KR0150154B1 - Method and apparatus for drawing optical glass fiber - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and apparatus for extracting an optical fiber which can minimize additional transmission loss of an optical fiber when drawing a base material manufactured using a quartz tube into an optical fiber.

2. Technical problem that the invention tries to solve

The present invention provides a method and apparatus for extracting an optical fiber which can minimize transmission loss which is very effective in extracting a large diameter optical fiber base material manufactured by the M.C.V.D method using a synthetic quartz tube.

3. Summary of Solution to Invention

The present invention is a quartz tube that prevents dust generation when passing through the annealing portion of the optical fiber in the annealing portion for gradually cooling without rapidly cooling the optical fiber drawn from the melting furnace, and the electrical resistance around the quartz tube A heating element driven by the thermocouple and a thermocouple detecting the temperature of the heating element between the quartz tube and the heating element, and an insulation for preventing the heat emitted from the heating element from being transferred to the outside around the heating element; Around the insulation, a tube for protecting the insulation from the outside, one side of the annealing is connected to the thermo-couple to control the internal temperature to the temperature required by the thermo-couple, the phase of the annealing, The lower end of the bracket for fixing the quartz tube and the tube, the upper and lower surfaces of the annealing portion is the internal heat flows up and down It is composed of the diaphragm for adjusting the size of the hole for the optical fiber to pass through to prevent.

4. Important uses of the invention

The present invention is very effective for drawing large diameter optical fiber base material manufactured by MCVD method using quartz tube, and even though increasing the withdrawal speed of the optical fiber, no additional transmission loss occurs, and the withdrawal speed of the optical fiber can be increased. It reduces the manufacturing cost of the optical fiber, improves the practicality, and also prevents the stress of the optical fiber due to the quenching of the cooling unit due to the installation of the annealing unit, and is not limited by the installation space for installing the optical fiber drawing device, In addition, there is an effect that can increase the strength of the optical fiber.

Description

Extraction method and device of optical fiber to minimize transmission loss

1 is a block diagram of an apparatus for performing a drawing process of a conventional optical fiber.

2 is a block diagram of an apparatus for performing an optical fiber drawing process that can minimize the transmission loss of the present invention.

3 is a cross-sectional view showing the configuration of the annealing portion in the apparatus for performing the drawing process of the optical fiber that can minimize the transmission loss of the present invention.

* Explanation of symbols for main parts of the drawings

10: base material 12: melting furnace

14: outer diameter measuring unit 16: annealing unit

18: cooling part 20: coating part

22 hardened part 24 coated optical fiber

26: Capstan 28: Spur

30: aperture 32: bracket

34: quartz tube 36: tube

38: control unit 40: summer-couple

42: heating element 44: insulation

23: uncovered optical fiber

The present invention relates to an optical fiber, and more particularly, to a method and apparatus for extracting an optical fiber capable of minimizing additional transmission loss of an optical fiber when drawing a large diameter optical fiber base material into an optical fiber.

FIG. 1 is a general block diagram of an apparatus for performing a conventional optical fiber drawing process. Referring to FIG. 1, the optical fiber drawing process will be described below.

The optical fiber base material 10 is slowly supplied to the melting furnace 12 by the position control mechanism of the base material position controller. The melting furnace 12 applies heat of thousands of degrees Celsius, typically about 2100 to 2200 degrees Celsius. As a result, the uncoated optical fiber 23 is drawn out from the cross-sectional area reducing portion from the base material 10. The output is uncoated optical fiber 23 is applied and provided from the capstan 26. The outer diameter measuring unit 14 measures whether the diameter of the uncoated optical fiber 23 to be drawn out is a predetermined length (typically 125 μm) and informs the diameter control paper, and the diameter controller measures the diameter of the uncoated optical fiber 23 to 125 μm. Control the capstan 26 so that is maintained. The capstan 26 is rotated in response to the control of the diameter controller to adjust the strength, weakness, of the uncoated optical fiber 23 to tension. In order to protect the uncovered optical fiber 23 quenched by the cooling unit 18, the coating unit 20 is coated with the uncoated optical fiber 23, which descends, with an acrylic resin or a silicone resin, and the coated optical fiber 24 Is cured in the curing unit 22. The coated optical fiber 24 drawn out by the output control of the capstan 26 is wound around the spool 28.

