Heterogeneous three-core anti-resonance optical fiber for transmission from visible light to intermediate infrared light

Abstract

The invention discloses a heterogeneous three-core anti-resonance optical fiber for transmission from visible light to intermediate infrared light, and belongs to the technical field of optical fiber communication. The heterogeneous three-core anti-resonance optical fiber comprises an outer cladding layer from outside to inside along the diameter of the optical fiber, a first inner cladding layer, a second inner cladding layer and a third inner cladding layer are arranged in the outer cladding layer, and a plurality of nesting pipe assemblies with the same structure are arranged in the first inner cladding layer, the second inner cladding layer and the third inner cladding layer at equal intervals in the circumferential direction. An upper air fiber core area, a lower left hollow fiber core area and a lower right air fiber core area are defined by the nesting pipe assembly. The upper air fiber core area, the lower left air fiber core area and the lower right air fiber core area respectively work in a 4m wave band, a 2m wave band and a 1m wave band, have extremely low limiting loss in the three working wave bands, and have good bending resistance performance at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber communication, and specifically relates to a heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission. Background Art

[0002] The visible light band is not only widely used in electromagnetic interference sensitive environments (such as hospitals, airplanes, etc.), but also due to its extremely small absorption and scattering coefficients in water, underwater visible light communication (UMVLC) has advantages such as high bandwidth and low latency compared with traditional acoustic communication, and is often used for high-speed information interaction between autonomous underwater vehicles (AUVs). The mid-infrared band is widely used in analyzing the spectral characteristics of biomolecules (such as proteins, fats, DNA, etc.), and with its coupled tissue absorption characteristics, it is used for precise cutting and treatment in laser surgery.

[0003] Currently, the research on hollow anti-resonant optical fibers mostly focuses on single-core and double-core optical fibers, and the research on three-core and composite structures is still relatively limited. In addition, the functions of existing optical fiber structures are single, limited to single-band or single-core low-loss transmission designs, and there are few hollow anti-resonant optical fibers that can meet the working requirements in the near-infrared band to the mid-infrared band. Summary of the Invention

[0004] The purpose of the present invention is to provide a heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission, which realizes ultra-low confinement loss in the visible light to mid-infrared band, and at the same time has extremely low bending loss, which is beneficial to realizing long-distance transmission and improving transmission quality.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] The present invention provides a heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission, which includes an outer cladding along the radial direction of the optical fiber from outside to inside, and a first inner cladding, a second inner cladding, and a third inner cladding are arranged inside the outer cladding.

[0007] A plurality of structurally identical nested tube assemblies are equidistantly arranged along the circumferential direction inside the first inner cladding, the second inner cladding, and the third inner cladding, and the plurality of structurally identical nested tube assemblies enclose to form an air core region.

[0008] The nested tube assemblies are respectively: a first nested tube assembly, a second nested tube assembly, and a third nested tube assembly;

[0009] The first nested tube assembly includes a first type of circular cladding tube, a first type of large elliptical cladding tube, and a first type of small elliptical cladding tube from outside to inside, all of which are tangent to the outer cladding and are welded to the outer cladding.

[0010] The second nested sleeve assembly includes, from outside to inside, a first type of semi-elliptical cladding tube, a second type of semi-elliptical cladding tube, and a third type of circular cladding tube. The first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are both welded to the outer cladding, and the third type of circular cladding tube is tangent to and welded to the outer cladding;

[0011] The third nested sleeve assembly includes, from outside to inside, a second type of circular cladding tube, a second type of large elliptical cladding tube, and a second type of small elliptical cladding tube, all of which are tangent to and welded to the outer cladding.

[0012] Preferably, a plurality of the first nested sleeve assemblies surround and form an upper air core region, a plurality of the second nested sleeve assemblies surround and form a lower left air core region, and a plurality of the third nested sleeve assemblies surround and form a lower right air core region. The upper air core region, the lower left air core region, and the lower right air core region are symmetrically distributed at 120°;

[0013] The upper air core region, the lower left air core region, and the lower right air core region operate in the 4 µm band, the 2 µm band, and the 1 µm band respectively.

[0014] Preferably, the diameter of the outer cladding is between 380 µm and 400 µm.

