High-single-mode ultra-low-loss hollow-core anti-resonance optical fiber

Abstract

The invention relates to a high-single-mode ultra-low-loss hollow-core anti-resonance optical fiber which comprises an outer cladding and an inner cladding, the inner cladding is composed of nested structure units, the nested structure units are arranged in the circumferential direction of the inner wall of the outer cladding and are connected with the inner wall of the outer cladding, a fiber core is formed by a central cavity wrapped by the inner cladding, and the fiber core is connected with the inner cladding through the nested structure units. The embedded glass tube is characterized in that each embedded structure unit comprises three or more layers of embedded glass tubes with different radiuses, at least one embedded glass tube with at least one layer of embedded glass tubes deflects towards one side relative to the adjacent outer embedded glass tube, and the deflection included angle is 5-55 degrees. According to the invention, through the change of the cladding structure, the reasonable nested structure unit shape capable of being prepared, the optimized nested size combination and the deflection of the embedded glass tube, the leakage loss of the LP11 mode is obviously improved, the influence on the fundamental mode performance is small, and finally the single-mode performance of the optical fiber is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of hollow core optical fibers, in particular to a high single-mode ultra-low loss hollow core anti-resonance optical fiber, belonging to the technical field of optical communication and transmission. Background Art

[0002] Hollow-core antiresonant optical fiber has a unique microstructure design that can confine the transmitted light wave in the air core, and has important applications in the fields of interaction between light and filling materials, nonlinear optics, gas detection, gas laser generation, optofluidic technology, etc.; due to its unique structure and light-guiding mechanism, it can obtain ultra-low Rayleigh scattering, low nonlinear coefficient, and adjustable dispersion characteristics, which can provide a higher laser damage threshold, making it potentially applicable in high-power laser transmission, ultraviolet / mid-infrared light transmission, pulse compression, and optical soliton transmission; the air core's ultra-low loss, low dispersion, low nonlinearity, and propagation speed close to the speed of light can realize the development of hollow-core optical fiber communication transmission and communication devices, laying the foundation for the construction and development of the next generation of ultra-large capacity, low-latency, and high-speed optical communication systems.

[0003] Even though hollow-core optical fiber has unique and huge advantages in design and application, the high-order modes of hollow-core optical fiber cannot be effectively filtered out like solid-core single-mode optical fiber because it does not naturally have high-order mode cutoff conditions. This will greatly limit its application scenarios in short-distance transmission. Research work in recent years has shown that reasonable structural design can improve the leakage loss of high-order mode modes to a certain extent, thereby producing an effect close to single-mode after a certain distance.

[0004] The commonly used method for filtering out high-order modes is to select a high-attenuation cladding mode and make it highly phase-matched with the LP11 mode in the fiber core through structural design, thereby effectively improving the leakage loss of the LP11 mode. The key factors in this design method are: the native attenuation of the cladding mode and its phase matching with the LP11 mode. Generally speaking, the higher the attenuation of the cladding mode and the higher the phase matching with the LP11 mode, the greater the improvement in the leakage of the LP11 mode and the better the single-mode property.

[0005] US Patent US11733451B2 discloses a single-ring hollow core antiresonant fiber. The patent proposes to use the high-loss antiresonant unit (ARE) mode to highly phase-match the core LP11 mode. The structure is very simple, the drawing difficulty is relatively low, and it can achieve an ultra-high high-order mode suppression ratio. When the cladding tube and core size ratio is about 0.68, a broadband high single-mode effect can be achieved, and the LP11 mode attenuation can reach 10 2However, this structure is difficult to achieve ultra-low attenuation transmission. Currently, the lowest attenuation in the near-infrared band is 4.3dB / km (1080nm), and the attenuation in the communication band is even higher. In addition, the bending resistance is poor, so it does not have much advantage in many applications in the near-infrared band.