The optical fiber formed by the above process is melted by heating the large-diameter base material 10 in the melting furnace 12 to a temperature of 2000 ℃ or more, and then drawn out to the uncovered optical fiber 23 having a diameter of 125μm. In this case, the uncoated optical fiber 23 is coated while passing through the coating unit 20 in order to prevent the strength characteristics of the uncoated optical fiber 23 from deteriorating due to moisture infiltration and to facilitate handling. In order to make the coating diameter of the optical fiber 24 uniform and to prevent bubble generation between the coating layer and the surface of the uncoated optical fiber 23, the surface temperature of the uncoated optical fiber 23 immediately before being coated should be 80 ° C or less, Even better, it should be around 40 ° C or 50 ° C, similar to the temperature of use of the coating material.

However, the surface temperature of the uncovered optical fiber 23 immediately after leaving the melting furnace 12 is a high temperature of 1600 ° C or higher, and the surface temperature of the uncovered optical fiber 23 naturally cools in the air as it moves away from the melting furnace 12. Is reduced.

At this time, the slope of the surface temperature change of the uncoated fiber 23 as it moves away from the melting furnace 12 is August 8, 1986 Journal of Lighwave Technology Vol. This is described in detail in the LT-4 High-Speed High-Strength Fiber Drawing.

Therefore, when the uncoated optical fiber 23 is taken out at a rate of 5 m / sec, the uncoated optical fiber 23 is naturally cooled from the high-temperature melting furnace 12 so that the surface temperature of the uncoated optical fiber 23 is about 50 ° C. In order to descend, the distance between the melting furnace 12 and the coating unit 20 should be maintained at about 800 cm, so the height of the optical fiber drawing device should be very high. Therefore, the manufacturing cost of the uncoated optical fiber 23 becomes very high, and the practicality is inferior.

In order to solve this problem, US Patent Nos. 318,374 and 4,437,870 describe a technique of forcibly cooling the optical fiber 23 by installing a cooling unit 18 between the melting furnace 12 and the coating unit 20.

The method implemented in the United States patent can reduce the distance between the melting furnace 12 and the coating portion 20 can reduce the manufacturing cost of the coated optical fiber 24, but the uncoated at a high temperature of 1600 ℃ or more When the optical fiber 23 is quenched at about 50 ° C., a large stress is applied to the uncovered optical fiber 23 during the cooling process, whereby the strength of the drawn coated optical fiber 24 is lowered and the transmission loss is reduced. An increasing problem has arisen.

In particular, this phenomenon is described by using a synthetic quartz tube. Seed. V. When the optical fiber base material 10 manufactured by the modified chemical vapor deposition (hereinafter referred to as MCVD) method is taken out, the transmission loss is greatly increased, and the faster the extraction rate of the uncovered optical fiber 23 is coated, The transmission loss of the optical fiber 24 becomes more and more, and the use of high-purity synthetic quartz tube to manufacture the large diameter base material 10 having a diameter of 40 mm or more with low loss by the M, C, V, D manufacturing method This is essential, but there is a problem in that the use of the synthetic quartz tube is limited due to an additional transmission loss increase problem generated during the extraction of the uncovered optical fiber 23.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a method and apparatus for extracting an optical fiber which does not generate a transmission loss which is very effective for sunriseing a large diameter optical fiber base material manufactured by the M.C.V.D method using a synthetic quartz tube.

Another object of the present invention is to provide a method and apparatus for extracting an optical fiber which does not generate additional transmission loss even when the extraction speed of the optical fiber is increased.

Still another object of the present invention is to provide a method and apparatus for drawing an optical fiber, which increases the strength of the optical fiber.

It is still another object of the present invention to provide a method and apparatus for drawing an optical fiber, which reduces the manufacturing cost of an inexpensive optical fiber.

Still another object of the present invention is to provide a method and apparatus for drawing an optical fiber which can prevent the stress of the optical fiber due to quenching of the cooling unit.

Still another object of the present invention is to provide a method and apparatus for extracting an optical fiber which is not limited by an installation space for installing the apparatus for extracting an optical fiber.

It is still another object of the present invention to provide a method and apparatus for drawing optical fibers which improves practicality due to the production of low cost optical fibers.

In order to achieve the above object, the present invention is the first step of melting the large diameter optical fiber base material of the silica component in the melting furnace to convert into an uncovered optical fiber, and uniformly to a certain size the diameter of the uncovered optical fiber drawn from the melting furnace The second step of controlling while continuously measuring the uncoated optical fiber in the outer diameter measuring unit for drawing, and the uncoated optical fiber of the high temperature uncoated optical fiber passing through the outer diameter measuring unit in the annealing unit is not rapidly cooled, but gradually cooled And a fourth step of forcibly cooling the uncovered optical fiber passing through the annealing part in the cooling part, and a fifth step of coating the uncovered optical fiber surface passing through the cooling part with an acrylic resin or a silicone resin in the coating part. A process, a sixth process of curing the coated optical fiber in a curing unit, and a sixth process The coated optical fiber is characterized by comprising a seventh step of winding through the capstan to the spool.

