A hollow-core antiresonant optical fiber with wide operating band, long distance and high energy transmission

Abstract

The present invention discloses a hollow core antiresonant optical fiber with wide working band, long distance and large energy transmission, belonging to the field of optical fiber technology, comprising: an outer cladding, an inner cladding and an air core region arranged in sequence from outside to inside; the outer cladding is a hollow cylinder with a certain thickness, covering the inner cladding and the air core region; the inner cladding is a nested cladding tube structure, including a circular cladding tube with a larger aperture and a circular nested tube with a smaller aperture arranged inside it, a first type of semi-elliptical cladding tube, a second type of semi-elliptical cladding tube and an elliptical nested tube arranged inside the two; the circular nested tube is inscribed with the circular cladding tube, and the inscribed point is in contact with the inner wall surface of the outer cladding and deviates from the x-axis by a certain angle; the elliptical nested tube is inscribed with the inner wall surface of the outer cladding and fixedly connected; the first type and the second type of semi-elliptical cladding tube are connected with the outer cladding. The present invention has a wider working band, has lower limiting loss and nonlinearity within the working wavelength, so that light waves can be transmitted over long distances and with large energy.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber technology, and more specifically to a hollow-core anti-resonance optical fiber with wide working band, long distance and large energy transmission. Background Art

[0002] With the rapid development of social informatization, optical fiber communication systems must meet the requirements of longer distances, higher powers, and greater capacities. However, traditional optical fibers based on quartz glass transmission have limited further performance improvements due to their intrinsic properties such as absorption, dispersion, nonlinearity, low damage threshold, and UV, mid-infrared, and other material properties, making them unable to meet the development of modern communication technology. In addition, in some special fields such as high power, ultrafast optics, and nonlinear optics, traditional optical fibers also show limitations due to materials.

[0003] In order to solve the bottlenecks encountered by the above-mentioned optical fibers, hollow core fibers (HCF) with air as the core came into being. Due to its special cladding structure, HCF limits the transmission of light to the air in the core, which can avoid the intrinsic limitation of light in quartz glass or other dielectric materials. As a special HCF, hollow-core anti-resonant fiber (HC-ARF) has lower transmission loss, high laser damage threshold and higher mode purity. Adding anti-resonant elements to the cladding of HC-ARF can significantly improve the performance of the optical fiber in terms of limiting loss and bending loss. In addition, HC-ARF with nested and non-contact anti-resonant tube elements can achieve lower losses. And because its cladding structure is very simple, the internal structure and specific dimensions of HCF can be flexibly designed for a specific transmission wavelength and practical application.

[0004] Although HC-ARF has been rapidly developed due to its excellent characteristics such as low loss, low dispersion and high damage threshold, it has broad application prospects in the fields of optical communications, sensors and lasers. However, the research on HC-ARF is still imperfect. First, although the hollow-core antiresonant optical fiber based on the nodeless nested ring structure continues to reach new low transmission loss records, the complexity of manufacturing the optical fiber increases with each additional layer of nested tubes, which in turn makes its later preparation more difficult, and also increases the bending loss, thus limiting the application of hollow-core antiresonant optical fiber in long-distance optical fiber communication; secondly, although the internal structure of HC-ARF can be flexibly designed to obtain a specific transmission wavelength, the transmission bandwidth of the HC-ARF currently studied with quartz glass as the substrate material is not wide enough, mostly below 1μm, which limits its scope of use; finally, for the existing HC-ARF, when the loss is 10 -1 dB / km, the transmission window is 10 1nm, transmission window is 10 2 nm, the corresponding loss level is 10 0 dB / km, so it is difficult to have both low loss and large transmission window.

[0005] Therefore, a new type of hollow-core antiresonant optical fiber is urgently needed to further reduce the limiting loss and restrictive loss, and at the same time increase the transmission bandwidth, so that it can achieve stable transmission of longer distances and higher energy within a larger working band. This has very important practical significance. Summary of the invention

[0006] Purpose of the invention: In view of the problems existing in existing hollow-core anti-resonant optical fibers, such as increased complexity of the optical fiber structure due to the addition of a nodeless nested ring structure, increased bending loss, and difficulty in simultaneously obtaining low loss and a large transmission window, the present invention proposes a hollow-core anti-resonant optical fiber with a wide working band, long distance, and large energy transmission, so as to obtain a large transmission bandwidth while reducing limiting loss and bending loss, thereby achieving excellent optical fiber transmission performance with stable transmission of longer distances and higher energy.

