CN113716862B

CN113716862B - Method and apparatus for manufacturing optical fiber

Info

Publication number: CN113716862B
Application number: CN202111020497.XA
Authority: CN
Inventors: 朱钱生; 杨郭杰; 叶阳; 曹珊珊; 刘志忠; 薛济萍; 薛驰
Original assignee: Jiangdong Technology Co ltd; Zhongtian Technologies Fibre Optics Co Ltd; Jiangsu Zhongtian Technology Co Ltd
Current assignee: Jiangdong Technology Co ltd; Zhongtian Technologies Fibre Optics Co Ltd; Jiangsu Zhongtian Technology Co Ltd
Priority date: 2021-09-01
Filing date: 2021-09-01
Publication date: 2023-03-21
Anticipated expiration: 2041-09-01
Also published as: CN113716862A

Abstract

The invention provides a preparation method of an optical fiber and a device thereof, relating to the technical field of optical fibers. The preparation method of the optical fiber comprises the following steps: providing an optical fiber preform; forming an optical fiber main body by melting and drawing the preform; annealing the optical fiber main body; coating the annealed optical fiber main body to form an inner coating layer and an outer coating layer; curing the coated optical fiber main body to form an optical fiber; the optical fiber is taken up on a take-up reel, and the take-up reel filled with the optical fiber is placed in a nitrogen atmosphere for heat treatment. The preparation device of the optical fiber comprises a rod feeding mechanism, a wire drawing furnace, an annealing device, a coating device, a curing device, a traction mechanism and a processing cabinet. The fiber collecting disc filled with the optical fibers is placed in a nitrogen atmosphere for heat treatment and then is subjected to optical fiber strength screening, so that the fiber breaking frequency of each 1000km of optical fibers can be reduced.

Description

Method and apparatus for manufacturing optical fiber

Technical Field

The invention relates to the technical field of optical fibers, in particular to a preparation method and a preparation device of an optical fiber.

Background

With the continuous increase of the requirements of high bandwidth and high speed of the network, the optical fiber is widely used in network wiring as a network transmission medium, and the common optical fiber types include a single mode optical fiber and a multimode optical fiber. Single mode fiber refers to fiber that has an operating wavelength that can only transmit one propagation mode. The multimode fiber is an optical fiber with a plurality of modes of possible propagation modes of the working wavelength, and the transmission mode of the multimode fiber can reach hundreds, so that the multimode fiber has a thicker core diameter and a larger numerical aperture than a single-mode fiber, and can couple more optical power from a light source.

In the related art, in the preparation process of the optical fiber, the optical fiber is directly sent to an optical fiber screening machine for strength detection after being filled on a fiber collecting disc.

However, the problem that the number of fiber breakage times per 1000km is high when the optical fiber is directly sent to an optical fiber screening machine for strength detection after being fully filled on a fiber collecting disc exists.

Disclosure of Invention

The invention provides a preparation method of an optical fiber and a device thereof, which are used for solving the problem that the optical fiber prepared by the existing preparation method has higher fiber breaking frequency per 1000 km.

In one aspect, the present invention provides a method for preparing an optical fiber, comprising the steps of:

providing an optical fiber preform;

forming an optical fiber body from the optical fiber preform by melting and drawing;

annealing the optical fiber main body;

coating the annealed optical fiber main body to form an inner coating layer and an outer coating layer;

curing the coated optical fiber main body to form an optical fiber;

and (3) collecting the optical fiber on a fiber collecting disc, and placing the fiber collecting disc filled with the optical fiber in a nitrogen atmosphere for heat treatment.

Optionally, the nitrogen purity in the nitrogen atmosphere is greater than or equal to 99.999%, and the temperature for performing the heat treatment in the nitrogen atmosphere is 45 ℃ to 60 ℃.

Optionally, the time for the optical fiber on the fiber take-up reel to be subjected to the heat treatment in the nitrogen atmosphere is 4 hours to 24 hours.

Optionally, the inner coating layer and the outer coating layer are both made of acrylic resin; the acrylic resin used for the inner coating layer has the elasticity modulus of less than or equal to 1.5Mpa after being cured, the viscosity of 1500-3000 mPa.s during coating, the elongation at break of more than or equal to 120 percent, the coating temperature range of 28-60 ℃ and the coating pressure of 0.1-2 MPa;

the elastic modulus of the acrylic resin used for the outer coating layer after curing is larger than or equal to 550Mpa, the viscosity during coating is 1500-3500 mPa.s, the elongation at break is larger than or equal to 5%, the coating temperature range is 28-60 ℃, and the coating pressure is 0.1-2 MPa.