[0015] Preferably, a plurality of the first nested sleeve assemblies are symmetrically distributed in a C5 pattern, and the plurality of the first nested sleeve assemblies do not contact each other;

[0016] A plurality of the second nested sleeve assemblies are symmetrically distributed in a C4 pattern, and the plurality of the second nested sleeve assemblies do not contact each other;

[0017] A plurality of the third nested sleeve assemblies are symmetrically distributed in a C5 pattern, and the plurality of the third nested sleeve assemblies do not contact each other.

[0018] Preferably, the diameter of the first type of circular cladding tube is between 75 µm and 79 µm, the diameter of the second type of circular cladding tube is between 53 µm and 57 µm, and the diameter of the third type of circular cladding tube is between 35 µm and 38 µm.

[0019] Preferably, the major axis of the first type of large elliptical cladding tube is between 32 µm and 34 µm, the minor axis is between 20 µm and 22 µm, the major axis of the second type of large elliptical cladding tube is between 23 µm and 25 µm, the minor axis is between 14 µm and 16 µm, the major axis of the first type of small elliptical cladding tube is between 14 µm and 17 µm, the minor axis is between 11 µm and 13 µm, and the major axis of the second type of small elliptical cladding tube is between 10 µm and 12 µm, the minor axis is between 7 µm and 9 µm;

[0020] The major axis of the first type of semi-elliptical cladding tube is 54 µm to 56 µm, and the minor axis is 36 µm to 38 µm. The major axis of the second type of semi-elliptical cladding tube is 36 µm to 38 µm, and the minor axis is 27 µm to 29 µm.

[0021] Preferably, the outer cladding, the second type of circular cladding tube, the second type of large elliptical cladding tube, and the second type of small elliptical cladding tube are all made of silica, and the refractive index range of the silica material is between 1.37 and 1.46.

[0022] Preferably, the first type of circular cladding tube, the third type of circular cladding tube, the first type of large elliptical cladding tube, the first type of small elliptical cladding tube, the first type of semi-elliptical cladding tube, and the second type of semi-elliptical cladding tube are all made of ZBLAN, and the refractive index range of the ZBLAN material is between 1.47 and 1.56.

[0023] Preferably, between the first type of circular cladding tube, the first type of large elliptical cladding tube, and the first type of small elliptical cladding tube, between the first type of semi-elliptical cladding tube, the second type of semi-elliptical cladding tube, and the third type of circular cladding tube, between the second type of circular cladding tube, the second type of large elliptical cladding tube, and the second type of small elliptical cladding tube, inside the first type of small elliptical cladding tube, the second type of small elliptical cladding tube, and the third type of circular cladding tube, and in the upper air core region, the lower left air core region, and the lower right air core region, air is filled.

[0024] Preferably, the wall thicknesses of the second type of circular cladding tube, the second type of large elliptical cladding tube, and the second type of small elliptical cladding tube all satisfy:

[0025] ;

[0026] where is the designed operating wavelength, represents the refractive index of the silica material of the cladding tube, represents the refractive index of air, is the anti-resonant order;

[0027] The wall thicknesses of the first type of circular cladding tube, the third type of circular cladding tube, the first type of large elliptical cladding tube, the first type of small elliptical cladding tube, the first type of semi-elliptical cladding tube, and the second type of semi-elliptical cladding tube all satisfy:

[0028] ;

[0029] where is the designed operating wavelength, represents the refractive index of the ZBLAN material of the cladding tube.

[0030] Adopting the above technical solution, the present invention has at least the following beneficial effects:

[0031] In addition to ensuring the characteristics of anti-resonant fiber, the heterogeneous three-core hollow anti-resonant fiber in the present invention ensures extremely low confinement loss during light transmission in the visible to mid-infrared wavelength range, and the maximum loss is 7.40×10 - 10 dB / m. At the same time, the bending loss of the fiber in the X direction at 2μm, 3μm, and 4μm wavelength bands is at most 5.60×10 -9 dB / m, and the maximum in the Y direction is 1.33×10 -9 dB / m, indicating good bending resistance of the fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic cross-sectional view of the overall structure of the heterogeneous three-core anti-resonant fiber for visible to mid-infrared transmission provided by an embodiment of the present invention;

[0033] Figure 2 are the fundamental mode diagram and 3D diagram of the cross-section of the upper air core region in an embodiment of the present invention;