[0007] Technical solution: To achieve the above-mentioned invention objectives, the present invention provides a hollow-core antiresonant optical fiber with a wide working band, long distance and large energy transmission, comprising an outer cladding, an inner cladding and an air core region, wherein the outer cladding is a hollow cylinder with a certain thickness, which wraps the inner cladding and the air core region.

[0008] The inner cladding is a nested cladding tube structure, which is a double-layer structure consisting of a circular nested tube with a smaller aperture, a circular cladding tube with a larger aperture, an elliptical nested tube, a first type of semi-elliptical cladding tube and a second type of semi-elliptical cladding tube, and the dielectric material of each tube is the same.

[0009] The circular nested tube with a smaller aperture is inscribed with the circular cladding tube with a larger aperture to form a double-layer nested cladding tube structure, and the inscribed point is in contact with the inner wall surface of the outer cladding and deviates from the x-axis by a certain angle.

[0010] The elliptical nested tube is inscribed and fixedly connected with the inner wall surface of the outer cladding, and is arranged inside the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube, thereby forming a double-layer nested cladding tube structure.

[0011] The first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are connected to the outer cladding, and the gaps between them and their adjacent circular cladding tubes are equal. The two first type of semi-elliptical cladding tubes and the elliptical nested tubes inside them are located on the positive semi-axis and negative semi-axis of x, respectively, and are symmetrical about the x-axis and the y-axis; the two second type of semi-elliptical cladding tubes and the elliptical nested tubes inside them are located on the positive semi-axis and negative semi-axis of y, and are symmetrical about the x-axis and the y-axis, and the vertex distance between the two first type of semi-elliptical cladding tubes is different from the vertex distance between the two second type of semi-elliptical cladding tubes.

[0012] The air core region is an air area, which is composed of the circular cladding tube with a larger aperture, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube, and is the main light guiding area of ​​the hollow core optical fiber.

[0013] Preferably, the base materials of the outer cladding, the circular nested tube with a smaller aperture, the circular cladding tube with a larger aperture, the elliptical nested tube, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are all silicon dioxide with a refractive index of 1.4342 to 1.4533.

[0014] Preferably, the outer cladding is a hollow cylinder with a certain thickness, the outer diameter of the outer cladding is 240-250 μm, and the wall thickness is 20-25 μm.

[0015] Preferably, the wall thickness of the circular nested tubes with smaller apertures, the circular clad tubes with larger apertures, the elliptical nested tubes, the first type of semi-elliptical clad tubes and the second type of semi-elliptical clad tubes is the same, which is 0.19 to 0.55 μm.

[0016] Preferably, the ratio of the diameter of the circular nested tubes with smaller apertures to the diameter of the circular cladding tubes with larger apertures is 0.4-0.6, and the ratio of the minor axis to the major axis of the elliptical nested tubes is 0.4-0.6.

[0017] Preferably, the outer diameter of the circular nested tube with smaller pore size is 20-42 μm, and the outer diameter of the circular cladding tube with larger pore size is 50-70 μm; the outer diameter of the major axis of the elliptical nested tube is 30-50 μm, and the outer diameter of the minor axis is 12-30 μm.

[0018] Preferably, the double-layer nested cladding tube structure composed of the circular nested tube with a smaller aperture and the circular cladding tube with a larger aperture deviates from the x-axis by an angle of 30° to 60°.

[0019] Preferably, the outer diameter of the major semi-axis of the first type of semi-elliptical cladding tube is 70-90 μm, and the outer diameter of the minor semi-axis is 20-30 μm, and the outer diameter of the major semi-axis of the second type of semi-elliptical cladding tube is 60-80 μm, and the outer diameter of the minor semi-axis is 30-40 μm.

