Special optical cable, preparation method and sensing device having the same

Abstract

The present invention discloses a special optical cable, a preparation method and a sensing device having the same. The special optical cable includes an optical fiber body, a high-temperature resistant coating layer, a primary buffer layer, a secondary buffer layer, a reinforcement layer and a sheath layer arranged in sequence from the inside to the outside. The high-temperature resistant coating layer includes an inner layer, a transition layer and an outer layer arranged in sequence from the inside to the outside. The present invention achieves efficient combination of the inner layer and the outer layer by designing a transition layer, avoids the delamination problem, and achieves significant improvement in the high-temperature resistance, bending and compression resistance and other properties of the optical cable; the special optical cable has many excellent properties such as light weight, high-temperature resistance, fast thermal conductivity, resistance to strong electric and magnetic fields, bending and compression resistance, high thermal sensitivity, high mechanical properties, high wear resistance, flame retardancy, radiation resistance, corrosion resistance, etc., and is suitable for use in structural health monitoring equipment that is resistant to electromagnetic interference, and realizes monitoring and storage of parameters such as temperature and vibration of the surface structure of an object or material, and serves in structural health monitoring and data storage of aircraft in a flight environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical cables, and in particular relates to a special optical cable, a preparation method and a sensing device having the same. Background Art

[0002] With the rapid development of data and information, fiber optic sensing technology has gradually become popular in a variety of fields, including aviation, electricity, thermal pipelines, and petroleum and petrochemicals. These fields have further requirements for the performance of optical fiber cables, such as high temperature resistance, high thermal conductivity, and wear resistance. In the aviation field, abnormal vibration of aircraft poses a significant threat to its structure and life safety. Therefore, aircraft structural health monitoring is of paramount importance.

[0003] To address the above-mentioned issues, a Chinese invention patent, publication number CN116750197A, is titled "A Multi-parameter Airborne Structural Health Monitoring System." The patent discloses that the system includes a power switch, a power module, a main control module, a storage module, a bus communication module, a universal electrical signal acquisition module, an optical fiber demodulation module, a sensor, a transmission cable, and a portable human-machine interface. The system can simultaneously acquire and store multiple bus signals, electrical signals, and optical signals, which can then be downloaded and processed by a portable human-machine interface on the ground via a transmission cable. By uniformly processing multiple parameters, the problem of mutual reference between parameters is resolved, providing a new solution for aircraft structural health monitoring and significantly improving the efficiency of field structural health monitoring. However, the patent does not disclose the structure of the transmission cable, nor is it clear what the performance of the transmission cable is.

[0004] Traditional optical fiber cable protective materials include polymers such as acrylic coatings, PET sheaths, and PE. The glass transition temperatures of these materials are all below 100°C, making them suitable only for cable installation in standard environments. Exposure to high temperatures can lead to softening, yellowing, and cracking, compromising the protection of the optical fiber cable. Therefore, to meet the requirements of specialized applications, such as aviation optical cables, which have temperature requirements, further improvements to the cable structure and polymer materials are needed.

[0005] Based on this, the present invention discloses a special optical cable, a preparation method and a sensing device having the same. Summary of the Invention

[0006] In order to solve the problems in the prior art, the purpose of the present invention is to provide a special optical cable, a preparation method and a sensing device having the same.

[0007] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0008] A special optical cable comprises an optical fiber body, a high-temperature resistant coating layer, a primary buffer layer, a secondary buffer layer, a reinforcement layer and a sheath layer which are arranged in sequence from the inside to the outside.

[0009] Furthermore, the optical fiber body adopts ordinary G652D single-mode optical fiber or multi-mode optical fiber.

[0010] Furthermore, the outer surface of the high temperature resistant coating layer is provided with a groove array with a period of 50 to 60 μm.

[0011] Furthermore, the high temperature resistant coating layer includes an inner layer, a transition layer and an outer layer arranged in sequence from the inside to the outside.

[0012] Furthermore, the raw materials for preparing the inner layer include the following components in parts by weight:

[0013] 40-50 parts of acrylate;

[0014] 30-40 parts of bisphenol A diacrylate;

[0015] 3-5 parts of spiropyran;

[0016] Modified nano-SiO2 15~25 parts.

