Optical fiber sensor, system, information processing method, device, equipment, storage medium and program product

Abstract

The invention relates to an optical fiber sensor and system, an information processing method and device, equipment, a storage medium and a program product, and relates to the technical field of optical communication. According to the invention, the measurement precision of temperature and strain can be improved. The optical fiber sensor comprises a hollow-core optical fiber and a few-mode optical fiber engraved with a long-period optical fiber grating, the few-mode optical fiber can be used for exciting an input optical signal into a multi-mode optical signal, the multi-mode optical signal is coupled through the long-period optical fiber grating, and then the coupled multi-mode optical signal is transmitted to the hollow-core optical fiber. The hollow-core optical fiber can be used for carrying out multimode interference on the coupled multimode optical signals and outputting the multimode optical signals after multimode interference, the multimode optical signals after multimode interference provide wavelength change information of harmonic peaks and interference peaks, and the wavelength change information is used for measuring temperature and strain changes acting on the optical fiber sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical communication, in particular to an optical fiber sensor, a system, an information processing method, an apparatus, an equipment, a storage medium and a program product. BACKGROUND

[0002] With the increasing requirements of monitoring precision and efficiency in the field of optical communication technology, multi-parameter optical fiber sensors can simultaneously measure multiple physical quantities due to their compact structure, remote monitoring and anti-electromagnetic interference, greatly simplifying the sensing system.

[0003] Among them, the dual-parameter optical fiber sensor can be used to measure temperature and strain. However, the traditional dual-parameter optical fiber sensor often has coupling due to the influence of the two parameters on the same sensing element, resulting in large decoupling error, and there is a technical problem of low measurement accuracy of temperature and strain. SUMMARY

[0004] Therefore, it is necessary to provide an optical fiber sensor, a system, an information processing method, an apparatus, an equipment, a storage medium and a program product for the above technical problems.

[0005] In a first aspect, the present application provides an optical fiber sensor, comprising: a hollow core optical fiber and a few-mode optical fiber engraved with a long-period fiber grating; wherein,

[0006] The few-mode optical fiber engraved with a long-period fiber grating is used to excite an input optical signal into a multi-mode optical signal, and to couple the multi-mode optical signal through the long-period fiber grating, and to transmit the coupled multi-mode optical signal to the hollow core optical fiber;

[0007] The hollow core optical fiber is used to make the coupled multi-mode optical signal undergo multi-mode interference, and output the multi-mode optical signal after multi-mode interference;

[0008] The multi-mode optical signal after multi-mode interference is used to provide wavelength change information of a resonance peak and an interference peak; the wavelength change information is used to measure the changes of temperature and strain acting on the optical fiber sensor; the resonance peak is a characteristic peak generated by the coupling; the interference peak is a characteristic peak generated by the multi-mode interference; the wavelength change information of the resonance peak represents the response of the wavelength of the resonance peak to the changes of the temperature and strain, and the wavelength change information of the interference peak represents the response of the wavelength of the interference peak to the changes of the temperature and strain.

[0009] In a second aspect, the present application further provides an optical fiber sensing system, comprising: the optical fiber sensor in the first aspect, and a light source module and a data acquisition and analysis module; wherein,

[0010] The light source module is configured to provide an input light signal to the optical fiber sensor.

[0011] The optical fiber sensor is configured to output an output light signal carrying wavelength variation information of the resonance peak and the interference peak in response to changes in temperature and strain.

[0012] The data acquisition and analysis module is configured to acquire the output light signal and display the wavelength variation information.

[0013] In a third aspect, the present application further provides an optical sensing information processing method, comprising:

[0014] acquiring wavelength variation information of a resonance peak and an interference peak carried by a to-be-analyzed light signal; wherein the to-be-analyzed light signal comprises a light signal output by the optical fiber sensor in the first aspect;

[0015] acquiring response sensitivity of the resonance peak to temperature and strain, and acquiring response sensitivity of the interference peak to temperature and strain;

[0016] determining changes in temperature and strain acting on the optical fiber sensor according to the wavelength variation information of the resonance peak and the interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain.

[0017] In a fourth aspect, the present application further provides an optical sensing information processing device, comprising:

[0018] an information acquisition module configured to acquire wavelength variation information of a resonance peak and an interference peak carried by a to-be-analyzed light signal; wherein the to-be-analyzed light signal comprises a light signal output by the optical fiber sensor in the first aspect;

[0019] a sensitivity acquisition module configured to acquire response sensitivity of the resonance peak to temperature and strain, and acquire response sensitivity of the interference peak to temperature and strain;

[0020] a change determination module configured to determine changes in temperature and strain acting on the optical fiber sensor according to the wavelength variation information of the resonance peak and the interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain.

[0021] In a fifth aspect, a computer device is further provided, comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps in the method of the third aspect when executing the computer program.

[0022] In a sixth aspect, a computer readable storage medium is provided, which stores a computer program, and the computer program is executed by a processor to implement the steps in the method of the third aspect.

[0023] In a seventh aspect, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the steps of the method of the third aspect.

