Polarization-maintaining hollow-core anti-resonance optical fiber

Abstract

The invention provides a polarization-maintaining hollow-core anti-resonance optical fiber, and relates to the technical field of optics and laser photoelectronics, the polarization-maintaining hollow-core anti-resonance optical fiber is characterized in that a cladding region is provided with a plurality of anti-resonance circular tube groups, and each anti-resonance circular tube group comprises a first anti-resonance circular tube and a second anti-resonance circular tube embedded in the inner side of the first anti-resonance circular tube; under a rectangular coordinate system constructed by taking the center of the hollow fiber core area as a circle center, a first embedding point is arranged between a first anti-resonance circular tube and a second anti-resonance circular tube in the anti-resonance circular tube group close to the X axis, and a second embedding point is arranged between a first anti-resonance circular tube and a second anti-resonance circular tube in the anti-resonance circular tube group close to the Y axis; the first embedding point is closer to the boundary of the hollow fiber core area than the second embedding point. The beneficial effects are that the purpose of maintaining the polarization state of a transmission light field in the optical fiber is achieved by constructing the difference of the cladding region structures in the X-axis direction and the Y-axis direction near the boundary of the hollow fiber core region; moreover, the polarization-dependent birefringence of the optical fiber can be regulated and controlled in a relatively large range, and the polarization-maintaining performance of the optical fiber is optimized.

Description

Technical Field

[0001] The invention relates to the field of optics and laser optoelectronic technology, and in particular to a polarization-maintaining hollow-core anti-resonance optical fiber. Background Art

[0002] Hollow-core fiber is a major research direction in fiber optics. Because it uses the air core as the light-guiding area, hollow-core fiber has ultra-low Rayleigh scattering and nonlinear coefficients. In principle, it can achieve ultra-low loss, high power, and low-delay optical transmission. At present, hollow-core fiber can be mainly divided into hollow-core photonic bandgap fiber and hollow-core antiresonant fiber. The theoretical loss of hollow-core photonic bandgap fiber is much lower than that of standard solid-core single-mode fiber, but in the preparation process, it is inevitable to introduce a thin glass wall that plays a supporting role in the cladding structure. The surface scattering introduced by the thin glass wall makes it difficult for the actual hollow-core photonic bandgap fiber loss to be lower than that of standard solid-core single-mode fiber. In addition, the relatively narrow working bandwidth of such optical fibers (generally less than 10nm) limits its application range. Hollow-core antiresonant fiber also has low theoretical loss and a wide working bandwidth (generally several hundred nm), and the overlap between the cladding structure and the light field is small. It is less affected by factors such as surface scattering and material absorption, and it is easier to achieve low loss in preparation. In recent years, Southampton ORC has prepared hollow-core antiresonant fiber with a minimum loss of less than 0.11dB / km.

[0003] Whether the polarization-maintaining performance is good or not is the key to whether the optical fiber can be widely used. Technologies such as precision interferometric sensing, quantum communication, transmission of strongly polarized light and coherent beam combining are all based on the polarization-maintaining performance of the optical fiber. Polarization maintenance can be achieved in hollow-core antiresonant fibers by introducing higher polarization-dependent birefringence into them. However, unlike solid-core fibers, hollow-core fibers lack mechanical stress and have a small overlap between the core mode and the cladding material in the guide window, making it difficult to introduce larger birefringence by constructing orthogonal axial stress differences and geometric asymmetry. Hollow-core antiresonant fibers can introduce higher birefringence by utilizing the polarization-dependent effective refractive index changes introduced by the anti-cross-coupling effect between the core mode and the high-refractive-index medium mode in the cladding. At present, some polarization-maintaining hollow-core antiresonant fiber designs in academia and industry use the anti-cross-coupling mechanism to introduce larger birefringence (10 -4 ), but since some designed cladding structures contain elliptical or semicircular anti-resonant thin walls, it is difficult to achieve in preparation.

