Low-loss high-order-mode high-purity transmission anti-resonance hollow-core optical fiber and manufacturing method thereof

Abstract

The low-loss high-order-mode high-purity transmission anti-resonance hollow-core optical fiber comprises an outer sleeve layer and a plurality of cladding tubes, and the cladding tubes are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-shaped tube and an outer D-shaped tube which are combined into a connected tube structure, the outer D-shaped tube is tangent to the outer sleeve, and one or more glass tubes can be nested in the outer D-shaped tube; the middle part surrounded by the plurality of cladding tubes forms a fiber core of the optical fiber; special gas which is colorless, odorless, safe and easy to store is filled in the cladding pipe; and the end part of the cladding pipe is heated and collapsed to form a first plugging layer. The manufacturing method comprises the following steps: drawing the optical fiber; optical fiber selective plugging; optical fiber selective gas filling; and packaging the optical fiber. In combination with an anti-resonance hollow-core optical fiber light guide theory, a selective gas filling technology and a discharge collapse technology, low-loss high-order-mode high-purity transmission is realized by adjusting a cladding tube structure, an optical fiber geometric structure, a gas refractive index and discharge parameters.

Description

Technical Field

[0001] The present invention belongs to the technical field of hollow-core optical fiber manufacturing in mode division multiplexing optical fiber communication and optical quantum information transmission and processing, and specifically relates to an anti-resonant hollow-core optical fiber with low-loss high-order mode high-purity transmission and a manufacturing method thereof. Background Art

[0002] The characteristics and applications of higher-order modes in optical fibers are gaining increasing attention. Compared with the LP01 fundamental mode, higher-order modes have significant advantages in some applications. For example, in high-resolution imaging and detail detection, higher-order modes provide higher mode resolution. In optical sensing to detect and measure the characteristics of samples, higher-order modes can improve the sensitivity of sensors. In laser technology and ultrafast optical applications, higher-order modes can induce optical frequency conversion and self-focusing effects. In order to realize these applications, it is necessary to solve the problem of how to efficiently excite high-purity higher-order modes.

[0003] Traditional mode converters, such as long-period fiber gratings, usually work based on resonant optical processes. This method can only achieve mode conversion at a specific wavelength, limiting its applicability. Another method is a mode converter based on the taper of photonic crystal solid-core fiber. This device can achieve broadband operation, but due to its reliance on adiabatic mode evolution, the manufacturing process is complex and the parameter control requirements are extremely high, making it difficult to apply in practical systems. In addition, the inherent dispersion and optical damage problems of solid-core fiber also limit its scope of use. In this context, antiresonant hollow-core fiber has shown great potential as an alternative technology. As one of the major innovations in the field of fiber optics in the past decade, antiresonant hollow-core fiber can bypass the limitations of solid dielectric core materials and achieve air light guidance. This type of fiber not only has the advantages of wide transmission passband and low transmission loss, but also has the unique characteristics of high laser damage threshold and selective mode filtering. Therefore, in terms of exciting and transmitting high-purity high-order modes, antiresonant hollow-core fiber shows unique advantages and broad application prospects.

[0004] There are two main types of high-purity antiresonant hollow-core fibers for high-order mode transmission. The first type achieves different mode loss levels by changing the azimuth distribution of the antiresonant unit and the gap between the units in the hollow-core fiber cladding. Based on the antiresonant hollow-core fiber with 10 cladding tubes, a pair of cladding tubes in the x direction are removed. This design makes the LP mode field distributed up and down. 11 Modes other than a are more likely to leak through the gap between the two structures, thus obtaining an LP 11 The antiresonant hollow core fiber transmits the a mode with the lowest loss. Since the working mechanism of the antiresonant hollow core fiber is based on the leakage of light in the cladding to achieve low-loss transmission, and the removal of the cladding tube will cause the loss to increase, so the LP 11The loss of the mode increases. The second type is to introduce the concept of a differential core-cladding refractive index. By changing the type and pressure of the gas, there is a certain difference between the gas refractive index in the core and the gas refractive index in the cladding tube. The gas is selectively sealed in the core or cladding tube using ultraviolet glue. In this way, the phase matching conditions of the fiber mode can continue to be regulated on the existing fiber structure. However, for antiresonant hollow-core fibers with uneven cladding tube structures, it is difficult to control the flow rate of ultraviolet glue in each cladding tube. And these two types of antiresonant hollow-core fibers are single-ring antiresonant hollow-core fibers (single ring-ARF) with only three antiresonant layers, and their losses are themselves at a relatively high level.

