CN110333571B - Double negative curvature anti-resonance hollow optical fiber and preparation method thereof - Google Patents
Double negative curvature anti-resonance hollow optical fiber and preparation method thereof Download PDFInfo
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- CN110333571B CN110333571B CN201910583190.7A CN201910583190A CN110333571B CN 110333571 B CN110333571 B CN 110333571B CN 201910583190 A CN201910583190 A CN 201910583190A CN 110333571 B CN110333571 B CN 110333571B
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/02—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor
- C03B37/025—Manufacture of glass fibres or filaments by drawing or extruding, e.g. direct drawing of molten glass from nozzles; Cooling fins therefor from reheated softened tubes, rods, fibres or filaments, e.g. drawing fibres from preforms
- C03B37/027—Fibres composed of different sorts of glass, e.g. glass optical fibres
- C03B37/02781—Hollow fibres, e.g. holey fibres
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02295—Microstructured optical fibre
- G02B6/023—Microstructured optical fibre having different index layers arranged around the core for guiding light by reflection, i.e. 1D crystal, e.g. omniguide
- G02B6/02304—Core having lower refractive index than cladding, e.g. air filled, hollow core
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02295—Microstructured optical fibre
- G02B6/02314—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes
- G02B6/02319—Plurality of longitudinal structures extending along optical fibre axis, e.g. holes characterised by core or core-cladding interface features
- G02B6/02323—Core having lower refractive index than cladding, e.g. photonic band gap guiding
- G02B6/02328—Hollow or gas filled core
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02395—Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture
Abstract
The invention discloses a double negative curvature anti-resonance hollow-core optical fiber, which comprises a cladding region and a fiber core region, wherein the cladding region sequentially comprises an outer cladding layer, a first anti-resonance layer and a second anti-resonance layer from outside to inside; wherein the first anti-resonance layer comprises a plurality of first capillaries which are rotationally symmetrically distributed and is tangent with the outer cladding layer; the second anti-resonance layer comprises a plurality of second capillaries which are distributed in a rotational symmetry manner, the second capillaries are tangent to the first capillaries and are arranged in a staggered manner, and the radius of the second capillaries is smaller than that of the first capillaries; the second anti-resonance layer is closer to the central line of the optical fiber relative to the first anti-resonance layer, and an irregular area formed by the surrounding of the boundaries of the first anti-resonance layer and the second anti-resonance layer is a fiber core area. The invention aims to solve the technical problems that the boundary advantage of the anti-resonance negative-curvature hollow fiber with small curvature radius is not fully exerted, the high-order mode loss ratio is low, the structural uniformity cannot be ensured, and the preparation difficulty of a vibration structure is high in the prior art.
Description
Technical Field
The invention belongs to the field of optical fibers, and particularly relates to a double-negative-curvature anti-resonance hollow optical fiber and a preparation method thereof.
Background
The intrinsic defects of the quartz matrix material of the fiber core of the solid optical fiber, such as nonlinearity, dispersion, photoinduced damage, ultraviolet and middle infrared light blockage and the like, which are widely used at present, limit the application of the solid optical fiber in the fields of communication data transmission, high-power short-pulse laser transmission, ultraviolet, middle infrared, terahertz, microwave transmission and the like. The hollow-core fiber is expected to break through the bottleneck of the existing solid-core fiber due to the extremely small nonlinearity, the lower modal dispersion, the high damage threshold, the wide transmission band and the transmission speed which is approximately equal to the optical speed.
The hollow-core optical fiber comprises a photonic band gap optical fiber, a kagome optical fiber and an anti-resonance negative-curvature hollow-core optical fiber, wherein the anti-resonance negative-curvature hollow-core optical fiber has a simple structure and high design flexibility, so that the anti-resonance negative-curvature hollow-core optical fiber is widely researched by people. The cladding of the anti-resonance hollow fiber with negative curvature is generally composed of a circle of mutually separated thin-wall rings, the thin-wall rings are suspended on the cladding, the central area surrounded by the thin-wall rings is the fiber core, and due to the principle of anti-resonance reflection of the thin wall, the transmission band of the fiber is divided into a section of anti-resonance area which is separated by resonance wavelengths with different orders. The negative curvature means that the bending direction of the fiber core boundary surrounded by the thin-wall ring is just opposite to the bending direction of the circular fiber core, and mode coupling can occur between the basic mode and the tube ring mode guided by the thin-wall ring, so that the size of the thin-wall ring around the fiber core must be strictly designed to achieve the advantage of inhibiting the mode coupling, thereby reducing the loss of the anti-resonance negative curvature hollow-core fiber.