[0004] However, high birefringence is not a necessary condition for achieving high-performance polarization maintenance in hollow-core antiresonant fibers. For example, a study reported that hollow-core antiresonant fibers that are uniformly symmetrical in structure and have almost no birefringence can also achieve polarization maintenance because the polarization mode coupling coefficient in the orthogonal direction in the core region is extremely small; however, the polarization maintenance performance of such fibers is less resistant to external perturbations such as fiber bending. Therefore, exploring the relationship between the structural design of hollow-core antiresonant fibers and high-performance polarization maintenance is still a scientific problem that needs to be solved urgently in the field. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a polarization-maintaining hollow-core anti-resonance optical fiber, comprising a hollow-core core region, a cladding region and an outer circular tube region arranged in sequence from the inside to the outside, wherein the cladding region is provided with a plurality of anti-resonance circular tube groups, each of the anti-resonance circular tube groups comprising a first anti-resonance circular tube and a second anti-resonance circular tube embedded inside the first anti-resonance circular tube;

[0006] In a rectangular coordinate system constructed with the center of the hollow core region as the center of the circle, there is a first embedding point between the first anti-resonance circular tube and the second anti-resonance circular tube in the anti-resonance circular tube group close to the X-axis, and there is a second embedding point between the first anti-resonance circular tube and the second anti-resonance circular tube in the anti-resonance circular tube group close to the Y-axis;

[0007] The first embedding point is closer to the boundary of the hollow core region than the second embedding point.

[0008] Preferably, a third embedding point is provided between the first anti-resonance circular tube in the anti-resonance circular tube group and the outer circular tube region;

[0009] The corresponding third embedding point in the anti-resonance circular tube group close to the X-axis is not in contact with the first embedding point;

[0010] The corresponding third embedded point in the anti-resonance circular tube group close to the Y-axis is in contact with the second embedded point.

[0011] Preferably, the angular spacings between the anti-resonance circular tube groups are the same.

[0012] Preferably, the first anti-resonance round tubes used in different anti-resonance round tube groups have the same specifications, and the second anti-resonance round tubes have the same specifications.

[0013] Preferably, the number of the anti-resonance circular tube groups is no less than 4.

[0014] Preferably, at least one layer of third anti-resonance circular tube is embedded inside the second anti-resonance circular tube in the anti-resonance circular tube group close to the X-axis, and the embedding point between the third anti-resonance circular tube and the second anti-resonance circular tube contacts the first embedding point.

[0015] Preferably, at least one layer of third anti-resonance circular tube is embedded inside the second anti-resonance circular tube in the anti-resonance circular tube group close to the X-axis, and the embedding point between the third anti-resonance circular tube and the second anti-resonance circular tube does not contact the first embedding point.

[0016] Preferably, at least one layer of fourth anti-resonance circular tube is embedded inside the second anti-resonance circular tube in the anti-resonance circular tube group close to the Y-axis, and the embedding point between the fourth anti-resonance circular tube and the second anti-resonance circular tube contacts the second embedding point.

[0017] The above technical solution has the following advantages or beneficial effects:

[0018] 1) By flexibly controlling the deflection angle between the embedding point between the first antiresonant circular tube and the second antiresonant circular tube relative to the embedding point between the first antiresonant circular tube and the outer circular tube area, the difference in the cladding area structure in the X and Y axis directions near the boundary of the hollow core area is constructed to achieve the purpose of maintaining the polarization state of the transmitted light field in the optical fiber; in addition, due to the different designs of the X and Y axis directions, the polarization-dependent birefringence of the optical fiber can be controlled in a larger range (10 -6 ~10 -4 ) to optimize the polarization-maintaining performance of optical fiber;

[0019] 2) The structure is relatively simple, the cladding area is formed by a combination of regular round tubes, and the yield of the preparation is relatively high;

[0020] 3) There are many adjustable degrees of freedom, and it has great potential for performance optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional structural diagram of the polarization-maintaining hollow-core antiresonant optical fiber in Example 1;

[0022] FIG2 is a diagram of the fundamental mode electric field polarized along the X-axis on the cross section of the polarization-maintaining hollow-core antiresonant optical fiber of Example 1;

[0023] Figure 3 is a fundamental mode electric field diagram polarized along the Y-axis on a cross section of the polarization-maintaining hollow-core antiresonant optical fiber of Example 1;

[0024] Figure 4 Schematic diagram of the birefringence curve of the polarization-maintaining hollow-core antiresonant optical fiber of Example 1;

[0025] Figure 5is a cross-sectional structural diagram of a polarization-maintaining hollow-core antiresonant optical fiber in Example 2;

[0026] Figure 6 is a cross-sectional structural diagram of a polarization-maintaining hollow-core antiresonant optical fiber in Example 3;

[0027] Figure 7 is a cross-sectional structural diagram of a polarization-maintaining hollow-core antiresonant optical fiber in Example 4;

[0028] Figure 8 is a cross-sectional structural diagram of a polarization-maintaining hollow-core antiresonant optical fiber in Example 5;

[0029] Fig. 9 is a cross-sectional structural diagram of a polarization-maintaining hollow-core antiresonant optical fiber in Example 6;

[0030] Fig.10 This is a cross-sectional structural diagram of the polarization-maintaining hollow-core antiresonant optical fiber in Example 7. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment, and other embodiments may also fall within the scope of the present invention as long as they conform to the gist of the present invention.