[0005] Therefore, the above two types of antiresonant hollow core optical fibers are difficult to meet the requirements of low-loss high-order mode high-purity transmission. Summary of the invention

[0006] In order to solve the above problems existing in the prior art, the present invention aims to provide a low-loss high-order mode high-purity transmission anti-resonant hollow-core optical fiber and a manufacturing method, aiming to reduce the high-order mode transmission loss, improve the mode purity, and meet the requirements of low-loss high-order mode high-purity transmission. Combining the anti-resonant hollow-core optical fiber light guiding theory, selective gas filling technology and discharge collapse technology, low-loss high-order mode high-purity transmission is achieved by adjusting the cladding tube structure, optical fiber geometry, gas refractive index and discharge parameters.

[0007] The technical solution adopted by the present invention is:

[0008] According to the first aspect, the present invention proposes an antiresonant hollow-core optical fiber with low-loss, high-order mode and high-purity transmission, comprising an outer sleeve layer and a plurality of cladding tubes, wherein the plurality of cladding tubes are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-type tube and an outer D-type tube combined into a conjoined tube structure, wherein the outer D-type tube is tangent to the outer sleeve; the middle part surrounded by the plurality of cladding tubes constitutes the core of the optical fiber; the cladding tube is filled with a special gas that is colorless, odorless, safe and easy to store; the end of the cladding tube collapses when heated to form a sealing layer.

[0009] Optionally, one or more glass tubes are nested inside the outer D-shaped tube.

[0010] Optionally, the cladding tube is made of silica glass or polymethyl methacrylate material that can be used in the terahertz band.

[0011] Optionally, the glass tube is a capillary tube or a conjoined tube.

[0012] Optionally, the special gas is one gas or a mixture of multiple gases selected from the group consisting of carbon dioxide, nitrogen, oxygen, argon and sulfur hexafluoride.

[0013] According to a second aspect, the present invention provides a method for manufacturing an anti-resonant hollow core optical fiber with low-loss high-order mode and high-purity transmission, comprising:

[0014] Drawing the optical fiber to have the following structure: comprising an outer sleeve layer and a plurality of cladding tubes, wherein the plurality of cladding tubes are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-shaped tube and an outer D-shaped tube combined into a conjoined tube structure, wherein the outer D-shaped tube is tangent to the outer sleeve, and the middle part surrounded by the plurality of cladding tubes constitutes the core of the optical fiber;

[0015] Selective plugging of optical fiber;

[0016] Selective gas filling of optical fiber;

[0017] Fiber optic packaging.

[0018] Optionally, the optical fiber selective blocking specifically includes:

[0019] Using a fusion splicer to perform discharge processing on both ends of the hollow-core optical fiber, so that each cladding tube is shortened inwardly by a first length at both ends, and the end surface of the cladding tube collapses and closes;

[0020] Injecting ultraviolet glue into the inner cavity of the core from both ends of the hollow-core optical fiber, the injection depth being a second length, the first length being shorter than the second length;

[0021] Using an ultraviolet lamp curing device to cure the ultraviolet glue in the fiber core to form a first plugging layer;

[0022] Part of the first blocking layer is cut off, so that the fiber core is blocked by the ultraviolet glue and the cladding tube is open to the outside.

[0023] Optionally, the optical fiber selectively fills with gas, specifically including:

[0024] The inner D-tube is filled with special gas alone, or the inner D-tube and the outer D-tube are filled with special gas at the same time.

[0025] Optionally, the optical fiber packaging specifically includes:

[0026] Cutting off the remaining parts of the first plugging layer at both ends of the fiber core 4, so that the fiber core and the cladding tube are open to the outside;

[0027] A fusion splicer is used to perform discharge treatment on both ends of the hollow-core optical fiber, so that each cladding tube collapses inward from both ends by a third length, and the end surface of the cladding tube collapses and closes to form a second blocking layer.

[0028] Optionally, the range of the third length does not exceed 200 μm.

