Underwater sound sensing optical cable and preparation method thereof
By adopting the sensing element matrix design and densely wound optical fiber connection method in the underwater acoustic sensing optical cable, the problems of reduced sensitivity and large loss caused by welding of traditional underwater acoustic sensing optical cables are solved, and the underwater acoustic sensing effect with efficient transmission and high sensitivity is achieved.
Patent Information
- Application Number
- CN202511032273.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-25
- Publication Date
- 2025-09-23
AI Technical Summary
The existing underwater acoustic sensing optical cables have the problems of reduced overall sensitivity and large splicing losses due to the fusion splicing of optical fiber sensing elements.
The sensor element matrix design is adopted, and the sensor element and the sensor element spanning optical fiber are connected by densely wound optical fiber, replacing the traditional fusion series process, combining the use of titanium alloy components and specific materials to improve structural stability and sensitivity.
The overall transmission effect of the underwater acoustic sensor cable is improved, the attenuation is reduced, the sensitivity is enhanced, and it adapts to the complex conditions of the marine environment.
Smart Images
Figure CN120685190A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optical signal transmission, and in particular to an underwater acoustic sensor optical cable and a preparation method thereof. Background Art
[0002] With the continuous development of people's exploration of marine resources, there is an urgent need to develop fiber optic sensing communication technology to better utilize fiber optic sensing technology to timely understand the distribution of marine life, marine resources, and coastal defense safety.
[0003] At present, underwater acoustic sensing optical cable products are mainly divided into two categories. One category uses large-pitch spiral winding of grating optical fiber and uses grating technology to manufacture underwater acoustic sensing optical cables to achieve real-time monitoring. The disadvantage of this type of product is low sensitivity; the other category is to first produce high-sensitivity optical fiber sensing elements separately, and then use optical fiber hot welding technology to connect multiple sensing elements together, and then put them in a protective tube to form a fiber optic sensing array to achieve real-time monitoring function.
[0004] However, the products in the related technology mainly use optical fiber sensing elements to sense changes in sound waves. However, since multiple sensing elements are fused and connected in series, there are many optical fiber joints and the overall fusion loss is very large, resulting in a decrease in overall sensitivity. Summary of the Invention
[0005] The present invention relates to an underwater acoustic sensing optical cable and its preparation method, which can eliminate the loss problem caused by fusion splicing in related technologies by improving the connection method of high-sensitivity optical fiber sensing elements. The technical solution is as follows: In one aspect, an underwater acoustic sensing optical cable is provided, comprising a central reinforcement member, a density adjustment layer, a sensing element matrix, a sensing element, a sensing element spanning optical fiber, and an outer sheath; The cross section of the underwater acoustic sensing cable is circular; The central reinforcement is located at the center of the hydroacoustic sensing cable; The density adjustment layer is located on the outer layer of the central reinforcement and is used to adjust the overall density of the optical cable; The sensing element matrix is located on the outer layer of the density adjustment layer, and the sensing element matrix is used to carry the sensing element and the sensing element spans the optical fiber; The sensing element is realized in the form of densely wound optical fiber; The sensing element and the sensing element are fixedly connected to the sensing element matrix across the optical fiber; The sensing elements are closely connected to the sensing element matrix, the sensing elements span the optical fiber, and the sensing elements are adjacent and alternately arranged; The outer sheath is located on the outer layer of the underwater acoustic sensor cable and is used for contact with the external environment.
[0006] In an optional embodiment, the sensing element matrix includes a matrix body; The sensing element base also has grooves, spiral grooves and titanium alloy components; The titanium alloy component is located on the surface of the sensing element substrate The grooves and the spiral grooves are formed on the base body, and the grooves and the spiral grooves are alternately distributed along the axial direction of the sensing element base body; The titanium alloy component is sleeved on the outside of the groove, and the titanium alloy component and the groove form an accommodating space; The accommodating space formed by the titanium alloy component and the groove is used to accommodate the sensing element; The spiral groove is used to accommodate the sensing element spanning the optical fiber.
[0007] In an optional embodiment, the intersection of the groove and the spiral groove produces a spiral transition.
[0008] In an optional embodiment, the material of the base body is thermoplastic polyurethane elastomer TPU.
[0009] In an alternative embodiment, the central reinforcement is realized as twisted steel wires.
[0010] In an optional embodiment, the density adjustment layer is made of polyethylene.