[0017] Furthermore, the raw materials for preparing the inner layer are prepared by the following steps:

[0018] In the first step, the SiO2 dispersion is ultrasonicated for 25 to 30 minutes, KH-570 ethanol solution is added, and hydrolyzed at 50 to 55°C for 50 to 70 minutes, followed by condensation at 75 to 85°C for 4 to 5 hours. Finally, the modified nano-SiO2 is obtained by centrifugation, washing, drying, and grinding.

[0019] In the second step, acrylate, bisphenol A diacrylate and modified nano-SiO2 were mixed uniformly by ultrasonic dispersion (40-50 kHz, 25-30 min) and three-roll milling, and the viscosity was adjusted to 900 ± 50 cP for standby use;

[0020] In the third step, spiropyran is added to the mixture obtained in the second step. The silanol (Si-OH) on SiO2 forms a weak hydrogen bond with the nitro group (-NO2) of spiropyran, achieving stable loading and forming SiO2-spiropyran particles. At the same time, bisphenol A diacrylate forms a cross-linked network during UV curing, further fixing the SiO2-spiropyran particles in the acrylate matrix to prevent molecular migration.

[0021] Furthermore, the raw materials for preparing the transition layer include the following components in parts by weight:

[0022] 60-70 parts of bismaleimide;

[0023] 30-40 parts of hydroxyethyl methacrylate;

[0024] 3-5 parts of polydopamine-coated carbon nanotubes;

[0025] 2-4 parts of barium titanate nanofibers.

[0026] Furthermore, the raw materials for preparing the transition layer are prepared by the following steps:

[0027] First, under nitrogen protection, bismaleimide and hydroxyethyl methacrylate were premixed in a composite solvent of N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF) with a volume ratio of 7:3 and stirred at 75-80°C for 2-2.5 hours to form a homogeneous solution.

[0028] Subsequently, polydopamine-coated carbon nanotubes and barium titanate nanofibers were added, and ultrasonic dispersion and triple-roll milling were performed to ensure uniform distribution of the materials.

[0029] Furthermore, the raw materials for preparing the outer layer include the following components in parts by weight:

[0030] 90-95 parts of polyamic acid solution;

[0031] 4-6 parts of aramid nanofiber dispersion;

[0032] 3-5 parts of molybdenum disulfide;

[0033] 3 to 5 parts of boron phenolic mixture.

[0034] Furthermore, the raw materials for preparing the outer layer are prepared by the following steps:

[0035] The polyamic acid solution, aramid nanofiber dispersion, molybdenum disulfide and boron phenolic mixture are blended in proportion, and high shear dispersion and three-roll grinding are performed to ensure uniform distribution of the materials.

[0036] Furthermore, the primary buffer layer is made of polytetrafluoroethylene film with no overlap, the width of the polytetrafluoroethylene film is 8~12mm, the thickness is 0.03~0.05mm, and the wrapping angle is 30~45°; the secondary buffer layer is made of hard plastic; the reinforcement layer is made of Kevlar aramid fiber; and the sheath layer is made of polytetrafluoroethylene material.

[0037] The present invention also discloses a method for preparing a special optical cable, comprising the following steps:

[0038] 1) Preparation of optical fiber body;

[0039] 2) The outer surface of the optical fiber body is coated in sequence to form an inner layer, a transition layer and an outer layer to form a high-temperature resistant coating layer;

[0040] 3) The outer surface of the high temperature resistant coating layer is wrapped with polytetrafluoroethylene film to form a primary buffer layer;

[0041] 4) Using hard plastic to form a secondary buffer layer on the outer surface of the primary buffer layer;

[0042] 5) Kevlar aramid fiber is used to form a reinforcement layer on the outer surface of the secondary buffer layer;

[0043] 6) The outer surface of the reinforcement layer is extruded with polytetrafluoroethylene material to form a sheath layer.