[0034] Figure 3 are the fundamental mode diagram and 3D diagram of the cross-section of the lower left air core region in an embodiment of the present invention;

[0035] Figure 4 are the fundamental mode diagram and 3D diagram of the cross-section of the lower right air core region in an embodiment of the present invention;

[0036] Figure 5 is a relationship diagram showing the variation of the confinement loss with the incident wavelength of a heterogeneous three-core anti-resonant fiber for visible to mid-infrared transmission provided by an embodiment of the present invention in the near-infrared to mid-infrared wavelength range;

[0037] Figure 6 is a relationship diagram showing the variation of the bending loss in the X direction with the bending radius at 2μm, 3μm, and 4μm of a heterogeneous three-core anti-resonant fiber for visible to mid-infrared transmission provided by an embodiment of the present invention;

[0038] Figure 7 is a relationship diagram showing the variation of the bending loss in the Y direction with the bending radius at 2μm, 3μm, and 4μm of a heterogeneous three-core anti-resonant fiber for visible to mid-infrared transmission provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Hereinafter, the specific embodiments of the present invention will be further described in detail in conjunction with the drawings and embodiments. The embodiments described by referring to the drawings are illustrative and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0040] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "end", "bottom", "side", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0041] In the present invention, unless otherwise clearly specified and defined, the terms "connection", "installation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a direct connection, or a connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Secondly, the so-called "one embodiment" or "embodiment" in the present invention refers to specific features, structures or characteristics that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not all refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0043] Please refer to Figure 1 , an embodiment of the present invention provides a heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission, which is applied to the visible light to mid-infrared band. From the outside to the inside along the radial direction of the optical fiber, it successively includes an outer cladding 1, a first inner cladding 2, a second inner cladding 3 and a third inner cladding 4 are arranged inside the outer cladding 1. The first inner cladding 2 includes an upper air core region 5, the second inner cladding 3 includes a lower left air core region 6, and the third inner cladding 4 includes a lower right air core region 7.

[0044] In this embodiment, the diameter of the outer cladding 1 is between 380 µm and 400 µm; such a thickness design of the outer cladding can minimize the optical field coupling degree of the upper air core region 5, the lower left air core region 6 and the lower right air core region 7 to the greatest extent, so as to operate stably in their respective independent bands.

[0045] In this embodiment, the upper air core region 5, the lower left air core region 6 and the lower right air core region 7 work in the 4 µm band, the 2 µm band and the 1 µm band respectively.

[0046] See Figure 2 , in this embodiment, a plurality of first embedded tube assemblies with the same structure are equidistantly arranged along the circumferential direction inside the first inner cladding 2. The plurality of first embedded tube assemblies are distributed in a C5 symmetry to surround and form the upper air core region 5. The first embedded tube assembly includes a first type of circular cladding tube 8, a first type of large elliptical cladding tube 9 and a first type of small elliptical cladding tube 10 from the outside to the inside. They are all tangent to the outer cladding 1 and are welded to the outer cladding 1. It should be noted that the plurality of first embedded tube assemblies do not contact each other.

[0047] See Figure 3 Figure 3 , in this embodiment, a plurality of second nested tube assemblies with the same structure are equidistantly arranged along the circumferential direction inside the second inner cladding 3. The plurality of second nested tube assemblies are symmetrically distributed in a C4 symmetry to enclose and form the lower left air core region 6. The second nested tube assembly includes a first type of semi-elliptical cladding tube 11, a second type of semi-elliptical cladding tube 12, and a third type of circular cladding tube 13 from the outside to the inside. The first type of semi-elliptical cladding tube 11 and the second type of semi-elliptical cladding tube 12 are both welded to the outer cladding 1. The third type of circular cladding tube 13 is tangent to the outer cladding 1 and welded to the outer cladding 1, and the first type of semi-elliptical cladding tube 11, the second type of semi-elliptical cladding tube 12, and the third type of circular cladding tube 13 do not contact each other. It should be noted that the plurality of second nested tube assemblies do not contact each other.