[0011] In an optional embodiment, the material of the outer protective layer is TPU.
[0012] On the other hand, a method for preparing an underwater acoustic sensor optical cable is provided, the method being used to prepare any of the above underwater acoustic sensor optical cables, the method comprising: Prepare the center reinforcement; A density adjustment layer is prepared on the periphery of the central reinforcement by an extrusion process; Prepare a sensing element matrix on the periphery of the density adjustment layer; preparing a sensing element on a sensing element substrate and a sensing element spanning an optical fiber; An outer protective layer is prepared on the periphery of the sensing element matrix through an extrusion process.
[0013] In an optional embodiment, the sensing element matrix includes a matrix body; The sensing element base also has grooves, spiral grooves and titanium alloy components; A sensing element matrix is prepared on the periphery of the density adjustment layer, including: A base body is prepared on the periphery of the density adjustment layer by an extrusion process, and a spiral groove is formed on the base body; forming a groove on the base body by a groove cutting machine; The titanium alloy component is sleeved at a position corresponding to the groove.
[0014] In an optional embodiment, the sensing element is prepared on a sensing element substrate and the sensing element spans an optical fiber, comprising: The sensing element is wound in the groove through the twisting cage rotation system of the optical fiber winding machine; The optical fiber winding machine uses a twisting cage rotation system and a pulling motion to wind the sensing element across the optical fiber in the spiral groove. Among them, the optical fiber winding machine is equipped with an optical fiber guide needle tube and an optical fiber guide wheel. The optical fiber guide needle tube and the optical fiber guide wheel are meshed with gears. By adjusting the position of the optical fiber guide tube and the optical fiber guide wheel, the switching between the dense winding form and the crossing form of the optical fiber can be achieved.
[0015] The technical effects of various embodiments of the present invention include at least: By designing the sensing element matrix inside the underwater acoustic sensor cable, the sensing elements in the sensing element matrix and the sensing element spanning optical fiber are combined into an optical fiber unit for transmission, replacing the fusion series process, so that the overall transmission effect of the sensing optical cable is good, the sensitivity is high, and the attenuation is low. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0017] Figure 1 A schematic structural diagram of an underwater acoustic sensing optical cable provided by an exemplary embodiment of the present application is shown.
[0018] Figure 2 A schematic cross-sectional view of an underwater acoustic sensor optical cable provided by an exemplary embodiment of the present application is shown.
[0019] Figure 3 A schematic structural diagram of a sensing element matrix provided by an exemplary embodiment of the present application is shown.
[0020] Figure 4 A schematic cross-sectional view of a sensing element matrix provided by an exemplary embodiment of the present application is shown.
[0021] Figure 5 A schematic diagram of the internal structure of a titanium alloy component provided by an exemplary embodiment of the present application is shown.
[0022] Figure 6 A schematic flow chart of a method for preparing an underwater acoustic sensor optical cable provided by an exemplary embodiment of the present application is shown.
[0023] Figure 7A schematic diagram of the working state of an optical fiber winding machine provided by an exemplary embodiment of the present application is shown.
[0024] Figure 8 A schematic diagram of the working state of another optical fiber winding machine provided by an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION
[0025] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0026] It should be noted that the underwater acoustic sensor cables involved in the embodiments of this application can be used for offshore oil exploration, marine fishery detection, earthquake detection, marine security, etc. The overall density of the optical cable can be adjusted according to the application environment, close to the actual water density, and can be suspended at various depths underwater.
[0027] Figure 1 FIG1 shows a schematic structural diagram of an underwater acoustic sensing optical cable provided by an exemplary embodiment of the present application. Figure 2 The corresponding cross-sectional diagram is shown. Figure 1 as well as Figure 2 ,, the underwater acoustic optical cable includes a central reinforcement member 1, a density adjustment layer 2, a sensing element matrix 3, a sensing element 4, a sensing element spanning optical fiber 5 and an outer sheath 6; the cross-section of the underwater acoustic sensing optical cable is circular; the central reinforcement member is located at the center of the underwater acoustic sensing optical cable; the density adjustment layer is located on the outer layer of the central reinforcement member, and the density adjustment layer is used to adjust the comprehensive density of the optical cable; the sensing element matrix is located on the outer layer of the density adjustment layer, and the sensing element matrix is used to carry the sensing element and the sensing element spanning optical fiber; the sensing element and the sensing element spanning optical fiber are fixedly connected to the sensing element matrix; the sensing element is implemented in the form of a densely wound optical fiber; the sensing element is densely wound with the sensing element matrix, and the sensing element spanning optical fiber and the sensing element are adjacent and alternately arranged; the outer sheath is located on the outer layer of the underwater acoustic sensing optical cable, and is used to contact the external environment.