[0044] The present invention also discloses a sensing device, comprising a special optical cable as described above, and also comprising a power module, a main control module, a storage module, a communication module, a coupler and an optical fiber sensor. The power module is connected to an onboard power supply to supply power to the entire sensing device. The main control module is connected to the power module, the storage module and the communication module. The optical fiber sensor is connected to the coupler via a special optical cable.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention discloses a special optical cable, a preparation method and a sensing device having the same, wherein the special optical cable comprises an optical fiber body, a high-temperature resistant coating layer, a primary buffer layer, a secondary buffer layer, a reinforcement layer and a sheath layer arranged in sequence from the inside to the outside, the high-temperature resistant coating layer comprises an inner layer, a transition layer and an outer layer arranged in sequence from the inside to the outside, the high-temperature resistant coating layer adopts a layer-by-layer reinforcement scheme of three coatings, and by designing the transition layer, an efficient combination of the inner layer and the outer layer can be achieved, thereby avoiding the delamination problem and significantly improving the high-temperature resistance, bending and compression resistance of the optical cable; the special optical cable has many excellent properties such as light weight, high-temperature resistance, fast thermal conductivity, radiation resistance, resistance to strong electric and magnetic field environments, bending and compression resistance, high thermal sensitivity, high mechanical properties, high wear resistance, flame retardancy, corrosion resistance, etc., and is suitable for application in structural health monitoring equipment resistant to electromagnetic interference, improving the level of integration, modularization and intelligence, realizing the monitoring and storage of parameters such as temperature and vibration of the surface structure of objects or materials, and serving in structural health monitoring and data storage of aircraft in flight environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of the three-dimensional structure of the special optical cable of the present invention;

[0048] Figure 2 is a schematic cross-sectional view of the special optical cable of the present invention;

[0049] Figure 3 is a principle block diagram of the sensing device of the present invention;

[0050] Among them, 1-optical fiber body, 2-high temperature resistant coating layer, 3-primary buffer layer, 4-secondary buffer layer, 5-reinforcement layer, 6-jacket layer, 7-power module, 8-main control module, 9-storage module, 10-communication module, 11-coupler, 12-optical fiber sensor, 13-special optical cable. DETAILED DESCRIPTION

[0051] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0052] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0053] like Figure 1-3 As shown, the present invention discloses a special optical cable 13, which includes an optical fiber body 1, a high-temperature resistant coating layer 2, a primary buffer layer 3, a secondary buffer layer 4, a strength member layer 5 and a sheath layer 6 arranged in sequence from the inside to the outside.

[0054] In some embodiments, the optical fiber body 1 can adopt common G652D single-mode optical fiber or multi-mode optical fiber, and can be flexibly selected according to actual needs.

[0055] In some embodiments, the high-temperature resistant coating layer 2 includes an inner layer, a transition layer, and an outer layer arranged sequentially from the inside to the outside. The high-temperature resistant coating layer 2 adopts a three-layer coating layer-by-layer reinforcement scheme to achieve significant improvements in high-temperature resistance, bending and compressive strength.

[0056] In some more specific embodiments, the raw materials for preparing the inner layer include the following components in parts by weight:

[0057] 40-50 parts of acrylate;

[0058] 30-40 parts of bisphenol A diacrylate;

[0059] 3-5 parts of spiropyran;

[0060] Modified nano-SiO2 15~25 parts.

[0061] In some more specific embodiments, the raw materials for the inner layer are prepared by the following steps:

[0062] The first step is to pre-treat SiO2 by ultrasonicating the SiO2 dispersion for 25-30 minutes, adding KH-570 ethanol solution, hydrolyzing at 50-55°C for 50-70 minutes, and then condensing at 75-85°C for 4-5 hours. Finally, centrifugation, washing, drying, and grinding are performed to obtain modified nano-SiO2.

[0063] In the second step, acrylate, bisphenol A diacrylate, and modified nano-SiO2 are mixed uniformly through ultrasonic dispersion (40-50kHz, 25-30 minutes) and three-roll milling, and the viscosity is adjusted to 900±50cP for later use. SiO2 can form a hydrogen bond network with the carbonyl group on the acrylate, which is used to enhance the thermal stability of the material. By adding bisphenol A diacrylate, the bisphenol A monomer is cross-linked on the main chain. One double bond of the molecule participates in the reaction with the main chain of the acrylate. The double benzene ring structure provides a rigid skeleton, increases the glass transition temperature, and enhances the high-temperature resistance of the acrylate.

[0064] In the third step, spiropyran is added to the mixture obtained in the second step, and the mixture is modified by adding spiropyran. The thermosensitive group of spiropyran participates in free radical copolymerization as a side chain graft. This substance is a thermosensitive material. Through free radical copolymerization with the double bond of acrylate, the spiro carbon atom (spiro-C) connects the indoline and benzopyran rings to form a heat / light response switch. The spiropyran is fixed to the side group of the polymer chain, which can improve the thermal sensitivity of the optical cable. At the same time, the silanol (Si-OH) on SiO2 can form a weak hydrogen bond with the nitro group (-NO2) on spiropyran to achieve stable loading and form SiO2-spiropyran particles. Bisphenol A diacrylate forms a cross-linked network during UV curing, which further fixes the SiO2-spiropyran particles in the acrylate matrix to prevent molecular migration.