[0024] The optical fiber sensor, the system, the information processing method, the device, the equipment, the storage medium and the program product, the optical fiber sensor includes a hollow core fiber and a long period fiber grating inscribed few-mode fiber, the long period fiber grating inscribed few-mode fiber can be used to excite the input optical signal into a multi-mode optical signal, and the multi-mode optical signal is coupled through the long period fiber grating, and then the coupled multi-mode optical signal is transmitted to the hollow core fiber, the hollow core fiber can be used to make the coupled multi-mode optical signal multi-mode interference, and output the multi-mode interference multi-mode optical signal, the multi-mode interference multi-mode optical signal can be used to provide wavelength change information of the resonance peak and the interference peak, and the wavelength change information can be used to measure the change of the temperature and the strain acting on the optical fiber sensor. Wherein, the resonance peak is a characteristic peak generated by coupling, the interference peak is a characteristic peak generated by multi-mode interference, the wavelength change information of the resonance peak represents the response of the wavelength of the resonance peak to the change of the temperature and the strain, and the wavelength change information of the interference peak represents the response of the wavelength of the interference peak to the change of the temperature and the strain.

[0025] Therefore, the two sensing mechanisms of mode coupling and multi-mode interference can be integrated in the optical fiber sensor, the optical signal is first mode-coupled in the long period fiber grating inscribed few-mode fiber and then multi-mode interfered through the hollow core fiber, the resonance peak of mode coupling is sensitive to the change of the temperature and the strain, the change of the wavelength of the resonance peak is linearly related to the change of the two, the interference peak of multi-mode interference is also sensitive to the change of the temperature and the strain, the change of the wavelength of the interference peak is also linearly related to the change of the two, and the response sensitivity of the resonance peak drift of the long period fiber grating to the temperature and the strain is significantly different from the response sensitivity of the interference peak drift of the hollow core fiber to the temperature and the strain, therefore, the wavelength change information of the resonance peak and the interference peak respectively carries the composite information of the temperature and the strain, and the response sensitivities of the two to the temperature and the strain are different, by recording the wavelength change information of the resonance peak and the interference peak respectively, the accurate values of the changes of the temperature and the strain can be independently separated from the wavelength change information, the measurement of the two parameters does not interfere with each other, the accurate measurement of the temperature and the strain is realized, the measurement accuracy of the temperature and the strain is improved, and the demand of high-precision monitoring scene is met. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0027] Figure 1 Structure diagram of an optical fiber sensor in an embodiment;

[0028] Figure 2 Structure diagram of an optical fiber sensor in another embodiment;

[0029] Figure 3 Structure diagram of an optical fiber sensor in yet another embodiment;

[0030] Figure 4 Structure diagram of an optical fiber sensor in still another embodiment;

[0031] Figure 5 Diagram of mode transmission of an optical fiber sensor in an embodiment;

[0032] Figure 6 Structure diagram of an optical fiber sensing system in an embodiment;

[0033] Figure 7 Flow diagram of an optical sensing information processing method in an embodiment;

[0034] Figure 8 Structure block diagram of an optical sensing information processing device in an embodiment;

[0035] Figure 9 Internal structure diagram of a computer device in an embodiment. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0037] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or can exist a middle element. The terms "first", "second", etc. used in the present application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "include" and "have" and any variations thereof used in the present application are intended to cover non-exclusive inclusion. The term "multiple" used in the present application refers to two and more than two. The term "and / or" used in the present application refers to one of the options or any combination of multiple options.

[0038] The terms involved in the embodiments of the present application are as follows:

[0039] SMF (Single-mode fiber): A kind of optical fiber with a core diameter of 9 or 10 μm (microns), only one transmission mode exists. The transmission loss and dispersion of single-mode fiber are relatively small, so in the communication system, especially in high-capacity communication systems, single-mode fiber is mostly used.

[0040] FMF (Few-mode fiber): A kind of optical fiber that can transmit a limited number of guided modes (usually 2 to several tens of modes), with the number of modes between single-mode fiber and multi-mode fiber. Compared with single-mode fiber, few-mode fiber allows a few different spatial modes to be transmitted simultaneously in the core by designing core size, refractive index distribution and other parameters; compared with multi-mode fiber, the number of modes is strictly controlled, which can significantly reduce inter-mode dispersion and crosstalk, and facilitate the implementation of mode multiplexing and demultiplexing technology.

[0041] HCF (Hollow-core fiber): A new type of optical fiber, whose core part is air or vacuum with low refractive index medium, rather than the high refractive index glass or plastic core used for light transmission in traditional optical fibers. It can form an optical confinement mechanism through a specific cladding structure to confine the light signal in the central air core area for transmission.

[0042] LPFG (Long period fiber grating): A periodic refractive index modulation structure written in an optical fiber, which works by using periodic refractive index changes to cause resonant coupling between modes in the fiber, thereby forming a specific wavelength loss peak in the transmission spectrum.

[0043] In an exemplary embodiment, as shown in Figure 1 An optical fiber sensor is provided, which includes a few-mode fiber 100 engraved with a long-period fiber grating 110 and a hollow-core fiber 200.

[0044] Among them, for the hollow-core fiber 200, as a new type of optical fiber, it has great application value in the field of multi-parameter fiber sensing. Its internal structure is hollow-core, and light mainly propagates in the air or gas-filled hollow-core region. Compared with traditional solid-core optical fibers, it has low transmission loss, low dispersion and other characteristics, and can be used for long-distance sensing and monitoring, with obvious advantages in high-speed data sensing and transmission scenarios. Based on these characteristics, the hollow-core fiber can build a high-sensitivity multi-parameter sensor, which can interact temperature and strain with optical signals, convert parameter changes into optical signal changes, and realize accurate measurement of temperature and strain.