[0048] See Figure 4 Figure 4 , in this embodiment, a plurality of third nested tube assemblies with the same structure are equidistantly arranged along the circumferential direction inside the third inner cladding 4. The plurality of third nested tube assemblies are symmetrically distributed in a C5 symmetry to enclose and form the lower right air core region 7. The third nested tube assembly includes a second type of circular cladding tube 14, a second type of large elliptical cladding tube 15, and a second type of small elliptical cladding tube 16 from the outside to the inside, all of which are tangent to the outer cladding 1 and welded to the outer cladding 1. It should be noted that the plurality of third nested tube assemblies do not contact each other.

[0049] In this embodiment, the upper air core region 5, the lower left air core region 6, and the lower right air core region 7 are symmetrically distributed at 120°. Such a symmetric structure distribution minimizes the optical field coupling degree of the three air core regions and enables them to operate stably in their independent bands.

[0050] For the technical solution of this embodiment, a perfectly matched layer is provided on the outer side of the outer cladding 1, and the thickness of the perfectly matched layer is 8 µm to 12 µm, which is used to eliminate the differences between the fiber in model calculation and actual transmission.

[0051] It should be noted that the perfectly matched layer (PML) in the optical fiber is a special dielectric layer. By setting the truncation boundary in the finite-difference time-domain region, the wave impedance of its dielectric is exactly matched with that of the adjacent dielectric. This design enables the incident wave to pass through the interface without reflection and enter the PML, thereby achieving lossless energy transmission. The introduction of the PML is mainly to solve the problem of the difference between the optical fiber model in the simulation environment and the actual optical fiber environment. By setting appropriate boundary conditions, the environmental difference between the two is effectively eliminated, making the simulation results closer to the actual situation. The implementation principle of the PML is to set boundary conditions on the outer side of the cladding of the optical fiber that are the same as the cladding material and have a matched wave impedance. Therefore, it can be regarded as a non-reflective absorption layer. When the light beam is incident on the PML, it will not be immediately reflected back, but will gradually decay until it is finally completely absorbed. This non-reflective characteristic makes the PML an ideal boundary condition in simulation analysis. Especially when performing simulation analysis on large-mode-area optical fibers, the use of the PML can significantly improve the accuracy of the simulation results.

[0052] For the technical solution of this embodiment, the diameter of the first type of circular cladding tube 8 is 75 µm to 79 µm, the diameter of the second type of circular cladding tube 14 is 53 µm to 57 µm, and the diameter of the third type of circular cladding tube 13 is 35 µm to 38 µm.

[0053] Furthermore, the major axis of the first type of large elliptical cladding tube 9 is 32 µm to 34 µm, and the minor axis is 20 µm to 22 µm. The major axis of the second type of large elliptical cladding tube 15 is 23 µm to 25 µm, and the minor axis is 14 µm to 16 µm. The major axis of the first type of small elliptical cladding tube 10 is 14 µm to 17 µm, and the minor axis is 11 µm to 13 µm. The major axis of the second type of small elliptical cladding tube 16 is 10 µm to 12 µm, and the minor axis is 7 µm to 9 µm.

[0054] Furthermore, the major axis of the first type of semi-elliptical cladding tube 11 is 54 µm to 56 µm, and the minor axis is 36 µm to 38 µm. The major axis of the second type of semi-elliptical cladding tube 12 is 36 µm to 38 µm, and the minor axis is 27 µm to 29 µm. This semi-elliptical structure design can make the incident light more concentrated in the lower left air core region 6 to facilitate the stable transmission of light energy.

[0055] For the technical solution of this embodiment, the first type of circular cladding tube 8, the third type of circular cladding tube 13, the first type of large elliptical cladding tube 9, the first type of small elliptical cladding tube 10, the first type of semi-elliptical cladding tube 11, and the second type of semi-elliptical cladding tube 12 are all made of ZBLAN material, and the refractive index range of the ZBLAN material is between 1.47 and 1.56, which is greater than the refractive index of the silica material. Compared with the traditional silica material, this material has weaker absorption characteristics in the mid-infrared band, which can reduce the loss during the optical transmission process.

[0056] The outer cladding 1, the second type of circular cladding tube 14, the second type of large elliptical cladding tube 15, and the second type of small elliptical cladding tube 16 are all made of silica material, and the refractive index range of the silica material is between 1.37 and 1.46.

