A hollow core anti-resonant optical fiber based on a polygonal outer jacket

Abstract

The application discloses a kind of hollow core anti-resonant optical fiber based on polygonal outer sleeve, including first type circular medium pipe, second type circular medium pipe, third type circular medium pipe, first type polygonal outer sleeve and air core surrounded by the outer wall of first type circular medium pipe, the first type circular medium pipe circumscribes first type polygonal outer sleeve, the third type circular medium pipe is inscribed in first type circular medium pipe, circumscribes second type circular medium pipe.The application uses the above-mentioned one kind of hollow core anti-resonant optical fiber based on polygonal outer sleeve, optical fiber has multiple anti-resonant layers, outer sleeve is polygonal, reduces cladding node, effectively reduces the limit loss, increases transmission bandwidth.In addition, optical fiber mode is mainly distributed in air hole, can effectively reduce the material absorption loss of optical fiber, improve the damage threshold of optical fiber, can be used for high-power laser transmission, fiber laser and fiber sensor.

Description

Technical Field

[0001] This invention relates to the field of optical fiber technology, and in particular to a hollow anti-resonant optical fiber based on a polygonal outer sheath. Background Technology

[0002] Hollow-core fiber is a type of optical fiber that primarily confines light to a central hollow region, with only a small portion of the light propagating within the solid fiber material. Due to its unique structure and light-guiding mechanism, hollow-core fiber overcomes the inherent limitations of traditional optical fiber waveguide materials. With the development of optical fiber technology, the shortcomings of traditional solid-core fiber, such as low damage threshold and high nonlinearity, have become increasingly apparent. Compared to traditional solid-core fiber, hollow-core fiber offers advantages such as simple structure, ease of fabrication, low loss, large bandwidth, high damage threshold, and low delay, and is therefore widely used in optical communication, optical sensors, high-power laser transmission, and fiber lasers.

[0003] The cladding of hollow antiresonant fiber typically consists of a ring of circular dielectric tubes, which are fixed to the fiber's outer sheath for structural stability. Nested hollow antiresonant fiber refers to a cladding tube with a smaller cladding tube nested within each cladding tube. Based on the principle of antiresonance reflection, the nested structure, by incorporating additional antiresonant glass layers, can further effectively reduce the fiber's confinement loss. The nested negative curvature hollow fiber prepared by WJ Belardi et al. [W. Belardi, Design and properties of hollow antiresonant fibers for the visible and near infrared spectral range. J. Lightw. Technol., 2015, 32: 4497~4503] has a loss of 175 dB / km at a wavelength of 480 nm. The dielectric wall thickness near the core differs significantly from that further away from the core, resulting in a high loss region. In 2016, X. Huang et al. from Nanyang Technological University [X. Huang, W. Qi, D. Ho, K. T. Yong, F. Luan, and S. Yoo, Hollow core anti-resonant fiber with split cladding. Opt. Express 24(7), 7670–7678(2016)] designed an improved hollow-core anti-resonant fiber composed of a triple-cladding ring. Anti-resonant reflection was supplemented by nesting a set of adjacent smaller circular tube arrays within the hollow-core anti-resonant fiber. However, this structure increases the number of cladding nodes in the fiber, and the coupling between the core mode and cladding mode caused by these nodes leads to increased loss. In common nested hollow-core anti-resonant fibers, adding dielectric layers is usually adopted to reduce loss; however, the added dielectric layers often increase the number of cladding nodes, failing to fully utilize the advantages of the additional anti-resonant glass wall layers. Summary of the Invention

[0004] The purpose of this invention is to provide a hollow-core antiresonant optical fiber based on a polygonal cladding tube. The fiber has multiple antiresonant layers, and the polygonal cladding tube reduces cladding nodes, effectively lowering confinement loss and increasing transmission bandwidth. Furthermore, the fiber modes are mainly distributed within the air holes, effectively reducing material absorption loss and increasing the fiber's damage threshold. This allows for applications in high-power laser transmission, fiber lasers, and fiber optic sensors.