[0028] In the embodiment of the present application, the cross section of the underwater acoustic sensor cable is realized as a cylindrical shape, combined with Figure 1 as well as Figure 2 As shown, in the structure of the underwater acoustic sensing cable, there are a central reinforcement member and an outer sheath for strengthening the overall structure. The central reinforcement member is located in the innermost layer of the underwater acoustic sensing cable structure, and the outer sheath is located in the outermost layer of the underwater acoustic sensing cable structure.
[0029] Optionally, to ensure structural strength, in the embodiments of this application, the central reinforcement member is constructed of twisted metal wire. Optionally, the metal is steel. This application does not limit the specific material of the central reinforcement member. Correspondingly, the outer sheath of the optical cable is constructed of a waterproof material.
[0030] In the embodiment of the present application, in order to adapt to the underwater working environment of the underwater acoustic sensor optical cable, its comprehensive density needs to be adjusted. Therefore, the density adjustment layer is made of a material with a density lower than that of seawater.
[0031] In the embodiment of the present application, the sensing element matrix is a structure that carries optical fibers, which is formed on the outer layer of the density adjustment layer and is used to carry sensing elements and sensing element spanning optical fibers. Within a preset length, the sensing element forms a unit of densely wound optical fibers, and the sensing element spanning optical fibers is used to realize communication between two adjacent sensing elements. That is, in the embodiment of the present application, the optical fiber sensing elements between different units are connected in the form of a sensing element spanning optical fiber connection method, replacing the traditional fusion splicing method, so as to improve the transmission efficiency of the optical fiber and reduce the attenuation rate of the optical fiber. It should be noted that the sensing element and the sensing element spanning optical fiber are two different densely wound forms of optical fibers in the underwater acoustic sensing cable. In actual applications, adjacent sensing elements and sensing element spanning optical fibers are realized as the same optical fiber.
[0032] In summary, the underwater acoustic sensor cable provided in the embodiment of the present application designs a sensor element matrix inside the underwater acoustic sensor cable, so that the sensor elements in the sensor element matrix and the sensor element spanning optical fiber are combined into an optical fiber unit for transmission, and replace the fusion series process, so that the overall transmission effect of the sensor cable is good, the sensitivity is high, and the attenuation is low.
[0033] Next, the specific structure of the underwater acoustic sensor optical cable involved in the embodiment of the present application is described: In an alternative embodiment, please refer to Figure 3 as well as Figure 4 The sensing element substrate 3 includes a substrate body; the sensing element substrate also has a groove 31, a spiral groove 32 and a titanium alloy component 33; the titanium alloy component is located on the surface of the sensing element substrate, the groove and the spiral groove are opened on the substrate body, and the groove and the spiral groove are alternately distributed along the axial direction of the sensing element substrate; the titanium alloy component is sleeved on the outside of the groove, and the titanium alloy component and the groove form an accommodating space; the accommodating space formed by the titanium alloy component and the groove is used to accommodate the sensing element; the spiral groove is used to accommodate the sensing element across the optical fiber.
[0034] Optionally, in the embodiment of the present application, the thickness of the base body is 3 mm, and four symmetrically distributed spiral grooves are extruded on the circumference of the base body, and grooves are provided every 10 mm.
[0035] Optionally, the width of the spiral groove is 1.5mm, the depth is 1.5mm, the bottom arc diameter is 1.5mm, and the spiral pitch is 300mm-600mm. The intersection between the spiral groove and the groove is an arc transition with a bending radius of 10mm. In an example, the length of the groove is 80mm and the depth is 1.5mm. Optionally, please refer to Figure 5 The outer surface 331 of the titanium alloy component is a smooth and round circumferential surface, and is sleeved on the outside of the groove. The inner side of the titanium alloy component is provided with a reinforcing rib 332, and the reinforcing rib 332 is implemented in a horizontal and vertical intersection form to form a cavity 333. Since underwater acoustic sensor cables are generally placed hundreds of meters or even deeper below the sea surface, the lateral pressure of seawater will seriously affect the sensing element, resulting in a decrease in sensing sensitivity. The titanium alloy component has high strength and large modulus. When subjected to a large load, it can maintain good elastic deformation and can effectively resist the lateral pressure of seawater. The multiple groups of cavities formed with the groove surface have the effect of amplifying the sound wave vibration, making it easier for the optical fiber sensing element to better receive signals.
