Distributed optical fiber sensing device for concrete structure

Abstract

The embodiment of the utility model provides a distributed optical fiber sensing device for a concrete structure. The distributed optical fiber sensing device comprises a laser emitting assembly, a sensing optical fiber and an acquisition assembly, the laser emitting assembly comprises a laser, a first electro-optical modulation module and a second electro-optical modulation module. The laser is connected with the first electro-optical modulation module and the second electro-optical modulation module. The sensing optical fiber is laid in the concrete structure, and the sensing optical fiber is connected with the first electro-optical modulation module and the second electro-optical modulation module; the acquisition assembly comprises a wavelength selection filter, a first acquisition module, a second acquisition module and a control module, and the wavelength selection filter is configured to select laser signals output by the sensing optical fiber; the control module is respectively connected with the first acquisition module and the second acquisition module, and the control module is configured to process the Raman light signal and the Rayleigh scattering light signal to obtain stress data of the concrete structure, so that accurate detection of the stress of the concrete structure is realized.

Description

[0001] This application claims the priority of the Chinese patent application filed with the China Patent Office on September 15, 2023, with application number 202322512110.3 and invention name “Distributed optical fiber sensing device for concrete structure”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of distributed optical fiber sensing detection technology, and in particular to a distributed optical fiber sensing device for concrete structures. Background Art

[0003] The Yellow River Basin is an important water resource area in my country. In order to effectively utilize the water resources in the Yellow River Basin, concrete structures are usually used for water conservancy project construction in the Yellow River Basin. The stress changes in the concrete structure during pouring, curing and application will affect the state of its structure, thereby affecting the overall performance of the water conservancy project.

[0004] In the related art, a distributed optical fiber sensing device is usually used to detect the stress in the concrete structure. The distributed optical fiber sensing device usually lays the sensing optical fiber in the concrete structure and analyzes the stress of the concrete structure by detecting and analyzing the scattering effects in the sensing optical fiber, such as Rayleigh scattered light signals and Brillouin scattered light signals.

[0005] However, changes in temperature and stress in concrete structures will cause frequency shifts in scattering effect light such as Rayleigh scattered light and Brillouin light, thereby affecting the accuracy of stress detection in concrete structures. Utility Model Content

[0006] The embodiment of the present application provides a distributed optical fiber sensing device for a concrete structure to solve the problem of the influence of temperature in the concrete structure on the accuracy of stress detection in the related art.

[0007] The embodiment of the present application provides a distributed optical fiber sensing device for concrete structures, including a laser emission component, a sensing optical fiber, and a collection component;

[0008] The laser emitting assembly comprises a laser for outputting a laser signal, a first electro-optical modulation module and a second electro-optical modulation module, wherein the output end of the laser is connected to the first input end of the first electro-optical modulation module and the first input end of the second electro-optical modulation module respectively;

[0009] The first electro-optical modulation module is configured to modulate the laser signal output by the laser to form a nanosecond pulse signal; the second electro-optical modulation module is configured to modulate the laser signal output by the laser to form a swept frequency pulse signal;

[0010] The sensing optical fiber is laid in the concrete structure, the input end of the sensing optical fiber is connected to the output end of the first electro-optical modulation module and the output end of the second electro-optical modulation module respectively, the sensing optical fiber is configured to receive and transmit nanosecond pulse signals and swept frequency pulse signals, the nanosecond pulse signals form Raman light signals in the sensing optical fiber, and the swept frequency pulse signals form Rayleigh scattered light signals in the sensing optical fiber;

[0011] The collection component includes a wavelength selection filter, a first collection module, a second collection module and a control module, the input end of the wavelength selection filter is connected to the output end of the sensing optical fiber, the first output end of the wavelength selection filter is connected to the input end of the first collection module, the second output end of the wavelength selection filter is connected to the input end of the second collection module, and the wavelength selection filter is configured to select the laser signal output by the sensing optical fiber to output the Raman light signal to the first collection module and output the Rayleigh scattered light signal to the second collection module;

[0012] The input end of the control module is connected to the output end of the first acquisition module and the output end of the second acquisition module respectively. The control module is configured to process the Raman light signal and the Rayleigh scattered light signal to obtain stress data of the concrete structure.

