An air cored anti-resonant optical fiber

Abstract

The application relates to a hollow core anti-resonant optical fiber, comprising an outer cladding, an anti-resonant region and a core region; the anti-resonant region comprises a plurality of nested units, the nested unit comprises a first anti-resonant tube and a second anti-resonant tube, the first anti-resonant tube is connected with the outer cladding, the second anti-resonant tube is connected with the first anti-resonant tube, the included angle theta between the first plane and the second plane of the nested unit is 0 DEG <= theta < 180 DEG, the first plane is a plane formed by the central axis of the first anti-resonant tube and the central axis of the second anti-resonant tube in the first anti-resonant tube, and the second plane is a plane formed by the central axis of the first anti-resonant tube and the central axis of the outer cladding; the core region comprises a region surrounded by the boundary between the first anti-resonant tube and the outer cladding. While realizing low loss, the application breaks the structural symmetry of the existing hollow core anti-resonant optical fiber, does not need to accurately control the fiber resonant ring joint position structure, reduces the preparation difficulty of the optical fiber, and is favorable for large-scale production of the optical fiber.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication technology, in particular to an air-core anti-resonant optical fiber. BACKGROUND

[0002] With the increasing demand for communication capacity and the special requirements for optical fiber link performance in certain communication scenarios, the performance of traditional solid-core optical fibers has reached its limit. Traditional quartz material optical fibers cannot meet the performance requirements of low attenuation, low latency, low nonlinearity, low dispersion, high bandwidth, etc., which limits the sustained development of optical fiber communication technology.

[0003] The air-core anti-resonant optical fiber is different from the conventional optical fiber. It allows light to be transmitted in the low refractive index air core through the anti-resonance phenomenon. The light transmitted in the air-core optical fiber has the advantages of low delay, low loss, low dispersion, low nonlinearity, high damage threshold, etc. Compared with the traditional optical fiber, the air-core optical fiber has a broad application prospect.

[0004] Although the air-core anti-resonant optical fiber has obvious performance advantages compared with ordinary optical fibers, the existing air-core anti-resonant optical fiber structure has high symmetry requirements. This special anti-resonant structure greatly increases the difficulty of manufacturing the optical fiber. Therefore, under the premise of meeting various performance requirements of the air-core anti-resonant optical fiber, adjusting the geometric structure of the air-core anti-resonant optical fiber is conducive to the research and development of the air-core anti-resonant optical fiber. SUMMARY

[0005] The embodiment of the present application provides an air-core anti-resonant optical fiber, which realizes the optical performance requirement of low loss while reducing the preparation difficulty of the optical fiber, and is conducive to large-scale production of the optical fiber.

[0006] The embodiment of the present application provides an air-core anti-resonant optical fiber, which includes a cladding region, an anti-resonant region and a core region.

[0007] The cladding region includes an outer cladding.

[0008] The anti-resonant region includes a plurality of nested units distributed in the outer cladding, the nested unit includes a first anti-resonant tube and a second anti-resonant tube nested in the first anti-resonant tube, the first anti-resonant tube is connected with the outer cladding, the second anti-resonant tube is connected with the first anti-resonant tube, the included angle θ between the first plane and the second plane of the nested unit is 0°≤θ<180°, the first plane is a plane formed by the central axis of the first anti-resonant tube and the central axis of the second anti-resonant tube in the first anti-resonant tube, and the second plane is a plane formed by the central axis of the first anti-resonant tube and the central axis of the outer cladding.

[0009] The core region includes a region surrounded by the boundary between the first anti-resonant tube and the outer cladding.

[0010] In some embodiments, the angle θ between the first plane and the second plane is 90°≤θ≤177°.

[0011] In some embodiments, the included angle θ between the first plane and the second plane of each nested unit is equal, partially equal, or unequal.