[0020] Preferably, there are four nested cladding tube structures that are formed by inscribed circular nested tubes with smaller apertures and circular cladding tubes with larger apertures to form a double-layer structure, which are respectively arranged between the first type of semi-elliptical cladding tubes and the second type of semi-elliptical cladding tubes and are symmetrical about the x-axis and the y-axis.

[0021] Preferably, the spaces between the circular cladding tube with larger aperture and the circular nested tube with smaller aperture, between the first type of semi-elliptical cladding tube and the elliptical nested tube, between the second type of semi-elliptical cladding tube and the elliptical nested tube, the air core region and other internal spaces are filled with air, and the refractive index is 1.

[0022] Beneficial effects: The present invention provides a hollow-core antiresonant optical fiber with wide working band, long distance and large energy transmission, which comprises, from outside to inside, an outer cladding, an inner cladding composed of a double-layer nested cladding tube structure and an air core; wherein the double-layer nested cladding tube structure meets the antiresonant reflection waveguide (ARROW) principle in design, and is specifically made of silica glass and has a certain thickness, and the double-layer nested cladding tube structure in the inner cladding region is respectively composed of a double-layer nested cladding tube structure composed of a circular nested tube with a smaller aperture and a circular cladding tube with a larger aperture, a double-layer nested cladding tube structure composed of an elliptical nested tube and a first type of semi-elliptical cladding tube, and a double-layer nested cladding tube structure composed of an elliptical nested tube and a second type of semi-elliptical cladding tube, which are arranged together, and the whole presents neat axial symmetry, and has a negative curvature relative to the air core, that is, it bends toward the outside of the air core; these double-layer nested cladding tube structures can produce double antiresonance to reduce losses. Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0023] (1) The optical fiber structure proposed by the present invention is simple and easy to prepare. It only uses nested cladding tube structures of common shapes such as circles, ellipses and semi-ellipses, and has only two layers of nesting. No other complex cladding structures are used.

[0024] (2) Compared with the existing common hollow-core antiresonant optical fiber, the present invention has good structural adjustability. The core size of the optical fiber can be adjusted by adjusting the diameter of the circular cladding tube, the long semi-axis of the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube, thereby obtaining lower confinement loss and bending loss, realizing long-distance low-loss transmission, and at the same time obtaining a larger transmission bandwidth, thereby broadening the scope of application; in addition, it also has the advantages of larger mode field area and lower nonlinearity, providing a transmission medium with excellent performance for high-power and large-energy transmission.

[0025] (3) The present invention can use common silica glass without adding other dielectric materials, and the preparation cost is low.

[0026] (4) Experiments show that the present invention can achieve a transmission loss of less than 10 within a wide transmission bandwidth of 0.8 to 2.25 μm. -3 dB / m, even lower than 4.6032×10 -5 dB / m@1.6μm ultra-low loss, achieving ultra-low loss transmission; in addition, the present invention also has a larger effective mode field area and lower restrictive loss, reaching 10 3 μm 2 and 10 -2 W -1 km -1 It can achieve high-power and high-energy laser transmission and reduce nonlinear effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 It is a schematic structural diagram of a hollow-core antiresonant optical fiber with a wide working band, long distance and large energy transmission provided by an embodiment of the present invention.

[0029] Figure 2 : is the electric field norm distribution diagram at a wavelength of 1.55 μm provided by an embodiment of the present invention. Figure 2 (a) is the electric field mode distribution diagram of the fundamental mode x polarization state, Figure 2 (b) is the electric field mode distribution diagram of the fundamental mode y polarization.

[0030] Figure 3 It is a relationship diagram of the fundamental mode x polarization state and the fundamental mode y polarization state limiting loss versus wavelength provided by an embodiment of the present invention.

[0031] Figure 4 It is a relationship diagram of the effective mode field area of ​​the fundamental mode x polarization state and the fundamental mode y polarization as a function of wavelength provided by an embodiment of the present invention.

[0032] Figure 5 It is a relationship diagram of the nonlinear coefficient of the fundamental mode x polarization state and the fundamental mode y polarization as a function of wavelength provided by an embodiment of the present invention.

