All-dielectric acoustic wave sensing optical cable

Abstract

This application relates to an all-dielectric acoustic wave sensing optical cable, comprising a reference optical unit, a damping layer, and a sheath layer arranged sequentially from the inside to the outside along the radial direction of the optical cable; wherein, a test optical unit is further disposed within the sheath layer, and the test optical unit is located outside the damping layer. This application provides an all-dielectric acoustic wave sensing optical cable that employs a dual-channel sensing optical unit design. The signal of the reference optical unit is used as ambient noise to demodulate and analyze the induced signal of the test optical unit. In environments with only vibration, the sensing system compares the induced signals of the reference optical unit and the test optical unit, and the conclusion drawn from the analysis of the test optical unit signal is ambient noise. When ambient vibration is superimposed with sound waves, the sensing system demodulates and accurately distinguishes the sound wave signal from the induced signal of the test optical unit through signal comparison, thereby achieving the sensing and precise positioning of ambient sound wave signals.

Description

Technical Field

[0001] This application relates to the field of optical fiber and cable technology, and in particular to an all-dielectric acoustic wave sensing optical cable. Background Technology

[0002] In the field of fiber optic sensing, phase-sensitive optical time-domain reflectometry (OTDR) is a distributed sensing technology that detects changes in physical quantities (such as sound and vibration) in the environment by detecting phase changes in Rayleigh scattered light at various points along the sensing fiber. The incident light interferes with the backscattered light at a point along the fiber; changes in sound or vibration at that point cause a linear change in the phase of the interfering light. Therefore, demodulating the phase of the interfering light at the receiving end allows determination of the change in sound or vibration. Due to the continuous distribution of optical fibers in space, changes in physical quantities occurring at any point along the fiber optic link can be quantitatively detected, thus achieving distributed sensing. This technology offers advantages such as long-distance operation, linear detection, and high stability, and has already been applied in fields such as railways, bridges, and perimeter security.

[0003] Distributed fiber optic acoustic sensing (DAS) technology is based on phase-sensitive optical time-domain reflectometry (OTDR) to detect and locate sound waves and weak vibration signals. In environments such as subways, tunnels, and bridges, sound waves often occur simultaneously with vibration signals. However, existing optical fiber optic cables cannot distinguish between sound waves and ambient vibration signals, leading to problems such as limited detection range and false alarms caused by the sensing system misinterpreting environmental vibration signals as sound waves.

[0004] Existing acoustic wave sensing optical cable designs have flaws, and there is an urgent need for innovative technologies to develop a new acoustic wave sensing optical cable to improve the detection range of acoustic wave signals. At the same time, the distributed fiber optic acoustic wave sensing system can accurately distinguish acoustic wave signals through the sensing optical cable even under the interference of a vibration environment. Summary of the Invention

[0005] This application provides an all-dielectric acoustic wave sensing optical cable to solve the problem in related technologies where distributed fiber optic acoustic wave sensing systems mistakenly alarm as acoustic wave signals when subjected to vibration interference.

[0006] This application provides an all-dielectric acoustic wave sensing optical cable, which includes a reference optical unit, a damping layer and a sheath layer arranged sequentially from the inside to the outside along the radial direction of the optical cable.

[0007] The sheath layer also includes a test light unit located outside the damping layer.

[0008] In some embodiments, the sheath layer is further provided with a sensitivity-enhancing layer, which is in contact with the test light unit.

[0009] In some embodiments, the sensitizing layer covers the outside of the damping layer, or the sensitizing layer covers the outside of the test light unit;

[0010] And / or, the material used in the sensitizing layer includes one or more of polyester elastomers, polyurethane elastomers, and nylon elastomers.

[0011] In some embodiments, the material used for the damping layer has a tensile strength of 5 MPa to 30 MPa, an elongation at break of 400% to 1000%, and a loss factor of 0.45 to 1.0.