[0045] Wherein, for the few-mode fiber 100 inscribed with the long-period fiber grating 110, the few-mode fiber 100 can excite a single-mode optical signal into a multi-mode optical signal, when the multi-mode optical signal passes through the long-period fiber grating 110, the periodic refractive index modulation of the grating can couple the core mode to the cladding mode or the high-order core mode, forming a resonance (attenuation) peak of a specific wavelength, the long-period fiber grating 110 can be used to realize the coupling of high-order modes, and the coupling condition can be determined by the grating period and the effective refractive index difference of the mode. When the optical signal propagates, the periodic refractive index modulation can cause energy transfer of the modes satisfying the phase matching condition, forming a resonance (attenuation) peak of a specific wavelength.

[0046] In the embodiment, the few-mode fiber 100 inscribed with the long-period fiber grating 110 can be used to excite an input optical signal into a multi-mode optical signal, and to make the multi-mode optical signal couple through the long-period fiber grating 110, and to transmit the coupled multi-mode optical signal to the hollow-core fiber 200. Wherein, the input optical signal can be a single-mode optical signal, and the input optical signal will excite a multi-mode optical signal after entering the few-mode fiber 100 inscribed with the long-period fiber grating 110, and when the multi-mode optical signal passes through the long-period fiber grating 110, the periodic refractive index modulation of the long-period fiber grating 110 can couple the core mode in the multi-mode optical signal to the cladding mode or the high-order core mode to obtain the coupled multi-mode optical signal, and the spectral diagram corresponding to the coupled multi-mode optical signal will have a resonance (attenuation) peak of a specific wavelength, and the resonance peak is sensitive to the changes of temperature and strain, and the drift amount thereof is linearly related to the change amount of the two. Wherein, the long-period fiber grating 110 is used to realize the coupling of high-order modes, and the coupling condition is determined by the grating period and the effective refractive index difference of the mode, and when the multi-mode optical signal propagates therein, the periodic refractive index modulation can cause energy transfer of the modes satisfying the phase matching condition, forming a resonance peak of a specific wavelength. The few-mode fiber 100 inscribed with the long-period fiber grating 110 can be connected with the hollow-core fiber 200, and the few-mode fiber 100 inscribed with the long-period fiber grating 110 transmits the coupled multi-mode optical signal to the hollow-core fiber 200.

[0047] In this embodiment, the hollow core fiber 200 can be used to make the coupled multi-mode optical signal multi-mode interference, output the multi-mode optical signal after multi-mode interference. Among them, the hollow core fiber 200 accesses the coupled multi-mode optical signal transmitted by the few-mode fiber 100 engraved with the long-period fiber grating 110, and the hollow core fiber 200 uses its hollow structure to make the coupled multi-mode optical signal multi-mode interference, and output the multi-mode optical signal after multi-mode interference. Among them, the optical signal containing multiple modes enters the hollow core fiber 200, and due to the hollow structure of the hollow core fiber 200, different modes will produce phase difference when propagating in it, and then multi-mode interference occurs. The optical spectrum of the multi-mode optical signal after multi-mode interference will have an interference peak, and the interference peak is also sensitive to temperature and strain, and its wavelength will also drift with the change of temperature and strain.

[0048] Based on this, the input optical signal is first excited to high-order mode in the few-mode fiber 100 engraved with the long-period fiber grating 110, and the periodic refractive index modulation of the long-period fiber grating 110 couples the core mode to the high-order mode, forms a resonance peak sensitive to temperature and strain, and the coupled multi-mode optical signal enters the hollow core fiber 200. The hollow core fiber 200 uses its hollow structure to produce multi-mode interference and output the multi-mode optical signal after multi-mode interference. The interference peak is also sensitive to temperature / strain. Therefore, the multi-mode optical signal after multi-mode interference can be used to provide wavelength change information of the resonance peak and the interference peak. The wavelength change information can include wavelength change information of the resonance peak and wavelength change information of the interference peak. Among them, the wavelength change information can be used to measure the change of temperature and strain acting on the optical fiber sensor. Among them, the resonance peak refers to the (wavelength) characteristic peak generated by coupling in the few-mode fiber 100 engraved with the long-period fiber grating 110, and the interference peak refers to the (wavelength) characteristic peak generated by multi-mode interference in the hollow core fiber 200. Among them, the wavelength change information of the resonance peak represents the response of the wavelength of the resonance peak to the change of temperature and strain, and the wavelength change information of the interference peak represents the response of the wavelength of the interference peak to the change of temperature and strain.

[0049] Therefore, for the resonance peak, when the temperature and strain change, the position and depth of the resonance peak are affected by changing the refractive index and grating period of the few-mode fiber 100 on which the long-period fiber grating 110 is inscribed. At the same time, the structure of the hollow core fiber 200 makes the propagation constants of different modes significantly different when light propagates in the air core, thereby generating a multimode interference, and the interference output light intensity is determined by the phase difference of each mode. When the temperature and strain change, the length and air core refractive index of the hollow core fiber 200 change, resulting in a shift in the interference peak wavelength. The resonance peak shift caused by the mode coupling characteristics of the long-period fiber grating 110 has a significant difference in response sensitivity to temperature and strain from the multimode interference peak shift caused by the multimode interference effect of the hollow core fiber 200. For example, the influence of temperature change on the long-period fiber grating 110 can be more significant (such as the response sensitivity of the long-period fiber grating 110 to temperature can be 5 to 10 times that of the hollow core fiber), and the strain modulation of the hollow core fiber 200 can be more intense (such as the strain sensitivity of the hollow core fiber 200 can be 3 to 8 times that of the long-period fiber grating 110). Therefore, the resonance peak shift of the long-period fiber grating 110 and the interference peak shift of the hollow core fiber 200 respectively carry the combined information of temperature and strain, and the response sensitivities of the two to temperature and strain are different. The independent values of temperature and strain can be separated from the shift amounts of the two characteristic peaks by establishing and solving a binary first-order equation system, and the precise measurement of the two parameters can be realized.