[0036] In the embodiment of the present application, the sensing element is densely wound on the surface of the titanium alloy component, and the thickness of the dense winding is 0.4mm-0.6mm.
[0037] Optionally, the sensing element and the optical fiber spanning the sensing element are both made of a thin-diameter, micro-bend-resistant single-mode optical fiber with a diameter of 0.16 mm.
[0038] In an optional embodiment, the intersection of the groove and the spiral groove produces a spiral transition, and the location of the spiral transition is used to achieve the transition from sensing element to sensing element across the optical fiber.
[0039] Next, the various materials used in underwater acoustic sensor cables are explained: In an optional embodiment, the material of the base body is thermoplastic polyurethane elastomer TPU.
[0040] In an optional embodiment, the central reinforcement is implemented as a twisted steel wire. In one example, the twisted steel wire is a combination of one central steel wire and six twisted steel wires.
[0041] In an optional embodiment, the material of the density adjustment layer is polyethylene. It should be noted that the density of the steel wire is about 7.85g / cm 3 , TPU material density is about 1.2g / cm 3 , the density of optical fiber is about 1.43g / cm 3 , which is much greater than the density of seawater, which is about 1.02 g / cm 3 Therefore, a low-density material is extruded outside the central reinforcement to form a density adjustment layer. Low-density polyethylene or other low-density materials can be used, or a foaming process can be used to adjust the actual comprehensive density of the optical cable by adjusting the volume of the density adjustment layer.
[0042] In an optional embodiment, the material of the outer protective layer is TPU, which is consistent with the material of the base body.
[0043] Correspondingly, in addition to providing an underwater acoustic sensor optical cable, the embodiment of the present application also provides: Figure 6 A method for preparing an underwater acoustic sensing optical cable is also provided. Figure 6 A schematic flow chart of a method for preparing an underwater acoustic sensor optical cable provided by an exemplary embodiment of the present application is shown. The method is used to prepare the underwater acoustic sensor optical cable as described in any of the above embodiments, and the method includes: Step 601: Prepare a central reinforcement member.
[0044] In the embodiment of the present application, during the preparation process of the central reinforcement, it is necessary to remove dust from the surface of the twisted steel wires to keep the surface clean, and to reduce vibration and straighten them through the dancing wheel and straightening device.
[0045] Step 602: Prepare a density adjustment layer on the periphery of the central reinforcement member through an extrusion process.
[0046] Optionally, in this process, the extrusion process is prepared by an extrusion process on the periphery of the central reinforcement.
[0047] Step 603: Prepare a sensing element matrix on the periphery of the density adjustment layer.
[0048] In the embodiment of the present application, corresponding to the structure of the sensor element matrix, the base body of the sensor element matrix is extruded outside the density adjustment layer. That is, through the mold core and mold sleeve of the extruder, the mold core and mold sleeve adopt an extrusion process, the TPU material is extruded from the extruder, tightly coated on the outside of the density adjustment layer, and formed into the sensor element matrix after cooling. In the sensor element matrix extrusion process, the mold sleeve of the extruder adopts a continuously rotating technology, and four evenly distributed "U"-shaped protrusions are left at the outlet bearing diameter of the mold sleeve. Under the linear traction action of the traction machine, four continuous U-shaped spiral grooves are formed on the surface of the sensor element matrix. The spiral pitch of the U-shaped spiral groove is controlled by adjusting the traction speed and the rotation speed of the mold sleeve. The height and width of the "U"-shaped protrusion are approximately 1.6mm*1.6mm, and the diameter of the circle is approximately 1.6mm.
[0049] After the extrusion of the fiber optic sensor body, the cable core is unwound from a pay-off frame and fed into a grooving machine. This machine consists of a rotating cutter head and precise transverse and longitudinal feed mechanisms. By adjusting the precision transverse and longitudinal feed mechanisms of the rotating cutter head, a groove of the width and depth meeting the design requirements is cut into the circumferential surface of the fiber optic sensor body. The fiber optic sensor body is then fitted with a titanium alloy assembly and fed into a fiber optic winding machine for dense fiber winding.