[0012] And / or, the material used in the damping layer includes one or more of thermoplastic vulcanized rubber, modified silicone rubber, polyurethane composite polyolefin foam material and polyurethane microcapsules;

[0013] And / or, the reference optical unit includes a first optical fiber, a tight-buffered layer, a reinforcing layer and an inner sheath layer arranged sequentially from the inside to the outside along its radial direction;

[0014] And / or, the test optical unit includes a second optical fiber, a protective layer, and an armor layer arranged sequentially from the inside to the outside along its radial direction;

[0015] And / or, the material used in the sheath layer includes one or more of flame-retardant polyolefins, flame-retardant polyester elastomers, flame-retardant polyurethane elastomers, and flame-retardant polystyrene elastomers.

[0016] In some embodiments, the outer wall of the sheath layer is provided with a plurality of groove arrays along the circumference of the sheath layer, the groove array including a plurality of grooves distributed along the axial direction of the sheath layer.

[0017] In some embodiments, the groove array is provided on both sides of the test optical unit along the circumferential direction of the sheath layer;

[0018] And / or, the cross-section of the groove is arc-shaped, conical, or square.

[0019] In some embodiments, the groove array includes a groove that extends along the axial direction of the sheath layer to both ends of the sheath layer;

[0020] Alternatively, the groove array may include multiple grooves, and the grooves in two adjacent groove arrays may be staggered or aligned.

[0021] In some embodiments, when the grooves in two adjacent groove arrays are staggered, the distance d between two adjacent grooves in one groove array is less than or equal to the length L of the groove in the other groove array along the axial direction of the sheath layer.

[0022] In some embodiments, the sheath layer also includes a reinforcement.

[0023] In some embodiments, the material used for the reinforcement includes one or more of glass fiber reinforced plastic rods (GFRP), aramid fiber reinforced plastic rods (KFRP), and fiber reinforced plastic flexible rods (FFRP).

[0024] The beneficial effects of the technical solution provided in this application include:

[0025] This application provides an all-dielectric acoustic wave sensing optical cable. The acoustic wave sensing optical cable provided by this application adopts a dual-channel sensing optical unit design. In a complex environment where environmental vibrations are superimposed with sound waves, the sensing system can accurately distinguish the sound wave signal through signal demodulation, thereby realizing the detection and precise positioning of environmental sound sources.

[0026] The acoustic wave sensing optical cable of this application is an all-dielectric design. It does not use metal materials or filler grease, so there are no electromagnetic shielding or electromagnetic interference problems. It can be used in complex electromagnetic scenarios. The reference optical unit and test optical unit in the cable are all compact structures without air gaps. All layers in the cable are also compact structures without air gaps. Each layer and each component forms an integral whole. Under external acoustic wave or vibration environment, there is no relative movement between the layers, thereby reducing the energy loss during the propagation of external acoustic waves, improving the coupling efficiency between acoustic wave energy and optical fiber deformation, and increasing the response amplitude of the optical fiber to external acoustic waves.

[0027] The acoustic wave sensing optical cable of this application has a test optical unit embedded within the sheath layer, directly contacting it. Furthermore, the second optical fiber within the test optical unit is only surrounded by a protective layer and an armor layer, bringing the second optical fiber as close to the sheath as possible. This reduces the thickness of the structure for sound wave propagation and increases the acoustic wave energy sensed by the test optical unit. Grooves are distributed on the sheath layer outside the test optical unit; these grooves can be one or more. Their function is to increase the contact area between the sheath layer and the sound wave, further enhancing the acoustic wave energy sensed by the acoustic wave sensing optical cable. A sensitive enhancement layer is tightly attached to the surface of the test optical unit. The deformation of the flexible material sensitive enhancement layer causes deformation of the test optical unit, thereby increasing the deformation of the second optical fiber within the test optical unit and contributing to the gain of sound pressure. Therefore, through these four design methods—grooves on the sheath layer, reduced structural thickness, a tight structure with no air gaps, and a tight attachment to the sensitive enhancement layer—the overall sound pressure sensitivity of the acoustic wave sensing optical cable is significantly improved, expanding the detection range of sound waves. Attached Figure Description

[0028] 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.