[0033] Figure 6 The diagram is a relationship diagram of bending loss versus bending radius when bending in the x-direction and the y-direction at a wavelength of 1.55 μm provided by an embodiment of the present invention. The two illustrations in the figure are respectively the electric field mode distribution diagrams when bending in the x-direction and the y-direction.

[0034] Figure 1 The various labels shown in:

[0035] Outer cladding 1, circular nested tube 2 with smaller aperture, circular cladding tube 3 with larger aperture, elliptical nested tube 4, first type semi-elliptical cladding tube 5, air core 6, second type semi-elliptical cladding tube 7; thickness t of all cladding tubes and nested tubes, outer diameter D1 of outer cladding 1, thickness d1 of outer cladding 1, outer diameter D2 of circular nested tube 2 with smaller aperture, outer diameter D3 of circular cladding tube 3 with larger aperture, major axis outer diameter a4 of elliptical nested tube 4, minor axis outer diameter b4 of elliptical nested tube, semi-major axis outer diameter a5 of first type semi-elliptical cladding tube 5, semi-minor axis outer diameter b5, semi-major axis outer diameter a7 of second type semi-elliptical cladding tube 7, minor axis outer diameter b7, angle of circular nested cladding tube structure deviating from x-axis is θ. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described and illustrated in conjunction with the drawings in the embodiments of the present invention. It should be pointed out that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of protection claimed in the present invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0037] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0038] See also Figure 1, a schematic diagram of the structure of a hollow-core antiresonant optical fiber with a wide working band, long distance and large energy transmission proposed by the present invention, comprising: an outer cladding, an inner cladding and an air core region arranged in sequence from the outside to the inside. Among them, the outer cladding 1 is a hollow cylinder with a certain thickness, covering the inner cladding and the air core region; the inner cladding is a nested cladding tube structure, consisting of a circular nested tube 2 with a smaller aperture, a circular cladding tube 3 with a larger aperture, an elliptical nested tube 4, a first type of semi-elliptical cladding tube 5 and a second type of semi-elliptical cladding tube 7, and the dielectric material of each tube is the same. The circular nested tube 2 with a smaller aperture is inscribed inwardly with the circular cladding tube 3 with a larger aperture, forming a double-layer nested cladding tube structure, and the inscribed point is in contact with and coincides with the inner wall surface of the outer cladding, and deviates from the x-axis by a certain angle; the elliptical nested tube 4 is inscribed inwardly with the inner wall surface of the outer cladding 1 and is fixedly connected, and is arranged inside the first type of semi-elliptical cladding tube 5 and the second type of semi-elliptical cladding tube 7, forming a double-layer nested cladding tube structure; the first type of semi-elliptical cladding tube 5 and the second type of semi-elliptical cladding tube 7 are connected to the outer cladding 1, and the gaps between the two and their respective adjacent circular cladding tubes are equal; The two first-type semi-elliptical cladding tubes 5 and the elliptical nested tubes 4 inside them are respectively located on the positive semi-axis and negative semi-axis of x, and are symmetrical about the x-axis and the y-axis; the two second-type semi-elliptical cladding tubes 7 and the elliptical nested tubes 4 inside them are located on the positive semi-axis and negative semi-axis of y, and are symmetrical about the x-axis and the y-axis, and the vertex distance between the two first-type semi-elliptical cladding tubes 5 is different from the vertex distance between the two second-type semi-elliptical cladding tubes 7; the air hole enclosed by the circular cladding tube 3 with a larger aperture, the first-type semi-elliptical cladding tube 5 and the second-type semi-elliptical cladding tube 7 is the air fiber core 6.

[0039] Among them, the outer diameter of the outer cladding 1 is D1, the thickness is d1, the thickness of the circular nested tube 2 with smaller aperture, the circular cladding tube 3 with larger aperture, the elliptical nested tube 4, the first type of semi-elliptical cladding tube 5 and the second type of semi-elliptical cladding tube 7 are the same, all of which are t; the outer diameter of the circular nested tube 2 with smaller aperture is D2; the outer diameter of the circular cladding tube 3 with larger aperture is D3; the outer diameter of the major axis of the elliptical nested tube is a4, and the outer diameter of the minor axis of the elliptical nested tube is b4; the outer diameter of the major semi-axis of the first type of semi-elliptical cladding tube 5 is a5, and the outer diameter of the minor semi-axis is b5, the outer diameter of the major semi-axis of the second type of semi-elliptical cladding tube 7 is a7, and the outer diameter of the minor semi-axis is b7, and the angle of the circular nested cladding tube structure deviating from the x-axis is θ.