Optionally, the maximum radius of the inner coating layer is 72.5 μm to 77.5 μm, the maximum radius of the outer coating layer is 87.5 μm to 92.5 μm, and the ratio of the thickness value of the inner coating layer to the thickness value of the outer coating layer is 1.

Optionally, the providing an optical fiber preform specifically includes:

preparing a germanium-doped silicon dioxide powder body by adopting an axial vapor deposition method;

carrying out dehydroxylation sintering on the germanium-doped silicon dioxide powder body to prepare a core rod;

preparing an inner cladding on the outer side of the core rod by adopting an axial vapor deposition method;

preparing a middle cladding on the outer side of the inner cladding of the optical fiber preform by adopting a chemical vapor deposition method;

preparing an outer cladding layer on the outer side of the middle cladding layer of the optical fiber preform by adopting a chemical vapor deposition method;

wherein the relative refractive index of the core rod relative to the outer cladding is 0.35-0.45%; the relative refractive index of the inner cladding relative to the outer cladding is 0; the relative refractive index of the middle cladding relative to the outer cladding is-0.1% -0.

On the other hand, the invention also provides a preparation device of the optical fiber, which comprises a rod feeding mechanism, a wire drawing furnace, an annealing device, a coating device, a curing device, a traction mechanism and a processing cabinet;

the rod feeding mechanism is used for feeding the optical fiber preform into the drawing furnace;

the drawing furnace is positioned at the downstream of the rod feeding mechanism and is used for heating and melting the prefabricated rod into a glass state and drawing the prefabricated rod into a filamentous optical fiber main body;

the annealing device is positioned at the downstream of the drawing furnace and is used for annealing the optical fiber main body;

the coating device is positioned at the downstream of the annealing device and is used for coating the annealed optical fiber main body;

the curing device is positioned at the downstream of the coating device and is used for curing the coated optical fiber main body to form an optical fiber;

the traction mechanism is positioned at the downstream of the curing device and is used for collecting the optical fiber onto a fiber collecting disc;

the processing cabinet is used for carrying out heat treatment on the fiber collecting disc filled with the optical fibers in a nitrogen atmosphere.

Optionally, the device also comprises a control device for the fiber drawing tension;

the control device for the optical fiber drawing tension comprises: the drawing tension acquiring module is used for acquiring the current drawing tension of the annealed optical fiber main body;

and the control module is used for adjusting the wire drawing speed of the traction mechanism in a manner of reducing the difference value between the current wire drawing tension and the target wire drawing tension according to the comparison between the current wire drawing tension and the target wire drawing tension.

Optionally, the control module is configured to adjust the drawing speed of the traction mechanism in a manner of reducing a difference between the current drawing tension and the target drawing tension according to the comparison between the current drawing tension and the target drawing tension, and specifically includes:

if the current wire drawing tension is greater than the first target wire drawing tension, reducing the wire drawing speed of the traction mechanism;

and if the current wire drawing tension is smaller than the second target wire drawing tension, improving the wire drawing speed of the traction mechanism.

Optionally, the first target wire drawing tension is the target wire drawing tension plus 1, and the second target wire drawing tension is the target wire drawing tension minus 1;

wherein the target drawing tension is the tension of the optical fiber body measured by a tension meter when the standard drawing speed of the optical fiber is more than 1800m/min, the cut-off wavelength of the optical fiber is between 1200nm and 1320nm and the bending loss standard of the optical fiber meets the G.657A1 standard in the preparation process of the optical fiber.

The invention provides a method and a device for preparing optical fibers, which are characterized in that a fiber collecting disc filled with optical fibers is placed in a nitrogen atmosphere for heat treatment and then is subjected to optical fiber strength screening, so that the fiber breaking frequency of each 1000km of optical fibers can be reduced.

In addition to the technical problems solved by the embodiments of the present invention, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions, other technical problems solved by the method for manufacturing an optical fiber and the apparatus thereof according to the embodiments of the present invention, other technical features included in the technical solutions, and advantages brought by the technical features will be further described in detail in the detailed description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of a radial cross-sectional structure of an optical fiber preform according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional refractive index profile of an optical fiber preform according to an embodiment of the present invention;

FIG. 3 is a schematic flow chart illustrating a method for fabricating an optical fiber preform according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a radial cross-sectional structure of an optical fiber according to an embodiment of the present invention;

FIG. 5 is a schematic flow chart of a method for manufacturing an optical fiber according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of an apparatus for manufacturing an optical fiber according to an embodiment of the present invention;

fig. 7 is a block diagram of an apparatus for controlling drawing tension of an optical fiber according to an embodiment of the present invention.