[0029] Figure 1 A schematic diagram of the cross-section of the all-dielectric acoustic wave sensing optical cable (one test optical unit) provided for an embodiment of this application;

[0030] Figure 2 A schematic diagram (elongated shape) of a groove array provided in an embodiment of this application;

[0031] Figure 3 A schematic diagram (short strip shape) of a groove array provided in an embodiment of this application;

[0032] Figure 4 A schematic diagram (dot-like) of a groove array provided in an embodiment of this application;

[0033] Figure 5 A schematic diagram of the cross-section of the all-dielectric acoustic wave sensing optical cable (two test optical units) provided in the embodiments of this application;

[0034] Figure 6 A schematic diagram of the cross-section of the all-dielectric acoustic wave sensing optical cable (three test optical units) provided in the embodiments of this application;

[0035] Figure 7 A schematic diagram of the cross-section of the all-dielectric acoustic wave sensing optical cable (four test optical units) provided for an embodiment of this application.

[0036] In the figure: 1. Reference optical unit; 11. First optical fiber; 12. Tight-buffered layer; 13. Reinforcing layer; 14. Inner sheath layer; 2. Test optical unit; 21. Second optical fiber; 22. Protective layer; 23. Armor layer; 3. Damping layer; 4. Sensitizing layer; 5. Sheath layer; 6. Reinforcing element; 7. Groove array; 8. Groove. Detailed Implementation

[0037] 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.

[0038] See Figure 1As shown, this application provides an all-dielectric acoustic wave sensing optical cable, which includes a reference optical unit 1, a damping layer 3 and a sheath layer 5 arranged sequentially from the inside to the outside along the radial direction of the optical cable; wherein, a test optical unit 2 is also provided inside the sheath layer 5, and the test optical unit 2 is located outside the damping layer 3.

[0039] In environments such as subways, tunnels, and bridges, signal sources are highly complex, with sound waves often accompanied by multiple vibration signals. Fiber optic acoustic wave sensing systems cannot accurately distinguish sound signals from interfering vibration signals. Therefore, this application employs a design with two sensing optical units: a reference optical unit located at the center of the optical cable, and a test optical unit housed within the sheath. In environments where sensing optical cables are laid, such as subways, bridges, and tunnels, the cables are fixed near subway tracks, on bridge decks, and on tunnel sidewalls. Under environmental vibration, the sensing optical cable vibrates along with the environment, transferring vibration energy to the optical fiber. Consequently, the sensing signals from both the reference and test optical fibers are environmental vibration signals with identical waveforms. When sound waves are present in the environmental vibration scenario, their propagation occurs from the sound source outwards. When the sound wave contacts the sensing optical cable, the signal sensed by the test optical unit is a mixture of sound wave and vibration, resulting in a waveform that is a hybrid of vibration and sound wave. As sound wave energy is gradually transmitted from the surface of the sensing optical cable to the center of the optical cable, the energy is gradually lost. Because a damping layer is set on the outer layer of the reference optical unit, the damping material has a small elastic modulus and a large deformation. Due to the action of stress or alternating stress, the damping material will lose energy due to molecular plastic slip or other reasons. The strain disappears, and the mechanical energy is converted into heat energy and dissipated into the environment. Thus, the sound wave energy is lost in the damping layer. The signal sensed by the reference optical unit is the vibration signal of the environment, and the waveform is the vibration waveform of the environment.

[0040] The distributed fiber optic acoustic wave sensing system compares the sensed signals of a reference optical unit and a test optical unit. Using the signal from the reference optical unit as ambient noise, it demodulates and analyzes the sensed signal from the test optical unit. In environments with only vibration, the system compares the sensed signals from the reference and test optical units, and the conclusion drawn from the test optical unit signal is considered ambient noise. When ambient vibration is superimposed with sound waves, the system demodulates and accurately distinguishes the sound wave signal from the sensed signal of the test optical unit through signal comparison, thus achieving the sensing and precise location of ambient sound wave signals.