[0065] In some more specific embodiments, the transition layer has an interface enhancement effect, and the raw materials for preparing the transition layer include the following components in parts by weight:

[0066] 60-70 parts of bismaleimide;

[0067] 30-40 parts of hydroxyethyl methacrylate;

[0068] 3-5 parts of polydopamine-coated carbon nanotubes;

[0069] 2-4 parts of barium titanate nanofibers.

[0070] In some more specific embodiments, the raw materials for preparing the transition layer are prepared by the following steps:

[0071] First, under nitrogen protection, bismaleimide and hydroxyethyl methacrylate were premixed in a composite solvent of N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF) with a volume ratio of 7:3 and stirred at 75-80°C for 2-2.5 hours to form a homogeneous solution.

[0072] Subsequently, polydopamine-coated carbon nanotubes and barium titanate nanofibers were added, and ultrasonic dispersion (40-45 kHz, 30 min) and triple-roll milling were performed to ensure uniform distribution of the materials.

[0073] In some more specific embodiments, the outer layer is prepared from raw materials comprising the following components in parts by weight:

[0074] 90-95 parts of polyamic acid solution;

[0075] 4-6 parts of aramid nanofiber dispersion;

[0076] 3-5 parts of molybdenum disulfide;

[0077] 3 to 5 parts of boron phenolic mixture.

[0078] In some more specific embodiments, the outer layer is prepared by the following steps:

[0079] A polyamic acid solution, aramid nanofiber dispersion, molybdenum disulfide, and a boron phenolic mixture are blended in appropriate proportions, subjected to high-shear dispersion (4500-5000 rpm for 30-40 minutes), and three-roll milling cycles to ensure uniform distribution of the materials. This method produces an outer layer with a uniform dispersion of the nanoreinforced phase, resulting in high-temperature stability, high mechanical strength, and excellent wear resistance.

[0080] The design of the transition layer in this invention enables efficient bonding between the inner layer (acrylate) and the outer layer (polyimide PI, obtained by imidization of a polyamic acid solution at elevated temperatures), avoiding delamination and improving the cable's high-temperature and compressive resistance. The bismaleimide (BMI) in the transition layer forms a high-temperature-resistant backbone. Its dynamic covalent bonds self-heal microcracks while also strongly bonding to the outer polyimide layer through π-π stacking. The hydroxyethyl methacrylate in the transition layer provides a flexible buffer, and its double bonds copolymerize with the inner layer to form a strong interface. Polydopamine-coated carbon nanotubes (PDA@CNT) are oriented for axial heat conduction and toughen the transition layer through hydrogen bonding. Barium titanate nanofibers utilize the piezoelectric effect to monitor stress in real time while dissipating vibration energy. These components collectively achieve thermal stress buffering (CTE gradient matching), mechanical property transition (modulus gradient from 1.5 to 3.0 GPa), and intelligent protection (self-healing and stress warning), significantly enhancing the cable's performance and lifespan under extreme conditions (-65 to 300°C).

[0081] The above-mentioned three-layer coating process of the inner layer, the transition layer and the outer layer is based on the traditional UV curing and adjusts the relevant parameters. It belongs to the existing technology and will not be described in detail here.

[0082] Laser micromachining technology is used on the optical fiber body 1 after the three-layer coating and curing is completed, and the microstructure of the outer surface of the high-temperature resistant coating layer 2 is designed. A groove array with a period of 50~60μm is produced on the outer surface of the high-temperature resistant coating layer 2. This method can reduce thermal expansion stress by 25~30%, increase the flexibility of the optical cable, and reduce the bending radius to 3~4mm.

[0083] In some embodiments, the primary buffer layer 3 is formed by wrapping a polytetrafluoroethylene film with no overlap. This protects the optical fiber and prevents direct contact between the optical fiber and the plastic, which could affect optical fiber loss. The film is resistant to strong electric and magnetic fields, withstanding high electric field strengths without breakdown, while maintaining stable electrical performance. The polytetrafluoroethylene film has a width of 8-12 mm, a thickness of 0.03-0.05 mm, and a wrapping angle of 30-45°.