[0013] In a feasible implementation, the distributed optical fiber sensing device further includes an optical switch, and the sensing optical fiber includes a first sensing optical fiber and a second sensing optical fiber;

[0014] The input end of the optical switch is connected to the output end of the first electro-optical modulation module and the output end of the second electro-optical modulation module respectively;

[0015] The output end of the optical switch is connected to the input end of the first sensing optical fiber and the input end of the second sensing optical fiber respectively;

[0016] The optical switch is configured to switch a transmission path of the laser signal;

[0017] The first sensing optical fiber is configured to transmit at least one of a nanosecond pulse signal or a swept frequency pulse signal;

[0018] The second sensing optical fiber is configured to transmit at least one of a nanosecond pulse signal or a swept frequency pulse signal.

[0019] In a feasible implementation, it also includes a first coupler and a second coupler, the input end of the first coupler is connected to the output end of the laser, the first output end of the first coupler is connected to the input end of the first electro-optical modulation module, and the second output end of the first coupler is connected to the input end of the second electro-optical modulation module;

[0020] The first input end of the second coupler is connected to the output end of the first electro-optical modulation module, the second input end of the second coupler is connected to the output end of the second electro-optical modulation module, and the output end of the second coupler is connected to the sensing optical fiber.

[0021] In a feasible implementation, the second electro-optical modulation module includes a first electro-optical modulator and a second electro-optical modulator;

[0022] The first input end of the first electro-optical modulator is connected to the second output end of the first coupler, the output end of the first electro-optical modulator is connected to the first input end of the second electro-optical modulator, and the output end of the second electro-optical modulator is connected to the second input end of the second coupler;

[0023] The first electro-optic modulator is configured to shift the frequency of the laser signal output by the laser;

[0024] The second electro-optic modulator is configured to modulate the laser signal shifted by the first electro-optic modulator to output a swept frequency pulse signal.

[0025] In a feasible implementation, the first acquisition module includes a first detector and a second detector, and the second acquisition module includes a third detector;

[0026] An input end of the first detector is connected to a first output end of the wavelength selective filter, and the first detector is configured to receive a Stokes light signal outputted from the first output end of the wavelength selective filter;

[0027] The input end of the second detector is connected to the second output end of the wavelength selective filter, and the second detector is configured to receive the anti-Stokes optical signal outputted from the second output end of the wavelength selective filter;

[0028] The input end of the third detector is connected to the third output end of the wavelength selective filter, and the third detector is configured to receive the Rayleigh scattered light signal outputted from the third output end of the wavelength selective filter;

[0029] The output end of the first detector, the output end of the second detector and the output end of the third detector are all connected to the input end of the control module.

[0030] In a feasible implementation, the first electro-optical modulation module includes a third electro-optical modulator and a first function generator;

[0031] The first input end of the third electro-optic modulator is connected to the output end of the laser, the second input end of the third electro-optic modulator is connected to the output end of the first function generator, and the output end of the third electro-optic modulator is connected to the input end of the sensing optical fiber;

[0032] The third electro-optic modulator is configured to modulate the laser signal output by the laser to form a nanosecond pulse signal;

[0033] The first function generator is configured to drive the third electro-optic modulator to modulate the laser signal output by the laser to form a nanosecond pulse signal.

[0034] In a feasible implementation, the laser emission assembly further includes an erbium-doped fiber amplifier, the input end of the erbium-doped fiber amplifier is connected to the output end of the second coupler, and the output end of the erbium-doped fiber amplifier is connected to the input end of the sensing fiber;

[0035] The erbium-doped fiber amplifier is configured to amplify the Raman optical signal and the Rayleigh scattered optical signal output by the second coupler.

[0036] In a feasible implementation, the second electro-optical modulation module further includes a second function generator;

[0037] The second input terminal of the first electro-optic modulator is connected to the first output terminal of the second function generator;

[0038] A second input terminal of the second electro-optic modulator is connected to a second output terminal of the second function generator;

[0039] The second function generator is configured to drive the first electro-optic modulator to shift the frequency of the laser signal output by the laser;

[0040] The second electro-optic modulator is further configured to drive the second electro-optic modulator to modulate the laser signal shifted by the first electro-optic modulator to output a swept frequency pulse signal.

[0041] In a feasible implementation, the laser emission component also includes a circulator, the input end of the circulator is connected to the output end of the erbium-doped fiber amplifier, the first output end of the circulator is connected to the sensing fiber, and the second output end of the circulator is connected to the wavelength selection filter.