Reference numerals:

1-optical fiber prefabricated rod; 10-a core rod; 20-inner cladding; 30-middle cladding;

40-an outer cladding; 50-inner coating layer; 60-an outer coating layer; 2-an optical fiber;

200-a rod feeding mechanism; 201-a wire drawing furnace; 202-an annealing device; 203-a coating device;

204-a curing device; 205-a traction mechanism; 206-a treatment cabinet; 207-control means;

2071-drawing tension obtaining module; 2072-a control module; 208-a tensiometer; 209-upper computer.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integral; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In order to solve the above problems, embodiments of the present invention provide a method and an apparatus for manufacturing an optical fiber, in which a fiber take-up reel filled with an optical fiber is placed in a nitrogen atmosphere to perform a heat treatment, and then an optical fiber strength screening is performed, so that the number of times of fiber breakage per 1000km of optical fiber can be reduced.

The following describes the method and apparatus for manufacturing an optical fiber according to the present invention in detail with reference to specific embodiments.

FIG. 1 is a schematic view of a radial cross-sectional structure of an optical fiber preform according to an embodiment of the present invention; fig. 2 is a schematic cross-sectional refractive index profile of an optical fiber preform according to an embodiment of the present invention.

As shown in fig. 1 and 2, an optical fiber preform 1 according to an embodiment of the present invention includes, from the inside to the outside, a core rod 10, an inner cladding 20, an intermediate cladding 30, and an outer cladding 40; the core rod 10 is mainly made of germanium-doped silicon dioxide, and the relative refractive index of the core rod relative to the outer cladding 40 of the optical fiber perform 1 is 0.35-0.45%; the inner cladding 20 of the optical fiber preform 1 is made of silica, and has a refractive index of 0 with respect to the outer cladding 40 of the optical fiber preform 1; the middle cladding 30 of the optical fiber perform 1 is mainly made of germanium-doped silicon dioxide, and the relative refractive index of the middle cladding 30 relative to the outer cladding 40 of the optical fiber perform 1 is-0.1% -0; the outer cladding 40 of the optical fiber preform 1 is made of silica.

In order to make the relative refractive indexes of the core rod 10, the inner cladding 20 and the middle cladding 30 of the optical fiber preform 1 to the outer cladding 40 in a step-type distribution, the refractive index of the core rod 10 is increased by using germanium-doped silica for the core rod 10, and the refractive index of the middle cladding 30 of the optical fiber preform 1 is decreased by using fluorine-doped silica.

In an alternative embodiment, the optical fiber preform 1 comprises, from the inside to the outside, a core rod 10, an inner cladding 20, an intermediate cladding 30 and an outer cladding 40; the core rod 10 is mainly made of germanium-doped silica, and has a relative refractive index of 0.35% with respect to the outer cladding 40 of the optical fiber preform 1; the inner cladding 20 of the optical fiber preform 1 is made of silica, and has a relative refractive index of 0 with respect to the outer cladding 40 of the optical fiber preform 1; the middle cladding 30 of the optical fiber preform 1 is mainly made of germanium-doped silica, and the relative refractive index of the middle cladding 30 relative to the outer cladding 40 of the optical fiber preform 1 is-0.1%; the outer cladding 40 of the optical fiber preform 1 is made of silica.

As shown in fig. 2, the radius of the core rod 10 is r1, the radius of the inner cladding 20 of the optical fiber preform 1 is r2, the radius of the intermediate cladding 30 of the optical fiber preform 1 is r3, and the radius of the outer cladding 40 of the optical fiber preform 1 is r4.

Fig. 3 is a schematic flow chart of a method for manufacturing an optical fiber preform according to an embodiment of the present invention.

As shown in fig. 3, an embodiment of the present invention provides a method for preparing an optical fiber preform 1, including the following steps:

and S10, preparing the germanium-doped silicon dioxide powder body by adopting an axial vapor deposition method.

And S20, dehydroxylating and sintering the germanium-doped silicon dioxide powder body to prepare the core rod 10.