[0006] Chinese patent CN110515152B discloses a single nested tube nodeless hollow core antiresonant fiber (Nested Anti-Resonant Nodeless Fiber, NANF) and a double nested tube nodeless hollow core antiresonant fiber (Double Nested Anti-Resonant Nodeless Fiber, DNANF). These two structures effectively reduce the transmission loss of the fundamental mode by increasing the number of antiresonant layers. For NANF fiber, its minimum attenuation has reached 0.22dB / km, and DNANF has broken the minimum attenuation record of traditional solid core fiber, reaching 0.11dB / km. However, while achieving ultra-low attenuation, the above two optical fibers also keep the loss of the LP11 mode at a very low level. When the NANF structure realizes the optimal resonant leakage design of the LP11 mode, the theoretical LP11 attenuation is about 10 2 ~10 3 dB / km level, under actual manufacturing and placement conditions, the current maximum can reach 2.6dB / m. The native attenuation of its cladding mode has been greatly reduced with the increase in the number of structural layers, so the attenuation of the LP11 mode cannot reach a sufficiently high level. This situation is more serious in the DNANF structure: first, the attenuation of the cladding mode in the DNANF structure is further reduced; second, there is not enough space in the cladding area of ​​the DNANF structure to achieve sufficient phase matching between the LP11 mode and the cladding mode, and the theoretical attenuation of the LP11 mode is already less than 10 2 dB / km, which means that DNANF fiber cannot effectively filter out high-order modes, seriously affecting the signal transmission quality. Summary of the invention

[0007] The problem to be solved by the present invention is to provide a high single-mode ultra-low loss hollow-core anti-resonant optical fiber to address the deficiencies of the above-mentioned prior art, thereby improving the high-order mode loss and achieving high-purity single-mode transmission through changes in the cladding structure.

[0008] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: it includes an outer cladding and an inner cladding, the inner cladding is composed of nested structural units, the nested structural units are arranged along the circumference of the inner wall of the outer cladding and connected to the inner wall of the outer cladding, and the central cavity covered by the inner cladding forms a fiber core, characterized in that the nested structural units include 3 or more layers of nested glass tubes with different radii, and at least one inner nested glass tube of at least one layer of inner nested glass tubes is deflected to one side relative to its adjacent outer nested glass tube, and the deflection angle is 5 to 55°.

[0009] According to the above scheme, the deflected inner nested glass tubes are included in 1 layer or 2 layers of inner nested glass tubes.

[0010] According to the above scheme, the nested structural unit includes three layers of nested glass tubes with different radii, including an outer nested glass tube, a first inner nested glass tube and a second inner nested glass tube from the outside to the inside. The first inner nested glass tube is deflected to one side relative to the outer nested glass tube or the second inner nested glass tube is deflected to one side relative to the first inner nested glass tube.

[0011] According to the above scheme, the nested structural unit includes three layers of nested glass tubes with different radii, including an outer nested glass tube, a first inner nested glass tube and a second inner nested glass tube from the outside to the inside. The first inner nested glass tube is deflected to one side relative to the outer nested glass tube and the second inner nested glass tube is deflected to one side relative to the first inner nested glass tube.

[0012] According to the above scheme, the first inner nested glass tube is deflected to one side relative to the outer nested glass tube, that is, the line L2 connecting the center of curvature O2 of the first inner nested glass tube and the center of curvature O1 of the outer nested glass tube forms a deflection angle with the extended line L1 connecting the center of curvature O1 of the outer nested glass tube and the geometric center O of the fiber core.

[0013] According to the above scheme, the second inner nested glass tube is deflected to one side relative to the first inner nested glass tube, that is, the line L3 connecting the curvature center O3 of the second inner nested glass tube and the curvature center O2 of the first inner nested glass tube forms a deflection angle with the extension line L2 connecting the curvature center O2 of the first inner nested glass tube and the curvature center O1 of the outer nested glass tube.

[0014] According to the above scheme, the inner cladding layer includes 4 to 6 nested structural units.

[0015] According to the above solution, the nested structural units are evenly spaced along the circumference of the inner wall of the outer cladding.

[0016] According to the above scheme, the outer cladding and the inner wall are both circular.

[0017] According to the above scheme, the nested glass tubes include circular nested glass tubes with different radii, each circular nested glass tube is tangent to another, and the outer nested glass tube is tangent to the inner cavity wall of the outer cladding.

[0018] According to the above scheme, the nested glass tubes include arc nested glass tubes and circular nested glass tubes with different radii, wherein each arc nested glass tube intersects with the inner wall of the outer cladding or with the adjacent outer nested glass tube, each circular nested glass tube is tangent to each circular nested glass tube, or each circular nested glass tube is tangent to the inner wall of the outer cladding.