[0032] In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a polarization-maintaining hollow-core anti-resonant optical fiber is provided. Figure 1 As shown, it includes a hollow core region 10, a cladding region 20 and an outer circular tube region 30 arranged in sequence from the inside to the outside, the cladding region 20 is provided with a plurality of anti-resonance circular tube groups 24, each anti-resonance circular tube group 24 includes a first anti-resonance circular tube 21 and a second anti-resonance circular tube 22 embedded inside the first anti-resonance circular tube 21;

[0033] In a rectangular coordinate system constructed with the center of the hollow core region 10 as the center, a first embedding point 23 is provided between the first anti-resonance circular tube 21 and the second anti-resonance circular tube 22 in the anti-resonance circular tube group 24 close to the X-axis, and a second embedding point 25 is provided between the first anti-resonance circular tube 21 and the second anti-resonance circular tube 22 in the anti-resonance circular tube group 24 close to the Y-axis;

[0034] The first embedding point 23 is closer to the boundary of the hollow core region 10 than the second embedding point 25 .

[0035] Specifically, in the present embodiment, the diameter d2 of the second anti-resonant circular tube 22 is smaller than the diameter d1 of the first anti-resonant circular tube 21, and each anti-resonant circular tube group 24 includes at least the first anti-resonant circular tube 21 and the second anti-resonant circular tube 22, wherein the first anti-resonant circular tube 21 in each anti-resonant circular tube group 24 is embedded in the inner side of the outer circular tube area 30 and is supported by the outer circular tube area 30.

[0036] In a preferred embodiment of the present invention, a third embedding point 31 is provided between the first anti-resonance circular tube 21 in the anti-resonance circular tube group 24 and the outer circular tube region 30;

[0037] The corresponding third embedding point 31 in the anti-resonance circular tube group 24 close to the X-axis is not in contact with the first embedding point 23;

[0038] The corresponding third embedding point 31 in the anti-resonance circular tube group 24 close to the Y-axis contacts the second embedding point 25 .

[0039] Specifically, the relative position relationship between the first embedding point and the second embedding point is described below with the central axis of the first anti-resonance circular tube 21 as the rotation axis:

[0040] The present invention controls the rotation angle of the first embedded point 23 between the first antiresonant circular tube 21 and the second antiresonant circular tube 22 in the antiresonant circular tube group 24 in the X-axis and Y-axis directions in the cladding region 20 relative to the third embedded point 31 between the first antiresonant circular tube 21 and the outer circular tube region 30 around the rotation axis, thereby constructing the structural difference of the cladding region 20 in the X-axis and Y-axis directions near the boundary of the hollow core region 10, and achieving the purpose of maintaining the polarization state of the transmitted light field. Specifically, the structural difference of the cladding region 20 in the X-axis and Y-axis directions causes the overlap of the fundamental mode of the optical fiber core region along the X-axis and Y-axis polarization and the cladding region structure to have a geometric difference, which gives the optical fiber the ability to maintain the polarization state of the transmitted light field. In addition, the structural difference of the cladding region 20 in the X-axis and Y-axis directions causes the action of a differentiated anti-cross coupling mechanism, which causes a difference in the effective mode refractive index between the fundamental modes along the X-axis and Y-axis polarizations, resulting in birefringence in orthogonal polarization directions, which can optimize the polarization-maintaining performance of the optical fiber to a certain extent. The present invention is based on the above principles to realize a polarization-maintaining hollow-core antiresonant optical fiber. Therefore, it can be understood that the parameters in all the structures disclosed in the present disclosure are only exemplary parameters and are not intended to limit the inventive concept of the present disclosure.

[0041] The range of the above rotation angle is (0°, 360°). It is understandable that the range of the above rotation angle does not include 0° and 360°. By adjusting the rotation angle, the difference degree of the hollow core anti-resonant fiber cladding region structure on the X and Y axes can be adjusted; specifically, adjusting the "difference degree" will change the coupling strength between the orthogonal polarization direction mode and the structure, thereby adjusting the polarization maintaining ability of the hollow core anti-resonant fiber.