Specifically, placing the germanium-doped silicon dioxide powder body in a dehydroxylation atmosphere to remove moisture and hydroxyl, wherein the dehydroxylation atmosphere comprises a carrier gas and a fluorine-containing gas, the carrier gas is chlorine, and the volume ratio of the fluorine-containing gas to the chlorine is 1: 9-1: 35, the temperature range of dehydroxylation atmosphere is 800-1100 ℃, and the germanium-doped silicon dioxide powder body is placed in the dehydroxylation atmosphere for 1-40 hours.

The relative refractive index of the core rod 10 with respect to the outer cladding 40 of the optical fiber preform 1 is 0.35% to 0.45% by adding germanium to silica. For example, the core rod 10 is germanium-doped silica having a relative refractive index of 0.35% with respect to the outer cladding 40 of the optical fiber preform 1.

And S30, preparing the inner cladding 20 of the optical fiber preform rod 1 on the outer side of the core rod by adopting an axial vapor deposition method.

Wherein the inner cladding 20 of the optical fiber preform 1 is made of silica.

And S40, preparing the middle cladding 30 of the optical fiber perform 1 outside the inner cladding 20 of the optical fiber perform 1 by adopting a chemical vapor deposition method.

The control of the refractive index of the intermediate cladding 30 relative to the outer cladding 40 of the optical fiber preform 1 is achieved by adding fluorine to silica. Wherein, the middle cladding 30 of the optical fiber perform 1 is mainly made of germanium-doped silicon dioxide, and the relative refractive index of the middle cladding 30 relative to the outer cladding 40 of the optical fiber perform 1 is-0.1% -0. Preferably, the intermediate cladding 30 of the optical fiber preform 1 is mainly made of germanium-doped silica, which has a relative refractive index of-0.1% with respect to the outer cladding 40 of the optical fiber preform 1.

And S50, preparing an outer cladding layer 40 of the optical fiber preform 1 outside the middle cladding layer 30 by adopting an external chemical vapor deposition method.

Wherein the outer cladding 40 of the optical fiber preform 1 is mainly made of silica.

Fig. 4 is a schematic radial cross-sectional structure diagram of an optical fiber according to an embodiment of the present invention.

As shown in fig. 4, the embodiment of the present invention further provides an optical fiber 2 including, from the inside to the outside, a core 101, an inner cladding 20, an intermediate cladding 30, an outer cladding 40, an inner cladding 50, and an outer cladding 60. The core 101 is mainly made of germanium-doped silica, and the relative refractive index of the core with respect to the outer cladding 40 of the optical fiber 2 is 0.35-0.45%; the inner cladding 20 of the optical fiber 2 is made of silica, and has a relative refractive index of 0 with respect to the outer cladding 40 of the optical fiber 2; the middle cladding 30 of the optical fiber 2 is mainly made of germanium-doped silicon dioxide, and the relative refractive index of the middle cladding 30 relative to the outer cladding 40 of the optical fiber 2 is-0.1% -0; the outer cladding 40 of the fiber 2 is made of silicon dioxide.

Wherein, the optical fiber 2 is formed by drawing and coating the optical fiber preform 1 by adopting a drawing furnace.

The relative refractive indexes of the fiber core 101, the inner cladding 20 and the middle cladding 30 of the optical fiber 2 to the outer cladding 40 are distributed in a step mode, so that light is prevented from overflowing from the fiber core 101, and the bending resistance of the optical fiber 2 is improved.

Alternatively, the maximum radius of the core 101 is 4 μm to 5 μm, the maximum radius of the inner cladding 20 of the optical fiber 2 is 7.5 μm to 12 μm, the maximum radius of the middle cladding 30 of the optical fiber 2 is 8 μm to 13.5 μm, the maximum radius of the outer cladding 40 of the optical fiber 2 is 62 μm to 63 μm, the maximum radius of the inner cladding 50 is 72.5 μm to 77.5 μm, and the maximum radius of the outer cladding 60 is 87.5 μm to 92.5 μm.

The outer coating 60 of the existing optical fiber is much larger in radius of 125 μm. The radius of the outer coating layer 60 of the optical fiber 2 is reduced to 87.5-92.5 μm, and the relative refractive indexes of the fiber core 101, the inner cladding 20 and the middle cladding 30 of the optical fiber 2 to the outer cladding 40 are distributed in a step type manner to ensure the bending resistance of the optical fiber 2, so that the optical fiber 2 is thinned, and the fiber capacity of the pipeline is further improved.

