Hollow-core and solid-core hybrid optical fiber cable

Abstract

The utility model belongs to the technical field of hollow-core optical fiber cables, and particularly discloses a hollow-core and solid-core hybrid optical fiber cable, which comprises at least two 8-shaped solid-core optical fiber and hollow-core optical fiber hybrid optical fiber bundles, each 8-shaped solid-core optical fiber and hollow-core optical fiber hybrid optical fiber bundle comprises a solid-core optical fiber, a hollow-core optical fiber and a connecting structure, the solid core optical fiber comprises a solid core optical fiber core, a first cladding and a first coating which are sequentially arranged from inside to outside; the hollow-core optical fiber and the solid-core optical fiber are equal in length, and the hollow-core optical fiber comprises a hollow-core optical fiber core, a second wrapping layer and a second coating which are sequentially arranged from inside to outside; the connecting structure wraps the first coating and the second coating so as to connect the first coating and the second coating into a whole. The hybrid optical fiber cable is based on hybrid cabling of the hollow-core optical fiber and solid-core optical fibers such as G.652D, G.654E or G.655, assistance can be provided for positioning of abnormal points of the hollow-core optical fiber by means of detection of the abnormal points of the solid-core optical fiber, meanwhile, a network can be rapidly recovered by means of the solid-core optical fiber, the fault influence is reduced, and the application and maintenance convenience of the hollow-core optical fiber is improved.

Description

Technical Field

[0001] This application belongs to the field of hollow fiber optic cable technology, and more specifically, relates to a hybrid hollow and solid fiber optic cable. Background Technology

[0002] Hollow-core optical fiber, with its air-core structure, completely breaks away from the traditional transmission paradigm of solid glass optical fiber. Optical signals no longer rely on glass for transmission but instead primarily transmit within the hollow air channel. This structural innovation directly restructures its working principle: abandoning the total internal reflection mechanism relied upon by traditional optical fibers for light confinement, it instead uses the precise microstructure of the cladding to confine light within the air channel. This primarily includes photonic bandgap fibers that construct an optical transmission bandgap based on the photonic bandgap effect and anti-resonant microstructure fibers that utilize the anti-resonant reflection principle to confine optical signals. Because light travels faster and loses less in air, hollow-core optical fiber can significantly reduce signal transmission delay and signal attenuation. With these irreplaceable technological advantages, it is considered a key technological direction for solving bottleneck problems in future high-speed communication, high-power laser transmission, and other fields.

[0003] Although hollow fiber has many technical advantages, it still faces some problems in engineering applications: the Fresnel reflection intensity of hollow fiber is low, and the measurement using an optical time domain reflectometer (OTDR) is inaccurate. When a link problem occurs, it is not easy to determine the location of the abnormal point. Moreover, the construction and splicing efficiency of hollow fiber is lower, more than 50% lower than that of solid fiber. Once a link fails, the maintenance time is long, resulting in excessively long signal interruption time and causing inconvenience to users. Utility Model Content

[0004] In response to the deficiencies or improvement needs of existing technologies, this application provides a hybrid optical fiber cable of hollow and solid cores, which aims to solve the problems of difficulty in detecting anomalies in hollow optical fibers and excessively long signal interruption time when anomalies occur.

[0005] To achieve the above objectives, this application provides a hybrid optical fiber cable containing hollow and solid fibers, specifically comprising at least two figure-eight shaped hybrid optical fiber bundles of solid and hollow fibers. Each figure-eight shaped hybrid optical fiber bundle of solid and hollow fibers includes:

[0006] A solid optical fiber, wherein the solid optical fiber comprises a solid optical fiber core, a first cladding, and a first coating arranged sequentially from the inside out;

[0007] Hollow-core optical fiber, the hollow-core optical fiber being of the same length as the solid-core optical fiber, comprising, from the inside out, a hollow-core optical fiber core, a second cladding, and a second coating; and

[0008] A connection structure is provided, which covers the outside of the first coating and the second coating, to connect the solid fiber and the hollow fiber in a radial direction into a figure-eight shaped hybrid fiber bundle.

[0009] As a further preferred embodiment, the solid optical fiber and the hollow optical fiber are arranged in parallel and spaced apart.

[0010] As a further preferred embodiment, the connection structure is provided in multiple intervals along the axial direction of the hybrid fiber bundle; the interval between two adjacent connection structures is less than 30 mm.

[0011] As a further preferred embodiment, the length of a single connection structure along the axial direction of the hybrid fiber bundle is 5-10 mm.