[0012] In some embodiments, in the nested unit, when the central axis of the second anti-resonant tube is located to the left of the second plane, it is denoted as the center position of the second anti-resonant tube rotating clockwise relative to the center of the first anti-resonant tube; when the central axis of the second anti-resonant tube is located to the right of the second plane, it is denoted as the center position of the second anti-resonant tube rotating counterclockwise relative to the center of the first anti-resonant tube.

[0013] The second anti-resonant transistors of each nested unit rotate clockwise, or all rotate counterclockwise, or a portion rotates clockwise and the other portion rotates counterclockwise.

[0014] In some embodiments, the outer wall of the first anti-resonant tube is tangent to the inner wall of the outer cladding, and the outer wall of the second anti-resonant tube is tangent to the inner wall of the first anti-resonant tube.

[0015] In some embodiments, the outer wall of the first anti-resonant tube intersects with the inner wall of the outer cladding layer, so that the first anti-resonant tube is an arc-shaped tube;

[0016] The outer wall of the second anti-resonant tube intersects with the inner wall of the first anti-resonant tube, so that the second anti-resonant tube is an arc-shaped tube.

[0017] In some embodiments, the outer wall of the first anti-resonant tube intersects with the inner wall of the outer cladding layer, forming a first overlapping region;

[0018] The outer wall of the second anti-resonant tube intersects with the inner wall of the first anti-resonant tube to form a second overlapping region;

[0019] The second overlapping region is located within the first overlapping region.

[0020] In some embodiments, the core region includes a core, which is a circular region formed by the circumscribed circles of each of the first anti-resonant transistors, and the diameter of the core is 20 to 40 micrometers.

[0021] In some embodiments, the wall thickness of the first anti-resonant tube and the second anti-resonant tube is 0.3 to 1.6 micrometers.

[0022] In some embodiments, the outer diameter of the outer cladding layer is 150–300 micrometers.

[0023] The beneficial effects of the technical solution provided in this application include:

[0024] The hollow-core anti-resonant optical fiber provided in this application embodiment achieves the low-loss optical performance requirement while breaking the structural symmetry of existing hollow-core anti-resonant optical fibers. It eliminates the need for precise control of the position and structure of the fiber resonant loop, reduces the difficulty of fiber fabrication, and facilitates large-scale production of optical fibers. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram (tangential) of a hollow anti-resonant optical fiber provided in an embodiment of this application;

[0027] Figure 2 A schematic diagram (intersecting) of a hollow anti-resonant optical fiber provided in an embodiment of this application;

[0028] Figure 3 This application provides attenuation versus wavelength curves at different included angles for embodiments of the present application;

[0029] Figure 4 This application provides a mode field distribution at a wavelength of 1550 nm when the included angle is 145° for embodiments of the present application;

[0030] Figure 5 The present application provides curves showing the relationship between the mode field diameter and wavelength at different included angles for embodiments of this application.

[0031] In the figure: 1. Outer cladding; 2. First anti-resonant diode; 3. Second anti-resonant diode; 4. First overlapping region; 5. Second overlapping region; 6. Fiber core. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] See Figure 1 and Figure 2As shown in the figure, this application provides a hollow-core anti-resonant optical fiber, which includes a cladding region, an anti-resonant region, and a core region. The cladding region includes an outer cladding 1, and the anti-resonant region includes multiple nested units spaced apart within the outer cladding 1. The nested units are distributed along the circumference of the outer cladding 1. Each nested unit includes a first anti-resonant tube 2 and a second anti-resonant tube 3 nested within the first anti-resonant tube 2. The first anti-resonant tube 2 is connected to the outer cladding 1, and the second anti-resonant tube 3 is connected to the first anti-resonant tube 2. The angle θ between a first plane and a second plane of the nested unit is 0° ≤ θ < 180°. The first plane is the plane formed by the central axis of the first anti-resonant tube 2 and the central axis of the second anti-resonant tube 3 within it, and the second plane is the plane formed by the central axis of the first anti-resonant tube 2 and the central axis of the outer cladding 1. The core region includes a region surrounded by the boundary between the first anti-resonant tube 2 and the outer cladding 1.

