical fiber accommodated in the treatment tank to an atmosphere of the deuterium-containing gas after the second step;
a fourth step of, after the third step, aspirating the deuterium-containing gas in the processing tank with a pump , pressurizing the aspirated deuterium-containing gas with a pressure increasing unit , and returning the gas to the piping;
It has
The pressure increasing unit is connected between the pump and the piping,
The pressurized deuterium-containing gas is stored in the piping without providing a dedicated gas tank.
How optical fiber is processed. The optical fiber processing method according to claim 4, wherein the second step includes a step of blowing the deuterium-containing gas into the processing tank under atmospheric pressure. The optical fiber processing method according to claim 4 or 5, further comprising a fifth step of reducing the pressure in the processing tank after the first step and before the second step, so that the pressure in the processing tank is in the range of 20 kPa or more and 90 kPa or less in absolute pressure. The optical fiber processing method according to any one of claims 4 to 6, wherein in the fourth step, the deuterium-containing gas in the processing tank is sucked in so that the pressure in the processing tank is in the range of 20 kPa or more and 90 kPa or less in absolute pressure.

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