[0012] As a further preferred embodiment, the connection structure includes a first connecting portion, a transition portion, and a second connecting portion. The first connecting portion covers the outside of the first coating, the second connecting portion covers the outside of the second coating, and the transition portion is located between the first connecting portion and the second connecting portion, for connecting the first connecting portion and the second connecting portion into a whole.

[0013] As a further preferred embodiment, the first connecting portion completely or partially covers the first coating; and / or, the second connecting portion completely or partially covers the second coating.

[0014] As a further preferred embodiment, the first connecting portion, the transition portion, and the second connecting portion are integrally formed.

[0015] As a further preferred embodiment, the thickness of the first connecting portion along the radial direction of the solid optical fiber and the thickness of the second connecting portion along the radial direction of the hollow optical fiber are equal.

[0016] As a further preferred embodiment, the thickness of the first connecting portion along the radial direction of the solid optical fiber and the thickness of the second connecting portion along the radial direction of the hollow optical fiber are both 3-8 μm.

[0017] As a further preferred embodiment, the width of the transition portion is 80-150 μm; and / or the height of the transition portion does not exceed 10 μm.

[0018] As a further preferred embodiment, the connection structure includes a first connection portion and a second connection portion, the first connection portion covering the outside of the first coating, the second connection portion covering the outside of the second coating, and an easy-tear structure provided between the first connection portion and the second connection portion.

[0019] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0020] 1. The hybrid optical fiber cable designed in this application uses a hollow optical fiber connected to a solid optical fiber, which can assist in the location of anomalies in the hollow optical fiber by using the detection of anomalies in the solid optical fiber.

[0021] 2. The solid fiber and hollow fiber in the hybrid fiber bundle of the hybrid fiber cable designed in this application are easy to separate. When the fiber is abnormal, since the splicing efficiency of the solid fiber is higher, the spliced ​​solid fiber can be quickly replaced to restore the network, thereby reducing the signal interruption time. After the hollow fiber is spliced, it can be switched back to the hollow fiber, thereby reducing the impact of the fault.

[0022] 3. Through the structural and dimensional design of the connection structure, this application can not only ensure the connection strength between hollow fiber and solid fiber, but also facilitate the separation of hollow fiber and solid fiber, so that the solid fiber can be used alone. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a fully enclosed figure-eight shaped hybrid fiber bundle containing solid and hollow optical fibers, provided in an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of a hybrid fiber bundle of solid and hollow optical fibers with a V-shaped structure provided in an embodiment of this application;

[0025] Figure 3 This is a schematic diagram of a partially clad figure-eight solid fiber and hollow fiber hybrid fiber bundle provided in an embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the connection structure provided in the embodiments of this application with solid-core optical fiber and hollow-core optical fiber;

[0027] Figure 5 This is a schematic diagram of a stranded hollow and solid hybrid optical fiber cable structure provided in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of a central tube-type hybrid optical fiber cable structure consisting of hollow and solid cores, provided in an embodiment of this application.

[0029] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0030] 1-Solid fiber, 2-Hollow fiber, 3-Connection structure, 11-Solid fiber core, 12-First cladding, 13-First coating, 21-Hollow fiber core, 22-Second cladding, 23-Second coating, 31-First connector, 32-Transition section, 33-Second connector, 34-Tearable structure; 41-Central reinforcement, 42-Outer sheath, 43-Loose tube, 44-Figure-8 mixed fiber bundle of solid and hollow fibers, 45-Reinforcing structure, 46-Water-blocking layer. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] Currently, the main method for anomaly detection in solid optical fibers is to use an optical time domain reflectometer (OTDR). This instrument emits narrow-pulse lasers into the fiber and analyzes the Rayleigh scattering and Fresnel reflection signals generated during the transmission of the optical signal, thereby enabling precise measurement of key parameters such as fiber length, attenuation coefficient, joint loss, and fault location (e.g., breakage, small-radius bend, poor fusion splicing, surface damage).

[0033] The anomalies detected in hollow-core optical fibers in this application mainly include signal interruption due to fiber breakage, loss anomalies caused by small-radius bending, and loss anomalies caused by fiber surface damage. Since the transmission medium of hollow-core optical fibers is air, their backscattering is approximately 40 dB lower than that of solid-core optical fibers, which is below the detection limit of traditional commercial OTDR technology, making it difficult to meet the requirements for fiber break detection. Even using photon-counting OTDRs or OTDRs with amplifiers, the reliability of the detection results is low due to weak signal strength and excessive noise interference. Therefore, how to accurately detect anomalies in hollow-core optical fibers has become a significant problem for researchers and has also limited the application of hollow-core optical fibers.