[0034] Specifically, see Figure 1 and Figure 2 As shown, the position of the central axis of the outer cladding layer 1 is marked as point A, the position of the central axis of the first anti-resonant tube 2 is marked as point B, and the position of the central axis of the second anti-resonant tube 3 is marked as point C. BC forms the first plane, BA forms the second plane, the outer wall of the second anti-resonant tube 3 is tangent to the inner wall of the first anti-resonant tube 2 at point D, and the outer wall of the first anti-resonant tube 2 is tangent to the inner wall of the outer cladding layer 1 at point E.

[0035] The second anti-resonant tube 3 moves within the first anti-resonant tube 2. When the central axis of the second anti-resonant tube 3 is located at point C', the angle θ between the first plane and the second plane is 180°. When the second anti-resonant tube 3 moves within the first anti-resonant tube 2 to a position between point B and point A, and is located on the second plane, the angle θ between the first plane and the second plane is 0°.

[0036] It is understandable that the circle formed by points B, C, and C' is the trajectory of the central axis of the second anti-resonant tube 3.

[0037] Understandably, the number of nested units mentioned above can be determined according to actual needs.

[0038] In this application, the center of the second anti-resonant tube 3 is not coplanar with the outer cladding 1 and the first anti-resonant tube 2, which causes the second anti-resonant tube 3 to rotate and move relative to the first anti-resonant tube 2, which is asymmetrical. This breaks the structural symmetry of the existing hollow anti-resonant optical fiber, eliminates the need for precise control of the optical fiber resonant loop position structure, reduces the difficulty of optical fiber fabrication, and is conducive to the large-scale production of optical fiber.

[0039] Furthermore, the angle θ between the first plane and the second plane can be designed according to the actual performance required by the optical fiber. For example, the angle θ between the first plane and the second plane is 90°≤θ≤177°.

[0040] Furthermore, the aforementioned nested units are distributed at equal intervals.

[0041] Furthermore, the included angle θ between the first plane and the second plane of each nested unit is equal, partially equal, or unequal.

[0042] Furthermore, in the nested unit, when the central axis of the second anti-resonant tube 3 is located to the left of the second plane, it is denoted as the center position of the second anti-resonant tube 3 rotating clockwise relative to the center of the first anti-resonant tube 2; when the central axis of the second anti-resonant tube 3 is located to the right of the second plane, it is denoted as the center position of the second anti-resonant tube 3 rotating counterclockwise relative to the center of the first anti-resonant tube 2; the second anti-resonant tube 3 of each nested unit rotates clockwise, or rotates counterclockwise, or a portion rotates clockwise and the other portion rotates counterclockwise.

[0043] As an example, see Figure 1 As shown, the top nested unit is the first nested unit, and the units are sorted clockwise.

[0044] For the first nested unit, with ABE as the dividing line, point C is to the left of the ABE dividing line, indicating that the center position of the second anti-resonant tube 3 in the first nested unit is rotated clockwise relative to the center of the first anti-resonant tube 2.

[0045] For the second nested unit, the center position of the second anti-resonant tube 3 rotates counterclockwise relative to the center of the first anti-resonant tube 2.

[0046] For the third nested unit, the center position of the second anti-resonant tube 3 rotates counterclockwise relative to the center of the first anti-resonant tube 2.

[0047] For the fourth nested unit, the center position of the second anti-resonant tube 3 rotates counterclockwise relative to the center of the first anti-resonant tube 2.

[0048] For the fifth nested unit, the center position of the second anti-resonant tube 3 rotates clockwise relative to the center of the first anti-resonant tube 2.

[0049] Further, see Figure 1 As shown, the outer wall of the first anti-resonant tube 2 is tangent to the inner wall of the outer cladding layer 1 at point E, and the outer wall of the second anti-resonant tube 3 is tangent to the inner wall of the first anti-resonant tube 2 at point D. Obviously, since the angle θ between the first plane and the second plane is 0°≤θ<180°, points E and D do not coincide.