In the negative-curvature hollow-core optical fiber, the loss of the anti-resonance negative-curvature hollow-core optical fiber can be reduced by the core boundary with a small curvature radius, the existing anti-resonance negative-curvature hollow-core optical fiber is a large number of circular tube rings, the size of the tube rings does not have the core boundary with a small curvature radius, and the core boundary with the small curvature radius of the anti-resonance negative-curvature hollow-core optical fiber has the advantage that the core boundary with the small curvature radius is not fully exerted.
Another method for reducing the loss of the anti-resonance negative-curvature hollow-core optical fiber is to increase the number of anti-resonance layers and enhance anti-resonance reflection, such as a nested ring structure, a connecting ring structure and the like, and the loss of 2 orders of magnitude can be reduced by the two-layer anti-resonance design, but the difficulty of preparation can be greatly increased by increasing the number of anti-resonance layers.
In addition, the core of the negative curvature hollow-core fiber is generally large, on the order of tens of microns, high-order modes easily exist in a fiber mode, the most important mode influencing the single-mode performance is the LP11 mode, and the most commonly used LP11 mode filtering method is that through structural design, a tube ring mode or an anti-resonant medium-class fundamental mode is coupled with the LP11 mode in the core, so that the LP11 mode in the core is suppressed, but the method ignores the LP21 mode of which the influence force is only second to the LP11 mode in the high-order mode, so that the high-order mode loss ratio of the negative curvature hollow-core fiber in the prior art is generally within the range of hundreds to thousands.
At present, aiming at the preparation method of the anti-resonance negative curvature hollow optical fiber, a central mold is generally used for positioning a capillary at two ends of a prefabricated rod, so that the capillary is clamped between the central mold and an outer sleeve, and the central mold is generally not placed at an effective part in the middle of the prefabricated rod. Because the inner part of the outer sleeve is circular, the capillary tube is positioned by the central die, and the processing precision of the central die is particularly important. In addition, in the preform, only two ends of the capillary tube are supported by the central mold, but the middle effective part is not supported by the central mold, so that once the two ends have deviation, such as structure distortion, the capillary tube can bear stress, the stress is released when the capillary tube is heated and melted, and the uniformity of the structure in the whole longitudinal direction is difficult to ensure. Therefore, in the actual preparation process of the anti-resonance negative-curvature hollow-core optical fiber, the biggest difficulty is the uniformity of the position and the size of each non-contact capillary ring, and the existing preparation process of the anti-resonance negative-curvature hollow-core optical fiber has the problem of non-uniformity to a certain extent; secondly, for the longitudinal uniformity of the structure, the mass production of the anti-resonance negative-curvature hollow-core optical fiber is difficult to realize at present.
Disclosure of Invention
Aiming at the defects or improvement requirements of the prior art, the invention provides a double-negative-curvature anti-resonance hollow optical fiber and a preparation method thereof, and aims to solve the technical problems that the core boundary advantage of the anti-resonance negative-curvature hollow optical fiber with small curvature radius is not fully exerted, the high-order mode loss ratio is low, the uniformity of a non-contact pipe ring structure cannot be ensured, and the preparation difficulty of a multilayer anti-resonance structure is high in the prior art.
To achieve the above objects, according to one aspect of the present invention, there is provided a double negative curvature anti-resonant hollow-core fiber, comprising a cladding region and a core region, the cladding region comprising, in order from the outside to the inside, an outer cladding layer, a first anti-resonant layer, and a second anti-resonant layer;
wherein the first antiresonant layer comprises a plurality of first capillaries distributed rotationally symmetrically and the first antiresonant layer is tangent to the outer cladding; the second anti-resonance layer comprises a plurality of second capillaries which are distributed in a rotational symmetry mode, the second capillaries are tangent to the first capillaries and are arranged in a staggered mode, and the radius of each second capillary is smaller than that of each first capillary;
the second anti-resonance layer is closer to the center of the optical fiber relative to the first anti-resonance layer, and an irregular area formed by the surrounding of the boundary of the first anti-resonance layer and the second anti-resonance layer is the fiber core area.
Preferably, the number of the first capillary and the number of the second capillary are equal and are 5-6.
Preferably, the first capillary and the second capillary have the same wall thickness, and the wall thickness ranges from 0.2 μm to 2.0 μm.
Preferably, the inner region surrounded by the second antiresonant layer boundary has a radius rcore, the radius of the first capillary is r1, the radius of the second capillary is r2, and the rcore, r1 and r2 satisfy the following formula:
r1/rcore＝0.7～0.9；r2/r1＝0.5～0.7。
preferably, r1/rcore is 0.85; r2/r1 is 0.76.