[0041] As can be seen, the acoustic wave sensing optical cable provided in this application adopts a dual-channel sensing optical unit design. In complex environments where environmental vibrations are superimposed with sound waves, the sensing system can accurately distinguish the sound wave signal through signal demodulation, thereby realizing the detection and precise positioning of environmental sound sources.

[0042] In existing technologies, the multi-layered structure, diverse materials, and components such as air gaps, grease, and steel pipes in sensing optical cables result in significant energy loss during the transfer of external acoustic wave energy from the cable surface to the fiber surface. Only a very small portion of the energy reaches the fiber surface, leading to relatively small local strain in the fiber, a small amplitude of the measured optical response, and a low signal-to-noise ratio. For weak external acoustic wave signals, the optical effects of the fiber may not even be detectable, thus reducing the fiber's sensitivity to external acoustic signals. When sound waves propagate in a medium, their energy is absorbed and weakened. Gases exhibit the strongest absorption and greatest attenuation, followed by liquids, while solids show the least absorption and least attenuation. Therefore, the acoustic wave sensing optical cable of this application is an all-dielectric design. No metal materials are used in the optical cable, and no grease is filled in. There will be no electromagnetic shielding or electromagnetic interference problems. It can be applied in complex electromagnetic scenarios. The reference optical unit and the test optical unit in the cable are all compact structures without air gaps. All layers in the cable are also compact structures without air gaps. Each layer and each component forms an integral whole. Under external acoustic wave or vibration environment, there is no relative movement between the layers, thereby reducing the energy loss during the propagation of external acoustic waves, improving the coupling efficiency between acoustic wave energy and optical fiber deformation, and increasing the response amplitude of the optical fiber to external acoustic waves.

[0043] To improve the sensitivity of acoustic wave detection, see [link to relevant documentation]. Figure 1 As shown, this application also provides a sensitivity-enhancing layer 4 inside the sheath layer 5, and the sensitivity-enhancing layer 4 is in contact with the test light unit 2.

[0044] A sensitive enhancement layer 4 is attached tightly to the surface of the test optical unit 2. The deformation of the sensitive enhancement layer 4, formed by the flexible material, can drive the test optical unit 2 to deform, thereby increasing the deformation of the optical fiber in the test optical unit 2 and playing a role in gaining the sound pressure.

[0045] There are many ways in which the sensitizing layer 4 comes into contact with the test optical unit 2. For example, as an example, Figure 1 As shown, the sensitizing layer 4 covers the damping layer 3 and is in contact with the test optical unit 2, which can reduce the manufacturing cost of the optical cable and reduce the complexity of the process implementation; for example, the sensitizing layer 4 directly covers the test optical unit 2. In the aforementioned two schemes, the sensitizing layer 4 is tubular. The sensitizing layer 4 can also be non-tubular, such as plate-shaped, in which case at least one side of the sensitizing layer 4 is in contact with the test optical unit 2.

[0046] The sensitizing layer 4 can be a single layer or multiple layers, depending on actual needs. The materials used in the sensitizing layer 4 include one or more of polyester elastomers, polyurethane elastomers, and nylon elastomers.

[0047] The damping layer 3 can be a single layer or multiple layers, depending on actual needs. The material used in the damping layer 3 has an elastic modulus of 1MPa to 10MPa, a tensile strength of 5MPa to 30MPa, an elongation at break of 400% to 1000%, and a loss factor of 0.45 to 1.0.

[0048] The materials used in the damping layer 3 include one or more of thermoplastic vulcanized rubber (TPV), high-damping rubber, modified silicone rubber, polyurethane composite polyolefin foam material, and polyurethane microcapsules.

[0049] The reference optical unit 1 can be circular or elliptical in appearance, and can be single or multiple as needed. The reference optical unit 1 includes a first optical fiber 11, a tight-fitting layer 12, a reinforcing layer 13 and an inner sheath layer 14 arranged sequentially from the inside to the outside along its radial direction.