[0050] Further, see Figure 2 As shown, the outer wall of the first anti-resonant tube 2 intersects with the inner wall of the outer cladding layer 1, so that the first anti-resonant tube 2 is an arc-shaped tube; the outer wall of the second anti-resonant tube 3 intersects with the inner wall of the first anti-resonant tube 2, so that the second anti-resonant tube 3 is an arc-shaped tube.

[0051] Further, see Figure 2 As shown, the outer wall of the first anti-resonant tube 2 intersects with the inner wall of the outer cladding layer 1, forming a first overlapping region 4; the outer wall of the second anti-resonant tube 3 intersects with the inner wall of the first anti-resonant tube 2, forming a second overlapping region 5; the second overlapping region 5 is located within the first overlapping region 4.

[0052] Further, see Figure 1 As shown, the fiber core region includes a fiber core 6, which is a circular region formed by the circumscribed circles of each of the first anti-resonant tubes 2. The diameter of the fiber core 6 is 20 to 40 micrometers, preferably 30 micrometers.

[0053] Furthermore, the wall thickness of the first anti-resonant tube 2 and the second anti-resonant tube 3 is 0.3 to 1.6 micrometers, preferably 0.4 micrometers.

[0054] Furthermore, the outer diameter of the outer cladding layer 1 is 150 to 300 micrometers, preferably 250 micrometers.

[0055] When the wall thicknesses of the first anti-resonant tube 2 and the second anti-resonant tube 3 satisfy the anti-resonance formula of interference cancellation, low-loss propagation of anti-resonant optical fiber can be achieved.

[0056] It is understood that the outer cladding layer 1, the first anti-resonant tube 2, and the second anti-resonant tube 3 can all adopt a glass tube structure, such as using a capillary tube.

[0057] It is understood that the fiber core region can be filled with air, the outer cladding 1 can also be filled with air, the first anti-resonant tube 2 can also be filled with air, and the second anti-resonant tube 3 can also be filled with air.

[0058] Example

[0059] A hollow-core anti-resonant optical fiber includes a cladding region, an anti-resonant region, and a core region. The cladding region includes an outer cladding 1. The anti-resonant region includes five equally spaced nested units distributed within the outer cladding 1. Each nested unit includes a first anti-resonant tube 2 and a second anti-resonant tube 3 nested within the first anti-resonant tube 2. The first anti-resonant tube 2 is tangent to the outer cladding 1, and the second anti-resonant tube 3 is tangent to the first anti-resonant tube 2. The angle between a first plane and a second plane of the nested unit is θ. The first plane is the plane formed by the central axis of the first anti-resonant tube 2 and the central axis of the second anti-resonant tube 3 within it, and the second plane is the plane formed by the central axis of the first anti-resonant tube 2 and the central axis of the outer cladding 1. The core region includes the area surrounded by the boundary between the first anti-resonant tube 2 and the outer cladding 1.

[0060] The outer cladding layer 1, the first anti-resonant tube 2, and the second anti-resonant tube 3 are made of silicon dioxide, while the other areas are made of air.

[0061] The fiber core 6 has a diameter of 30 micrometers, the first anti-resonant tube 2 and the second anti-resonant tube 3 have a wall thickness of 0.4 micrometers, and the outer diameter of the outer cladding 1 is 250 micrometers.

[0062] Using finite element method (FEM) software, the optical fiber modes in this embodiment were simulated, and the relationship curves between the mode field distribution, confinement loss, mode field diameter, and corresponding wavelength of the hollow-core antiresonant fiber at different θ angles were calculated, as follows: Figure 3 , Figure 4 and Figure 5 As shown.

[0063] The attenuation curve shows that when 135° ≤ θ < 180°, the maximum attenuation is less than 0.03 dB / km, and when θ is 90° ≤ θ < 135°, the maximum attenuation is less than 0.3 dB / km.