[0042] An embodiment of the present application provides a distributed optical fiber sensing device for concrete structures. The laser signal output by the laser can be modulated into a nanosecond pulse signal and output to the sensing optical fiber through a first electro-optical modulation module, and the nanosecond pulse signal can generate a temperature-sensitive Raman optical signal in the sensing optical fiber. The embodiment of the present application can modulate the laser signal output by the laser into a swept-frequency pulse signal through a second electro-optical modulation module, and the swept-frequency pulse signal can generate a Rayleigh scattered optical signal that is sensitive to both stress and temperature in the sensing optical fiber.

[0043] In the embodiment of the present application, the output end of the sensing optical fiber is connected to the first acquisition module and the second acquisition module through a wavelength selection filter, so that the Raman light signal and the Rayleigh scattered light signal can be respectively collected through the wavelength selection filter, and then the Raman light signal and the Rayleigh scattered light signal are output to the control module through the first acquisition module and the second acquisition module. The control module demodulates the Raman light signal to obtain temperature data in the sensing optical fiber, and the control module demodulates the Rayleigh scattered light signal to obtain mixed data of temperature data and stress data in the sensing optical fiber.

[0044] The embodiment of the present application calculates the mixed data obtained by demodulating the Rayleigh scattered light signal and the temperature data obtained by demodulating the Raman light signal to obtain stress data, that is, the temperature data obtained by demodulating the Raman light signal can compensate for the mixed data obtained by demodulating the Rayleigh scattered light signal, and accurate temperature data and stress data can be obtained, thereby improving the detection accuracy of the temperature and stress of the concrete structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0046] Figure 1 This is a schematic diagram of the structure of a distributed optical fiber sensing device for concrete structure provided in one embodiment of the present application. Figure 1 ;

[0047] Figure 2 This is a schematic diagram of the structure of a distributed optical fiber sensing device for concrete structure provided in one embodiment of the present application. Figure 2 .

[0048] Description of reference numerals:

[0049] 100-laser emission component; 200-sensing optical fiber; 300-collection component;

[0050] 110-laser; 120-first coupler; 130-first electro-optical modulation module; 131-third electro-optical modulator; 132-first function generator; 140-second electro-optical modulation module; 141-first electro-optical modulator; 142-second electro-optical modulator; 143-second function generator; 150-second coupler; 160-erbium-doped fiber amplifier; 170-circulator;

[0051] 210 - optical switch; 220 - first sensing optical fiber; 230 - second sensing optical fiber;

[0052] 310 - wavelength selection filter; 320 - first acquisition module; 321 - first detector; 322 - second detector; 330 - second acquisition module; 331 - third detector; 340 - control module; 341 - acquisition card; 342 - controller. DETAILED DESCRIPTION

[0053] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0054] It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific implementation methods disclosed below.

[0055] In the description of the present application, it should be understood that the terms "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the present application, unless otherwise clearly specified and limited, a first feature being "upper" or "lower" than a second feature may be when the first and second features are in direct contact, or when the first and second features are in indirect contact through an intermediate medium.

[0056] In this application, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. However, if it is indicated as a direct connection, it means that the two connected entities are not connected through an intermediate structure, but are only connected to form a whole through a connecting structure. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0057] In this application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0058] The Yellow River Basin is an important water resource area in my country. In order to effectively utilize the water resources in the Yellow River Basin, concrete structures are usually used for water conservancy project construction in the Yellow River Basin. The stress changes in the concrete structure during pouring, curing and application will affect the state of its structure, thereby affecting the overall performance of the water conservancy project.

[0059] In the related art, a distributed optical fiber sensing device is usually used to detect the stress in the concrete structure. The distributed optical fiber sensing device usually lays the sensing optical fiber in the concrete structure and analyzes the stress of the concrete structure by detecting and analyzing the scattering effects in the sensing optical fiber, such as Rayleigh scattered light signals and Brillouin scattered light signals.

[0060] For example, taking the distributed fiber optic acoustic wave sensor device detecting stress in a concrete structure as an example, the sensing fiber in the distributed fiber optic acoustic wave sensor device is laid in the concrete structure, and the sensing device obtains stress data in the concrete structure by detecting and analyzing the Rayleigh scattered light signal in the sensing fiber. Since the climate in the Yellow River Basin has the characteristics of a large daily temperature difference, and the temperature will affect the offset of the Rayleigh scattered light signal, the data obtained by the sensing device through detecting and analyzing the Rayleigh scattered light signal in the sensing fiber is stress data that has a certain relationship with the temperature, that is, mixed data of temperature data and stress data. Therefore, judging the stress of the concrete structure only by the data obtained after the sensing device analyzes the collected Rayleigh scattered light signal has a large temperature error, thereby affecting the accuracy of the stress detection in the concrete structure.