[0029] The beneficial effects of the present invention are:

[0030] The present invention proposes an antiresonant hollow-core optical fiber for low-loss high-order mode high-purity transmission, which combines the antiresonant hollow-core optical fiber light guiding theory, selective gas filling technology and discharge collapse technology, and realizes low-loss high-order mode high-purity transmission by adjusting the cladding tube structure, optical fiber geometric structure, gas refractive index and discharge parameters. In the specific implementation, by adding multiple layers of medium in the cladding, the reflection of light in the entire cladding area is increased, and the transmission of light from the core to the outside is reduced; the antiresonant hollow-core optical fiber with a conjoined tube cladding structure has the characteristics of uniform structure and easy drawing. The conjoined tube cladding structure composed of an inner D-type tube and an outer D-type tube with almost the same size has five layers of medium. One or more glass tubes are nested inside the outer D-type tube tangent to the outer tube to further reduce the leakage of light and realize ultra-low loss transmission. At the same time, since the sizes of the inner D-type tube and the outer D-type tube are almost the same, the consistency of the amount of gas filled in the cladding tube can be well controlled, which is conducive to the selective filtering of the mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 It is a schematic diagram of the end face structure of an anti-resonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission according to an embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of an enlarged cross-sectional structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission after optical fiber drawing according to an embodiment of the present invention;

[0034] Figure 3 It is an enlarged schematic diagram of the end face structure of an antiresonant hollow core optical fiber after discharge collapse based on low-loss high-order mode high-purity transmission in an embodiment of the present invention;

[0035] Figure 4 It is a schematic diagram of an enlarged cross-sectional structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission after discharge collapse according to an embodiment of the present invention;

[0036] Figure 5 It is an enlarged schematic diagram of the cross-sectional structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission when selective plugging is performed on an optical fiber according to an embodiment of the present invention;

[0037] Figure 6 It is an enlarged schematic diagram of the cross-sectional structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission during selective plugging according to an embodiment of the present invention;

[0038] Figure 7 It is an enlarged schematic diagram of the cross-sectional structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission during selective gas filling according to an embodiment of the present invention;

[0039] Figure 8 It is an enlarged schematic diagram of the cross-sectional structure of the antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission in an embodiment of the present invention after the remaining first plugging layer at both ends of the fiber core is cut off;

[0040] Fig. 9 It is an enlarged schematic diagram of the cross-sectional structure of the final product of the anti-resonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission according to an embodiment of the present invention;

[0041] Fig.10 It is an enlarged schematic diagram of the final product end face structure of an antiresonant hollow-core optical fiber based on low-loss high-order mode high-purity transmission in an embodiment of the present invention.

[0042] Markings in the accompanying drawings:

[0043] 1-outer casing layer; 2-cladding tube; 21-semicircular structure; 3-inner D-tube; 3'-outer D-tube; 3'1-capillary tube; 3'2-conjoined tube; 4-fiber core; 41-second plugging layer; 5-special gas; 6-first plugging layer. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0045] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0046] In the related art, different mode loss levels are achieved by changing the azimuth distribution of the anti-resonant unit and the gap between the units in the fiber cladding. Based on the anti-resonant hollow-core fiber with 10 cladding tubes, a pair of cladding tubes in the x direction are removed. This design makes the LP mode field distributed up and down. 11 Modes other than a are more likely to leak through the gap between the two structures, thus obtaining an LP 11 The a-mode is transmitted with the lowest loss in the antiresonant hollow core fiber. Although this method achieves high purity LP 11 a mode transmission, but the removal of the cladding tube will cause the loss to increase, thus making LP 11The loss of the mode increases. Based on the introduction of differential core-cladding refractive index, the selective gas filling and blocking of the optical fiber, the method of resonantly filtering out the core fundamental mode from the cladding tube has almost no effect on the loss of high-order modes. However, this method uses ultraviolet glue to block the gas, and for anti-resonant hollow-core optical fibers with uneven cladding tube structures, it is difficult to control the flow rate of ultraviolet glue in each cladding tube. In addition, both types of anti-resonant hollow-core optical fibers are single-loop anti-resonant hollow-core optical fibers with only three anti-resonant layers, and their losses are already at a relatively high level.