[0050] The first optical fiber 11 is a silica-based optical fiber, which can be single or multiple, and can be single-mode or multimode optical fiber; the tight-buffered layer 12 is the outer layer of the first optical fiber 11, with the first optical fiber 11 tightly attached to the tight-buffered layer 12, and the tight-buffered layer 12 can be polyvinyl chloride, low-smoke halogen-free flame-retardant polyolefin, polyester elastomer, polyurethane or nylon; the reinforcing layer 13 is the tensile element of the reference optical unit 1, and can be aramid yarn, water-blocking aramid yarn, glass yarn or water-blocking yarn, and the yarn can be placed longitudinally along the tight-buffered layer 12, or it can be spirally wrapped or woven on the outside of the tight-buffered layer 12; the inner sheath layer 14 is the sheath of the reference optical unit 1, and can be polyvinyl chloride, low-smoke halogen-free flame-retardant polyolefin or flame-retardant polyethylene.

[0051] The test optical unit 2 can be circular, elliptical or flat, and can be one, two or more as needed. Multiple test optical units are evenly distributed along the circumference of the optical cable. The test optical unit 2 includes a second optical fiber 21, a protective layer 22 and an armor layer 23 arranged in sequence from the inside to the outside along its radial direction.

[0052] The second optical fiber 21 is a silica-based optical fiber, which can be single or multiple, and can be single-mode or multimode optical fiber. Preferably, it can be a bending loss-insensitive single-mode optical fiber or a micro-bending resistant multimode optical fiber. The protective layer 22 is the outer layer of the second optical fiber 21, with the second optical fiber 21 closely attached to the protective layer 22. The protective layer 22 can be a nylon elastomer, polyester elastomer TPEE, ethylene-tetrafluoroethylene copolymer ETFE, fluorinated ethylene propylene copolymer FEP, or polyether ether ketone (PEEK). The armor layer 23 is the tensile element of the test optical unit 2, and can be an aramid yarn braided layer, a water-blocking aramid yarn braided layer, or a glass yarn tape. Preferably, the aramid yarn braided layer can be aramid yarn with a linear density of 930 dtex or 1610 dtex, braided with 8 spindles, 16 spindles, or 32 spindles, with a braiding density of 40% to 85%.

[0053] The sheath layer 5 is a flame-retardant sheath layer for the optical cable. The materials used in the sheath layer 5 include one or more of flame-retardant polyolefin, flame-retardant polyester elastomer, flame-retardant polyurethane elastomer and flame-retardant polystyrene elastomer. Preferably, it is a flame-retardant material with high flame retardancy, high hardness, ceramicization, and low coefficient of friction, with an oxygen index greater than or equal to 40, a hardness greater than Shore hardness 55D, and a sliding friction coefficient less than 0.25.

[0054] In existing sensing optical cables, the outermost layer is a circular sheath. When sound waves come into contact with the sheath, their energy rapidly attenuates due to reflection and scattering. As the sound waves propagate within the sensing optical cable, the energy attenuation increases with the cable's thickness; the attenuation amount equals the product of the attenuation coefficient and the path length. Therefore, to improve the sensitivity of sound wave detection, see [reference needed]. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, on the outer wall of the sheath layer 5, along the circumference of the sheath layer 5, there are a plurality of groove arrays 7, the groove array 7 including a plurality of grooves 8 distributed along the axial direction of the sheath layer 5.