[0084] In some embodiments, the secondary buffer layer 4 is made of a hard plastic such as PEEK, which is melt-extruded. This hard plastic can replace traditional metal armor and possesses superior water resistance, high temperature resistance, and chemical corrosion resistance. Furthermore, PEEK-reinforced optical cables can be used in applications such as airborne sensing and deep-sea seismic sensing.

[0085] In some embodiments, the reinforcement layer 5 is made of Kevlar aramid fiber. Multiple strands can be placed as required, typically in a straight-lay arrangement. However, for aircraft optical cables, the Kevlar aramid fibers can be braided using a braiding machine. This process ensures the cable's roundness while maintaining tensile strength.

[0086] In some embodiments, the sheath layer 6 is made of polytetrafluoroethylene. The optical cable made of this material has good flame retardancy, radiation resistance, corrosion resistance, and bending resistance.

[0087] The present invention also discloses a method for preparing a special optical cable, comprising the following steps:

[0088] 1) Preparation of optical fiber body 1

[0089] The optical fiber body 1 adopts ordinary G652D single-mode optical fiber or multi-mode optical fiber;

[0090] 2) forming an inner layer, a transition layer and an outer layer on the outer surface of the optical fiber body 1 in sequence to form a high temperature resistant coating layer 2;

[0091] 3) The outer surface of the high temperature resistant coating layer 2 is wrapped with a polytetrafluoroethylene film to form a primary buffer layer 3;

[0092] 4) A hard plastic such as PEEK is used on the outer surface of the primary buffer layer 3 to form a secondary buffer layer 4;

[0093] 5) Kevlar aramid fiber is used to form a reinforcement layer 5 on the outer surface of the secondary buffer layer 4;

[0094] 6) The outer surface of the reinforcement layer 5 is extruded with polytetrafluoroethylene material to form a sheath layer 6.

[0095] The present invention also discloses a sensing device, including a special optical cable 13 as described above, and also including a power module 7, a main control module 8, a storage module 9, a communication module 10, several couplers 11 and several optical fiber sensors 12, wherein the power module 7 is connected to the onboard power supply, and the output voltage is 2~5V, which provides power for the entire sensing device. The optical fiber sensor 12 is connected to the coupler 11 through the special optical cable 13, and can collect flight parameters of the aircraft, including temperature, vibration and other parameters. The main control module 8 is connected to the power module 7, the storage module 9 and the communication module 10.

[0096] In some embodiments, the power module 7 , the main control module 8 , the storage module 9 , the communication module 10 , and the coupler 11 are connected via a bus.

[0097] In some embodiments, the storage module 9 is used to effectively store the converted data, and the stored data can be demodulated to analyze the aircraft status after getting off the aircraft.

[0098] In some embodiments, the communication module 10 includes a spectrometer, a signal converter, and a receiver. The spectrometer is used to excite optical signals, and the signal converter is used to receive and convert optical signals, converting frequency signals into wavelengths, greatly reducing storage capacity and facilitating subsequent data storage.

[0099] In some embodiments, coupler 11 utilizes a 1xN optical splitter, where N is determined based on the specific application scenario. Wavelength division multiplexing (WDM) is used to distribute different optical signals to different fiber optic sensors 12, each corresponding to a specific wavelength. This allows for wavelength-based signal differentiation, thereby increasing system capacity. Furthermore, a multi-way coupler is used to combine the reflected signals from multiple fiber optic sensors 12 into a single optical fiber. The signals are then transmitted to a communication module for signal conversion and ultimately stored in a storage device.

[0100] In some embodiments, the special optical cable 13 is attached to the wing of the aircraft or other structural parts that need to be monitored by bonding.

[0101] The working principle of the sensing device disclosed in the present invention is:

[0102] Under the control of the FPGA controller of the main control module 8, the spectrometer transmits an optical signal from the light source to the fiber optic sensor connection port through the coupler 11. Under the control of the FPGA controller, the receiver receives the modulated optical signal sent back by the fiber optic sensor 12, completes the signal conversion, and finally caches it in the storage module 9. After the machine is offline, the signal is demodulated.

[0103] The present invention has at least the following advantages:

[0104] The special optical cable of the present invention is not only resistant to electromagnetic interference but also exhibits excellent properties such as high temperature resistance, corrosion resistance, light weight, thermal sensitivity, and electromagnetic interference resistance. The present invention utilizes special optical cables to create a sensing device with a high degree of functional module integration. Through onboard installation, it can effectively and accurately monitor changes in temperature, vibration, and other factors during flight, and process and store the monitored data. After disembarking, the device can be easily unplugged, and the data in the storage module 9 can be demodulated and analyzed on the ground. The device is lightweight and does not increase the aircraft's flight burden, resolving the existing problems of aircraft structural health monitoring and storage.