According to another aspect of the present invention, there is provided a method for manufacturing a double negative curvature anti-resonant hollow-core optical fiber, the method comprising the steps of:
s1, drawing a capillary tube, namely drawing two capillaries with different radiuses by using a first glass tube, wherein the number of the capillaries with the two different radiuses is the same and is multiple;
s2, assembling the preform rod, namely, using a second glass tube as an outer sleeve, drawing one end of the outer sleeve into a cone, and then putting the two capillaries with different radiuses into the outer sleeve in a staggered mode, wherein the capillary with a large radius is tightly attached to the outer sleeve, the capillary with a small radius is tightly attached to the capillary with a large radius, and the capillary with a small radius is closer to the center of the outer sleeve than the capillary with a large radius;
using two capillary rods with different lengths as a central mold, wherein the short capillary rod is positioned at one tapered end of the outer sleeve and used for fixing the two capillaries with different radiuses together with the outer sleeve, and the long capillary rod is positioned at the central position of the outer sleeve and can move up and down relative to the outer sleeve, so that the assembly of the precast rod is completed;
s3, preparing an intermediate, namely feeding the assembled prefabricated rod into a wire drawing furnace to obtain the intermediate, wherein in the process that the prefabricated rod enters the wire drawing furnace, the distance between the lower end face of the long capillary rod and the upper edge of a hot zone of the wire drawing furnace is kept unchanged;
and S4, drawing the intermediate into an optical fiber.
Preferably, in step S3, the distance between the lower end surface of the long capillary rod and the upper edge of the hot zone of the drawing furnace is 50mm to 200 mm.
Preferably, in step S2, when the two capillaries with different radii are placed in the outer sleeve in a staggered manner, the auxiliary capillary rods with the same number and length as the capillaries are placed between the outer sleeve and the two capillaries with different radii to assist in positioning the capillaries; and when the integral structure of the preform is stable, taking out the auxiliary capillary rod.
Preferably, in step S2, the long capillary rod is connected to the outside of the outer sleeve by a wire so as to be movable up and down relative to the outer sleeve.
In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:
(1) the invention provides a double-negative-curvature anti-resonance hollow-core optical fiber which is provided with a double-layer anti-resonance layer, wherein the first anti-resonance layer comprises a plurality of first capillary radii which are rotationally and symmetrically distributed, the second anti-resonance layer comprises a plurality of second capillary radii which are rotationally and symmetrically distributed, the first capillary radii are larger than the second capillary radii, the second anti-resonance layer is closer to the center of the optical fiber relative to the first anti-resonance layer, and an irregular area formed by surrounding the boundaries of the first anti-resonance layer and the second anti-resonance layer is a fiber core area and has double negative curvatures. By additionally adding a small-radius anti-resonance layer on the basis of a common single-layer anti-resonance structure, a mode coupling inhibiting effect can be provided, the loss of the optical fiber is further reduced, and meanwhile, the leakage loss of the conventional negative-curvature hollow-core optical fiber between the tube ring gaps can be further reduced due to the staggered arrangement of the first anti-resonance layer and the second anti-resonance layer.
(2) The double negative curvature anti-resonance hollow optical fiber provided by the invention has good structural symmetry, the structural symmetry is superior to that of a negative curvature hollow optical fiber with a non-contact pipe ring structure, and the double negative curvature anti-resonance hollow optical fiber is suitable for mass production.
(3) The double negative curvature anti-resonance hollow fiber provided by the invention has extremely high-order mode loss ratio, and due to the double-layer anti-resonance layer structure, the quasi-fundamental mode in one anti-resonance layer can be coupled with the LP11 mode in the fiber core, and the quasi-fundamental mode in the other anti-resonance layer is coupled with the LP21 mode in the fiber core, so that the LP11 mode and the LP21 mode in the high-order mode of the fiber core are inhibited at the same time, the high-order mode loss ratio can reach more than 1 ten thousand, and is improved by one order of magnitude compared with the prior art.
(4) The invention provides a preparation method of a double negative curvature anti-resonance hollow optical fiber, wherein a capillary tube with a large radius and a capillary tube with a small radius can be mutually supported during preparation, and a central die only needs to be used for supporting, so that a circular die is adopted, additional processing is not needed, the preparation difficulty is greatly reduced, and the technical problems that most central dies in the prior art are negative curvature structures, and the processing difficulty is higher than the processing precision requirement are solved.