[0040] In some embodiments, the outer cladding 1, the circular nested tube 2 with a smaller aperture, the circular cladding tube 3 with a larger aperture, the elliptical nested tube 4, the first type of semi-elliptical cladding tube 5, the second type of semi-elliptical cladding tube 7 and the base material are all silicon dioxide with a refractive index of 1.4342 to 1.4533.

[0041] In some embodiments, the outer cladding 1 is a hollow cylinder with a certain thickness, an outer diameter of 240-250 μm, and a wall thickness of 20-25 μm.

[0042] In some embodiments, the wall thickness of the circular nested tubes 2 with smaller pore size, the circular cladding tubes 3 with larger pore size, the elliptical nested tubes 4, the first type of semi-elliptical cladding tubes 5 and the second type of semi-elliptical cladding tubes 7 are the same, which is 0.19 to 0.55 μm.

[0043] In some embodiments, the ratio of the diameter of the round nested tube 2 with a smaller aperture to the diameter of the round cladding tube 3 with a larger aperture is 0.4 to 0.6.

[0044] In some embodiments, the ratio of the minor axis to the major axis of the elliptical nested tubes 4 is 0.4 to 0.6.

[0045] In some embodiments, the outer diameter of the round nested tube 2 with a smaller pore size is 20-42 μm, and the outer diameter of the round cladding tube 3 with a larger pore size is 50-70 μm.

[0046] In some embodiments, the double-layer nested cladding tube structure composed of the circular nested tube with a smaller aperture and the circular cladding tube with a larger aperture deviates from the x-axis by an angle of 30° to 60°.

[0047] In some embodiments, the outer diameter of the major axis of the elliptical nested tubes 4 is 30-50 μm, and the outer diameter of the minor axis is 12-30 μm.

[0048] In some embodiments, the outer diameter of the long semi-axis of the first type of semi-elliptical cladding tube is 70-90 μm, and the outer diameter of the short semi-axis is 20-30 μm, and the outer diameter of the long semi-axis of the second type of semi-elliptical cladding tube is 60-80 μm, and the outer diameter of the short semi-axis is 30-40 μm.

[0049] In some embodiments, there are four nested cladding tube structures formed by the circular nested tube with smaller aperture and the circular cladding tube with larger aperture inscribed in a double-layer structure, which are respectively arranged between the first type semi-elliptical cladding tube 5 and the second type semi-elliptical cladding tube 7, and are symmetrical about the x-axis and the y-axis.

[0050] In some embodiments, the air core region and other internal spaces are filled with air with a refractive index of 1.

[0051] The design advantages of the present invention are described below by the following embodiments:

[0052] Example

[0053] See also Figure 1 , a schematic diagram of the detailed structure of the hollow-core optical fiber; in this embodiment, the detailed structure of the hollow-core antiresonant optical fiber with a wide working band, long distance and large energy transmission includes:

[0054] Outer cladding 1: outer diameter D1 is: 250μm; thickness d1 is: 25μm; material is selected as silicon dioxide;

[0055] The nested cladding tube structure in the inner cladding region, wherein: the outer diameter D2 of the circular nested tube 2 with a smaller aperture is 30 μm, the outer diameter D3 of the circular cladding tube 3 with a larger aperture is 60 μm, the angle θ of the double-layer nested cladding tube structure composed of the circular nested tube with a smaller aperture and the circular cladding tube with a larger aperture deviates from the x-axis by 45°, the major axis outer diameter a4 of the elliptical nested tube 4 is 40 μm, the minor axis outer diameter b4 is 20 μm, the major semi-axis outer diameter a5 of the first type of semi-elliptical cladding tube 5 is 80 μm, the minor semi-axis outer diameter b5 is 25 μm, the major semi-axis outer diameter a7 of the second type of semi-elliptical cladding tube is 70 μm, and the minor semi-axis outer diameter b5 is 35 μm; the thickness t of all nested tubes and cladding tubes is the same, which is 0.372 μm; the dielectric material is silicon dioxide.