[0019] According to the above scheme, the nested glass tubes include arc-shaped nested glass tubes with different radii, and each arc-shaped nested glass tube intersects with the inner wall of the outer cladding.

[0020] According to the above scheme, all the inner nested glass tubes in one layer of the inner nested glass tubes are deflected to the same side relative to their adjacent outer nested glass tubes, and the deflection angles are the same or substantially the same.

[0021] According to the above solution, all the first inner nested glass tubes are deflected to the same side relative to the outer nested glass tubes, and the deflection angles are the same or substantially the same, and all the second inner nested glass tubes are not deflected relative to the first inner nested glass tubes.

[0022] According to the above scheme, all the first inner nested tubes are deflected to the same side relative to the outer nested glass tube, and the deflection angles are the same or substantially the same, and all the second inner nested tubes are deflected to the opposite side relative to the first inner nested glass tube, and the deflection angles are the same or substantially the same.

[0023] According to the above scheme, all the inner nested glass tubes of the first inner nested tubes are deflected to the same side relative to the outer nested glass tubes, and the deflection angles are the same or substantially the same, and all the inner nested glass tubes of the second inner nested tubes are deflected to the same side relative to the first inner nested glass tubes, and the deflection angles are the same or substantially the same.

[0024] According to the above scheme, the second inner nested tube is a circular nested glass tube, the first inner nested tube is a circular nested glass tube or an arc nested glass tube, and the outer nested glass tube is an arc nested glass tube.

[0025] According to the above scheme, the second inner nested tube is an arc nested glass tube, the first inner nested tube is an arc nested glass tube or a circular nested glass tube, and the outer nested glass tube is an arc nested glass tube.

[0026] According to the above scheme, the deflection angle is 15 to 55°; further, the deflection angle is 25 to 50°; further, the deflection angle is 35 to 45°.

[0027] According to the above solution, the outer cladding layer and the base material of the nested structural unit are both pure quartz glass.

[0028] According to the above scheme, the wall thickness of the inner and outer nested glass tubes is 0.3 to 1.5 μm.

[0029] According to the above scheme, the ratio of the outer diameter of the outer nested glass tube to the first inner nested glass tube is 1:0.5-0.65, and the ratio of the outer diameter of the first inner nested glass tube to the second inner nested glass tube is 1:0.3-0.5.

[0030] According to the above scheme, the core region and other hollow regions within the outer cladding are filled with gas.

[0031] According to the above scheme, the gas is argon, nitrogen, helium, air or a mixture of multiple gases.

[0032] According to the above solution, the fundamental mode loss of the optical fiber is 0.05-0.5 dB / km. Furthermore, the fundamental mode loss of the optical fiber is lower than 0.15 dB / km.

[0033] According to the above solution, the high-order mode loss of the optical fiber is 3-20 dB / m, and further, the high-order mode loss of the optical fiber is higher than 8 dB / m.

[0034] The beneficial effects of the present invention are as follows: 1. In the structure of the present invention, the inner cladding includes a multi-layer anti-resonant quartz wall and an air layer, and the transmitted fundamental mode is effectively confined in the core, and the limiting loss is reduced; the present invention significantly improves the leakage loss of the LP11 mode through the change of the cladding structure, and has a reasonable and manufacturable nested structural unit shape, an optimized nested size combination and a deflection of the inner nested glass tube, and has a small impact on the fundamental mode performance, and finally effectively improves the single-mode performance of the optical fiber. The key to the present invention is that when the ratio of the outer diameter of the outer nested glass tube to the inner nested glass tube is optimized to the best, the inner nested glass tube is deflected to one side in the outer nested glass tube, and the structure can improve the leakage efficiency of the LP11 mode, thereby obtaining higher single-mode performance. 2. The present invention designs the phase matching of the core high-order mode and the mode of the inner air region, and designs to increase the cladding mode loss, so that the high-order mode leaks more efficiently, further improves the attenuation of the high-order mode, and has excellent single-mode transmission performance; 3. The single-mode performance of the present invention does not have wavelength selectivity, and highly single-mode transmission can be achieved within the working wavelength. The present invention provides a hollow core optical fiber that takes into account both attenuation and single-mode characteristics, and provides a transmission medium with excellent performance for the fields of high-speed communication, high-power transmission, gas lasers, gas detection, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a radial cross-sectional structural diagram of the first embodiment of the present invention.