[0005] To achieve the above objectives, the present invention provides an air-core anti-resonant optical fiber based on a polygonal outer tube, comprising a first type of circular dielectric tube, a second type of circular dielectric tube, a third type of circular dielectric tube, a first type of polygonal outer tube, and an air core surrounded by the outer wall of the first type of circular dielectric tube. The first type of circular dielectric tube is externally tangent to the first type of polygonal outer tube, and the third type of circular dielectric tube is internally tangent to the first type of circular dielectric tube and externally tangent to the second type of circular dielectric tube.

[0006] The second type of circular dielectric tube is connected to the third type of circular dielectric tube and has no node with the first type of circular dielectric tube. The air fiber core is surrounded by the outer walls of multiple first type of circular dielectric tubes, and the radius of the inscribed circle of the surrounding contour is the radius r of the air fiber core. core .

[0007] Preferably, the thickness of the first type of circular dielectric tube, the second type of circular dielectric tube, and the third type of circular dielectric tube is all t.

[0008] Preferably, the first type of circular medium tube contains two third type of circular medium tubes, and has two tangent points with the first type of polygonal outer tube. The two tangent points of the first type of circular medium tube and the first type of polygonal outer tube are located on the inner and outer walls of the first type of circular medium tube at the same position as the two tangent points of the first type of circular medium tube and the third type of circular medium tube.

[0009] Preferably, the first type of polygonal outer sleeve is rectangular, pentagonal, or hexagonal.

[0010] Preferably, the number of the first type of circular dielectric tubes is 4, 5, or 6.

[0011] Preferably, the optical fiber is made of any one of silicon dioxide, soft glass, or plastic.

[0012] Therefore, this invention employs a hollow-core antiresonant optical fiber based on a polygonal cladding tube. The fiber has multiple antiresonant layers, and the polygonal cladding tube reduces cladding nodes, effectively lowering confinement loss and increasing transmission bandwidth. Furthermore, the fiber modes are primarily distributed within the air holes, effectively reducing material absorption loss and increasing the fiber's damage threshold. This allows for applications in high-power laser transmission, fiber lasers, and fiber optic sensors.

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a nested hollow anti-resonant optical fiber with a pentagonal outer tube, based on an embodiment of the present invention.

[0015] Figure 2 This is a schematic diagram of a nested hollow anti-resonant optical fiber with a rectangular outer tube, based on an embodiment of the present invention of a hollow anti-resonant optical fiber with a polygonal outer tube.

[0016] Figure 3 This is a schematic diagram of a nested hollow anti-resonant optical fiber with a hexagonal outer tube, based on an embodiment of the present invention.

[0017] Figure 4 This is a schematic diagram of the limiting loss of the fundamental mode in Embodiment 1 of the hollow anti-resonant optical fiber based on a polygonal outer tube according to the present invention;

[0018] Figure 5 This is a schematic diagram of the limiting loss of the fundamental mode in Embodiment 2 of the hollow anti-resonant optical fiber based on a polygonal outer tube according to the present invention;

[0019] Figure 6 This is a schematic diagram of the limiting loss of the fundamental mode in Embodiment 3 of the hollow anti-resonant optical fiber based on a polygonal outer tube according to the present invention.

[0020] Figure Labels

[0021] 1. Type I circular dielectric tube; 2. Type II circular dielectric tube; 3. Type III circular dielectric tube; 4. Type I polygonal outer tube; 5. Core region. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Example 1

[0025] This invention provides a nested hollow anti-resonant optical fiber based on a pentagonal outer tube, such as... Figure 1As shown, it includes a first type of circular dielectric tube 1, a second type of circular dielectric tube 2, a third type of circular dielectric tube 3, a first type of polygonal outer tube 4, and an air fiber core surrounded by the outer wall of the first type of circular dielectric tube 1. The function of the first type of circular dielectric tube 1, the second type of circular dielectric tube 2, and the third type of circular dielectric tube 3 is to reduce losses.