[0061] The embodiment of the present application provides a distributed optical fiber sensing device for concrete structures. By detecting and analyzing Rayleigh scattered light signals and Raman light signals in the sensing optical fiber, temperature data and mixed data (mixed data includes temperature data and stress data) are obtained respectively. The mixed data is compensated by the temperature data to obtain accurate stress data, thereby solving the technical problem of errors in stress detection in concrete structures in related technologies.

[0062] Figure 1 This is a schematic diagram of the structure of a distributed optical fiber sensing device for concrete structure provided in one embodiment of the present application. Figure 1 .

[0063] The present application embodiment provides a distributed optical fiber sensing device for concrete structures, referring to Figure 1 , including a laser emitting component 100, a sensing optical fiber 200 and a collection component 300.

[0064] The laser emitting assembly 100 includes a laser 110 for outputting a laser signal, a first electro-optical modulation module 130 and a second electro-optical modulation module 140, wherein the output end of the laser 110 is respectively connected to the first input end of the first electro-optical modulation module 130 and the first input end of the second electro-optical modulation module 140. The first electro-optical modulation module 130 is configured to modulate the laser signal output by the laser 110 to form a nanosecond pulse signal; the second electro-optical modulation module 140 is configured to modulate the laser signal output by the laser 110 to form a swept frequency pulse signal.

[0065] The sensing optical fiber 200 is laid in the concrete structure, and the input end of the sensing optical fiber 200 is connected to the output end of the first electro-optical modulation module 130 and the output end of the second electro-optical modulation module 140 respectively. The sensing optical fiber 200 is configured to receive and transmit nanosecond pulse signals and swept-frequency pulse signals. The nanosecond pulse signals form Raman light signals in the sensing optical fiber 200, and the swept-frequency pulse signals form Rayleigh scattered light signals in the sensing optical fiber 200.

[0066] The acquisition component 300 includes a wavelength selective filter 310, a first acquisition module 320, a second acquisition module 330 and a control module 340. The input end of the wavelength selective filter 310 is connected to the output end of the sensing optical fiber 200, the first output end of the wavelength selective filter 310 is connected to the input end of the first acquisition module 320, the second output end of the wavelength selective filter 310 is connected to the input end of the second acquisition module 330, and the wavelength selective filter 310 is configured to select the laser signal output by the sensing optical fiber 200 to output the Raman light signal to the first acquisition module 320 and output the Rayleigh scattered light signal to the second acquisition module 330.

[0067] The input end of the control module 340 is connected to the output end of the first acquisition module 320 and the output end of the second acquisition module 330 respectively. The control module 340 is configured to process the Raman light signal and the Rayleigh scattered light signal to obtain stress data of the concrete structure.

[0068] It is feasible that the laser 110 emits a laser signal, and the laser signal passes through the first electro-optical modulation module 130, a part of the laser signal is modulated in the first electro-optical modulation module 130 to form a nanosecond pulse signal, and at the same time, another part of the laser signal is modulated in the second electro-optical modulation module 140 to form a swept frequency pulse signal.

[0069] The nanosecond pulse signal enters the sensing optical fiber 200 and generates a temperature-sensitive Raman light signal in the sensing optical fiber 200 . The swept frequency pulse signal enters the sensing optical fiber 200 and generates a stress-sensitive Rayleigh scattered light signal in the sensing optical fiber 200 .

[0070] The Raman optical signal is output to the first acquisition module 320 via the wavelength selection filter 310, and then output to the control module 340 by the first acquisition module 320. The Rayleigh scattered optical signal is output to the second acquisition module 330 via the wavelength selection filter 310, and then output to the control module 340 by the second acquisition module 330. The control module 340 demodulates the Raman optical signal and the Rayleigh scattered optical signal respectively. The control module 340 demodulates the Raman optical signal to obtain temperature data. The control module 340 demodulates the Rayleigh scattered optical signal to obtain mixed data of temperature data and stress data. The control module 340 then compensates the mixed data with the temperature data to obtain stress data.