[0036] Figure 2 yes Figure 1 A detailed enlarged view of one of the nested tubes.

[0037] Figure 3 Graph showing how the fundamental mode and LP11 mode losses vary with the rotation angle in the first embodiment of the present invention.

[0038] Figure 4 Graph showing how the fundamental mode and LP11 mode losses vary with wavelength in the first embodiment of the present invention.

[0039] Figure 5 It is a radial cross-sectional structural diagram of the second embodiment of the present invention.

[0040] Figure 6 It is a radial cross-sectional structural diagram of the third embodiment of the present invention.

[0041] Figure 7 It is a radial cross-sectional structural diagram of the fourth embodiment of the present invention.

[0042] Figure 8 It is a radial cross-sectional structural diagram of the fifth embodiment of the present invention.

[0043] Fig. 9 4 is a graph showing the variation of fundamental mode and LP11 mode losses with wavelength in the fifth embodiment of the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below in conjunction with the embodiments of the present invention and the accompanying drawings.

[0045] The commonly used high-order mode filtering method in hollow-core optical fiber is to select a high-attenuation cladding mode and make it highly phase-matched with the LP11 mode in the core through structural design, thereby effectively improving the leakage loss of the LP11 mode. In general, the designed LP11 mode attenuation depends on the native attenuation of the cladding mode and its phase matching degree with the LP11 mode. In general, the higher the attenuation of the cladding mode and the higher the phase matching degree with the LP11 mode, the greater the leakage improvement of the LP11 mode and the better the single-mode property.

[0046] The first embodiment of the present invention is Figure 1 , 2As shown, it includes an outer cladding 1 and an inner cladding, the inner cladding is composed of 4 nested structural units, the nested structural units are arranged at intervals along the circumference of the inner wall of the outer cladding, the nested structural units include 3 layers of nested glass tubes with different radii, including an outer nested glass tube 2, a first inner nested glass tube 3 and a second inner nested glass tube 4 from the outside to the inside, forming an anti-resonance unit, the nested glass tubes include an arc nested glass tube and two circular nested glass tubes with different radii, wherein the outer nested glass tube is an arc nested glass tube with a diameter of d1, the first inner nested glass tube and the second inner nested glass tube are circular nested glass tubes, the diameters of the first inner nested glass tube and the second inner nested glass tube are d2 and d3 respectively, the outer nested glass tube and the inner wall of the outer cladding are 100 mm thick, and the outer nested glass tube is 100 mm thick. The first inner nested glass tube is tangent to the inner wall of the outer cladding and deflects to one side, that is, the line L2 connecting the center of curvature (center of circle) of the first inner nested glass tube and the center of curvature (center of circle) of the outer nested glass tube forms a deflection angle with the extended line L1 connecting the center of curvature of the outer nested glass tube and the geometric center of the fiber core, and the deflection angle is θ1. The second inner nested glass tube is tangent to the first inner nested glass tube, and the tangent point is located at the same point where the first inner nested glass tube is tangent to the inner wall of the outer cladding; the line L3 connecting the center of curvature (center of circle) of the first inner nested glass tube and the center of curvature (center of circle) of the second inner nested glass tube forms an opposite deflection angle with L2, and the deflection angle is θ2; the deflection directions of all inner nested glass tubes are consistent. The central cavity covered by the inner cladding forms the fiber core 5, and the fiber core area and other internal spaces are filled with gas. The gas is argon, nitrogen, helium, air or a mixture of multiple gases. Specifically: the relevant parameters of this embodiment are: the core diameter D is 29μm, the outer diameter d1 of the outer nested glass tube is 44μm, and the circumference angle of the arc is 245°; the outer diameter d2 of the first inner nested glass tube is 24μm, and the ratio to the outer diameter of the outer nested glass tube is 0.55; the outer diameter d3 of the second inner nested glass tube is 10μm, and the ratio to the outer diameter of the first inner nested glass tube is 0.41; the inner diameter of the outer cladding (outer cladding cavity diameter) is 105μm. In this embodiment, the wall thickness of each nested glass tube is 1.1μm. When the wall thickness of each nested glass tube is about 0.95μm, the second resonant working band is extended to 1310nm. When the first anti-resonance window is used as the communication working band, the wall thickness of each nested glass tube is about 0.5μm. Figure 3The optimization process of the rotation angle θ1 of this embodiment is demonstrated: when θ1 is 0°, all structures are not deflected, and the LP01 and LP11 mode losses are 0.025dB / km and 2200dB / km (2.2dB / m) respectively; when θ1 is 15°, the LP01 and LP11 mode losses are 0.026dB / km and 2500dB / km (2.5dB / m) respectively; when θ1 is 30°, the LP01 and LP11 mode losses are 0.032dB / km and 3500d / km respectively. B / km(3.5dB / m); when θ1 is 35°, the LP01 and LP11 mode losses are 0.037dB / km and 4500dB / km(4.5dB / m) respectively; when θ1 is 40°, the LP01 and LP11 mode losses are 0.045dB / km and 6300dB / km(6.3dB / m) respectively; when θ1 is 44°, the LP01 and LP11 mode losses are 0.053dB / km and 8300dB / km(8.3dB / m) respectively. The increase of the rotation angle θ1 greatly improves the single-mode performance of the optical fiber, and does not significantly increase the fundamental mode loss.