[0050] That is, corresponding to the specific structure of the sensing element matrix, the process includes: preparing the matrix body on the periphery of the density adjustment layer through an extrusion process, and forming a spiral groove on the matrix body; forming a groove on the matrix body through a grooving machine; and sleeved the titanium alloy component at the position corresponding to the groove.
[0051] Step 604: Prepare a sensing element on a sensing element substrate and a sensing element spanning optical fiber.
[0052] In the embodiments of the present application, the winding of the optical fiber is completed by an optical fiber winding machine. In one example, the optical fiber winding machine is mainly divided into three parts: ① The cage rotation system, which consists of a motor, a cage, and a central hollow shaft. The number of rotations of the cage is the number of turns the optical fiber is wound around the sensing element matrix; ② The optical fiber pay-off system is responsible for precisely controlling the pay-off tension of the optical fiber. Due to the use of fine-diameter optical fiber, the pay-off tension of the optical fiber is controlled at 30g±5g, and the optical fiber is evenly paid out to ensure uniform tension throughout the entire optical cable; ③ The optical fiber arrangement system, which uses a precision cable arranger to achieve dense winding and neat arrangement of the optical fiber sensing elements.
[0053] When winding the fiber optic sensor element, the production line's traction machine remains stationary. The stranding cage rotates according to the set number of turns, while the fiber optic cable arrangement system moves back and forth to precisely control the fiber optic cable pitch to complete the required winding of the sensor element. After the sensor element is completed, the stranding cage slowly rotates and traction advances, driving the sensor element across the fiber into the U-shaped spiral groove, and then the sensor element is again wound closely. This continuous winding process of multiple sensor elements and sensor elements across the fiber forms a fiber optic sensor element array.
[0054] To ensure that the tightly wound optical fibers are neatly arranged and to avoid breakage when the fibers cross, please refer to Figure 7 as well as Figure 8 , an optical fiber guide needle tube 110 and two optical fiber guide wheels 111 are designed at the fiber outlet of the guide rod of the cable arranger. The inner diameter of the optical fiber guide needle tube is about 0.25mm, and the diameter of the optical fiber guide wheel is about 8mm, which is a "U"-shaped groove. The optical fiber guide needle tube and the optical fiber guide wheel are meshed with gears. When the sensing element is in operation, the two optical fiber guide wheels open to both sides, and the optical fiber guide needle tube extends forward, close to the surface of the titanium alloy component on the center groove, so that the longitudinal force of the precision wiring is accurately transmitted to the optical fiber, ensuring that the densely wound optical fiber is tight, neat and uniform. When winding the sensing element across the optical fiber, the optical fiber guide needle tube retracts backward, and the two optical fiber guide wheels move closer to the middle. The front end of the optical fiber guide needle tube does not exceed the center of the two guide wheels, and the optical fiber is pulled out from the guide wheel to avoid breaking at the end of the optical fiber guide needle tube.
[0055] The cable core after being wound with the optical fiber sensing element array is pulled and wound onto the turnover disk on the take-up frame.
[0056] That is, the process includes: winding the sensing element in the groove through the cage rotation system of the optical fiber winding machine; winding the sensing element across the optical fiber in the spiral groove through the cage rotation system of the optical fiber winding machine in combination with the traction movement; the optical fiber winding machine is equipped with an optical fiber guide needle tube and an optical fiber guide wheel, and the optical fiber guide needle tube and the optical fiber guide wheel are engaged with each other by gears. By adjusting the position of the optical fiber guide tube and the optical fiber guide wheel, the switching between the dense winding form and the spanning form of the optical fiber is realized.
[0057] Step 605: Prepare an outer protective layer on the periphery of the sensor element substrate through an extrusion process.
[0058] In the embodiment of the present application, the outer protective layer is formed on the periphery of the sensing element substrate through an extrusion process to become the outer protective layer.
[0059] At this point, the preparation of the underwater acoustic sensing optical cable is completed.
[0060] In summary, the method provided in the embodiment of the present application designs a sensor element matrix inside the underwater acoustic sensor cable, so that the sensor elements in the sensor element matrix and the sensor element spanning optical fiber are combined into an optical fiber unit for transmission, and replaces the fusion series process, so that the overall transmission effect of the sensor cable is good, the sensitivity is high, and the attenuation is low.