[0042] Embodiment 1:

[0043] It can be seen Figure 1The figure shows the case where the rotation angle is 180 degrees clockwise. In this embodiment, the number of anti-resonance circular tube groups 24 is six, which are symmetrically distributed relative to the X-axis / Y-axis. Among them, the anti-resonance circular tube group 24 of the first embedding point 23 obtained by rotating the third embedding point 31 180 degrees clockwise is close to the X-axis and located on the X-axis. Figure 1 The structure shown is simulated using the finite element method, and under certain exemplary constraints on structural parameters, the following results are obtained: Figure 2a The fundamental mode electric field diagram along the X-axis polarization on the cross section of the optical fiber shown in the figure is as follows: Figure 2b The fundamental mode electric field diagram along the Y-axis polarization on the optical fiber cross section shown in FIG. Figure 3 The electric field cross-section diagram of the X- and Y-axis orthogonal polarization fundamental modes in the X-axis direction is shown as an enlarged diagram within the range of 27.5μm to 32.5μm on the X-axis.

[0044] from Figure 2a and Figure 2b It can be seen that the degree of overlap between the fundamental mode polarized along the Y axis and the cladding structure of the optical fiber in the X axis direction is significantly higher than the degree of overlap between the fundamental mode polarized along the X axis and the cladding structure of the optical fiber in the X axis direction.

[0045] from Figure 3 It can be seen that the fundamental mode energy of the Y-axis polarization is distributed in the second antiresonant circular tube in the X-axis direction, while the fundamental mode energy of the X-axis polarization is mainly distributed near the core. The fundamental modes polarized in the X and Y directions overlap with the cladding structure in the X-axis direction with obvious differences, indicating that the waveguide structures in different directions have different constraints on the light field. Figure 4 The finite element simulation is given Figure 1 The birefringence curve of the structure shown is in the window (1.4 μm-1.8 μm) under certain exemplary constraints on structural parameters.

[0046] In a preferred embodiment of the present invention, the angular spacings between the anti-resonance circular tube groups 24 are the same, that is, the anti-resonance circular tube groups 24 are evenly distributed in the cladding region 20 .

[0047] In a preferred embodiment of the present invention, the first anti-resonance circular tubes 21 used in different anti-resonance circular tube groups 24 have the same specifications, and the second anti-resonance circular tubes 22 have the same specifications. The specifications here refer to that the first anti-resonance circular tubes 21 used in different anti-resonance circular tube groups 24 have the same diameter, wall thickness and material, and the second anti-resonance circular tubes 22 used in different anti-resonance circular tube groups 24 also have the same diameter, wall thickness and material, and the first anti-resonance circular tubes 21 and the second anti-resonance circular tubes 22 in the same anti-resonance circular tube group 24 can have the same wall thickness and material, or different wall thickness and material.

[0048] In a preferred embodiment of the present invention, the number of the anti-resonance circular tube groups 24 is not less than 4, and can be an odd number or an even number, which is not limited here.

[0049] Embodiment 2:

[0050] like Figure 5 As shown, Figure 1 The same six antiresonant circular tube groups 24 are used, but the two antiresonant circular tube groups 24 located on the X-axis may not have a symmetrical structure, that is, in each antiresonant circular tube group 24 close to the X-axis, the rotation angle of the first embedded point 23 relative to the third embedded point 31 may be different, and its purpose is also to adjust the degree of difference in the cladding region structure of the hollow-core antiresonant optical fiber on the X and Y axes; specifically, adjusting the "degree of difference" will change the coupling strength between the orthogonal polarization direction mode and the structure, thereby adjusting the polarization maintaining ability of the hollow-core antiresonant optical fiber.

[0051] Embodiment 3:

[0052] like Figure 6 As shown, Figure 1 The same six anti-resonance circular tube groups 24 are used, but Figure 1 In the figure, there are two anti-resonant circular tube groups 24 close to the X-axis and four anti-resonant circular tube groups 24 close to the Y-axis. In the present embodiment, there are four anti-resonant circular tube groups 24 close to the X-axis and two anti-resonant circular tube groups 24 close to the Y-axis. The six anti-resonant circular tube groups 24 are also axially symmetrically distributed about the X-axis / Y-axis.