(5) According to the preparation method provided by the invention, in the drawing process, the lower end of the prefabricated rod is fixed in the wire drawing furnace, the long capillary rod in the central mold is fixed at the upper edge of the hot zone of the wire drawing furnace for a certain distance, and the structure of the prefabricated rod is always fixed by the long capillary rod in the central mold along with the continuous entering of the prefabricated rod into the wire drawing furnace, so that the length of the prefabricated rod can be greatly improved on the premise of ensuring the longitudinal uniformity of the structure, and the effective utilization rate of the prefabricated rod is improved. In addition, the preparation method provided by the invention is particularly suitable for mass production of the hollow-core optical fiber with the negative curvature.
Drawings
FIG. 1 is a schematic structural diagram of a double negative curvature anti-resonant hollow-core optical fiber provided by the present invention;
FIG. 2 is a schematic cross-sectional view of an assembled preform produced by the method of the present invention;
FIG. 3 is a schematic longitudinal sectional view of an assembled preform produced by the method of the present invention;
FIG. 4 is a graph showing the comparison of the loss of the fundamental mode and the high-order mode of the double negative curvature anti-resonant hollow-core fiber prepared in the present embodiment;
FIG. 5 is a graph of the loss contrast of a double negative curvature anti-resonant hollow core fiber prepared in this example with other comparative fibers;
the same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein:
1-an outer cladding; 2-a first capillary; 3-a second capillary; 4-capillary with large radius; 5-capillary with small radius; 6-outer sleeve; 7-auxiliary capillary rod; 8-long capillary rods; 9-short capillary rods; 10-a feed system; 11-hot zone of the drawing furnace.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention provides a double negative curvature anti-resonance hollow-core optical fiber, the structure of which is shown in figure 1 and comprises a cladding region and a core region, wherein the cladding region sequentially comprises an outer cladding layer 1, a first anti-resonance layer and a second anti-resonance layer from outside to inside;
wherein the first anti-resonance layer comprises a plurality of first capillaries 2 which are rotationally symmetrically distributed and is tangent to the outer cladding layer 1; the second anti-resonance layer comprises a plurality of second capillaries 3 which are rotationally symmetrically distributed, the second capillaries 3 are tangent to the first capillaries 2 and are arranged in a staggered manner, and the radius of each second capillary 3 is smaller than that of each first capillary 2;
the second anti-resonance layer is closer to the central line of the optical fiber relative to the first anti-resonance layer, and an irregular area formed by the surrounding of the boundaries of the first anti-resonance layer and the second anti-resonance layer is a fiber core area.
Because the double-negative-curvature anti-resonance hollow optical fiber provided by the invention has the structure, the core area formed by surrounding the boundary of the first anti-resonance layer and the second anti-resonance layer has double negative curvatures, and the hollow optical fiber has the following advantages:
the mode coupling inhibiting effect can be provided, the loss of the optical fiber is further reduced, and meanwhile, the leakage loss of the conventional hollow-core optical fiber with the negative curvature between the tube ring gaps can be further reduced due to the staggered arrangement of the first anti-resonance layer and the second anti-resonance layer;
the anti-resonance layer is positioned by the mutual support of the first capillary 2 and the second capillary 3, and the uniform and symmetrical distribution of the structure can be ensured as long as the sizes of the capillaries with the same type are ensured to be equal, the structural symmetry is good, and the method is suitable for mass production;
the fiber core has extremely high-order mode loss ratio, the similar fundamental mode in one anti-resonance layer can be coupled with the LP11 mode in the fiber core, and the similar fundamental mode in the other anti-resonance layer is coupled with the LP21 mode in the fiber core, so that the LP11 mode and the LP21 mode in the high-order mode of the fiber core can be inhibited at the same time, the high-order mode loss ratio can reach more than 1 ten thousand, and the fiber core is improved by one order of magnitude compared with the prior art.
Preferably, the number of the first capillary 2 and the second capillary 3 is equal to 5-6.
Preferably, the first capillary 2 and the second capillary 3 have the same wall thickness, and the wall thickness ranges from 0.2 μm to 2.0 μm.
Preferably, the radius of the inner region formed by the boundary of the second antiresonant layer is rcore, the radius of the first capillary 2 is r1, the radius of the second capillary 3 is r2, and the rcore, r1 and r2 satisfy the formula:
r1/rcore＝0.7～0.9；r2/r1＝0.5～0.7。
preferably, r1/rcore is 0.85; r2/r1 is 0.76.