In order to achieve the above object, the present invention does not rapidly cool the uncovered optical fiber drawn from the molten furnace roll, and prevents dust generation when the uncovered optical fiber passes through the annealing part inside the annealing part for gradually cooling. A quartz tube, a heating element driven by an electrical resistance around the quartz tube, a thermocouple for sensing the temperature of the heating element between the quartz tube and the heating element, and heat emitted from the heating element around the heating element Insulation to prevent the transfer to the outside, and around the insulation to the tube to protect the insulation from the outside, and one side of the annealing is connected to the thermo-couple inside to the temperature required by the thermo-couple A control unit for controlling temperature, upper and lower ends of the annealing unit, a bracket fixing the quartz tube and the tube, The lower surface portion is characterized by consisting of a diaphragm for adjusting the size of the hole for the optical fiber to pass through in order to prevent the internal heat yucheul the upper and lower direction.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram of an apparatus for performing an optical fiber drawing process to minimize additional transmission loss implemented in the present invention. Referring to FIG. 2, the optical fiber drawing process will be described below.

A first process of heating the optical fiber base material 10 to 2000 ° C. or more in the melting furnace 12, and then pulling out the coated optical fiber 24 having a diameter of 125 μm, and the coated optical fiber extracted from the melting furnace 12 ( In order to uniformly withdraw the diameter of the 24 to a predetermined size (125μm) and the second step of controlling while measuring the uncoated optical fiber 23 continuously in the outer diameter measuring section 14, and the outer diameter measuring section 14 A third step of gradually cooling the high-temperature uncoated optical fiber 23 passed through the annealing unit 16 without cooling it rapidly until the surface temperature of the uncoated optical fiber 23 becomes 800 ° C. or lower, and at this time, The temperature control range of the ring part 16 is 25 degreeC-1200 degreeC. In addition, after heating the optical fiber base material 10 in the melting furnace 12, when the optical fiber 24 is drawn out at a rate of 5.0 m / sec, the heating temperature of the annealing portion 16 is 1100 ℃. In addition, a fourth forcibly cooling the uncoated optical fiber 23 gradually cooled to 800 ° C. or less in the annealing unit 16 such that the surface temperature of the uncoated optical fiber 23 is approximately 50 ° C. in the cooling unit 18. And a fifth step of coating the uncoated optical fiber 23 surface having passed through the cooling unit 18 with an acrylic resin or a silicone resin in the coating unit 20, and curing the coated optical fiber 24 with the curing unit ( 22) and a sixth step of curing, and the coated optical fiber 24 through the sixth step is a seventh step of winding through the capstan 26 to the spool (28).

The transmission and reception of the coated optical fiber 24 drawn out in the above manner is about 0.33 dB / km at 1310 nm wavelength.

The drawing apparatus of the optical fiber capable of minimizing the transmission loss according to the present invention does not rapidly cool the uncovered optical fiber 23 drawn from the melting furnace 12, as shown in FIG. In order to prevent dust generation when the uncoated optical fiber 23 passes through the annealing portion 16, 34 formed of an inner diameter of 25 mm and a length of 600 mm is provided inside the annealing portion 16 formed to a length. A plurality of heating elements 42 driven by electric resistance are installed around the quartz tube 34, and a thermo sensor for sensing the temperature of the heating element 42 between the quartz tube 34 and the heating element 42. Couple 40 is installed in a downward direction, the heat insulating member 44 is installed around the heat generator 42 to prevent the heat released from the heat radiator 42 to the outside, the heat insulator ( 44) surrounding the insulation 44 to the outside A tube 36 formed of stainless steel is installed for protection, and one side of the annealing 16 is connected to the thermo-couple 40 to control the internal temperature to a temperature required by the thermo-couple 40. The control unit 38 is installed, wherein the control unit 38 is formed to control the temperature within the range of 25 ℃ ~ 1200 ℃, the upper and lower ends of the annealing 16 is the quartz tube 34 And a bracket 32 for fixing the tube 36 and the upper and lower surfaces of the annealing portion 16 pass through the uncovered optical fiber 23 to prevent internal heat from flowing out in the up and down directions. The aperture 30 to adjust the size of the hole to be installed.