[0056] The present invention uses finite element simulation software COMSOL Multiphysics to perform simulation tests on this embodiment, adopts the finite element method and combines the perfect matching layer boundary absorption condition to perform theoretical calculations, and obtains the mode field distribution diagram of the present invention, the relationship between the restrictive loss, the effective mode field area and the nonlinear coefficient with the wavelength, the bending loss with the bending change curve, and the mode field distribution diagram in different bending directions through calculation.

[0057] See also Figure 2 From the mode field distribution diagram of the fundamental mode of the embodiment of the present invention, it can be seen that the energy of the x-polarization state and the y-polarization state of the fundamental mode of the hollow-core antiresonant optical fiber constructed in this embodiment is concentrated in the core region, indicating that the light is confined in the core region.

[0058] See also Figure 3 From the relationship diagram of the restrictive loss versus wavelength of the embodiment of the present invention, it can be seen that the fundamental mode x polarization state and y polarization state of the hollow core antiresonant optical fiber constructed in this embodiment have relatively low restrictive losses, reaching 10 -4 dB / m and 10 -5 dB / m order of magnitude; the lowest fundamental mode x polarization state measured at a transmission wavelength of 1.6μm is 1.4068×10 - 4 dB / m, y polarization state is 4.6032×10 -5 dB / m; the limit loss is 10 at the transmission wavelength of 1 to 2 μm. -5 dB / m~10 -3 Even in the entire test range of 0.8 to 2.25 μm, the limiting loss is 10 -2 The dB / m order of magnitude and below indicates that the embodiments of the present invention have both a large transmission window and low restrictive loss.

[0059] See also Figure 4From the relationship diagram of the effective mode field area versus wavelength of the embodiment of the present invention, it can be seen that the fundamental mode x polarization state and y polarization state of the hollow core antiresonant optical fiber constructed in this embodiment have large effective mode field areas, reaching 10 3 μm 2 It can transmit high-power and high-energy lasers and improve conversion efficiency.

[0060] See also Figure 5 From the relationship diagram of the nonlinear coefficient of the embodiment of the present invention with the wavelength, it can be seen that the fundamental mode x polarization state and y polarization state of the hollow core antiresonant optical fiber constructed in this embodiment have relatively low nonlinear coefficients, reaching 10 -2 It can reduce nonlinear effects and transmission delays, and increase transmission distance and capacity.

[0061] See also Figure 6 From the relationship diagram of the bending loss versus bending radius of the embodiment of the present invention, it can be seen that the hollow-core antiresonant optical fiber constructed in this embodiment has low bending losses when bending in the x-direction and in the y-direction under the condition of a transmission wavelength of 1.55 μm. When the bending radius is 14 cm, the bending loss of the optical fiber when bending in the x-direction reaches 10 - 3 The bending loss when bending in the y direction is as high as 10 -4 dB / m level; when the bending radius is 18 cm, the bending loss of the optical fiber when bending in the x direction and in the y direction reaches 10 -4 dB / m level; when the bending radius is 22cm, the bending loss when bending in the x direction even reaches 10 -5 The dB / m level indicates that this embodiment has good anti-bending performance.

[0062] See also Figure 2 , Figure 3 and Figure 4 From the graph showing the relationship between the nonlinear coefficient and wavelength of the embodiment of the present invention, it can be seen that the working wavelength range of the embodiment is 0.8 to 2.25 μm, and the entire working bandwidth reaches 1.45 μm. In the existing optical fiber simulation research, the transmission bandwidth is generally around 0.5 μm, which is about 2 to 3 times that of the existing research.

[0063] In summary, the hollow-core antiresonant optical fiber with wide working band, long distance and large energy transmission described in the present invention has both low limiting loss and large transmission bandwidth, and has good anti-bending performance, and can achieve low-loss long-distance transmission. Specifically, within the transmission wavelength range of 0.8 to 2.25 μm, 1×10 -3The limiting loss of dB / m and below; at the same time, the hollow-core antiresonant optical fiber described in the present invention also has a large effective mode field area and low limiting loss, and can carry out high-power, high-energy laser transmission.