[0055] The acoustic wave sensing optical cable of this application has a test optical unit embedded within the sheath layer 5, directly contacting the sheath layer 5. Furthermore, the second optical fiber within the test optical unit is only surrounded by a protective layer and an armor layer, bringing the second optical fiber as close to the sheath as possible. This reduces the thickness of the acoustic wave propagation structure, lowers energy loss during propagation, and increases the acoustic wave energy sensed by the test optical unit. Grooves 8 are distributed on the sheath layer 5 outside the test optical unit. These grooves can be one or multiple. Their function is to increase the contact area between the sheath layer and the acoustic wave, while simultaneously reducing the sheath thickness of the outer sheath layer 5 at the grooves, further reducing the thickness of the acoustic wave propagation structure and lowering energy loss during propagation, thereby increasing the acoustic wave energy sensed by the acoustic wave sensing optical cable. A sensitive enhancement layer is tightly attached to the surface of the test optical unit. The deformation of the flexible material sensitive enhancement layer causes deformation of the test optical unit, thereby increasing the deformation of the second optical fiber within the test optical unit and contributing to the gain of the sound pressure level. Therefore, by using four design methods—grooves on the sheath layer, reducing the thickness of the structure, creating a tight structure without air gaps, and closely adhering to the sensitizing layer—the overall sound pressure sensitivity of the acoustic wave sensing optical cable is greatly improved, expanding the detection range of sound waves.

[0056] The requirements for the thickness of the sheath of the sensing optical cable vary under different laying conditions. The thickness of the sheath layer at the groove should be as thin as possible while meeting the construction requirements for laying the sensing optical cable.

[0057] The groove 8 can have various shapes. For example, the cross-section of the groove 8 can be arc-shaped, conical, or square, where the arc shape can be U-shaped, circular, or elliptical.

[0058] To further improve the sensitivity of sound pressure detection, see [link to relevant documentation]. Figure 1 As shown, along the circumference of the sheath layer 5, the groove array 7 is provided on both sides of the test light unit 2.

[0059] The groove array 7 can take many forms; for example, see [link to example]. Figure 2 As shown, the groove array 7 includes a groove 8, which is elongated and extends along the axial direction of the sheath layer 5 to both ends of the sheath layer 5.

[0060] For example, the groove array 7 includes multiple grooves 8. For example, Figure 3 In the middle, groove 8 is a short strip, while Figure 4 The grooves 8 in the sheath layer 5 are dot-shaped, and multiple grooves 8 are distributed at intervals along the axial direction of the sheath layer 5. Furthermore, the grooves 8 in two adjacent groove arrays 7 can be arranged in a specific pattern. Figure 3 or Figure 4 The arrangement can be staggered in one way, allowing for alignment.

[0061] See Figure 3 or Figure 4 As shown, when the grooves 8 in two adjacent groove arrays 7 are staggered, the distance d between two adjacent grooves 8 in one groove array 7 is less than or equal to the length L of the groove 8 in the other groove array 7 along the axial direction of the sheath layer 5. The advantage of this staggered arrangement, where d ≤ L, is that the total length of the grooves 8 in the two adjacent groove arrays 7 along the axial direction of the sheath layer 5 can cover the entire length of the test optical unit 2, thus ensuring that the portion of the test optical unit 2 between two adjacent grooves 8 can also respond quickly to sound pressure.

[0062] The structural form of the acoustic wave sensing optical cable can be determined based on the location of the sensing optical cable, the different requirements of the environment, and the different sources of ambient sound waves.

[0063] For example, see Figure 1 As shown, in this structure, there is one test optical unit 2.

[0064] For example, see Figure 5 As shown, in this structure, there are two test optical units 2.

[0065] For example, see Figure 6 As shown, in this structure, there are three test optical units 2.

[0066] For example, see Figure 7 As shown, in this structure, there are four test optical units 2.

[0067] The sheath layer 5 also includes reinforcing members 6. These reinforcing members 6 are the main load-bearing elements of the optical cable, and there can be two, four, or more. The reinforcing members 6 can be circular, elliptical, or square. The materials used for the reinforcing members 6 include one or more of glass fiber reinforced plastic (GFRP), aramid fiber reinforced plastic (KFRP), and fiber reinforced plastic flexible rod (FFRP). The reinforcing members 6 are placed on both sides of the test optical unit 2 and embedded within the sheath layer 5. The surface of the reinforcing members 6 has an adhesive coating to increase the adhesion between them and the sheath layer 5, making them a unified whole. During the installation and laying of the optical cable, there is no slippage between the reinforcing members 6 and the sheath layer 5, and the sheath layer will not deform, stretch, or be damaged. Under ambient temperature changes after the optical cable is laid, the reinforcing members 6 support the entire optical cable structure, suppressing the thermal expansion and contraction of the sheath layer 5, the sensitizing layer 4, the damping layer 3, and other polymer material layers, ensuring that the morphology of the optical fibers in the test optical unit 2 and the reference optical unit 1 remains unaffected under the operating ambient temperature.