[0047] Based on this, in various embodiments of the present application, an antiresonant hollow core fiber with low-loss high-order mode and high-purity transmission is proposed. Combining the antiresonant hollow core fiber light guiding theory, selective gas filling technology and discharge collapse technology, low-loss high-order mode and high-purity transmission is achieved by adjusting the cladding tube structure, optical fiber geometry, gas refractive index and discharge parameters.

[0048] like Figure 1-Figure 10 As shown, the embodiment of the present application proposes an antiresonant hollow-core optical fiber with low-loss, high-order mode and high-purity transmission, comprising an outer sleeve layer 1 and multiple cladding tubes 2, wherein the multiple cladding tubes 2 are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-type tube 3 and an outer D-type tube 3' which are combined into a conjoined tube structure, wherein the outer D-type tube 3' is tangent to the outer sleeve 1, and one or more glass tubes can be nested inside the outer D-type tube 3'; the middle part surrounded by the multiple cladding tubes constitutes the core 4 of the optical fiber; the cladding tube 2 is filled with a special gas 5 which is colorless, odorless, safe and easy to store; the end of the cladding tube 2 collapses due to heat to form a first sealing layer 6.

[0049] The antiresonant hollow core optical fiber is dominated by limiting (leakage) loss, which is mainly manifested as the attenuation of optical power caused by the light transmitting out of the optical fiber from the quartz-air interface on the lateral interface. This embodiment increases the reflection of light in the entire cladding area by adding multiple layers of medium in the cladding, and reduces the transmission of light from the core to the outside world. It is an efficient and useful method. The antiresonant hollow core optical fiber with a conjoined tube cladding structure has the characteristics of uniform structure and easy drawing. The conjoined tube cladding structure composed of an inner D-tube 3 and an outer D-tube 3' with almost the same size has five layers of medium. One or more glass tubes are nested inside the outer D-tube 3' that is tangent to the outer tube 1 to further reduce the leakage of light and realize ultra-low loss transmission. At the same time, since the sizes of the inner D-tube 3 and the outer D-tube 3' are almost the same, the consistency of the amount of gas filled in the cladding tube 2 can be well controlled, which is conducive to the selective filtering of the mode.

[0050] In a specific implementation, the outer sleeve layer 1 is made of quartz.

[0051] In some embodiments, the cladding tube 2 is made of silica glass.

[0052] In some embodiments, the cladding tube 2 is made of polymethyl methacrylate (PMMA) material that can be used in the terahertz band.

[0053] It should be noted that, in the terahertz band, the cladding tube 2 can be made of polymethyl methacrylate (PMMA) tube material, and the refractive index (real part) of the material is approximately equal to that of silicon dioxide.

[0054] In some embodiments, see Figure 1 , the glass tube is a capillary tube 3'1 or a conjoined tube 3'2.

[0055] In some embodiments, the special gas 5 is one gas or a mixture of multiple gases selected from carbon dioxide, nitrogen, oxygen, argon and sulfur hexafluoride. The molecular weights of the gases are shown in Table 1.

[0056] Table 1

[0057] gas <![CDATA[CO2]]> <![CDATA[N2]]> <![CDATA[O2]]> <![CDATA[Ar2]]> <![CDATA[SF6]]> Molecular weight 44.01 28.01 32 39.95 146.06

[0058] The present application proposes a method for manufacturing an anti-resonant hollow-core optical fiber with low-loss, high-order mode and high-purity transmission, comprising steps S01 to S05.

[0059] S01, draw the optical fiber so that it has the following specific structure: Figure 1 , Figure 2 , including an outer sleeve layer 1 and multiple cladding tubes 2, the multiple cladding tubes 2 are tangent to the inner surface of the outer sleeve layer; the cladding tube includes an inner D-type tube 3 and an outer D-type tube 3' which are combined into a conjoined tube structure, the outer D-type tube 3' is tangent to the outer sleeve 1, and one or more glass tubes can be nested inside the outer D-type tube 3'; the middle part surrounded by the multiple cladding tubes constitutes the core 4 of the optical fiber.

[0060] S02, optical fiber selective blocking.

[0061] Step S02 specifically includes steps S021 to S024.