[0034] Based on this, this application conducted research and design, proposing a hybrid hollow and solid fiber optic cable. This hybrid cable comprises at least two figure-eight shaped bundles of solid and hollow fibers. By designing a novel fiber bundle structure, specifically by externally connecting solid fibers to the hollow fibers (i.e., mixing hollow and solid fibers into a cable), the ease of detecting anomalies in solid fibers is utilized to assist in the detection of anomalies in hollow fibers. Figure 1As shown, each of the figure-eight hybrid fiber bundles of solid and hollow fibers includes a solid fiber 1, a hollow fiber 2, and a connecting structure 3. The hollow fiber 2 serves as the main structure of the optical cable, used for transmitting optical signals. The solid fiber 1 serves as the secondary structure of the optical cable, used to assist in locating anomalies in the hollow fiber, and can also temporarily replace the main structure to achieve optical signal transmission when the hollow fiber is faulty. The solid fiber 1 and hollow fiber 2 are of equal length, and the connecting structure 3 connects them together radially along the hollow fiber 2 to form a figure-eight hybrid fiber bundle. By ensuring the solid fiber 1 and hollow fiber 2 are of equal length, the detected length of the solid fiber is the same as the length of the hollow fiber, thus enabling the location of anomalies using the solid fiber.

[0035] Combination Figure 1 and Figure 2 The solid fiber 1 comprises, from the inside out, a solid fiber core 11, a first cladding 12, and a first coating 13. The solid fiber core 11 is solid and has a diameter of 8-10 μm. The first cladding 12, made of glass, surrounds the solid fiber core 11 and has an outer diameter of 125±1 μm. The first coating 13, made of polypropylene resin and with a thickness of 20-80 μm, coats the outside of the first cladding 12 and serves as a protective layer to protect the fiber from mechanical damage and environmental corrosion. Specifically, the solid fiber 1 can be a single-mode fiber, multimode fiber, or other special fiber, such as G.652D, G.654E, or G.655. Furthermore, the solid fiber 1 and the hollow fiber 2 are arranged parallel and spaced apart, which facilitates the cabling of mixed fiber bundles and the effective location of anomalies.

[0036] Furthermore, the hollow-core optical fiber 2 includes a hollow-core optical fiber core 21, a second cladding 22, and a second coating 23 arranged sequentially from the inside out. The hollow-core optical fiber core 21 is an air core, and the second cladding 22 wraps around the outside of the hollow-core optical fiber core 21. The second coating 23 is coated and wrapped around the outside of the second cladding 22, and is made of polyacrylic acid resin with a thickness of 40-70 μm. In this embodiment, the hollow-core optical fiber 2 can be an anti-resonant hollow-core optical fiber or a photonic bandgap optical fiber.

[0037] Furthermore, the connecting structure 3 covers the exterior of the first coating 13 and the second coating 23, and is used to connect the solid fiber 1 and the hollow fiber 2 radially into a whole, thereby forming a figure-eight shaped hybrid fiber bundle. Preferably, the connecting structure 3 includes a first connecting portion 31, a transition portion 32, and a second connecting portion 33, wherein the first connecting portion 31 covers the exterior of the first coating 13, the second connecting portion 33 covers the exterior of the second coating 23, and the transition portion 32 is located between the first connecting portion 31 and the second connecting portion 33, and is used to connect the first connecting portion 31 and the second connecting portion 33 into a whole.

[0038] In a preferred embodiment, the first connecting portion 31, the transition portion 32, and the second connecting portion 33 are integrally formed, specifically using a photocuring process, and the material is acrylic resin. The specific photocuring process is prior art and is not limited in this application; commercially available acrylic resin can be used.

[0039] In a preferred embodiment, the thickness of the first connecting part 31 along the radial direction of the solid optical fiber 1 and the thickness N of the second connecting part 33 along the radial direction of the hollow optical fiber 2 are equal, preferably 3-8 μm. At this thickness, the material of the connecting part is less likely to generate stress during curing and shrinkage, thus avoiding excessive optical fiber loss. At the same time, it can ensure a reliable connection with the optical fiber and prevent it from falling off.