The invention also provides a preparation method of the double negative curvature anti-resonance hollow-core optical fiber, which comprises the following steps:
s1, drawing a capillary tube, namely drawing two capillaries with different radiuses by using a first glass tube, wherein the number of the capillaries with the two different radiuses is the same as that of the capillaries with the two different radiuses;
s2, assembling the prefabricated rod, namely, using a second glass tube as an outer sleeve 6, drawing one end of the outer sleeve 6 into a cone, and then putting two capillaries with different radiuses into the outer sleeve 6 in a staggered mode, wherein the capillary 4 with a large radius is attached to the outer sleeve 6, the capillary 5 with a small radius is attached to the capillary 4 with a large radius, and the capillary 5 with a small radius is closer to the center of the outer sleeve 6 relative to the capillary 4 with a large radius;
two capillary rods with different lengths are used as a central die, wherein a short capillary rod 9 is positioned at one tapered end of the outer sleeve 6 and used for fixing two capillaries with different radiuses together with the outer sleeve 6, and a long capillary rod 8 is positioned at the central position of the outer sleeve 6 and can move up and down relative to the outer sleeve 6, so that the assembly of the prefabricated rod is completed;
s3, preparing an intermediate, namely feeding the assembled prefabricated rod into a wire drawing furnace to be drawn to obtain the intermediate, wherein in the process that the prefabricated rod enters the wire drawing furnace, the lower end face of a long capillary rod 8 and the upper edge of a hot zone 11 of the wire drawing furnace keep a certain distance;
and S4, drawing the intermediate into an optical fiber.
According to the preparation method of the hollow optical fiber, the capillary 4 with the large radius and the capillary 5 with the small radius can be mutually supported during preparation, and the central mold only needs to be used for supporting, so that the circular mold is adopted, additional processing is not needed, the preparation difficulty is greatly reduced, and the technical problems that in the prior art, most central molds are negative curvature structures, and the processing difficulty is higher than the processing precision requirement are solved.
In addition, because the drawing in-process, the prefabricated stick lower extreme is fixed in the wire drawing stove, and long capillary stick 8 in the central mould is fixed at one section distance of wire drawing stove hot zone top edge, and along with prefabricated stick constantly gets into the wire drawing stove, its structure is fixed by long capillary stick 8 in the central mould all the time, consequently, can promote prefabricated stick length greatly under the prerequisite of guaranteeing the vertical homogeneity of structure, promotes prefabricated stick's effective utilization. In addition, the preparation method provided by the invention is particularly suitable for mass production of the hollow-core optical fiber with the negative curvature.
Preferably, in step S3, the distance between the lower end surface of the long capillary 8 and the upper edge of the hot zone 11 of the drawing furnace is 50mm to 200 mm.
Preferably, in step S2, when two capillaries with different radii are placed in the outer sleeve in a staggered manner, the auxiliary capillary rods 7 with the same number and length as the capillaries are placed between the outer sleeve 6 and the two capillaries with different radii to assist in positioning the two capillaries; when the whole structure of the preform is stable, the auxiliary capillary rod 7 is taken out.
Preferably, in step S2, the long capillary bar 8 is connected to the outside of the outer sleeve 6 by a wire so as to be movable up and down relative to the outer sleeve 6.
Example 1:
a double negative curvature anti-resonance hollow-core optical fiber comprises a cladding region and a core region, wherein the cladding region sequentially comprises an outer cladding layer 1, a first anti-resonance layer and a second anti-resonance layer from outside to inside, the first anti-resonance layer comprises a plurality of first capillary tubes 2 which are rotationally and symmetrically distributed, and the first anti-resonance layer is tangent to the outer cladding layer 1; the second anti-resonance layer comprises a plurality of second capillaries 3 which are rotationally symmetrically distributed, the second capillaries 3 are tangent to the first capillaries 2 and are arranged in a staggered mode, the second anti-resonance layer is closer to the central line of the optical fiber relative to the first anti-resonance layer, an irregular area formed by the surrounding of the boundaries of the first anti-resonance layer and the second anti-resonance layer is a fiber core area with double negative curvatures, the number of the first capillaries 2 and the number of the second capillaries 3 in the cladding area are 6, and the wall thickness is 0.5 mu m. The radius rcore of the inner region formed around the boundary of the second antiresonant layer is 20 μm, the radius r1 of the first capillary 2 is 17 μm, and the radius r2 of the second capillary 3 is 13 μm.
Example 2:
a preparation method of a double negative curvature anti-resonance hollow-core optical fiber comprises the following steps:
(1) drawing a capillary tube:
the first glass tube with phi 50mm and 2.5mm wall thickness is used for drawing 6 capillaries with two different radiuses, the specifications of the capillaries are respectively phi 4.51mm, 0.17mm wall thickness and 1000mm length, and phi 5.90mm wall thickness and 0.17mm length and 1000mm length, and the internal pressure of the glass tube is respectively set to be 2mabr and 5mbar when the capillaries with the two specifications are drawn at the temperature of a wire drawing furnace of 1980 ℃.