[0062] S021, using a fusion splicer to perform discharge processing on both ends of the hollow-core optical fiber, so that each cladding tube 2 is shortened inwardly by a first length at both ends, and the end surface of the cladding tube collapses and closes.

[0063] In the specific implementation, the fusion splicer can use Fujikura FSM-100P+ fusion splicer, set the discharge current and discharge time according to the geometric size of the optical fiber, and perform discharge treatment on both ends of the hollow-core optical fiber, so that each cladding tube 2 is shortened a certain distance inward from both ends, such as Figure 3 , Figure 4 As shown, a semicircular structure 21 is formed on the end surface.

[0064] In some embodiments, the first length range of each cladding tube 2 shortened inward from both ends does not exceed 200 μm. In the example, the cladding tube 2 collapses by 180 μm.

[0065] S022, injecting ultraviolet glue into the inner cavity of the fiber core 4 from both ends of the hollow-core optical fiber, and the injection depth is a second length.

[0066] In the specific implementation, by observing under a microscope, UV glue is injected into the inner cavity of the fiber core 4 at both ends of the hollow-core optical fiber, specifically, a high-transmittance UV curing resin of Japan NTT-AT6001. Due to the capillary effect, the UV glue flows along the glass wall into the fiber core 4, and the second length range of the injection depth is 200μm to 300μm. In the embodiment, it is 250um.

[0067] S023 , using an ultraviolet lamp curing device to cure the ultraviolet glue in the fiber core to form a second blocking layer 41 .

[0068] In the specific implementation, a Thorlabs--CS20K2 UV lamp curing device is used, the power is set to 100%, and the curing time is set to 60s to cure the UV glue in the fiber core 4, such as Figure 5 As shown, a second blocking layer 41 is formed.

[0069] S024, partially cutting off the second plugging layer 41, so that the fiber core is plugged by the ultraviolet glue and the cladding tube is open to the outside.

[0070] In a specific implementation, the side of the optical fiber is observed under a microscope. Figure 5 The sealing layer at both ends of the cladding tube 2 is cut off with a cutting knife at the dotted line position. In the embodiment, 220 μm is cut off. Figure 6 The cross section of an optical fiber with the core 4 sealed by UV glue and the cladding tube 2 open.

[0071] S03, optical fiber selective gas filling.

[0072] In a specific implementation, the inner D-shaped tube 3 and the outer D-shaped tube 3' are selectively filled with special gas 5 according to the experimental requirements. The special gas 5 is one gas or a mixed gas selected from carbon dioxide, nitrogen, oxygen, argon and sulfur hexafluoride as shown in Table 1 above. In this example, the inner and outer D-shaped tubes are filled with sulfur hexafluoride gas at an atmospheric pressure, such as Figure 7 As shown, sulfur hexafluoride is inside the cladding tube.

[0073] In some embodiments, the special gas may be filled into the inner D-shaped tube 3 alone, or the special gas may be filled into the inner D-shaped tube 3 and the outer D-shaped tube 3 ′ at the same time.

[0074] S04, fiber optic packaging.

[0075] Step S04 specifically includes steps S041 to S042.

[0076] S041, cutting off the remaining second plugging layer at both ends of the fiber core 4, so that the fiber core and the cladding tube are open to the outside.

[0077] In a specific implementation, the side of the optical fiber is observed under a microscope, such as Figure 7 As shown, the second plugging layer at both ends of the fiber core 4 is cut off with a cutting knife along the dotted line. In the embodiment, 50 μm is cut off. Figure 8 The special gas 5 filled in the cladding tube is sulfur hexafluoride gas, the fiber core is filled with air, and both the fiber core and the cladding tube are open to the outside.

[0078] S042, using a fusion splicer to perform discharge treatment on both ends of the hollow-core optical fiber, so that each cladding tube 2 collapses inward from both ends by a third length, and the end surface of the cladding tube collapses and closes, forming a first blocking layer 6.

[0079] In the specific implementation, the Fujikura FSM-100P+ fusion splicer is used to set the discharge current and discharge times, and discharge treatment is performed on both ends of the hollow-core optical fiber, so that each cladding tube 2 is shortened inward by a certain distance at both ends, such as Fig. 9 and Fig.10 As shown, a first blocking layer 6 is formed. Specifically, the two ends of each cladding tube 2 collapse inwardly by a third length not exceeding 200 μm, and in the example by 190 μm, and finally an antiresonant hollow core optical fiber with low loss, high-order mode and high-purity transmission is obtained.