It should be noted that the optical fiber 2 provided by the present application, which has a small size and a good bending resistance, has a transmission loss of less than or equal to 0.45dB per kilometer at a wavelength of 1550nm with a radius of 10mm for a single turn.

Optionally, the ratio of the thickness of the inner coating layer 50 to the outer coating layer 60 ranges from 1:0.67 to 1:1.15.

wherein, the materials of the inner coating layer 50 and the outer coating layer 60 are acrylic resin; the elastic modulus of the acrylic resin used for the inner coating layer 50 after being cured is less than or equal to 1.5Mpa, the viscosity of the acrylic resin used for the inner coating layer 50 during coating is 1500-3000 mPa.s, the elongation at break of the acrylic resin used for the inner coating layer 50 is more than or equal to 120 percent, the coating temperature range is 28-60 ℃, and the coating pressure is 0.1-2 Mpa; the elastic modulus of the acrylic resin used for the outer coating layer 60 after being cured is greater than or equal to 550MPa, the viscosity of the acrylic resin used for the outer coating layer 60 during coating is 1500 to 3500 mPa.s, the elongation at break of the acrylic resin used for the outer coating layer 60 is greater than or equal to 5 percent, the coating temperature range is 28 to 60 ℃, and the coating pressure is 0.1 to 2MPa.

By the thickness ratio of the inner coating layer 50 to the outer coating layer 60 ranging from 1:0.67 to 1:1.15, the bending resistance of the optical fiber 2 can be improved when the radius of the outer coating layer 60 of the optical fiber 2 is decreased to 92.5 μm or less.

Fig. 5 is a schematic flow chart of a method for manufacturing an optical fiber according to an embodiment of the present invention.

As shown in fig. 5, an embodiment of the present invention provides a method for manufacturing an optical fiber, including the following steps:

step S100, providing an optical fiber preform 1.

Wherein the structure of the optical fiber preform 1 may be the same as that of the above-described optical fiber preform. In other embodiments, the structure of the optical fiber preform may be different from that of the optical fiber preform described above, and is not specifically configured here.

Step S110, the optical fiber preform 1 is melted and drawn to form an optical fiber body.

Specifically, the optical fiber preform 1 is melted and drawn into an optical fiber body in a drawing furnace, the temperature in the drawing furnace is 1800 ℃ to 2200 ℃, and the drawing furnace is filled with protective gas.

In order to ensure the stability of the fiber preform 1 in heat transfer by the drawing furnace, the gap between the fiber preform 1 and the inner wall of the drawing furnace is 5 mm-15 mm.

The optical fiber body includes a core 101, an inner cladding 20, an intermediate cladding 30, and an outer cladding 40 of the optical fiber 2.

It is also noted that the shielding gas in the draw furnace is one or more of helium and argon.

And step S120, annealing the optical fiber body.

Specifically, the optical fiber body is cooled in an annealing device, the residence time of the optical fiber body in the annealing device is 0.067 s-0.3 s, and the temperature in the annealing device is 1400-1700 ℃.

It should be noted that the annealing device comprises a plurality of heat preservation furnaces, the heat preservation furnaces are sequentially arranged from top to bottom, and the temperature of the heat preservation furnaces is sequentially and gradiently decreased from top to bottom.

Step S130, coating the annealed optical fiber main body to form an inner coating layer 50 and an outer coating layer 60.

Wherein, the 60 materials of the inner coating layer 50 and the outer coating layer are acrylic resin, the elastic modulus of the acrylic resin used for the inner coating layer 50 after being cured is less than or equal to 1.5Mpa, the viscosity of the acrylic resin used for the inner coating layer 50 when being coated is 1500-3000 mPa.s, and the breaking elongation of the acrylic resin used for the inner coating layer 50 is more than or equal to 120%; the elastic modulus of the acrylic resin used for the outer coating layer 60 after curing is greater than or equal to 550Mpa, the viscosity of the acrylic resin used for the outer coating layer 60 during coating is 1500Mpa · s to 3500Mpa · s, and the elongation at break of the acrylic resin used for the outer coating layer 60 is greater than or equal to 5%.

It should be noted that the viscosity of the acrylic resin used for the inner coating layer 50 at 25 ℃ is 3500mPa · s to 7500mPa · s, the coating temperature range is 28 ℃ to 60 ℃, and the coating pressure is 0.1mPa to 2mPa; the viscosity of the outer coating layer 60 at 25 ℃ is 3500 mPa.s-7500 mPa.s by using acrylic resin, the coating temperature range is 28-60 ℃, and the coating pressure is 0.1-2 MPa.