[0026] The first type of circular medium tube 1 is externally tangent to the first type of polygonal outer tube 4 and has two points of tangency with the first type of polygonal outer tube 4. Two third type of circular medium tubes 3 are disposed inside the first type of circular medium tube 1. The third type of circular medium tube 3 is internally tangent to the first type of circular medium tube 1 and externally tangent to the second type of circular medium tube 2. The two points of tangency between the first type of circular medium tube 1 and the first type of polygonal outer tube 4, and the two points of tangency between the first type of circular medium tube 1 and the third type of circular medium tube 3, are located on the inner and outer walls of the first type of circular medium tube 1 at the same position.

[0027] Both the first type of circular dielectric tube 1 and the third type of circular dielectric tube 3 are connected to the first type of polygonal outer tube 4. The second type of circular dielectric tube 2 is connected to the third type of circular dielectric tube 3 and has no node with the first type of circular dielectric tube 1. The absence of nodes between the two achieves the effect of high bandwidth and low loss.

[0028] The thicknesses of the first type circular dielectric tube 1, the second type circular dielectric tube 2, and the third type circular dielectric tube 3 are all t, and they satisfy the anti-resonance reflection waveguide principle. The air fiber core is surrounded by the outer walls of multiple first type circular dielectric tubes 1, and the radius of the inscribed circle of the enclosing contour fiber core region 5 is the fiber core radius r. core Air cores can effectively reduce the material absorption loss of optical fibers.

[0029] The first type of polygonal outer tube 4 has a pentagonal cross-section; the first type of circular dielectric tube 1 and the second type of circular dielectric tube 2 each have 5; the third type of circular dielectric tube 3 has 10; the optical fiber material is any one of silicon dioxide, soft glass or plastic.

[0030] In this embodiment, the outer dielectric tube radius of the first type of circular dielectric tube 1 is 21.0 μm, the outer dielectric tube radius of the second type of circular dielectric tube 2 is 10.0 μm, and the outer dielectric tube radius of the third type of circular dielectric tube 3 is 7.4 μm. The thickness of all dielectric tubes is t = 0.58 μm, and the radius of the air core in the central region is 16.5 μm. This embodiment was simulated and tested using the finite element simulation software Comsol Multiphysics. Figure 4As shown, at a wavelength of 1.40 μm, the confinement loss of the fundamental mode obtained by numerical simulation is 0.017 dB / km. The lowest confinement loss in this embodiment is measured at 1.47 μm, which is 0.005 dB / km. Within the operating wavelength range of 1.34 μm-1.69 μm, the confinement loss of the fiber core fundamental mode can be lower than 0.1 dB / km, with a bandwidth of 350 nm.

[0031] Example 2

[0032] This invention provides a nested hollow anti-resonant optical fiber based on a rectangular outer tube, such as... Figure 2 As shown, the first type of polygonal outer tube 4 has a rectangular cross-section, the first type of circular dielectric tube 1 and the second type of circular dielectric tube 2 are both 4, and the third type of circular dielectric tube 3 is 8; the optical fiber material is any one of silicon dioxide, soft glass or plastic.

[0033] In this embodiment, the outer dielectric tube radius of the first type of circular dielectric tube 1 is 25.0 μm, the outer dielectric tube radius of the second type of circular dielectric tube 2 is 12.0 μm, and the outer dielectric tube radius of the third type of circular dielectric tube 3 is 9.4 μm. The thickness of all dielectric tubes is t = 0.58 μm, and the radius of the air core in the central region is 16.5 μm. This embodiment was simulated and tested using the finite element simulation software Comsol Multiphysics. Figure 5 As shown, at a wavelength of 1.40 μm, the confinement loss of the fundamental mode obtained by numerical simulation is 0.286 dB / km. The lowest confinement loss in this embodiment is measured at 1.62 μm, which is 0.092 dB / km. Within the operating wavelength range of 1.34 μm-1.80 μm, the confinement loss of the fiber core fundamental mode can be lower than 0 dB / km, with a bandwidth of 460 nm.