[0047] The present invention combines a reasonable and manufacturable nested structural unit shape, an optimized nested size combination and a deflection of the inner nested glass tube, which comprehensively produces the following technical effects: significantly improving the leakage loss of the LP11 mode, with less impact on the fundamental mode performance, and ultimately effectively improving the single-mode performance of the optical fiber. Figure 4 This is the optimized attenuation spectrum curve of this embodiment, at which the deflection angle between L1 and L2 is 44°, and the reverse deflection angle between L2 and L3 is 40°. In a wide band, the design effect of ultra-low attenuation and ultra-high single-mode performance is shown.

[0048] The second embodiment of the present invention is Figure 5As shown, it is different from the first embodiment in that the inner cladding is composed of 5 nested structural units, the outer nested glass tube is a circular nested glass tube, the outer nested glass tube is tangent to the inner wall of the outer cladding, the first inner nested glass tube is tangent to the outer nested glass tube and does not deflect relative to the outer nested glass tube, that is, the line L2 connecting the center of curvature (center of circle) of the first inner nested glass tube and the center of curvature (center of circle) of the outer nested glass tube, and the extended line L2 connecting the center of curvature of the outer nested glass tube and the geometric center of the fiber core 1 overlaps; the second inner nested glass tube is tangent to the first inner nested glass tube, and the second inner nested glass tube is deflected to one side relative to the tangent point between the first inner nested glass tube and the inner wall of the outer cladding, that is, a line L3 connecting the center of curvature (center of circle) of the second inner nested glass tube and the center of curvature (center of circle) of the first inner nested glass tube has a deflection angle with an extension line L2 connecting the center of curvature of the first inner nested glass tube and the center of curvature of the outer nested glass tube, and the deflection angle is 30°; the deflection directions of all the inner nested glass tubes are consistent.

[0049] The third embodiment of the present invention is Figure 6 As shown, it is different from the second embodiment in that the outer nested glass tube is an arc nested glass tube, the circumferential angle of the arc is about 320°, and the outer nested glass tube intersects with the inner wall of the outer cladding. The first inner nested glass tube is tangent to the inner wall of the outer cladding and deflects to one side, that is, the line L2 connecting the center of curvature (center of circle) of the first inner nested glass tube and the center of curvature (center of circle) of the outer nested glass tube forms a deflection angle with the extended line L1 connecting the center of curvature of the outer nested glass tube and the geometric center of the fiber core, and the deflection angle is 35°. The second inner nested glass tube is tangent to the first inner nested glass tube, and the tangent point is located at the same point where the first inner nested glass tube is tangent to the inner wall of the outer cladding. The line L3 connecting the center of curvature (center of circle) of the first inner nested glass tube and the center of curvature (center of circle) of the second inner nested glass tube forms an opposite deflection angle with L2, and the deflection angle is 30°.