[0105] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0106] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A special optical cable, characterized in that: The optical fiber comprises an optical fiber body, a high-temperature resistant coating layer, a primary buffer layer, a secondary buffer layer, a reinforcement layer and a jacket layer, which are sequentially arranged from the inside to the outside. The high-temperature resistant coating layer comprises an inner layer, a transition layer and an outer layer, which are sequentially arranged from the inside to the outside. The raw materials for preparing the inner layer include the following components in parts by weight: 40-50 parts of acrylate; 30-40 parts of bisphenol A diacrylate; 3-5 parts of spiropyran; Modified nano-SiO2 15-25 parts; The raw materials for preparing the transition layer include the following components in parts by weight: 60-70 parts of bismaleimide; 30-40 parts of hydroxyethyl methacrylate; 3-5 parts of polydopamine-coated carbon nanotubes; 2-4 parts of barium titanate nanofibers; The raw materials for preparing the outer layer include the following components in parts by weight: 90-95 parts of polyamic acid solution; 4-6 parts of aramid nanofiber dispersion; 3-5 parts of molybdenum disulfide; 3 to 5 parts of boron phenolic mixture.

2. A special optical cable according to claim 1, characterized in that: The outer surface of the high-temperature resistant coating layer is provided with a groove array with a period of 50 to 60 μm.

3. The special optical cable according to claim 1, characterized in that: The raw materials for the inner layer are prepared by the following steps: In the first step, the SiO2 dispersion is ultrasonicated for 25 to 30 minutes, KH-570 ethanol solution is added, and hydrolyzed at 50 to 55°C for 50 to 70 minutes, followed by condensation at 75 to 85°C for 4 to 5 hours. Finally, the modified nano-SiO2 is obtained by centrifugation, washing, drying, and grinding. In the second step, acrylate, bisphenol A diacrylate and modified nano-SiO2 were mixed uniformly by ultrasonic dispersion and three-roll milling, and the viscosity was adjusted to 900±50 cP for standby use; In the third step, spiropyran is added to the mixture obtained in the second step. The silanol group on SiO2 forms a weak hydrogen bond with the nitro group of spiropyran to achieve stable loading. At the same time, bisphenol A diacrylate forms a cross-linked network during UV curing, fixing the SiO2-spiropyran particles in the acrylate matrix to prevent molecular migration.

4. The special optical cable according to claim 1, characterized in that: The raw materials for preparing the transition layer are prepared by the following steps: First, under nitrogen protection, bismaleimide and hydroxyethyl methacrylate were premixed in a composite solvent and stirred at 75-80°C for 2-2.5 h to form a homogeneous solution. Subsequently, polydopamine-coated carbon nanotubes and barium titanate nanofibers were added, and ultrasonic dispersion and triple-roll milling were performed to ensure uniform distribution of the materials.

5. The special optical cable according to claim 1, characterized in that: The raw materials for preparing the outer layer are prepared by the following steps: The polyamic acid solution, aramid nanofiber dispersion, molybdenum disulfide and boron phenolic mixture are blended in proportion, and high shear dispersion and three-roll grinding are performed to ensure uniform distribution of the materials.

6. The method for preparing a special optical cable according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Preparation of optical fiber body; 2) The outer surface of the optical fiber body is coated in sequence to form an inner layer, a transition layer and an outer layer to form a high-temperature resistant coating layer; 3) The outer surface of the high temperature resistant coating layer is wrapped with polytetrafluoroethylene film to form a primary buffer layer; 4) Using hard plastic to form a secondary buffer layer on the outer surface of the primary buffer layer; 5) Kevlar aramid fiber is used to form a reinforcement layer on the outer surface of the secondary buffer layer; 6) The outer surface of the reinforcement layer is extruded with polytetrafluoroethylene material to form a sheath layer.

7. A sensing device, characterized in that: It comprises a special optical cable as described in any one of claims 1 to 5, and also includes a power module, a main control module, a storage module, a communication module, a coupler and an optical fiber sensor, the power module is connected to the airborne power supply to power the entire sensing device, the main control module is connected to the power module, the storage module and the communication module, and the optical fiber sensor is connected to the coupler through a special optical cable.

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