The annealing portion 16 configured as described above is heat emitted from the coated optical fiber 24 when the uncoated optical fiber 23 having a high temperature of 1600 ° C. or more just passed from the melting furnace 12 passes through the annealing portion 16. The silver heats up the quartz tube 34 installed inside the annealing portion 16, and the inner heat of the heated quartz tube 34 is heat-insulated between the tube 36 and the quartz tube 34, which constitute the outer layer. By means of the 44, it cannot be easily taken out.

According to the present invention as described above, the method and apparatus for extracting optical fibers that can minimize transmission loss are very effective for extracting large-diameter optical fiber base materials manufactured by MCVD using synthetic quartz tubes, and increase the extraction speed of optical fibers. Even though this does not cause any additional transmission loss, the extraction speed of the optical fiber can be increased, thereby reducing the manufacturing cost and improving the practicality of the optical fiber, and also preventing the stress of the optical fiber due to the quenching of the cooling unit due to the installation of the annealing part. It can be, and is not limited by the installation space for installing the optical fiber drawing device, it is also effective to increase the strength of the optical fiber.

Claims (9)

1. A method of extracting an optical fiber, comprising: a first step of melting a large-diameter optical fiber base material 10 of silica component in a melting furnace 12 and converting it into an uncovered optical fiber 23; and an uncovered optical fiber extracted from the melting furnace 12. A second step of controlling the outer diameter measuring unit 14 while continuously measuring the uncoated optical fiber 23 by uniformly drawing the diameter of the 23 to a constant size, and passing through the outer diameter measuring unit 14. A third process of cooling the uncoated optical fiber 23 at the high temperature uncoated optical fiber 23 by the annealing unit 16 without being rapidly cooled, and the uncoated optical fiber 23 passing through the annealing unit 16. ) Is a fourth step of forcibly cooling the cooling unit 18 and a fifth step of coating the surface of the uncoated optical fiber 23 passing through the cooling unit 18 with an acrylic resin or a silicone resin in the coating unit 20. And, the coated optical fiber 24 is hardened in the hardened portion 22 The sixth process to make, and the coated optical fiber 24 through the sixth process is made of a seventh process of passing through the capstan 26 and wound on the spool 28 can minimize the transmission loss Drawing method of optical fiber. The method of claim 1, wherein the annealing unit (16) is cooled until the surface temperature of the optical fiber (24) is 800 ° C or less. The method of claim 1, wherein the temperature control range of the annealing unit (16) is 25 ° C ~ 1200 ° C. The heating temperature of the annealing unit 16 is 1100 when the optical fiber base material 10 is heated in the melting furnace 12 and the optical fiber 24 is drawn out at a speed of 5.0 m / sec. Withdrawal method of the optical fiber that can minimize the transmission loss, characterized in that the ℃. In the apparatus for extracting an optical fiber, an unannealed portion (not an uncovered optical fiber 23) is provided inside the annealing portion 16 for gradually cooling the uncovered optical fiber 23 drawn out from the melting furnace 12 without sudden cooling. 16, quartz tube 34 to prevent dust generation when passing through, the heating element 42 is driven by an electrical resistance around the quartz tube 34, the quartz tube 34 and the heating element 42 Between the thermo-couple 40 for sensing the temperature of the heating element 42 and the heat insulating material 44 to prevent the heat emitted from the heating element 42 to be transferred to the outside around the heating element 42 ), A tube 36 that protects the heat insulator 44 from the outside, and one side of the annealing 16 is connected to a thermo-couple 40 to surround the heat insulator 44. The controller 38 for controlling the internal temperature to the temperature required by the 40, and the upper and lower ends of the annealing 16 are the quartz Bracket 32 for fixing the 34 and the tube 36, and the upper and lower surfaces of the annealing portion 16 is passed through the optical fiber 24 to prevent the internal heat from flowing out in the up and down directions Pulling device of the optical fiber that can minimize the transmission loss, characterized in that consisting of an aperture 30 to adjust the size of the hole. The apparatus of claim 5, wherein the length of the annealing portion (16) is formed to be 200 mm or more. 6. The apparatus of claim 5, wherein the quartz tube (34) has an inner diameter of less than 5 mm. 6. The apparatus of claim 5, wherein the material of the tube is made of stainless steel. The control unit 38 is a device for extracting the optical fiber does not cause a transmission loss, characterized in that formed to control the temperature in the range of 25 ℃ ~ 1200 ℃.