It is also noted that the maximum radius of the inner coating layer 50 is 72.5 to 77.5 μm, the maximum radius of the outer coating layer 60 is 87.5 to 92.5 μm, and the thickness ratio of the inner coating layer 50 to the outer coating layer 60 is in the range of 1:0.67 to 1:1.15.

And step S140, curing the coated optical fiber body to form the optical fiber 2.

Specifically, the coated optical fiber body is formed into an optical fiber 2 in a curing oven that is insulated with one or more of nitrogen, helium, and argon, and the oxygen concentration in the curing oven is less than 50ppm.

Wherein the curing furnaces are arranged from top to bottom in sequence, and the gas quantity of each curing furnace is 10L-15L.

And S150, taking the optical fiber 2 up to the fiber take-up reel, and placing the fiber take-up reel filled with the optical fiber 2 in a nitrogen atmosphere for heat treatment.

Wherein, the optical fiber 2 is drawn to the fiber collecting disc by the cured optical fiber 2 through the traction mechanism.

The take-up reel filled with the optical fibers 2 is placed in a processing cabinet 206 for heat treatment, and the time for placing the take-up reel filled with the optical fibers 2 in the processing cabinet ranges from 4 hours to 24 hours.

It should be noted that, when the processing cabinet 206 is used, the processing cabinet 206 is vacuumized to 0.015Mpa, and then the processing cabinet 206 is filled with nitrogen, the purity of the nitrogen is greater than or equal to 99.999%, the concentration of oxygen in the processing cabinet 206 is not greater than 100ppm, and the temperature range in the processing cabinet 206 is 45-60 ℃.

The optical fiber 2 is prepared by the preparation method of the optical fiber, the fiber drawing speed is 1800m/min, and three optical fibers 2 with different maximum diameters of the outer coating layer 60 are obtained, and the technical parameters are shown in table 1.

TABLE 1 technical parameters of different embodiments of optical fibers

The maximum diameter of the outer coating layer is reduced to 175-185 μm, and the bending resistance of the optical fiber 2 prepared at the fiber drawing speed of 1800m/min and by the preparation method of the optical fiber can still meet the ITU-T G.657A1 optical fiber standard.

Fig. 6 is a schematic structural diagram of an optical fiber manufacturing apparatus according to an embodiment of the present invention.

As shown in fig. 6, an embodiment of the present invention further provides an optical fiber manufacturing apparatus, which includes a rod feeding mechanism 200, a drawing furnace 201, an annealing device 202, a coating device 203, a curing device 204, a drawing mechanism 205, and a processing cabinet 206.

Wherein the rod feeding mechanism 200 is used to feed the optical fiber preform into the drawing furnace 201. The rod feeding mechanism 200 comprises a rod feeding motor, a driving wheel, a driven wheel, a crawler belt, a rod feeding platform capable of moving up and down and a clamping piece, wherein the clamping piece is used for clamping the optical fiber perform rod; the caterpillar band is installed on a driving wheel and a driven wheel, the rod feeding motor is connected with the driving wheel, the rod feeding platform is installed on the caterpillar band, the clamping piece is installed on the rod feeding platform, the rod feeding mechanism is installed on the driving wheel and the driven wheel, the rod feeding motor is connected with the driving wheel, the rod feeding platform is installed on the caterpillar band, the moving piece can be installed on the rod feeding platform in a left-right moving mode, and the clamping piece can be installed on the moving piece in a front-back moving mode.

The drawing furnace 201 is located downstream of the rod feeding mechanism 200, and is used for heating and melting the optical fiber preform into a glass state and drawing the optical fiber preform into a filamentous optical fiber body.

The temperature in the wire drawing furnace 201 is 1800-2200 ℃, and the wire drawing furnace 201 is filled with protective gas. The protective gas in the drawing furnace is one or more of helium and argon.

In order to ensure the stability of the fiber preform heat transfer by the fiber drawing furnace 201, the gap between the fiber preform and the inner wall of the fiber drawing furnace 201 is 5mm to 15mm.

An annealing device 202 is located downstream of the drawing furnace 201 for annealing the optical fiber body.

The residence time of the optical fiber main body in the annealing device 202 is 0.067 s-0.3 s, and the temperature in the annealing device 202 is 1400 ℃ -1700 ℃.