[0080] The above content is only used to illustrate the technical solution of the present invention rather than to limit it. The present invention is not limited to the above optional implementation modes. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field, regardless of any changes in its shape or structure, should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An anti-resonant hollow core optical fiber with low loss, high order mode and high purity transmission, characterized in that: It comprises an outer sleeve layer and a plurality of cladding tubes, wherein the plurality of cladding tubes are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-shaped tube and an outer D-shaped tube which are combined into a conjoined tube structure, wherein the outer D-shaped tube is tangent to the outer sleeve; the middle part surrounded by the plurality of cladding tubes constitutes the core of the optical fiber; the cladding tube is filled with a special gas which is colorless, odorless, safe and easy to store; the end of the cladding tube collapses under heat to form a first blocking layer.

2. The anti-resonant hollow core optical fiber with low loss, high order mode and high purity transmission according to claim 1, characterized in that: One or more glass tubes are nested inside the outer D-shaped tube.

3. The anti-resonant hollow core optical fiber with low loss, high order mode and high purity transmission according to claim 1, characterized in that: The cladding tube is made of silica glass or polymethyl methacrylate material that can be used in the terahertz band.

4. The anti-resonant hollow core optical fiber with low loss, high order mode and high purity transmission according to claim 1, characterized in that: The glass tube is a capillary tube or a conjoined tube.

5. The anti-resonant hollow core optical fiber with low loss, high order mode and high purity transmission according to claim 1, characterized in that: The special gas is one gas or a mixed gas of carbon dioxide, nitrogen, oxygen, argon and sulfur hexafluoride.

6. A method for manufacturing an anti-resonant hollow core optical fiber with low loss, high-order mode and high purity transmission, characterized in that: include: Drawing the optical fiber to have the following structure: comprising an outer sleeve layer and a plurality of cladding tubes, wherein the plurality of cladding tubes are tangent to the inner surface of the outer sleeve layer; the cladding tube comprises an inner D-shaped tube and an outer D-shaped tube combined into a conjoined tube structure, wherein the outer D-shaped tube is tangent to the outer sleeve, and the middle part surrounded by the plurality of cladding tubes constitutes the core of the optical fiber; Selective plugging of optical fiber; Selective gas filling of optical fiber; Fiber optic packaging.

7. The method for manufacturing a low-loss high-order mode high-purity transmission anti-resonant hollow-core optical fiber according to claim 6, characterized in that: The optical fiber selective blocking specifically includes: Using a fusion splicer to perform discharge processing on both ends of the hollow-core optical fiber, so that each cladding tube is shortened inwardly by a first length at both ends, and the end surface of the cladding tube collapses and closes; Injecting ultraviolet glue into the inner cavity of the core from both ends of the hollow-core optical fiber, the injection depth being a second length, the first length being shorter than the second length; Using an ultraviolet lamp curing device to cure the ultraviolet glue in the fiber core to form a second plugging layer; Part of the second blocking layer is cut off, so that the fiber core is blocked by the ultraviolet glue and the cladding tube is open to the outside.

8. The method for manufacturing a low-loss high-order mode high-purity transmission anti-resonant hollow-core optical fiber according to claim 7, characterized in that: The optical fiber selective gas filling specifically comprises: The inner D-tube is filled with special gas alone, or the inner D-tube and the outer D-tube are filled with special gas at the same time.

9. The method for manufacturing a low-loss high-order mode high-purity transmission anti-resonant hollow-core optical fiber according to claim 8, characterized in that: The optical fiber package specifically includes: Cutting off the remaining part of the second plugging layer at both ends of the fiber core 4, so that the fiber core and the cladding tube are open to the outside; A fusion splicer is used to perform discharge treatment on both ends of the hollow-core optical fiber, so that each cladding tube collapses inward from both ends by a third length, and the end surface of the cladding tube collapses and closes to form a first blocking layer.

10. The method for manufacturing a low-loss high-order mode high-purity transmission anti-resonant hollow-core optical fiber according to claim 9, characterized in that: The third length ranges from no more than 200 μm.

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