[0068] 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.

[0069] 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.

[0070] 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 fully dielectric acoustic wave sensing optical cable, characterized in that, It includes a reference optical unit (1), an acoustic damping layer (3), and a sheath layer (5) arranged sequentially from the inside to the outside along the radial direction of the optical cable; The sheath layer (5) is further provided with a test light unit (2), and the test light unit (2) is located outside the acoustic damping layer (3); On the outer wall of the sheath layer (5), a plurality of groove arrays (7) are provided along the circumference of the sheath layer (5), and the groove array (7) includes a plurality of grooves (8) distributed along the axial direction of the sheath layer (5).

2. The all-dielectric acoustic wave sensing optical cable as described in claim 1, characterized in that: The sheath layer (5) is further provided with an acoustic wave sensitizing layer (4), which is in contact with the test light unit (2).

3. The all-dielectric acoustic wave sensing optical cable as described in claim 2, characterized in that: The acoustic sensitizing layer (4) is wrapped around the acoustic damping layer (3), or the acoustic sensitizing layer (4) is wrapped around the test light unit (2); And / or, the material used in the acoustic sensitizing layer (4) includes one or more of polyester elastomers, polyurethane elastomers and nylon elastomers.

4. The all-dielectric acoustic wave sensing optical cable as described in claim 1, characterized in that: The material used in the acoustic damping layer (3) has a tensile strength of 5MPa~30MPa, an elongation at break of 400%~1000%, and a loss factor of 0.45~1.

0. And / or, the material used in the acoustic damping layer (3) includes one or more of thermoplastic vulcanized rubber, modified silicone rubber, polyurethane composite polyolefin foam material and polyurethane microcapsules; And / or, the reference optical unit (1) includes a first optical fiber (11), a tight-fitting layer (12), a reinforcing layer (13) and an inner sheath layer (14) arranged sequentially from the inside to the outside along its radial direction. And / or, the test optical unit (2) includes a second optical fiber (21), a protective layer (22) and an armor layer (23) arranged sequentially from the inside to the outside along its radial direction. And / or, the material used for the sheath layer (5) includes one or more of flame-retardant polyolefins, flame-retardant polyester elastomers, flame-retardant polyurethane elastomers and flame-retardant polystyrene elastomers.

5. The all-dielectric acoustic wave sensing optical cable as described in claim 1, characterized in that: Along the circumference of the sheath layer (5), the groove array (7) is provided on both sides of the test light unit (2). And / or, the cross-section of the groove (8) is arc-shaped, conical, or square.

6. The all-dielectric acoustic wave sensing optical cable as described in claim 1, characterized in that: The groove array (7) includes a groove (8) that extends along the axial direction of the sheath layer (5) to both ends of the sheath layer (5); Alternatively, the groove array (7) may include a plurality of grooves (8), and the grooves (8) in two adjacent groove arrays (7) may be staggered or aligned.

7. The all-dielectric acoustic wave sensing optical cable as described in claim 6, characterized in that: When the grooves (8) in two adjacent groove arrays (7) are staggered, the distance d between two adjacent grooves (8) in one groove array (7) is less than or equal to the length L of the groove (8) in the other groove array (7) in the axial direction of the sheath layer (5).

8. The all-dielectric acoustic wave sensing optical cable as described in claim 1, characterized in that: The sheath layer (5) is also provided with a reinforcing member (6).

9. The all-dielectric acoustic wave sensing optical cable as described in claim 8, characterized in that: The reinforcing member (6) is made of one or more of the following materials: glass fiber reinforced plastic rod (GFRP), aramid fiber reinforced plastic rod (KFRP), and fiber reinforced plastic flexible rod (FFRP).

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