(2) And (3) assembling a prefabricated rod:
a second glass tube with a diameter of 40mm, a wall thickness of 7.75mm and a length of 1000mm is used as the outer sleeve 6, one end of the outer sleeve 6 is drawn into a cone, and the diameter of an inner hole at the cone end is less than 5 mm. The drawn capillaries with two different radii are placed in the outer sleeve 6 in a staggered arrangement, wherein the capillary 4 with a large radius is attached to the outer sleeve 6, the capillary 5 with a small radius is attached to the capillary 4 with a large radius, and the capillary 5 with a small radius is closer to the center of the outer sleeve 6 than the capillary 4 with a large radius. During the assembly process, 6 auxiliary capillary rods 7 with phi 4.27mm and length of 1000mm are used for assisting the positioning of the capillary tubes. Two capillary rods with the length of phi 6.94mm and the length of 500mm are respectively used as a central die, wherein the capillary rod 9 with the length of 200mm is positioned at one tapered end of the outer sleeve 6 and is used for fixing the capillary together with the outer sleeve 6; a500 mm long capillary rod 8 is positioned at the center of the outer jacket tube 6 for fixing the center structure of the preform, and the assembled preform has a cross-sectional view as shown in FIG. 2. After the whole structure is stable, the capillary rod with the diameter of 4.27mm is taken out, the surface of the capillary rod 8 with the length of 500mm is polished and can slide in the prefabricated rod, the capillary rod is connected to the outside of the outer sleeve 6 through an iron wire with the diameter of 0.5mm, and the assembled longitudinal section schematic diagram is shown in fig. 3.
(3) Preparation of an intermediate:
the assembled preform is fixed to a fixture of a feed system 10 of a draw tower and fed to a rod turning position. In the process that the prefabricated rod enters the wire drawing furnace, the position of the long capillary rod 8 is moved through the iron wire, the lower end face of the long capillary rod 8 and the upper edge of a hot zone 11 of the wire drawing furnace are kept at 100mm, the iron wire is straightened and fixed at a certain fixed position right above the prefabricated rod and does not move along with a feeding system 10 of a wire drawing tower. After turning around at 2050 ℃, the temperature is rapidly reduced to 1980 ℃, the internal pressure of the outer sleeve 6 and the internal pressure of the capillary are respectively set to 2mabr and 5mbar, the feeding speed is kept at 10mm/min, the traction speed of the intermediate is kept at 0.16m/min, and the diameter of the drawn intermediate is 10 mm. In the drawing process, the long capillary rod 8 always fixes the structure of the prefabricated rod in a close distance from the hot zone, and the longitudinal uniformity of the prepared intermediate is ensured.
(4) Drawing an optical fiber:
the intermediate 10mm in diameter was drawn into an optical fiber 125 μm in a drawing furnace at 1930 ℃ and the pressures in the core part and the surrounding capillary parts of two different radii were set at 30mbar and 50mbar, respectively. Finally, a capillary 4 having a large radius was drawn into a first capillary 2, a capillary 5 having a small radius was drawn into a second capillary 3, and an outer jacket 6 was drawn into an outer cladding 1, to prepare an optical fiber having a structure of rcore 20 μm, r1 17 μm, r2 13 μm, and t 0.5 μm.
FIG. 4 is a graph showing the comparison of the loss of the fundamental mode and the high-order mode of the double negative curvature anti-resonant hollow-core fiber prepared in this example. In the wavelength range of 1150-1350 nm, the loss ratio of the high-order mode to the fundamental mode of the double-negative-curvature anti-resonance hollow-core optical fiber prepared by the embodiment can reach 10 ten thousand, which is far higher than the reported loss ratio of hundreds to thousands.
FIG. 5 is a graph of the loss of a double negative curvature anti-resonant hollow core fiber prepared in this example compared to other comparative fibers. Wherein, in the figure, (a) is the structure of a comparison optical fiber 1, and the comparison optical fiber 1 is a single-layer anti-resonance hollow-core optical fiber; (b) the structure of the comparison optical fiber 2 is that the comparison optical fiber 2 is a nested ring double-layer anti-resonance hollow optical fiber; (c) the structure of the comparison optical fiber 3 is that the comparison optical fiber 3 is a connecting ring double-layer anti-resonance hollow optical fiber; (d) a graph comparing the loss of the fiber of this example with that of three comparative fibers. Under the same condition that rcore is 20 μm and the wall thickness t is 0.5 μm, the loss of the double negative curvature hollow core optical fiber prepared by the embodiment of the present invention is reduced by more than two orders of magnitude compared with the comparative optical fiber 1 (tube ring radius of 17 μm); compared with a comparison optical fiber 2 (the diameter of a large ring is 17 mu m, the diameter of a small ring is 11 mu m) and a comparison optical fiber 3 (the radius of a tube ring is 17 mu m, and the distance between the circle centers of the two rings is 10 mu m), the double negative curvature hollow-core optical fiber prepared by the embodiment of the invention achieves the same level of short wavelength loss, and is even better.