[0040] In a preferred embodiment, the width S of the transition portion 32 (the portion of the connecting structure 3 located between the first coating 13 and the second coating 23) is (along the direction perpendicular to the line connecting the center of the hollow fiber and the center of the solid fiber). Figure 3 The horizontal dimension of the transition section 32 is preferably designed to be 80-150 μm. This design ensures a secure connection with the optical fiber and prevents detachment, while also facilitating subsequent separation of the hollow and solid optical fibers. The height H of the transition section 32 (along the line connecting the center of the hollow and solid optical fibers) is... Figure 3 The vertical direction (i.e., the distance between the first coating 13 and the second coating 23) should not exceed 10μm to avoid the solid fiber and the hollow fiber being too far apart. When the hollow fiber is damaged, the solid fiber will not be damaged due to the distance, resulting in the inability to detect the abnormality of the hollow fiber through the solid fiber.

[0041] In a preferred embodiment, such as Figure 2 As shown, the connection structure 3 includes a first connection portion 31 and a second connection portion 33. The first connection portion 31 covers the outside of the first coating 13, and the second connection portion 33 covers the outside of the second coating 23. An easy-tear structure 34 is provided between the first connection portion 31 and the second connection portion 33. Specifically, the easy-tear structure can be a V-shaped structure, that is, the part of the connection structure 3 located between the solid fiber 1 and the hollow fiber 2 has an inwardly concave structure to facilitate the separation of the solid fiber 1 and the hollow fiber 2.

[0042] In a preferred embodiment, such as Figure 1 and Figure 3 As shown, the first connecting portion 31 completely or partially covers the first coating 13, and the second connecting portion 33 completely or partially covers the second coating 23. When partially covered, the first connecting portion 31 covers at least half of the first coating 13 circumferentially, and the second connecting portion 33 covers at least half of the second coating 23 circumferentially. This ensures the bonding of the two optical fibers while reducing resin usage, thereby reducing the additional stress caused by resin curing.

[0043] In a preferred embodiment, such as Figure 4 As shown, multiple connection structures 3 are spaced apart along the axial direction of the hollow fiber 2. These connection structures 3 can be evenly or unequally spaced, with the spacing M between adjacent connection structures 3 being less than 30mm. By using multiple spaced connection structures 3, the fiber stress caused by resin curing is reduced, and the overall bending performance of the fiber bundle is improved. The length L of a single connection structure 3 along the axial direction of the hollow fiber 2 is 5-10mm, thus ensuring a balance between connection strength and bending performance.

[0044] The following describes the method for preparing the hybrid fiber bundle of this application. Specifically, solid fiber and hollow fiber are released through a fiber release frame, passed through an "8"-shaped mold, and acrylic resin is injected into the mold to coat the surface of the fiber with acrylic resin. Then, the fiber is cured by ultraviolet light to form the hybrid fiber bundle. The specific curing process is existing technology and is not limited in this application.

[0045] Furthermore, hybrid hollow and solid optical fiber cables can have structures such as stranded type and central tube type. For example, ... Figure 5 As shown, the stranded hollow and solid hybrid optical fiber cable includes a central strengthening member 41, at least one optical unit, and an outer sheath 42. At least one optical unit is stranded around the central strengthening member 41. Each optical unit includes a loose tube 43 and at least one figure-eight shaped solid and hollow fiber hybrid fiber bundle 44 disposed within the loose tube 43. The outer sheath 42 wraps around the optical unit. Water-blocking structures are provided between the loose tube 43 and the central strengthening member 41, and between the loose tube 43 and the outer sheath 42. The water-blocking structure can be grease, water-blocking yarn, etc. The design location and specific type of the water-blocking structure are existing technologies and are not limited in this application. Reinforcing structures 45 are uniformly arranged circumferentially inside the outer sheath 42 to reduce cable core shrinkage caused by the shrinkage of the outer sheath.

[0046] like Figure 6 As shown, the central tube-type hybrid hollow and solid fiber optic cable includes at least one figure-eight-shaped hybrid fiber bundle 44 of solid and hollow fibers located at the center, a loose tube 43 fitted outside the figure-eight-shaped hybrid fiber bundle 44, a water-blocking layer 46 covering the loose tube 43, and an outer sheath 42 wrapped around the water-blocking layer 46. The water-blocking layer 46 can be a water-blocking tape or other water-blocking material, which is prior art and is not limited in this application.