[0050] The embodiment of the present application can integrate two sensing mechanisms in a single structure, can abandon the complex optical coupling components of traditional multi-parameter sensors, simplify the composition of the sensing system, and unlike the traditional dual-parameter sensor which often has coupling due to the influence of the two parameters on the same sensing element, resulting in large decoupling error, the embodiment of the present application can use the mode coupling characteristics of the long-period fiber grating 110 and the multimode interference effect of the hollow core fiber 200 to realize temperature and strain dual-parameter decoupling measurement by combining the differential response of the two to temperature and strain. The measurement of the two parameters does not interfere with each other, which can greatly reduce the temperature and strain measurement error, improve the measurement accuracy, meet the demand of high-precision monitoring scene, and break through the limitation of traditional single-parameter or dual-parameter sensor caused by cross-sensitivity. In addition, the structure of the hollow core fiber 200 makes light mainly propagate in air medium, which significantly reduces the influence of the physical properties of the fiber material, and the low dispersion and low loss characteristics reduce the interference to the transmission of optical signals.

[0051] As an example, for the few-mode fiber 100 with the long-period fiber grating 110, the cladding diameter can be around 125 μιη, such as 124.5 ± 1.0 μιη or 125 ± 0.7 μιη, to ensure the compatibility of fiber fusion and the stability of mode transmission. In terms of core diameter, the few-mode fiber core diameter can be of a specification of 19 ± 1 μιη, and a suitable core diameter helps to excite high-order modes and achieve mode coupling of the long-period fiber grating. The grating period of the long-period fiber grating 110 is usually tens to hundreds of microns, such as when a CO2laser is used for inscription, the grating period and duty cycle can be selected optimally according to the required sensing sensitivity and operating wavelength range. Among them, the grating period: an exemplary value is 746 μιη, which can ensure effective coupling near the commonly used wavelength (1550 nm band) of communication, forming a clear resonance attenuation peak. The grating length: to ensure the depth of the resonance peak (i.e., the mode coupling efficiency), the grating length needs to be sufficient to accumulate the phase difference between the modes, and an exemplary value is 10-50 millimeters (mm). This length range can make the attenuation peak depth reach 10-30 decibels (dB), which is convenient for a spectrometer to detect the wavelength shift. The inscription position: the long-period fiber grating 110 can be inscribed in the middle region of the few-mode fiber 100, which can be 5-10 mm away from the input end of the few-mode fiber 100 or the fusion end of other fibers, or 5-10 mm away from the output end of the few-mode fiber 100 or the fusion end of other fibers, thereby reducing the interference of fusion loss on mode coupling. The operating wavelength range: can match the commonly used wavelength range of a broadband light source (BBS) and an optical spectrum analyzer (OSA), and the resonance peak center wavelength of the long-period fiber grating 110 can be set at 1520-1580 nanometers (nm) (C band), which can be spectrally distinguished from the multi-mode interference peak of the hollow core fiber 200, facilitating subsequent decoupling calculation.

[0052] As an example, for the hollow core fiber 200, the hollow core structure inside the hollow core fiber 200, the cladding is usually designed based on microstructure, consisting of a series of micro air holes, similar to a honeycomb-like arrangement. The microstructure parameters of the air holes, such as size, shape, arrangement period, and cladding thickness, affect the propagation characteristics of light in it, such as the difference in propagation constants of different modes, and thus affect the multi-mode interference effect. Hollow core diameter: To ensure effective confinement and multi-mode transmission of light in the hollow core region, the hollow core diameter needs to be adapted to the core size of the few-mode fiber, with an exemplary value of 30 μm. This size can support the stable transmission of multiple high-order modes in the hollow core, ensuring that the phase difference between modes accumulates to form a clear multi-mode interference peak. Cladding structure and thickness: The hollow core fiber 200 can adopt a nested cladding structure (formed by periodically arranged glass capillaries or quartz skeletons to form optical confinement), and the cladding thickness has an exemplary value of 60 μm, which ensures effective binding of the optical signal in the hollow core and reduces the loss caused by mode leakage. Fiber length: The clarity of multi-mode interference is directly related to the length of the hollow core fiber 200. If the length is too short, the phase difference is insufficient, and if the length is too long, the loss increases. Combining the measurement range of temperature (-50°C~150°C) and strain, the exemplary value is 20 cm. This length can make the wavelength drift of the interference peak within the detection range of the spectrometer (such as the 1520-1580 nm wavelength band) form a distinguishable difference, meeting the sensitivity requirements. Hollow core refractive index: The hollow core region is filled with air (the refractive index is about 1.0003 at normal temperature and pressure), which ensures that light is mainly transmitted in the low refractive index hollow core, reduces the interaction with the fiber material, and reduces the interference of material properties on temperature and strain response.

[0053] The fiber sensor of the embodiment can integrate both mode coupling and multi-mode interference sensing mechanisms in the fiber sensor, allowing the light signal to first undergo mode coupling in the few-mode fiber with a long-period fiber grating and then undergo multi-mode interference in the hollow core fiber. The resonance peak of mode coupling is sensitive to changes in temperature and strain, and the change in the wavelength of the resonance peak is linearly related to the changes in temperature and strain. The interference peak of multi-mode interference is also sensitive to changes in temperature and strain, and the change in the wavelength of the interference peak is also linearly related to the changes in temperature and strain. Moreover, the response sensitivity of the resonance peak drift of the long-period fiber grating to temperature and strain is significantly different from the response sensitivity of the interference peak drift of the hollow core fiber to temperature and strain. Therefore, the wavelength change information of the resonance peak and the interference peak respectively carries the combined information of temperature and strain, and the response sensitivities of the two to temperature and strain are different. By recording the wavelength change information of the resonance peak and the interference peak respectively, the accurate values of the changes in temperature and strain can be independently separated from them. The measurement of the two parameters does not interfere with each other, achieving accurate measurement of temperature and strain, improving the measurement accuracy of temperature and strain, and meeting the demand of high-precision monitoring scenarios.