[0064] As can be seen from the figure, the hollow anti-resonant optical fiber provided in the embodiment has the characteristic of low confinement loss in the C+L communication band.

[0065] It can also be seen that the fiber mode energy of the corresponding structure in the embodiment is concentrated in the fiber core region.

[0066] As can be seen, the hollow-core anti-resonant fiber provided in this application, while achieving the optical performance requirement of low loss, breaks the structural symmetry of existing hollow-core anti-resonant fibers, eliminates the need for precise control of the fiber resonant loop position structure, reduces the difficulty of fiber fabrication, and is conducive to the large-scale production of optical fibers.

[0067] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0068] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0069] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A hollow-core anti-resonant optical fiber, characterized in that, The hollow anti-resonant optical fiber includes a cladding region, an anti-resonant region, and a core region. The cladding region includes an outer cladding layer (1); The anti-resonance region includes multiple nested units spaced apart within the outer cladding layer (1). Each nested unit includes a first anti-resonance tube (2) and a second anti-resonance tube (3) nested within the first anti-resonance tube (2). The first anti-resonance tube (2) is connected to the outer cladding layer (1), and the second anti-resonance tube (3) is connected to the first anti-resonance tube (2). The angle θ between the first plane and the second plane of the nested unit is 90°≤θ≤175°. The first plane is the plane formed by the central axis of the first anti-resonance tube (2) and the central axis of the second anti-resonance tube (3) within it, and the second plane is the plane formed by the central axis of the first anti-resonance tube (2) and the central axis of the outer cladding layer (1). The fiber core region includes the area surrounded by the boundary between the first anti-resonant tube (2) and the outer cladding (1); The outer wall of the first anti-resonant tube (2) intersects with the inner wall of the outer cladding (1) so that the first anti-resonant tube (2) is an arc-shaped tube; The outer wall of the second anti-resonant tube (3) intersects with the inner wall of the first anti-resonant tube (2) so that the second anti-resonant tube (3) is an arc-shaped tube; The outer wall of the first anti-resonant tube (2) intersects with the inner wall of the outer cladding (1) and forms a first overlapping region (4). The outer wall of the second anti-resonant tube (3) intersects with the inner wall of the first anti-resonant tube (2) and forms a second overlapping region (5); The second overlapping region (5) is located within the first overlapping region (4).

2. The hollow-core anti-resonant optical fiber as described in claim 1, characterized in that: The angle θ between the first plane and the second plane of each nested unit is equal, partially equal, or unequal.

3. The hollow-core anti-resonant optical fiber as described in claim 1, characterized in that: In the nested unit, when the central axis of the second anti-resonant tube (3) is located on the left side of the second plane, it is recorded as the center position of the second anti-resonant tube (3) rotating clockwise relative to the center of the first anti-resonant tube (2); when the central axis of the second anti-resonant tube (3) is located on the right side of the second plane, it is recorded as the center position of the second anti-resonant tube (3) rotating counterclockwise relative to the center of the first anti-resonant tube (2). The second anti-resonant tube (3) of each nested unit rotates clockwise, or rotates counterclockwise, or a portion rotates clockwise and the other portion rotates counterclockwise.

4. The hollow-core anti-resonant optical fiber as described in claim 1, characterized in that: The core region includes a core (6), which is a circular region formed by the circumscribed circles of each of the first anti-resonant tubes (2) simultaneously, and the diameter of the core (6) is 20 to 40 micrometers.

5. The hollow-core anti-resonant optical fiber as described in claim 1, characterized in that: The wall thickness of the first anti-resonant tube (2) and the second anti-resonant tube (3) is 0.3 to 1.6 micrometers.

6. The hollow-core anti-resonant optical fiber as described in claim 1, characterized in that: The outer diameter of the outer cladding layer (1) is 150 to 300 micrometers.

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