[0057] For the technical solution of this embodiment, between the first type of circular cladding tube 8, the first type of large elliptical cladding tube 9, and the first type of small elliptical cladding tube 10, between the first type of semi-elliptical cladding tube 11, the second type of semi-elliptical cladding tube 12, and the third type of circular cladding tube 13, between the second type of circular cladding tube 14, the second type of large elliptical cladding tube 15, and the second type of small elliptical cladding tube 16, and inside the first type of small elliptical cladding tube 10, the second type of small elliptical cladding tube 16, and the third type of circular cladding tube 13, the upper air core region 5, the lower left air core region 6, and the lower right air core region 7 are all filled with air, and the refractive index of the air is less than the refractive indices of the silica and ZBLAN materials, ensuring that the refractive index of the air is less than the refractive index of the silica material, which is convenient for making the incident light concentrate in the upper air core region 5, the lower left air core region 6, and the lower right air core region 7.

[0058] For the technical solution of this embodiment, the wall thicknesses of the second type of circular cladding tube 14, the second type of large elliptical cladding tube 15, and the second type of small elliptical cladding tube 16 all satisfy:

[0059] ;

[0060] wherein, is the designed working wavelength, represents the refractive index of the cladding silica material, represents the refractive index of the air, is the anti-resonant order number, which is a positive integer.

[0061] Furthermore, the wall thicknesses of the first type of circular cladding tube 8, the third type of circular cladding tube 13, the first type of large elliptical cladding tube 9, the first type of small elliptical cladding tube 10, the first type of semi-elliptical cladding tube 11, and the second type of semi-elliptical cladding tube 12 all satisfy:

[0062] ;

[0063] Among them, is the working wavelength of the design, represents the refractive index of the cladding ZBLAN material, represents the refractive index of air, is the anti-resonant order, which is a positive integer.

[0064] Furthermore, based on the working wavelength of this embodiment and the selected refractive indices of silica and ZBLAN materials, the wall thicknesses of the first type of circular cladding tube 8, the first type of large elliptical cladding tube 9, and the first type of small elliptical cladding tube 10 are 0.2 µm to 0.4 µm, the wall thicknesses of the first type of semi-elliptical cladding tube 11, the second type of semi-elliptical cladding tube 12, and the third type of circular cladding tube 13 are 0.4 µm to 0.8 µm, and the wall thicknesses of the second type of circular cladding tube 14, the second type of large elliptical cladding tube 15, and the second type of small elliptical cladding tube 16 are 0.8 µm to 1.1 µm.

[0065] For the technical solution of this embodiment, the number of embedded tube assemblies in the upper air core region and the lower right air core region is 5, and the number of embedded tube assemblies in the lower left air core region is 4, effectively reducing the leakage of optical signals and avoiding the generation of node losses.

[0066] Furthermore, use the finite element simulation software COMSOL Multiphysics to perform simulation tests on this embodiment, adopt the finite element method and combine the perfectly matched layer boundary absorption condition for theoretical calculation to obtain the confinement loss and the corresponding wavelength.

[0067] From Figure 5 it can be seen from the confinement loss of the fundamental mode that the maximum confinement loss of this optical fiber from the visible light, high-power transmission, optical communication band to the mid-infrared band is 7.4×10 -10 dB / m. Compared with 2.2×10 -4 dB / km of the traditional single-core hollow anti-resonant optical fiber, the loss is greatly reduced. At the same time, as shown in Figure 6 , Figure 7 , the maximum bending loss of this optical fiber in the X direction at 2 µm, 3 µm, and 4 µm bands is 5.60×10 -9 dB / m, and the maximum in the Y direction is 1.33×10 -9 dB / m, and the optical fiber has good anti-bending performance.