[0054] In one exemplary embodiment, as Figure 2As shown, the fiber sensor can further include a first single-mode fiber 300. The first single-mode fiber 300 can be used to transmit the input optical signal to the few-mode fiber 100 with the long-period fiber grating 110.

[0055] In this embodiment, one end of the first single-mode fiber 300 can be used to inject the input optical signal, and the other end of the first single-mode fiber 300 can be connected to the few-mode fiber 100 with the long-period fiber grating 110. After the input optical signal is injected into the first single-mode fiber 300, the first single-mode fiber 300 transmits the single-mode input optical signal to the few-mode fiber 100 with the long-period fiber grating 110. As an example, the first single-mode fiber 300 can stably transmit single-mode light at the operating wavelength, and a standard single-mode fiber (G.652 fiber) can be used, which has low loss and low dispersion near 1550 nm wavelength. Thus, the scheme of this embodiment can access single-mode light from the light source module through the first single-mode fiber 300, ensure efficient injection of optical signals, reduce loss and interference in the transmission process, and ensure stable optical signals for subsequent mode coupling and interference measurement.

[0056] In one exemplary embodiment, as shown in Figure 3 As shown, the fiber sensor can further include a second single-mode fiber 400. The second single-mode fiber 400 is used to convert the multi-mode optical signal after multi-mode interference output by the hollow core fiber 200 into an output optical signal. The output optical signal carries wavelength change information of the resonance peak and the interference peak.

[0057] In this embodiment, one end of the second single-mode fiber 400 can be connected to the hollow core fiber 200 to access the multi-mode optical signal after multi-mode interference output by the hollow core fiber 200, and the other end of the second single-mode fiber 400 can be used to output the output optical signal and can be connected to a data acquisition and analysis module (such as a spectrometer) for collecting and analyzing the optical signal. After the second single-mode fiber 400 accesses the multi-mode optical signal after multi-mode interference output by the hollow core fiber 200, only the fundamental mode is allowed to be transmitted, so the output is a single-mode output optical signal, which carries wavelength change information of the resonance peak and the interference peak and can be used to provide subsequent data acquisition and analysis modules (such as a spectrometer) for analysis to display wavelength change information of the resonance peak and the interference peak, etc. As an example, the second single-mode fiber 400 can stably transmit single-mode light at the operating wavelength, and a standard single-mode fiber (G.652 fiber) can be used, which has low loss and low dispersion near 1550 nm wavelength. Thus, the scheme of this embodiment can transmit the output optical signal to the data acquisition and analysis module for analysis through the second single-mode fiber 400, ensure efficient output of optical signals, reduce loss and interference in the transmission process, and ensure stable optical signals for subsequent temperature and strain change measurement.

[0058] In one embodiment, such as Figure 4 As shown, the fiber optic sensor may further include: a first single-mode fiber 300 and a second single-mode fiber 400. The first single-mode fiber 300 can be used to transmit the input optical signal to a few-mode fiber 100 etched with a long-period fiber grating 110. The second single-mode fiber 400 can be used to convert the multimode optical signal after multimode interference output from the hollow-core fiber 200 into an output optical signal. The output optical signal carries wavelength variation information of the resonance peak and interference peak.

[0059] In this embodiment, combined with Figure 5 After the input optical signal is injected into the first single-mode fiber 300, it is transmitted in the first single-mode fiber 300 in the form of single-mode (mode 1). The single-mode input optical signal is transmitted from the first single-mode fiber 300 to the few-mode fiber 100 engraved with a long-period fiber grating 110, which can excite multi-mode optical signals (mode 1, mode 2, mode 3, etc.). The multi-mode optical signals undergo mode coupling under the action of the long-period fiber grating 110. The coupled multi-mode optical signals are transmitted to the hollow fiber 200. The coupled multi-mode optical signals generate multi-mode interference in the hollow fiber 200. The hollow fiber 200 transmits the multi-mode optical signals after multi-mode interference to the second single-mode fiber 400. The second single-mode fiber 400 outputs the single-mode (mode 1) output optical signal to the subsequent data acquisition and analysis module for analysis.

[0060] In this embodiment, the first single-mode fiber 300, the few-mode fiber 100 etched with a long-period fiber grating 110, the hollow-core fiber 200, and the second single-mode fiber 400 can be sequentially fused together to form a fiber optic sensor, enabling simultaneous and accurate measurement of temperature and strain. Furthermore, by utilizing the differentiated responses of the two sensing mechanisms, the interference of temperature on strain measurement results in traditional sensors is resolved, significantly improving measurement accuracy. The combination of the few-mode fiber 100 and the hollow-core fiber 200 also simplifies the structure of the dual-parameter sensing system, providing a high-performance dual-parameter sensing solution.

[0061] In an exemplary embodiment, the few-mode fiber 100 with a long-period fiber grating 110 is directly connected to the hollow fiber 200, or the few-mode fiber 100 with a long-period fiber grating 110 is connected to the hollow fiber 200 through the few-mode fiber.