[0061] The method provided in the embodiment of the present application provides a preparation device corresponding to the spiral groove structure through the design of the optical fiber guide needle tube and the optical fiber guide wheel of the optical fiber winding machine, thereby further improving the structural stability of the underwater acoustic sensor optical cable.
[0062] The above are only optional embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. An underwater acoustic sensing optical cable, characterized in that: The underwater acoustic sensing optical cable comprises a central reinforcement member, a density adjustment layer, a sensing element matrix, a sensing element, a sensing element spanning optical fiber and an outer sheath; The cross section of the underwater acoustic sensor optical cable is circular; The central reinforcement member is located at the center of the underwater acoustic sensing cable; The density adjustment layer is located on the outer layer of the central reinforcement member, and the density adjustment layer is used to adjust the comprehensive density of the optical cable; The sensing element matrix is located on the outer layer of the density adjustment layer, and the sensing element matrix is used to carry the sensing element and the sensing element spans the optical fiber; The sensing element and the sensing element are fixedly connected to the sensing element base across the optical fiber; The sensing element is implemented in the form of a densely wound optical fiber; The sensing elements are closely connected to the sensing element matrix, the sensing elements span the optical fiber, and the sensing elements are adjacent and alternately arranged; The outer sheath is located on the outer layer of the underwater acoustic sensor optical cable and is used for contacting the external environment.
2. The underwater acoustic sensing optical cable according to claim 1, characterized in that: The sensing element matrix includes a matrix body; The sensing element base body also has a groove, a spiral groove and a titanium alloy component; The titanium alloy component is located on the surface of the sensing element matrix The grooves and the spiral grooves are formed on the base body, and the grooves and the spiral grooves are alternately distributed along the axial direction of the sensing element base body; The titanium alloy component is sleeved on the outside of the groove, and the titanium alloy component and the groove form an accommodating space; The accommodating space formed by the titanium alloy component and the groove is used to accommodate the sensing element; The spiral groove is used to accommodate the sensing element spanning the optical fiber.
3. The underwater acoustic sensor optical cable according to claim 2, characterized in that: The intersection of the groove and the spiral groove produces a spiral transition.
4. The underwater acoustic sensing optical cable according to claim 2, characterized in that: The material of the base body is thermoplastic polyurethane elastomer TPU.
5. The underwater acoustic sensor optical cable according to claim 1, characterized in that: The central reinforcement is realized as a stranded steel wire.
6. The underwater acoustic sensing optical cable according to claim 1, characterized in that: The material of the density adjustment layer is polyethylene.
7. The underwater acoustic sensor optical cable according to claim 1, characterized in that: The material of the outer protective layer is TPU.
8. A method for preparing an underwater acoustic sensor optical cable, characterized in that: The method is used to prepare the underwater acoustic sensor optical cable according to any one of claims 1 to 7, and the method comprises: Prepare the center reinforcement; preparing a density adjustment layer on the periphery of the central reinforcement by an extrusion process; Prepare a sensing element matrix on the periphery of the density adjustment layer; preparing a sensing element on the sensing element substrate and a sensing element spanning an optical fiber; An outer protective layer is prepared on the periphery of the sensing element matrix through an extrusion process.
9. The method according to claim 8, characterized in that The sensing element matrix includes a matrix body; The sensing element base body also has a groove, a spiral groove and a titanium alloy component; The step of preparing a sensing element matrix on the periphery of the density adjustment layer comprises: preparing a base body on the periphery of the density regulating layer by an extrusion process, and forming the spiral groove on the base body; forming a groove on the base body by a groove cutting machine; The titanium alloy component is sleeved at a position corresponding to the groove.
10. The method according to claim 9, characterized in that The method of preparing the sensing element on the sensing element substrate and spanning the optical fiber by the sensing element comprises: Winding the sensing element in the groove by means of a twisting cage rotating system of an optical fiber winding machine; Winding the sensing element across the optical fiber in the spiral groove is performed by a twisting cage rotation system of an optical fiber winding machine in combination with a pulling motion; Among them, the optical fiber winding machine is equipped with an optical fiber guide needle tube and an optical fiber guide wheel. The optical fiber guide needle tube and the optical fiber guide wheel are engaged with each other by gears. By adjusting the positions of the optical fiber guide tube and the optical fiber guide wheel, the switching between the dense winding form and the crossing form of the optical fiber can be achieved.