[0050] The fourth embodiment of the present invention is Figure 7 As shown, the difference between it and the second embodiment is that the second inner nested glass tube is a circular nested glass tube, the first inner nested glass tube is an arc nested glass tube, and the outer nested glass tube is an arc nested glass tube. The outer nested glass tube and the first inner nested glass tube both intersect with the inner wall of the outer cladding, the first inner nested glass tube does not deflect relative to the outer nested glass tube, and the deflection angle is 0, and the second inner nested glass tube deflects to one side relative to the first inner nested glass tube, that is, the line L3 connecting the center of curvature of the second inner nested glass tube and the center of curvature of the first inner nested glass tube forms a deflection angle with the extension line L2 connecting the center of curvature of the first inner nested glass tube and the center of curvature of the outer nested glass tube, and the deflection angle is 35°.

[0051] The fifth embodiment of the present invention is Figure 8 As shown, it is different from the first embodiment in that the outer nested glass tube and the first inner nested glass tube are arc nested glass tubes, the second inner nested glass tube is a circular nested glass tube, the outer nested glass tube and the first inner nested glass tube intersect with the inner wall of the outer cladding, and the second inner nested glass tube is tangent to the inner wall of the outer cladding; all the first inner nested glass tubes are deflected to the same side relative to the outer nested glass tube, and the deflection angles are the same or substantially the same, that is, the connection of the curvature center (center of circle) of the first inner nested glass tube and the curvature center (center of circle) of the outer nested glass tube is Line L2 forms a deflection angle with the extension line L1 of the line connecting the center of curvature of the outer nested glass tube and the geometric center of the fiber core, and the deflection angle is 28°. All the second inner nested tubes are deflected to the opposite side relative to the first inner nested glass tube, and the deflection angles are the same or substantially the same, that is, the line L3 connecting the center of curvature of the second inner nested glass tube and the center of curvature of the first inner nested glass tube forms an opposite deflection angle with the extension line L2 connecting the center of curvature of the first inner nested glass tube and the center of curvature of the outer nested glass tube, and the deflection angle is 24°. Specifically, the relevant parameters of this embodiment are: the core diameter D is 29 μm, the outer diameter d1 of the outer nested glass tube is 44 μm, and the circumference angle of the arc is 245°; the outer diameter d2 of the first inner nested glass tube is 28 μm, and the ratio to the outer diameter of the outer nested glass tube is 0.64; the outer diameter d3 of the second inner nested glass tube is 10 μm, and the ratio to the outer diameter of the first inner nested glass tube is 0.36; the inner diameter of the outer cladding (the outer cladding cavity diameter) is 105 μm. In this embodiment, the wall thickness of each nested glass tube is 1.1 μm. Fig. 9 According to the attenuation spectrum curve of this embodiment, it can be achieved that within a broadband range, the LP11 mode attenuation reaches nearly 10000 dB / km (10 dB / m) and the fundamental mode transmission loss is less than 0.1 dB / km.

Claims

1. A high single-mode ultra-low loss hollow-core anti-resonant optical fiber, comprising an outer cladding and an inner cladding, wherein the inner cladding is composed of nested structural units, the nested structural units are arranged along the circumference of the inner wall of the outer cladding and connected to the inner wall of the outer cladding, and the central cavity covered by the inner cladding forms a fiber core, characterized in that The nested structural unit comprises 3 or more layers of nested glass tubes with different radii, and at least one inner nested glass tube of at least one layer is deflected to one side relative to its adjacent outer nested glass tube, and the deflection angle is 5-55°.

2. The high single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1, characterized in that The deflected inner nested glass tubes are included in 1 layer or 2 layers of inner nested glass tubes.

3. The high single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 2, characterized in that The nested structural unit includes three layers of nested glass tubes with different radii, including an outer nested glass tube, a first inner nested glass tube and a second inner nested glass tube from the outside to the inside. The first inner nested glass tube is deflected to one side relative to the outer nested glass tube or the second inner nested glass tube is deflected to one side relative to the first inner nested glass tube.

4. The high single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 2, characterized in that The nested structural unit includes three layers of nested glass tubes with different radii, including an outer nested glass tube, a first inner nested glass tube and a second inner nested glass tube from the outside to the inside. The first inner nested glass tube is deflected to one side relative to the outer nested glass tube and the second inner nested glass tube is deflected to one side relative to the first inner nested glass tube.

5. The high single-mode ultra-low loss hollow-core anti-resonance optical fiber according to claim 3 or 4, characterized in that The first inner nested glass tube is deflected to one side relative to the outer nested glass tube, that is, a line L2 connecting the curvature center O1 of the first inner nested glass tube and the curvature center O2 of the outer nested glass tube forms a deflection angle with an extended line L1 connecting the curvature center O1 of the outer nested glass tube and the core geometric center O.