It should be noted that the annealing device 202 includes a plurality of holding furnaces, the holding furnaces are sequentially arranged from top to bottom, and the temperatures of the holding furnaces are sequentially and gradiently decreased from top to bottom.

A coating device 203 is located downstream of the annealing device 202 for coating the annealed fiber body.

A curing device 204 is located downstream of the coating device 203 for curing the coated optical fiber body to form the optical fiber 2.

A drawing mechanism 205 is located downstream of the curing device 204 for providing a drawing speed and taking up the optical fiber 2 onto a take-up reel.

And a treatment cabinet 206 for heat-treating the take-up reel filled with the optical fiber.

When the processing cabinet 206 is used, firstly, the processing cabinet 206 is vacuumized to 0.015Mpa, then nitrogen is filled into the processing cabinet, the purity of the nitrogen is more than or equal to 99.999 percent, the concentration of oxygen in the processing cabinet is not more than 100ppm, and the temperature range in the processing cabinet is 45-60 ℃.

Optionally, as shown in fig. 7, the apparatus for preparing an optical fiber according to the embodiment of the present invention further includes a control device 207 for fiber drawing tension and a tension meter 208.

The control device 207 for the drawing tension of the optical fiber includes: a drawing tension obtaining module 2071, configured to obtain a current drawing tension of the annealed optical fiber body. And a control module 2072, configured to adjust the drawing speed of the traction mechanism 205 in a manner of reducing a difference between the current drawing tension and the target drawing tension according to the comparison between the current drawing tension and the target drawing tension.

A tension meter 208 is provided between the annealing device 202 and the coating device 203. The tension meter 208 is connected to the control device 207 through a signal line. The tension meter 208 is configured to detect a current drawing tension of the annealed optical fiber body, and transmit a signal of the detected current drawing tension of the optical fiber body to the control device 207.

The upper computer 209 is connected with the control device 207 through a control line.

The current drawing tension of the optical fiber body can be calculated by the following formula:

in the formula, F is the current drawing tension of the optical fiber main body; eta _T Viscosity, as a function of temperature; s is the cross-sectional area of the optical fiber main body; g _Z Is the axial velocity gradient.

It can be seen that the magnitude of the current draw tension of the optical fiber body is primarily related to the viscosity and axial velocity gradient, which are controlled by the furnace temperature and draw speed. The uniformity of the cross-section of the fiber body also has some effect on the magnitude of the current draw tension of the fiber body. The influence of the drawing speed of the traction mechanism 205 on the current drawing tension is embodied as follows: the drawing speed of the traction mechanism 205 is increased, the viscosity is increased, and the current drawing tension is increased; the drawing speed of the drawing mechanism 205 decreases, the viscosity decreases, and the current drawing tension decreases.

Acquiring the current drawing tension of the annealed optical fiber main body through a tension meter 208; the control device 207 compares and analyzes the obtained current drawing tension with a target drawing tension set by the upper computer 209, and then adjusts the drawing speed of the traction mechanism 205 to reduce the difference between the current drawing tension and the target drawing tension.

The target drawing tension set by the upper computer 209 is the tension of the optical fiber body measured by a tension meter when the standard drawing speed of the optical fiber is higher than 1800m/min, the cut-off wavelength of the optical fiber is 1200 nm-1320 nm, and the bending loss standard of the optical fiber meets the G.657A1 standard in the preparation process of the optical fiber.

Optionally, if the current drawing tension is greater than the first target drawing tension, the drawing speed of the traction mechanism is reduced.

Specifically, the drawing speed of the traction mechanism 205 is reduced by the control device 207 according to the change per second of not less than 1m/min, then the current drawing tension of the optical fiber body is detected by the tension meter 208, the detected current drawing tension signal of the optical fiber body is transmitted to the control device 207, finally the control device 207 compares and analyzes the obtained current drawing tension with a first target drawing tension set by an upper computer, if the current drawing tension of the optical fiber body is less than or equal to the first target drawing tension, the adjustment of the drawing speed of the traction mechanism 205 is stopped, and if the current drawing tension of the optical fiber body is still greater than the first target drawing tension, the drawing speed of the traction mechanism 205 is continuously adjusted in the above manner.