[0062] In the embodiment, the position relationship between the few-mode fiber 100 with the long-period fiber grating 110 and the hollow-core fiber 200 needs to meet that the light signal first passes through the long-period fiber grating 110 to complete mode coupling, and then enters the hollow-core fiber 200 for multi-mode interference, so as to realize the sensing mechanism. Therefore, the few-mode fiber 100 with the long-period fiber grating 110 can be directly connected with the hollow-core fiber 200, which can reduce the mode transmission loss and ensure that the multi-mode signal enters the hollow-core fiber 200 efficiently. In order to adapt to more application scenarios, the few-mode fiber 100 with the long-period fiber grating 110 can also be connected with the hollow-core fiber 200 through a few-mode fiber. The connection of the two through the few-mode fiber can meet the condition that the fiber inserted between the two does not destroy the "multi-mode signal transmission".

[0063] In one example embodiment, as shown in FIG. 1, a fiber sensing system is provided, which can include the fiber sensor according to any one of the above embodiments, and a light source module and a data acquisition and analysis module. The light source module can be configured to provide an input light signal to the fiber sensor. The fiber sensor can be configured to output an output light signal carrying wavelength change information of resonance peaks and interference peaks in response to changes in temperature and strain. The data acquisition and analysis module can be configured to acquire the output light signal and display the wavelength change information. Figure 6

[0064] In the embodiment, the fiber sensing system can be a test system. The fiber sensor can be placed in a temperature box or other test environment for temperature and strain measurement and testing. The light source module can be configured to provide an input light signal to the fiber sensor through a fiber connected to the fiber sensor. The temperature box can provide a temperature range of -50°C to 150°C with an accuracy of ±0.1°C. The temperature box can also be provided with a strain clamp connected to a micro-displacement platform. The fiber sensor can be fixed on the strain clamp in the temperature box, and the strain loading direction can be parallel to the axis of the fiber sensor. The fiber sensor can include a first single-mode fiber 300, a few-mode fiber 100 with a long-period fiber grating 110, a hollow-core fiber 200, and a second single-mode fiber 400 connected in sequence. The first single-mode fiber 300 can be used to connect a broadband light source, and the second single-mode fiber 400 can be used to connect to a data acquisition and analysis module (a spectrometer). The light source module can be configured to provide an input light signal to the fiber sensor. The fiber sensor can be configured to output an output light signal carrying wavelength change information of resonance peaks and interference peaks in response to changes in temperature and strain to the data acquisition and analysis module. The data acquisition and analysis module can be configured to acquire the output light signal and display the wavelength change information.

[0065] ​For the light source module, the wavelength range: the light source wavelength range needs to cover the wavelength range required for the operation of the optical fiber sensor. The long-period fiber grating 110 and the hollow-core fiber 200 are sensitive to temperature and strain changes in a specific wavelength range, forming an interference spectrum to realize parameter measurement. The broadband light source wavelength range provided by the light source module can cover the C band (1528-1563 nm) or a wider C+L band (1528-1603 nm). Spectral flatness: the spectral flatness needs to be good, and a large spectral fluctuation will interfere with the measurement accuracy. If the light source spectrum is not flat, there is a large intensity fluctuation, which will be superimposed on the interference spectrum, making it difficult to accurately distinguish the characteristic peak drift caused by temperature and strain, resulting in measurement errors. A flat ASE (Amplified Spontaneous Emission) broadband light source can be used, which has an output spectral flatness of ≤1 dB in the C band. This low flatness light source can reduce interference with the interference spectrum and improve the accuracy and reliability of the measurement. Stability: high stability, including short-term and long-term stability. A light source with a short-term stability (15 minutes) of ≤0.02 dB and a long-term stability (8 hours) of ≤0.05 dB can ensure the stability of the light signal intensity and wavelength during the measurement process. If the light source stability is poor, the light intensity or wavelength fluctuation will cause the characteristic peak of the interference spectrum to drift, leading to misjudgment of temperature and strain changes and affecting the measurement accuracy.

[0066] For the strain clamp, the strain clamp can include two relatively fixed clamping components, which can be used to clamp the two ends of the optical fiber sensor body, respectively (for example, near the positions of the first single-mode optical fiber 300 and the second single-mode optical fiber 400). For strain loading, the strain loading direction is parallel to the axis of the optical fiber sensor. When the strain is loaded, the micro-displacement platform can drive the strain clamp to produce relative stretching or compression (usually stretching, which is more consistent with the actual sensing scenario) along the axis direction, thereby applying axial strain to the optical fiber sensor.

[0067] For the temperature change mode, the target temperature of the temperature box is set to change the internal temperature according to the preset value (such as gradually increasing the temperature, decreasing the temperature, or maintaining a specific temperature), thereby changing the temperature environment of the optical fiber sensor and realizing the regulation of the temperature parameter. For the strain change mode, the micro-displacement platform is controlled to move and drive the strain clamp to apply axial stretching or compression force to the optical fiber sensor, causing the optical fiber sensor to deform and change the strain it bears. This method can accurately regulate the amount of strain change, so that the response of the optical fiber sensor to strain can be tested. Through the above methods, the temperature and strain can be changed individually or simultaneously. The drift data of the characteristic peaks in the output spectrum can be collected by the spectrometer (OSA), and then the measurement performance of the optical fiber sensor for the dual parameters can be analyzed.