6. The high single-mode ultra-low loss hollow-core anti-resonance optical fiber according to claim 3 or 4, characterized in that The second inner nested glass tube is deflected to one side relative to the first inner nested glass tube, that is, a line L3 connecting the curvature center O3 of the second inner nested glass tube and the curvature center O2 of the first inner nested glass tube forms a deflection angle with an extension line L2 connecting the curvature center O2 of the first inner nested glass tube and the curvature center O1 of the outer nested glass tube.

7. The high single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The inner cladding layer comprises 4 to 6 nested structural units.

8. The high single-mode ultra-low loss hollow-core anti-resonance optical fiber according to claim 1 or 2, characterized in that The nested structural units are evenly spaced along the circumference of the inner wall of the outer cladding.

9. The high single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The outer cladding and the inner wall are both circular.

10. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The nested glass tubes include circular nested glass tubes with different radii, each circular nested glass tube is tangent to another, and the outer nested glass tube is tangent to the inner cavity wall of the outer cladding.

11. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The nested glass tubes include arc nested glass tubes and circular nested glass tubes with different radii, wherein each arc nested glass tube intersects with the inner wall of the outer cladding or with the adjacent outer nested glass tube, each circular nested glass tube is tangent to each circular nested glass tube, or each circular nested glass tube is tangent to the inner wall of the outer cladding.

12. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The nested glass tubes include arc-shaped nested glass tubes with different radii, and each arc-shaped nested glass tube intersects with the inner wall of the outer cladding.

13. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that All the inner nested glass tubes of one layer in the inner nested glass tubes are deflected to the same side relative to their adjacent outer nested glass tubes, and the deflection angles are the same or substantially the same.

14. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3, characterized in that All the first inner nested glass tubes are deflected to the same side relative to the outer nested glass tubes, and the deflection angles are the same or substantially the same, and all the second inner nested glass tubes are not deflected relative to the first inner nested glass tubes.

15. The high single-mode ultra-low loss hollow-core anti-resonance optical fiber according to claim 4, characterized in that All the first inner nested tubes are deflected to the same side relative to the outer nested glass tube, and the deflection angles are the same or substantially the same. All the second inner nested tubes are deflected to the opposite side relative to the first inner nested glass tube, and the deflection angles are the same or substantially the same.

16. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 4, characterized in that All the first inner nested tubes are deflected to the same side relative to the outer nested glass tube, and the deflection angles are the same or substantially the same. All the second inner nested tubes are deflected to the same side relative to the first inner nested glass tube, and the deflection angles are the same or substantially the same.

17. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The second inner nested tube is a circular nested glass tube, the first inner nested tube is a circular nested glass tube or an arc nested glass tube, and the outer nested glass tube is an arc nested glass tube.

18. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The second inner nested tube is an arc nested glass tube, the first inner nested tube is an arc nested glass tube or a round nested glass tube, and the outer nested glass tube is an arc nested glass tube.

19. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The deflection angle is 15-55°.

20. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The deflection angle is 25-50°.

21. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The deflection angle is 35-45°.

22. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The outer cladding layer and the base material of the nested structural unit are both pure quartz glass.

23. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The wall thickness of the inner and outer nested glass tubes is 0.3 to 1.5 μm.

24. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 3 or 4, characterized in that The ratio of the outer diameters of the outer nested glass tube to the first inner nested glass tube is 1:0.5-0.65, and the ratio of the outer diameters of the first inner nested glass tube to the second inner nested glass tube is 1:0.3-0.

5.

25. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The core region and other hollow regions within the outer cladding are filled with gas.

26. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 25, characterized in that The gas is argon, nitrogen, helium, air or a mixture of multiple gases.

27. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The fundamental mode loss of the optical fiber is 0.05-0.5 dB / km.

28. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The fundamental mode loss of the optical fiber is lower than 0.15 dB / km.

29. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The high-order mode loss of the optical fiber is 3-20 dB / m.

30. The highly single-mode ultra-low loss hollow-core anti-resonant optical fiber according to claim 1 or 2, characterized in that The high-order mode loss of the optical fiber is higher than 8dB / m.

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