It will be understood by those skilled in the art that the foregoing is merely a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included within the scope of the present invention.
Claims (7)
1. A method for preparing a double negative curvature anti-resonant hollow-core fiber, the hollow-core fiber comprising a cladding region and a core region, the method comprising the steps of:
s1, drawing a capillary tube, namely drawing two capillaries with different radiuses by using a first glass tube, wherein the number of the capillaries with the two different radiuses is the same and is multiple;
s2, assembling the preform rod, namely, using a second glass tube as an outer sleeve, drawing one end of the outer sleeve into a cone, and then putting the two capillaries with different radiuses into the outer sleeve in a staggered mode, wherein the capillary with a large radius is tightly attached to the outer sleeve, the capillary with a small radius is tightly attached to the capillary with a large radius, and the capillary with a small radius is closer to the center of the outer sleeve than the capillary with a large radius;
using two capillary rods with different lengths as a central mold, wherein the short capillary rod is positioned at one tapered end of the outer sleeve and used for fixing the two capillaries with different radiuses together with the outer sleeve, and the long capillary rod is positioned at the central position of the outer sleeve and can move up and down relative to the outer sleeve, so that the assembly of the precast rod is completed;
the cladding region sequentially comprises an outer cladding layer, a first anti-resonance layer and a second anti-resonance layer from outside to inside; the first antiresonant layer comprises a plurality of first capillaries distributed rotationally symmetrically and the first antiresonant layer is tangent to the outer cladding; the second anti-resonance layer comprises a plurality of second capillaries which are distributed in a rotational symmetry mode, and the second capillaries are tangent to the first capillaries and are arranged in a staggered mode; an inner region formed by the boundary of the second anti-resonance layer is of a radius rcore, the radius of the first capillary is r1, the radius of the second capillary is r2, and the rcore, r1 and r2 satisfy the following formula:
r1/rcore=0.7~0.9；r2/r1=0.65~0.85；
s3, preparing an intermediate, namely feeding the assembled prefabricated rod into a wire drawing furnace to obtain the intermediate, wherein in the process that the prefabricated rod enters the wire drawing furnace, the distance between the lower end face of the long capillary rod and the upper edge of a hot zone of the wire drawing furnace is kept unchanged;
s4, drawing the intermediate into an optical fiber;
in the step S3, the distance between the lower end face of the long capillary rod and the upper edge of the hot zone of the wire drawing furnace is 50 mm-200 mm.
2. The manufacturing method according to claim 1, wherein in step S2, when the two capillaries with different radii are placed in the outer sleeve in a staggered manner, auxiliary capillary rods having the same number and length as the capillaries are placed between the outer sleeve and the two capillaries with different radii to assist in positioning the capillaries; and when the integral structure of the preform is stable, taking out the auxiliary capillary rod.
3. The method of claim 1, wherein in step S2, the long capillary rod is connected to the outside of the outer sleeve by a wire so as to be movable up and down relative to the outer sleeve.
4. A double negative curvature anti-resonant hollow-core optical fiber comprising a cladding region and a core region, characterized by being produced by the production method according to any one of claims 1 to 3;
the cladding region sequentially comprises an outer cladding layer, a first anti-resonance layer and a second anti-resonance layer from outside to inside;
wherein the first antiresonant layer comprises a plurality of first capillaries distributed rotationally symmetrically and the first antiresonant layer is tangent to the outer cladding; the second anti-resonance layer comprises a plurality of second capillaries which are distributed in a rotational symmetry mode, the second capillaries are tangent to the first capillaries and are arranged in a staggered mode, and the radius of each second capillary is smaller than that of each first capillary;
the second anti-resonance layer is closer to the center of the optical fiber relative to the first anti-resonance layer, and an irregular area formed by the surrounding of the boundary of the first anti-resonance layer and the second anti-resonance layer is the fiber core area;
wherein an inner region formed around the boundary of the second anti-resonance layer has a radius rcore, the first capillary has a radius r1, the second capillary has a radius r2, and the rcore, r1 and r2 satisfy the following formula:
r1/rcore=0.7~0.9；r2/r1=0.65~0.85。
5. the dual negative curvature anti-resonant hollow-core fiber of claim 4, wherein the number of the first capillaries and the number of the second capillaries are equal to 5-6.