Specifically, the drawing speed of the traction mechanism 205 is increased by the control device 207 according to the change per second of not less than 1m/min, then the current drawing tension of the optical fiber body is detected by the tension meter 208, the detected current drawing tension signal of the optical fiber body is transmitted to the control device 207, finally the control device 207 compares and analyzes the obtained current drawing tension with a second target drawing tension set by an upper computer, if the current drawing tension of the optical fiber body is greater than or equal to the second target drawing tension, the adjustment of the drawing speed of the traction mechanism 205 is stopped, and if the current drawing tension of the optical fiber body is still less than the second target drawing tension, the drawing speed of the traction mechanism 205 is continuously adjusted in the above manner.

It should be noted that, in the process of preparing the optical fiber, the fiber drawing standard speed is higher than 1800m/min, the fiber cut-off wavelength is between 1200nm and 1320nm, and the standard of the fiber bending loss meets the G.657A1 standard, the tension of the optical fiber body is measured by the tension meter 208, and the tension is the target drawing tension. The first target wire drawing tension is an upper limit value of the allowable fluctuation of the target wire drawing tension; the second target drawing tension is a lower limit value of the target drawing tension allowed to fluctuate.

In an alternative embodiment, the first target drawing tension is the target drawing tension plus 1 and the second target drawing tension is the target drawing tension minus 1.

According to the comparison result between the current drawing tension and the target drawing tension, the control device 207 provided by the embodiment of the application adjusts the drawing speed of the traction machine 70 to reduce the difference between the current drawing tension and the target drawing tension, so that the stability of the optical fiber body in the annealing device 202 can be effectively improved, the refractive index profile distortion of the optical fiber can be avoided, and the bending resistance of the optical fiber 2 can still meet the ITU-TG.657A1 optical fiber standard when the maximum diameter of the obtained outer coating layer is reduced to 175-185 μm.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method of making an optical fiber, comprising the steps of:

providing an optical fiber preform;

annealing the optical fiber main body;

curing the coated optical fiber main body to form an optical fiber;

collecting the optical fibers on a fiber collecting disc, and placing the fiber collecting disc filled with the optical fibers in a nitrogen atmosphere for heat treatment;

the method for providing the optical fiber preform specifically comprises the following steps:

2. The method for producing an optical fiber according to claim 1, wherein the nitrogen gas purity in the nitrogen gas atmosphere is 99.999% or more, and the temperature at which the heat treatment is performed in the nitrogen gas atmosphere is 45 to 60 ℃.

3. The method of claim 2, wherein the optical fiber on the take-up reel is heat-treated in the nitrogen atmosphere for a period of time of 4 to 24 hours.

4. The method of claim 1, wherein the inner coating layer and the outer coating layer are made of acrylic resin; the acrylic resin used for the inner coating layer has the elasticity modulus of less than or equal to 1.5Mpa after being cured, the viscosity of 1500-3000 mPa.s during coating, the elongation at break of more than or equal to 120 percent, the coating temperature range of 28-60 ℃ and the coating pressure of 0.1-2 MPa;

5. The method of manufacturing an optical fiber according to claim 4, wherein the maximum radius of the inner coating layer is 72.5 μm to 77.5 μm, the maximum radius of the outer coating layer is 87.5 μm to 92.5 μm, and the ratio of the thickness value of the inner coating layer to the thickness value of the outer coating layer is 1.

6. An optical fiber manufacturing apparatus for manufacturing an optical fiber according to any one of claims 1 to 5, comprising a rod feeding mechanism, a drawing furnace, an annealing device, a coating device, a curing device, a drawing mechanism, and a processing cabinet;

7. The apparatus for manufacturing an optical fiber according to claim 6, further comprising a control means for controlling the drawing tension of the optical fiber;

8. The apparatus according to claim 7, wherein the control module is configured to adjust the drawing speed of the pulling mechanism in a manner that reduces a difference between the current drawing tension and the target drawing tension according to the comparison between the current drawing tension and the target drawing tension, and comprises:

9. The apparatus for manufacturing an optical fiber according to claim 8, wherein the first target drawing tension is the target drawing tension plus 1, and the second target drawing tension is the target drawing tension minus 1;

10. The apparatus for manufacturing an optical fiber according to any one of claims 6 to 9, wherein the nitrogen gas in the nitrogen gas atmosphere has a purity of 99.999% or more, and the temperature at which the heat treatment is performed in the nitrogen gas atmosphere is 45 ℃ to 60 ℃;

and the time for carrying out heat treatment on the optical fiber on the fiber collecting disc in the nitrogen atmosphere is 4-24 hours.