[0064] The basic principle, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed for protection.

Claims

1. A hollow-core antiresonant optical fiber with a wide working band, long distance and large energy transmission, comprising an outer cladding, an inner cladding and an air core region, wherein the outer cladding is a hollow cylinder with a certain thickness, covering the inner cladding and the air core region; characterized in that: The inner cladding is a nested cladding tube structure, which is a double-layer structure consisting of a round nested tube with a smaller aperture, a round cladding tube with a larger aperture, an elliptical nested tube, a first type of semi-elliptical cladding tube, and a second type of semi-elliptical cladding tube, and the dielectric material of each tube is the same, wherein: The circular nested tube with a smaller aperture is inscribed with the circular cladding tube with a larger aperture to form a double-layer nested cladding tube structure, and the inscribed point is in contact with the inner wall surface of the outer cladding and deviates from the x-axis by a certain angle; The elliptical nested tube is inscribed and fixedly connected with the inner wall surface of the outer cladding, and is arranged inside the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube, thereby forming a double-layer nested cladding tube structure; The first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are connected to the outer cladding, and the gaps between them and their adjacent circular cladding tubes are equal; the two first type of semi-elliptical cladding tubes and the elliptical nested tubes inside them are respectively located on the positive semi-axis and negative semi-axis of x, and are symmetrical about the x-axis and the y-axis; the two second type of semi-elliptical cladding tubes and the elliptical nested tubes inside them are located on the positive semi-axis and negative semi-axis of y, and are symmetrical about the x-axis and the y-axis; the distance between the vertices of the two first type of semi-elliptical cladding tubes is different from the distance between the vertices of the two second type of semi-elliptical cladding tubes; The air core region is an air area, which is composed of the circular cladding tube with a larger aperture, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube, and is the main light guiding area of ​​the hollow core anti-resonant optical fiber.

2. A hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The base materials of the outer cladding, the circular nested tube with a smaller aperture, the circular cladding tube with a larger aperture, the elliptical nested tube, the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube are all silicon dioxide, and the refractive index is 1.4342-1.4533.

3. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The outer cladding is a hollow cylinder with a certain thickness. The outer diameter of the outer cladding is 240-250 μm and the wall thickness is 20-25 μm.

4. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The wall thickness of the circular nested tube with a smaller aperture, the circular clad tube with a larger aperture, the elliptical nested tube, the first type of semi-elliptical clad tube and the second type of semi-elliptical clad tube is the same, which is 0.19-0.55 μm.

5. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The ratio of the diameter of the circular nested tube with a smaller aperture to the diameter of the circular cladding tube with a larger aperture is 0.4 to 0.6, and the ratio of the minor axis to the major axis of the elliptical nested tube is 0.4 to 0.

6.

6. A hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1 or 5, characterized in that: The outer diameter of the circular nested tube with a smaller aperture is 20-42 μm, and the outer diameter of the circular cladding tube with a larger aperture is 50-70 μm; the outer diameter of the major axis of the elliptical nested tube is 30-50 μm, and the outer diameter of the minor axis is 12-30 μm.

7. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The angle of the double-layer nested cladding tube structure composed of the circular nested tube with a smaller aperture and the circular cladding tube with a larger aperture deviates from the x-axis by 30° to 60°.

8. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The outer diameter of the long semi-axis of the first type of semi-elliptical cladding tube is 70-90 μm, and the outer diameter of the short semi-axis is 20-30 μm. The outer diameter of the long semi-axis of the second type of semi-elliptical cladding tube is 60-80 μm, and the outer diameter of the short semi-axis is 30-40 μm.

9. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: There are four nested cladding tube structures that form a double-layer structure by incising the circular nested tube with a smaller aperture and the circular cladding tube with a larger aperture, which are respectively arranged between the first type of semi-elliptical cladding tube and the second type of semi-elliptical cladding tube and are symmetrical about the x-axis and the y-axis.

10. The hollow-core antiresonant optical fiber with wide operating band, long distance and large energy transmission according to claim 1, characterized in that: The air core region and other internal spaces are filled with air, and the refractive index is 1.

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