[0068] The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A heterogeneous three-core antiresonant optical fiber for visible light to mid-infrared transmission, comprising an outer cladding from the outside to the inside along the radial direction of the optical fiber, wherein a first inner cladding, a second inner cladding and a third inner cladding are arranged in the outer cladding, characterized in that: A plurality of nested tube assemblies with the same structure are arranged equidistantly in the circumferential direction inside the first inner cladding, the second inner cladding and the third inner cladding, and the plurality of nested tube assemblies with the same structure together form an air core region; The nested tube assemblies are respectively: a first nested tube assembly, a second nested tube assembly and a third nested tube assembly; The first nested tube assembly includes, from outside to inside, a first type of circular cladding tube, a first type of large elliptical cladding tube, and a first type of small elliptical cladding tube, all of which are tangent to the outer cladding and fused to the outer cladding; The second nested tube assembly comprises, from outside to inside, a first type of semi-elliptical cladding tube, a second type of semi-elliptical cladding tube and a third type of circular cladding tube, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are both fused to the outer cladding, and the third type of circular cladding tube is tangent to and fused to the outer cladding; The third nested tube assembly includes, from outside to inside, a second type of circular cladding tube, a second type of large elliptical cladding tube, and a second type of small elliptical cladding tube, all of which are tangent to the outer cladding and fused to the outer cladding.

2. A heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: A plurality of the first nested tube assemblies together form an upper air core region, a plurality of the second nested tube assemblies together form a lower left air core region, and a plurality of the third nested tube assemblies together form a lower right air core region, and the upper air core region, the lower left air core region, and the lower right air core region are symmetrically distributed at 120°; The upper air core region, the lower left air core region and the lower right air core region respectively operate in the 4µm band, the 2µm band and the 1µm band.

3. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The outer cladding has a diameter of 380µm to 400µm.

4. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The plurality of first nested tube assemblies are distributed in C5 symmetry, and the plurality of first nested tube assemblies do not contact each other; The plurality of second nested tube assemblies are distributed in C4 symmetry, and the plurality of second nested tube assemblies do not contact each other; The plurality of third nested tube assemblies are distributed in C5 symmetry, and the plurality of third nested tube assemblies do not contact each other.

5. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The diameter of the first type of circular cladding tube is 75µm ~79µm, the diameter of the second type of circular cladding tube is 53µm ~57µm, and the diameter of the third type of circular cladding tube is 35µm ~38µm.

6. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The first type of large elliptical cladding tube has a major axis of 32µm ~34µm and a minor axis of 20µm ~22µm, the second type of large elliptical cladding tube has a major axis of 23µm ~25µm and a minor axis of 14µm ~16µm, the first type of small elliptical cladding tube has a major axis of 14µm ~17µm and a minor axis of 11µm ~13µm, the second type of small elliptical cladding tube has a major axis of 10µm ~12µm and a minor axis of 7µm ~9µm; The major axis of the first type of semi-elliptical cladding tube is 54µm ~56µm, and the minor axis is 36µm ~38µm. The major axis of the second type of semi-elliptical cladding tube is 36µm ~38µm, and the minor axis is 27µm ~29µm.

7. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The outer cladding, the second type circular cladding tube, the second type large elliptical cladding tube and the second type small elliptical cladding tube are all made of silica, and the refractive index of the silica material ranges from 1.37 to 1.

46.

8. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 7, characterized in that: The first type of circular cladding tube, the third type of circular cladding tube, the first type of large elliptical cladding tube, the first type of small elliptical cladding tube, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are all made of ZBLAN material, and the refractive index range of the ZBLAN material is between 1.47 and 1.

56.

9. A heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to any one of claims 4, 5 or 6, characterized in that: The first type of circular cladding tube, the first type of large elliptical cladding tube and the first type of small elliptical cladding tube, the first type of semi-elliptical cladding tube, the second type of semi-elliptical cladding tube and the third type of circular cladding tube, the second type of large elliptical cladding tube and the second type of small elliptical cladding tube, and the interior of the first type of small elliptical cladding tube, the second type of small elliptical cladding tube and the third type of circular cladding tube, the upper air core region, the lower left air core region and the lower right air core region are all filled with air.

10. The heterogeneous three-core anti-resonant optical fiber for visible light to mid-infrared transmission according to claim 1, characterized in that: The wall thickness of the second type of circular cladding tube, the second type of large elliptical cladding tube and the second type of small elliptical cladding tube All meet the following requirements: ； in, is the designed working wavelength, represents the refractive index of the silica material of the cladding tube, is the refractive index of air, is the anti-resonance order; The wall thickness of the first type of circular cladding tube, the third type of circular cladding tube, the first type of large elliptical cladding tube, the first type of small elliptical cladding tube, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube All meet the following requirements: ； in, is the designed working wavelength, Indicates the refractive index of the ZBLAN material of the cladding tube.

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