[0053] By changing the number of antiresonant tube groups 24 on both sides of the X and Y axis directions and the rotation angle of the embedding point between the first antiresonant tube 21 and the second antiresonant tube 22, the difference degree of the hollow-core antiresonant optical fiber cladding region structure on the X and Y axes can be adjusted.

[0054] Embodiment 4:

[0055] like Figure 7 As shown, a structure with five anti-resonance circular tube groups 24 is used, wherein the anti-resonance circular tube group 24 close to the X-axis can be located on the X-axis or on both sides of the X-axis, and the anti-resonance circular tube group 24 close to the Y-axis can be partially located on the Y-axis.

[0056] It can be seen that the number of anti-resonance circular tube groups 24 in the positive direction and negative direction of the X-axis can be different; the number of anti-resonance circular tube groups 24 on both sides of the Y-axis direction orthogonal to the X-axis can also be different. By changing the number of anti-resonance circular tube groups 24 on both sides of the X-axis and Y-axis directions, the difference in the cladding region structure of the hollow-core anti-resonance optical fiber on the X-axis and Y-axis can be adjusted.

[0057] Example 5

[0058] At least one layer of third anti-resonance circular tubes 26 is embedded inside the second anti-resonance circular tubes 22 in the anti-resonance circular tube group 24 close to the X-axis, and the embedding point between the third anti-resonance circular tube 26 and the second anti-resonance circular tube 22 is not in contact with the first embedding point 23 .

[0059] like Figure 8 As shown, in the anti-resonant circular tube group 24 on both sides of the X-axis direction, the third anti-resonant circular tube 26 is embedded in the second anti-resonant circular tube 22, and the central axis of the second anti-resonant circular tube 22 is used as the rotation axis. The embedding point between the second anti-resonant circular tube 22 and the third anti-resonant circular tube 26 is rotated 180 degrees clockwise compared to the embedding point between the first anti-resonant circular tube 21 and the second anti-resonant circular tube 22.

[0060] It should be noted that: the third anti-resonance circular tube additionally embedded in the above manner, or the multi-layer nested tubes in this manner, can add one or more layers of anti-resonance circular tubes in the X-axis direction, so that the part of light leaked from the hollow core region 10 to the cladding region 20 through the embedding point between the first anti-resonance circular tube 21 and the second anti-resonance circular tube 22 on the X-axis and anti-resonated back to the core is increased, on the one hand, the difference in the structure of the cladding region of the hollow core anti-resonance optical fiber on the X and Y axes is adjusted, and on the other hand, the transmission loss of the polarization-maintaining hollow core anti-resonance optical fiber is reduced.

[0061] Embodiment 6:

[0062] At least one layer of fourth anti-resonance circular tubes 27 is embedded inside the second anti-resonance circular tubes 22 in the anti-resonance circular tube group 24 close to the Y-axis, and the embedding point between the fourth anti-resonance circular tube 27 and the second anti-resonance circular tube 22 contacts the second embedding point 31 .

[0063] like Fig. 9 As shown, in the anti-resonance circular tube group 24 on both sides of the Y-axis direction, the fourth or multiple anti-resonance circular tubes are embedded inside the second anti-resonance circular tube 22, and the central axis of the second anti-resonance circular tube 22 is used as the rotation axis. The embedding point between the second and fourth anti-resonance circular tubes is rotated 0 degrees clockwise compared to the embedding point between the first and second anti-resonance circular tubes.

[0064] It can be understood that the third or multiple layers of antiresonant circular tubes embedded in the Y-axis direction can adjust the difference in the cladding region structure of the hollow-core antiresonant optical fiber on the X and Y axes on the one hand, and reduce the transmission loss of the polarization-maintaining hollow-core antiresonant optical fiber on the other hand.

[0065] Embodiment 7:

[0066] At least one layer of third anti-resonance circular tubes 26 is embedded inside the second anti-resonance circular tubes 22 in the anti-resonance circular tube group 24 close to the X-axis, and the embedding point between the third anti-resonance circular tube 26 and the second anti-resonance circular tube 22 contacts the first embedding point 23 .

[0067] like Fig.10As shown, in the anti-resonance circular tube group 24 on both sides of the X-axis direction, the third anti-resonance circular tube 26 is embedded inside the second anti-resonance circular tube 22, and the central axis of the second anti-resonance circular tube 22 is used as the rotation axis. The embedding point between the second and third anti-resonance circular tubes is rotated 0 degrees clockwise compared to the embedding point between the first and second anti-resonance circular tubes.