[0068] In an exemplary embodiment, as shown in FIG. 1, the optical fiber sensor includes a first single-mode optical fiber 300, a second single-mode optical fiber 400, a long-period fiber grating 110, and a hollow-core fiber 200. The first single-mode optical fiber 300 and the second single-mode optical fiber 400 are connected to the long-period fiber grating 110 and the hollow-core fiber 200, respectively. The long-period fiber grating 110 and the hollow-core fiber 200 are connected in series, and the long-period fiber grating 110 is connected to the first single-mode optical fiber 300 and the second single-mode optical fiber 400. Figure 7As shown, a light sensing information processing method is provided, which can be executed by a computer device such as a terminal or a server, and can include the following steps:

[0069] In step S701, wavelength variation information of the resonance peak and the interference peak carried by the to-be-analyzed light signal is acquired.

[0070] In this step, the to-be-analyzed light signal can include the light signal output by the optical fiber sensor according to any one of the above embodiments. The computer device can be in communication connection with a data acquisition and analysis module, for acquiring the wavelength variation information of the resonance peak and the interference peak carried by the to-be-analyzed light signal from the data acquisition and analysis module. The data acquisition and analysis module can be used to acquire the output light signal of the optical fiber sensor carrying the wavelength variation information of the resonance peak and the interference peak and analyze the wavelength variation information. The wavelength variation information can include the variation values of the wavelengths of the resonance peak and the interference peak.

[0071] In step S702, the response sensitivity of the resonance peak to temperature and strain is acquired, and the response sensitivity of the interference peak to temperature and strain is acquired.

[0072] In step S703, the changes of temperature and strain acting on the optical fiber sensor are determined according to the wavelength variation information of the resonance peak and the interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain.

[0073] Specifically, let the variation value of the wavelength of the resonance peak be , and the variation value of the wavelength of the interference peak be . The response sensitivities of the two sensing mechanisms to temperature and strain are different. Let the response sensitivity of the resonance peak to temperature be (unit: nm / ℃, nanometer per degree Celsius), and the response sensitivity of the resonance peak to strain be (unit: , nanometer per micro dielectric constant), the response sensitivity of the interference peak to temperature be (unit: nm / ℃), and the response sensitivity of the interference peak to strain be (unit: ).

[0074] Due to the changes of temperature and strain and , the drifts (changes) of the two characteristic peaks will be caused, and the drift amounts are linearly related to the two, so the following equation set can be established:

[0075]

[0076] wherein is the change of temperature and the change of strain The result of the joint action, the contribution of which is respectively and weighted; Similarly.

[0077] Based on this, the response sensitivity of the resonance peak to temperature and strain and the response sensitivity of the interference peak to temperature and strain can be obtained through experimental calibration, and then the change value of the wavelength of the resonance peak and the interference peak is measured, substituted into the above equation set, and the equation set is solved. Through solving, the change of temperature and the change of strain can be separated out, and the independent measurement of the two parameters is realized. Through the difference in response sensitivity of the two sensing mechanisms, it can be ensured that the equation set has a unique solution, so that the independent values of temperature and strain are decoupled from the coupled characteristic peak drift, and the cross interference is eliminated.

[0078] Specifically, in the spectrum, the abscissa can be wavelength, and the ordinate can be relative light intensity, which shows the resonance peak and the interference peak. Among them, the initial wavelength of the resonance peak can be set as 1550nm, and the initial wavelength of the interference peak can be set as 1560nm.

[0079] Initial spectrum: After the optical signal passes through the few-mode optical fiber 100 and the hollow-core optical fiber 200 engraved with the long-period fiber grating 110, the spectrum in the spectrum can contain the spectrum of the resonance peak and the interference peak. At this time, the change of temperature is 0, the change of strain is 0, and the wavelengths of the resonance peak and the interference peak are stable.

[0080] Spectrum response when a single parameter changes: in the case of only temperature change, the drift amount (100pm (picometer)) of the resonance peak is much larger than the drift amount (10pm) of the interference peak, which reflects the high sensitivity of the resonance peak to temperature. In the case of only strain change, the drift amount (100pm) of the interference peak is much larger than the drift amount (20pm) of the resonance peak, which reflects the high sensitivity of the interference peak to strain.

[0081] When temperature and strain change at the same time, the total drift amount of the resonance peak and the interference peak is the superposition of the two, the drift amount of the resonance peak is 120pm=100pm+20pm, and the drift amount of the interference peak is 110pm=10pm+100pm. Combined with the response sensitivity set before, substitute into the binary equation set to get and .

[0082] The embodiment realizes the separation of the independent change values of temperature and strain from the drift of the resonance peak and the interference peak in the spectrum, and realizes the decoupling when the two parameters change at the same time.

[0083] It should be understood that although each step in the flowchart involved in the above-described embodiments is shown in sequence according to the arrow, the steps are not necessarily executed in the order indicated by the arrow. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, at least some of the steps in the flowchart involved in the above-described embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the steps or stages is not necessarily sequential, but can be alternately or alternately executed with at least some of the other steps or steps or stages in the other steps. It can be understood that the steps in different embodiments can be freely combined as needed, and various non-contradictory schemes formed by the combination are within the scope of protection of the present application.

[0084] Based on the same inventive concept, the embodiments of the present application also provide an optical sensing information processing device for implementing the above-mentioned optical sensing information processing method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more optical sensing information processing device embodiments provided below can refer to the limitations of the optical sensing information processing method described above, which will not be repeated here.

[0085] In one exemplary embodiment, as shown in Figure 8 An optical sensing information processing device is provided, which can include:

[0086] An information acquisition module 801 is configured to acquire wavelength variation information of a resonance peak and an interference peak carried by a to-be-analyzed optical signal; wherein the to-be-analyzed optical signal is an optical signal output by the optical fiber sensor according to any one of the above embodiments.