[0034] Example 3

[0035] This invention provides a nested hollow anti-resonant optical fiber based on a hexagonal outer tube, such as... Figure 3 As shown, the first type of polygonal outer tube 4 has a hexagonal cross-section, the first type of circular dielectric tube 1 and the second type of circular dielectric tube 2 are both 6, and the third type of circular dielectric tube 3 is 12; the optical fiber material is any one of silicon dioxide, soft glass or plastic.

[0036] In this embodiment, the outer dielectric tube radius of the first type of circular dielectric tube 1 is 16.0 μm, the outer dielectric tube radius of the second type of circular dielectric tube 2 is 8.4 μm, and the outer dielectric tube radius of the third type of circular dielectric tube 3 is 5.0 μm. The thickness of all dielectric tubes is t = 0.58 μm, and the core radius in the central region is 16.5 μm. This embodiment was simulated and tested using the finite element simulation software Comsol Multiphysics. Figure 6 As shown, at a wavelength of 1.40 μm, the confinement loss of the fundamental mode obtained by numerical simulation is 0.027 dB / km. The lowest confinement loss in this embodiment is measured at 1.45 μm, which is 0.019 dB / km. Within the operating wavelength range of 1.34 μm-1.50 μm, the confinement loss of the fiber core fundamental mode can be lower than 0.1 dB / km, with a bandwidth of 160 nm.

[0037] Therefore, this invention employs a hollow-core antiresonant optical fiber based on a polygonal cladding tube. The fiber has multiple antiresonant layers, and the polygonal cladding tube reduces cladding nodes, effectively lowering confinement loss and increasing transmission bandwidth. Furthermore, the fiber modes are primarily distributed within the air holes, effectively reducing material absorption loss and increasing the fiber's damage threshold. This allows for applications in high-power laser transmission, fiber lasers, and fiber optic sensors.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A hollow anti-resonant optical fiber based on a polygonal outer sheath, characterized in that: It includes a first type of circular dielectric tube, a second type of circular dielectric tube, a third type of circular dielectric tube, a first type of polygonal outer tube, and an air fiber core surrounded by the outer wall of the first type of circular dielectric tube. The first type of circular dielectric tube is externally tangent to the first type of polygonal outer tube, and the third type of circular dielectric tube is internally tangent to the first type of circular dielectric tube and externally tangent to the second type of circular dielectric tube. The second type of circular dielectric tube is connected to the third type of circular dielectric tube and has no node with the first type of circular dielectric tube. The air fiber core is surrounded by the outer walls of multiple first type of circular dielectric tubes, and the radius of the inscribed circle of the surrounding contour is the radius r of the air fiber core. core ; The first type of circular medium tube contains two third type of circular medium tubes, and has two tangent points with the first type of polygonal outer tube. The two tangent points of the first type of circular medium tube and the first type of polygonal outer tube are located on the inner and outer walls of the first type of circular medium tube at the same position as the two tangent points of the first type of circular medium tube and the third type of circular medium tube.

2. The hollow anti-resonant optical fiber based on a polygonal outer tube according to claim 1, characterized in that: The thickness of the first type of circular dielectric tube, the second type of circular dielectric tube, and the third type of circular dielectric tube is all t.

3. The hollow anti-resonant optical fiber based on a polygonal outer tube according to claim 1, characterized in that: The radius of the first type of circular medium tube is larger than the radius of the second type of circular medium tube, and the radius of the second type of circular medium tube is larger than the radius of the third type of circular medium tube.

4. The hollow-core anti-resonant optical fiber based on a polygonal outer tube according to claim 1, characterized in that: The first type of polygonal outer sleeve is rectangular, pentagonal, or hexagonal.

5. The hollow anti-resonant optical fiber based on a polygonal outer tube according to claim 1, characterized in that: The number of circular dielectric tubes of the first type is 4, 5, or 6.

6. The hollow anti-resonant optical fiber based on a polygonal outer tube according to claim 1, characterized in that: The optical fiber is made of any one of silicon dioxide, soft glass, or plastic.

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