6. The dual negative curvature anti-resonant hollow-core fiber of claim 4, wherein the first capillary and the second capillary have a wall thickness that is equal, the wall thickness ranging from 0.2 μm to 2.0 μm.
7. The dual negative curvature anti-resonant hollow-core fiber of claim 4, wherein r1/rcore = 0.85; r2/r1= 0.76.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111043986B (en) * | 2019-12-25 | 2021-11-09 | 武汉工程大学 | Device and method for measuring curvature of optical fiber |
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| CN114815042B (en) * | 2022-05-13 | 2023-03-24 | 中国科学院上海光学精密机械研究所 | Single-mode anti-resonance hollow optical fiber with square-field fundamental mode |
| CN115072983B (en) * | 2022-06-10 | 2024-01-16 | 武汉长盈通光电技术股份有限公司 | Preparation method of hollow anti-resonance optical fiber intermediate preform |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61279517A (en) * | 1985-06-05 | 1986-12-10 | Mitsubishi Electric Corp | Manufacture of frp structure for beautiful facing |
| JP2991338B1 (en) * | 1998-11-13 | 1999-12-20 | 住友電気工業株式会社 | Optical fiber drawing method and drawing furnace |
| JP3991613B2 (en) * | 2001-04-17 | 2007-10-17 | 新神戸電機株式会社 | Manufacturing method of resin gears |
| WO2005102742A1 (en) * | 2004-04-27 | 2005-11-03 | Toyo Tire & Rubber Co., Ltd. | Run flat tire support body, method of manufacturing the same, and run flat tire on which run flat tire support body is fixedly mounted |
| US8227082B2 (en) * | 2007-09-26 | 2012-07-24 | Ut-Battelle, Llc | Faceted ceramic fibers, tapes or ribbons and epitaxial devices therefrom |
| US8904828B2 (en) * | 2008-10-30 | 2014-12-09 | Corning Incorporated | Methods for forming cladding portions of optical fiber preform assemblies |
| DK2877337T3 (en) * | 2012-07-05 | 2017-09-11 | Lm Wp Patent Holding As | Method and molding system for producing a fiber-reinforced polymer blank via a feedback flow control system |
| KR101311999B1 (en) * | 2012-11-01 | 2013-09-27 | 한국건설기술연구원 | Manufacturing method and apparatus for hybrid frp bar, and nozzle for such apparatus |
| CN103645551B (en) * | 2013-12-18 | 2016-05-25 | 江苏大学 | A kind of micro-nano fiber assembly and manufacture method thereof |
| US9962887B2 (en) * | 2014-07-21 | 2018-05-08 | Hitachi Chemical Company, Ltd. | Method of manufacturing fiber substrate and method of manufacturing resin rotator |
| CN204780428U (en) * | 2015-06-16 | 2015-11-18 | 河南省黄河防爆起重机有限公司 | Compound steel wire hoist cable of light |
| CN204966080U (en) * | 2015-09-25 | 2016-01-13 | 苏州国华特种线材有限公司 | Compound cable |
| CN105198201B (en) * | 2015-10-21 | 2019-02-12 | 长飞光纤光缆股份有限公司 | A kind of preparation method of silica glass preform |
| CN205333932U (en) * | 2015-12-01 | 2016-06-22 | 河南仕佳通信科技有限公司 | Novel extrusion formula mould |
| JP6288056B2 (en) * | 2015-12-02 | 2018-03-07 | 住友電気工業株式会社 | Glass base material manufacturing apparatus and manufacturing method |
| CN208459624U (en) * | 2018-07-02 | 2019-02-01 | 苏州龙格库塔光电科技有限公司 | Super model interference filter and fiber optic wavelength tunable mode-locked laser |
| CN108640502B (en) * | 2018-07-26 | 2020-12-22 | 杭州富通通信技术股份有限公司 | Method for manufacturing optical fiber |
| CN109143460B (en) * | 2018-09-12 | 2019-08-30 | 华中科技大学 | A kind of negative cruvature hollow-core fiber and preparation method thereof |
| CN109212696A (en) * | 2018-11-08 | 2019-01-15 | 江苏中煤电缆有限公司 | Coal mine low smoke and zero halogen Plastic-sheathed Cable high-temperature resistant optical fiber and its manufacturing method |
-
2019
- 2019-07-01 CN CN201910583190.7A patent/CN110333571B/en active Active
Non-Patent Citations (1)
| Title |
|---|
| Double negative curvature anti-resonance hollow core fiber;XIANG CHEN等;《OPTICS EXPRESS》;20190626;第27卷(第14期);第19548-19554页，附图1-5 * |
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