[0047] In practical applications, after laying hybrid hollow and solid fiber optic cables in the existing network, if an abnormal signal interruption occurs during normal fiber communication, an OTDR device can be used immediately to locate the anomaly in the solid fiber. After confirming the breakpoint, when repairing the breakpoint, the solid fiber can be quickly spliced ​​first to restore network communication. After the hollow fiber splicing is completed, switch back to the hollow fiber line to complete the maintenance. Alternatively, when the line attenuation abnormally increases, use an OTDR to detect whether there are abnormal steps or curve dips in the solid fiber on the link to determine if the cable has pressure loss or abnormal bending, locate the problem, and then refer to the above methods for link repair.

[0048] In general, this application integrates solid-core and hollow-core optical fibers into a single unit. When an optical fiber malfunctions, such as a small-radius bend, breakage, or external force fracture, the entire unit simultaneously experiences the same small-radius bend, breakage, or external force fracture. Although the location of the malfunction cannot be detected in hollow-core fibers due to limitations in testing methods, solid-core fibers can be tested using an OTDR to detect excessive loss, steps, spikes, or signal interruptions, and the location can be accurately determined. Therefore, this application's design can achieve the same level of malfunction detection and location for hollow-core fibers as it utilizes the malfunction detection and location of solid-core fibers. Each hollow-core fiber in this application is connected to a solid-core fiber. During line maintenance, solid-core fibers can be quickly spliced ​​to replace the hollow-core fibers while maintaining line communication. After the hollow-core fiber maintenance is completed, the connection can be switched back to the hollow-core link, thereby reducing the impact of faults.

[0049] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0050] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this application.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0052] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hybrid optical fiber cable containing both hollow and solid cores, characterized in that, It includes at least two figure-eight hybrid fiber bundles of solid and hollow fibers, each of which comprises: Solid optical fiber (1), the solid optical fiber (1) includes a solid optical fiber core (11), a first cladding (12) and a first coating (13) arranged sequentially from the inside to the outside; Hollow-core optical fiber (2), the hollow-core optical fiber (2) being of the same length as the solid-core optical fiber (1), comprising, from the inside out, a hollow-core optical fiber core (21), a second cladding (22), and a second coating (23); and The connection structure (3) covers the outside of the first coating (13) and the second coating (23) to connect the solid fiber (1) and the hollow fiber (2) in a radial direction into a figure-eight hybrid fiber bundle.

2. The hybrid hollow and solid fiber optic cable as described in claim 1, characterized in that, The solid fiber (1) and the hollow fiber (2) are arranged in parallel and spaced apart.

3. The hybrid hollow and solid optical fiber cable as described in claim 1, characterized in that, Multiple connection structures (3) are spaced apart along the axial direction of the hybrid fiber bundle; the spacing between two adjacent connection structures (3) is less than 30 mm.

4. The hybrid hollow and solid optical fiber cable as described in claim 3, characterized in that, The length of a single connection structure (3) along the axis of the hybrid fiber bundle is 5-10 mm.

5. The hybrid hollow and solid optical fiber cable as described in claim 1, characterized in that, The connection structure (3) includes a first connection part (31), a transition part (32) and a second connection part (33). The first connection part (31) covers the outside of the first coating (13), and the second connection part (33) covers the outside of the second coating (23). The transition part (32) is located between the first connection part (31) and the second connection part (33) and is used to connect the first connection part (31) and the second connection part (33) into a whole.

6. The hybrid hollow and solid optical fiber cable as described in claim 5, characterized in that, The first connecting portion (31) completely or partially covers the first coating (13); and / or, the second connecting portion (33) completely or partially covers the second coating (23).

7. The hybrid hollow and solid optical fiber cable as described in claim 5, characterized in that, The first connecting part (31), the transition part (32), and the second connecting part (33) are integrally formed.

8. The hybrid hollow and solid optical fiber cable as described in claim 5, characterized in that, The thickness of the first connecting part (31) along the radial direction of the solid optical fiber (1) is equal to the thickness of the second connecting part (33) along the radial direction of the hollow optical fiber (2); And / or, the thickness of the first connecting portion (31) along the radial direction of the solid fiber (1) and the thickness of the second connecting portion (33) along the radial direction of the hollow fiber (2) are both 3-8 μm.

9. The hybrid hollow and solid optical fiber cable as described in claim 5, characterized in that, The width of the transition portion (32) is 80-150 μm; and / or the height of the transition portion (32) is no more than 10 μm.

10. The hybrid hollow and solid optical fiber cable as described in claim 1, characterized in that, The connection structure (3) includes a first connection part (31) and a second connection part (33). The first connection part (31) covers the outside of the first coating (13), and the second connection part (33) covers the outside of the second coating (23). An easy-tear structure (34) is provided between the first connection part (31) and the second connection part (33).

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