[0087] A sensitivity acquisition module 802 is configured to acquire response sensitivity of the resonance peak to temperature and strain, and to acquire response sensitivity of the interference peak to temperature and strain.

[0088] A variation determination module 803 is configured to determine variation of temperature and strain acting on the optical fiber sensor according to the wavelength variation information of the resonance peak and the interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain.

[0089] Each module in the above optical sensing information processing device can be realized by software, hardware, and a combination thereof, in whole or in part. The above modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to be called and executed by the processor to perform the operations corresponding to the above modules.

[0090] In an exemplary embodiment, a computer device, which can be a terminal, is provided, and an internal structure diagram of the computer device can be as shown in FIG. 1. Figure 9 The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for running the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is configured to exchange information between the processor and external devices. The communication interface of the computer device is configured to perform wired or wireless communication with external terminals. The wireless communication can be achieved through WIFI, mobile cellular network, Near Field Communication (NFC) or other technologies. The computer program is executed by the processor to implement an optical sensing information processing method. The display unit of the computer device is configured to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer overlaid on the display screen, or a key, a trackball or a touchpad arranged on the shell of the computer device, or an external keyboard, a touchpad or a mouse, etc.

[0091] Those skilled in the art can understand that the structure shown in FIG. 1 is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components. Figure 9

[0092] In an embodiment, a computer device is also provided, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0093] In an embodiment, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments.

[0094] In an embodiment, a computer program product is provided, which includes a computer program. The computer program is executed by a processor to implement the steps in the above method embodiments. ​

[0095] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant regulations.

[0096] It can be understood by those skilled in the art that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing related hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments of each method. In the embodiments provided in the present application, any reference to memory, database or other medium can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive random access memory (Resistive Random Access Memory, ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (Artificial Intelligence, AI) processor, etc., without being limited thereto.

[0097] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, any combination of these technical features is deemed to be within the scope of the present application.

[0098] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An optical fiber sensor, characterized in that, The fiber optic sensor comprises: a hollow-core optical fiber and a few-mode optical fiber etched with a long-period fiber grating; wherein... The few-mode fiber with a long-period fiber grating is used to excite the input optical signal into a multi-mode optical signal, and to couple the multi-mode optical signal through the long-period fiber grating, and then transmit the coupled multi-mode optical signal to the hollow fiber. The hollow-core optical fiber is used to perform multimode interference on the coupled multimode optical signal and output the multimode optical signal after multimode interference. The multimode optical signal after multimode interference is used to provide wavelength change information of the resonant peak and the interference peak; the wavelength change information is used to measure the temperature and strain changes acting on the optical fiber sensor; the resonant peak is a characteristic peak generated by the coupling; the interference peak is a characteristic peak generated by the multimode interference; the wavelength change information of the resonant peak characterizes the response of the wavelength of the resonant peak to the temperature and strain changes, and the wavelength change information of the interference peak characterizes the response of the wavelength of the interference peak to the temperature and strain changes.

2. The fiber optic sensor according to claim 1, characterized in that, The fiber optic sensor further includes: a first single-mode fiber; the first single-mode fiber is used to transmit the input optical signal to the few-mode fiber optic cable etched with a long-period fiber grating.

3. The fiber optic sensor according to claim 1, characterized in that, The fiber optic sensor further includes: a second single-mode fiber; the second single-mode fiber is used to convert the multimode optical signal after multimode interference output from the hollow fiber into an output optical signal; the output optical signal carries wavelength change information of the resonance peak and interference peak.

4. The fiber optic sensor according to any one of claims 1 to 3, characterized in that, The few-mode fiber with a long-period fiber grating is directly connected to the hollow fiber, or the few-mode fiber with a long-period fiber grating is connected to the hollow fiber through the few-mode fiber.

5. A fiber optic sensing system, characterized in that, include: The fiber optic sensor according to any one of claims 1 to 4, as well as the light source module and the data acquisition and analysis module; wherein, The light source module is used to provide an input light signal to the fiber optic sensor; The fiber optic sensor is used to respond to changes in temperature and strain, and output an output optical signal carrying wavelength change information of resonance peaks and interference peaks. The data acquisition and analysis module is used to acquire the output optical signal and display the wavelength change information.

6. A method for processing optical sensing information, characterized in that, The method includes: The wavelength variation information of the resonance peak and interference peak carried by the optical signal to be analyzed is obtained; wherein, the optical signal to be analyzed includes the optical signal output by the optical fiber sensor according to any one of claims 1 to 4; The response sensitivity of the resonance peak to temperature and strain is obtained, and the response sensitivity of the interference peak to temperature and strain is obtained. Based on the wavelength variation information of the resonance peak and interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain, the temperature and strain changes acting on the fiber optic sensor are determined.

7. A light-sensing information processing device, characterized in that, The device includes: An information acquisition module is used to acquire wavelength variation information of the resonance peak and interference peak carried by the optical signal to be analyzed; wherein, the optical signal to be analyzed includes the optical signal output by the optical fiber sensor according to any one of claims 1 to 4; A sensitivity acquisition module is used to acquire the response sensitivity of the resonance peak to temperature and strain, and to acquire the response sensitivity of the interference peak to temperature and strain. The change determination module is used to determine the changes in temperature and strain acting on the fiber optic sensor based on the wavelength change information of the resonance peak and the interference peak, the response sensitivity of the resonance peak to temperature and strain, and the response sensitivity of the interference peak to temperature and strain.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method described in claim 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in claim 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in claim 6.

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