[0068] It can be understood that the third or multiple layers of anti-resonance circular tubes embedded in the X-axis direction can adjust the difference in the cladding region structure of the hollow-core anti-resonance optical fiber on the X and Y axes.

[0069] Embodiment 8:

[0070] The first anti-resonance round tube 21 and the second anti-resonance round tube 22 in the same anti-resonance round tube group 24 may have the same wall thickness and material, or may have different wall thickness and material.

[0071] In this embodiment, the first anti-resonance circular tube 21 and the second anti-resonance circular tube 22 have different wall thicknesses.

[0072] It can be understood that adjusting the wall thickness of the first antiresonant circular tube 21 and the wall thickness of the second antiresonant circular tube 22 respectively can control the degree of structural difference in the orthogonal direction of the hollow-core antiresonant optical fiber, control the polarization-maintaining performance of the optical fiber and change the magnitude of the polarization-dependent birefringence.

[0073] Embodiment 9:

[0074] In this embodiment, the first anti-resonance tube 21 and the second anti-resonance tube 22 in the cladding region 20 are made of different materials.

[0075] It can be understood that the essence of changing the material of the antiresonance tube wall is to change the refractive index of the antiresonance tube wall, which is equivalent to changing the wall thickness of the antiresonance tube wall, thereby regulating the degree of structural difference in the orthogonal direction of the hollow-core antiresonance optical fiber, regulating the polarization-maintaining performance of the optical fiber and changing the size of the polarization-dependent birefringence.

[0076] In summary, the optical fiber structure of the present invention is simple and reasonable, and is relatively easy to prepare. In addition, the optical fiber structure disclosed herein has great optimization potential, and can improve the polarization maintaining performance within a wide window and reduce the transmission loss of light by continuing to add new antiresonant circular tubes, adjusting the size of the hollow core, the embedding point depth, the size of each antiresonant circular tube, and the number of antiresonant circular tube groups in the orthogonal axis direction.

[0077] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A polarization-maintaining hollow-core antiresonant optical fiber, characterized in that: It includes a hollow core region, a cladding region and an outer circular tube region which are arranged in sequence from the inside to the outside, wherein the cladding region is provided with a plurality of anti-resonance circular tube groups, and each of the anti-resonance circular tube groups includes a first anti-resonance circular tube and a second anti-resonance circular tube embedded inside the first anti-resonance circular tube; In a rectangular coordinate system constructed with the center of the hollow core region as the center of the circle, there is a first embedding point between the first anti-resonance circular tube and the second anti-resonance circular tube in the anti-resonance circular tube group close to the X-axis, and there is a second embedding point between the first anti-resonance circular tube and the second anti-resonance circular tube in the anti-resonance circular tube group close to the Y-axis; The first embedding point is closer to the boundary of the hollow core region than the second embedding point.

2. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: A third embedding point is provided between the first anti-resonance circular tube in the anti-resonance circular tube group and the outer circular tube region; The corresponding third embedding point in the anti-resonance circular tube group close to the X-axis is not in contact with the first embedding point; The corresponding third embedded point in the anti-resonance circular tube group close to the Y-axis is in contact with the second embedded point.

3. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: The angular spacings between the anti-resonance circular tube groups are the same.

4. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: The first anti-resonance round tubes used in different anti-resonance round tube groups have the same specifications, and the second anti-resonance round tubes have the same specifications.

5. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: The number of the anti-resonance circular tube groups is no less than 4.

6. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: At least one layer of third anti-resonance circular tubes is embedded inside the second anti-resonance circular tubes in the anti-resonance circular tube group close to the X-axis, and an embedding point between the third anti-resonance circular tube and the second anti-resonance circular tube contacts the first embedding point.

7. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: At least one layer of third anti-resonance circular tubes is embedded inside the second anti-resonance circular tubes in the anti-resonance circular tube group close to the X-axis, and the embedding point between the third anti-resonance circular tube and the second anti-resonance circular tube does not contact the first embedding point.

8. The polarization-maintaining hollow-core antiresonant optical fiber according to claim 1, characterized in that: At least one layer of fourth anti-resonance circular tubes is embedded inside the second anti-resonance circular tubes in the anti-resonance circular tube group close to the Y axis, and an embedding point between the fourth anti-resonance circular tube and the second anti-resonance circular tube contacts the second embedding point.

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