[0071] The embodiment of the present application provides a distributed optical fiber sensing device for concrete structures. The laser signal output by the laser 110 can be modulated into a nanosecond pulse signal and output to the sensing optical fiber 200 through the first electro-optical modulation module 130, and the nanosecond pulse signal can generate a temperature-sensitive Raman optical signal in the sensing optical fiber 200. The embodiment of the present application can modulate the laser signal output by the laser 110 into a swept-frequency pulse signal through the second electro-optical modulation module 140, and the swept-frequency pulse signal can generate a Rayleigh scattered optical signal that is sensitive to both stress and temperature in the sensing optical fiber 200.

[0072] In the embodiment of the present application, the output end of the sensing optical fiber 200 is connected to the first acquisition module 320 and the second acquisition module 330 through the wavelength selection filter 310, so that the Raman light signal and the Rayleigh scattered light signal can be respectively collected through the wavelength selection filter 310, and then the Raman light signal and the Rayleigh scattered light signal are output to the control module 340 through the first acquisition module 320 and the second acquisition module 330. The control module 340 demodulates the Raman light signal to obtain the temperature data in the sensing optical fiber 200. The control module 340 demodulates the Rayleigh scattered light signal to obtain mixed data of the temperature data and stress data in the sensing optical fiber 200.

[0073] The embodiment of the present application calculates the mixed data obtained by demodulating the Rayleigh scattered light signal and the temperature data obtained by demodulating the Raman light signal to obtain stress data, that is, the temperature data obtained by demodulating the Raman light signal can compensate for the mixed data obtained by demodulating the Rayleigh scattered light signal, and accurate temperature data and stress data can be obtained, thereby improving the detection accuracy of the temperature and stress of the concrete structure.

[0074] Figure 2 This is a schematic diagram of the structure of a distributed optical fiber sensing device for concrete structure provided in one embodiment of the present application. Figure 2 .

[0075] In some examples, reference Figure 2The distributed optical fiber sensing device also includes an optical switch 210, and the sensing optical fiber 200 includes a first sensing optical fiber 220 and a second sensing optical fiber 230; the input end of the optical switch 210 is respectively connected to the output end of the first electro-optical modulation module 130 and the output end of the second electro-optical modulation module 140; the output end of the optical switch 210 is respectively connected to the input end of the first sensing optical fiber 220 and the input end of the second sensing optical fiber 230; the optical switch 210 is configured to switch the transmission path of the laser signal.

[0076] The first sensing optical fiber 220 is configured to transmit at least one of a nanosecond pulse signal or a swept frequency pulse signal. The second sensing optical fiber 230 is configured to transmit at least one of a nanosecond pulse signal or a swept frequency pulse signal.

[0077] It should be noted that the optical switch 210 is a device having one or more selectable transmission windows and capable of performing mutual conversion or logical operations on optical signals in an optical transmission line or an integrated optical circuit.

[0078] Exemplarily, the first sensing optical fiber 220 and the second sensing optical fiber 230 may be disposed in the same optical cable.

[0079] For example, when detecting the stress of a concrete structure, when it is necessary to obtain the temperature data inside the concrete structure, only the first electro-optical modulation module 130 is turned on, and the laser signal emitted by the laser 110 is modulated by the first electro-optical modulation module 130 to form a nanosecond pulse signal. The optical switch 210 adjusts the transmission path of the laser signal to the first sensing optical fiber 220, and the nanosecond pulse signal enters the first sensing optical fiber 220 through the optical switch 210, forming a temperature-sensitive Raman optical signal in the first sensing optical fiber 220, and the Raman optical signal is output to the acquisition component 300.

[0080] When it is necessary to obtain stress data in the concrete structure, only the second electro-optical modulation module 140 is turned on, and the laser signal emitted by the laser 110 is modulated by the second electro-optical modulation module 140 to form a swept-frequency pulse signal. The optical switch 210 adjusts the transmission path of the laser signal to the second sensing optical fiber 230, and the swept-frequency pulse signal enters the second sensing optical fiber 230 through the optical switch 210, forming a Rayleigh light signal sensitive to stress and temperature in the second sensing optical fiber 230, and the Rayleigh light signal is output to the acquisition component 300.

[0081] It is feasible that the first sensing optical fiber 220 and the second sensing optical fiber 230 may be optical fibers arranged in different optical cables.

[0082] For example, the first sensing optical fiber 220 and the second sensing optical fiber 230 can be laid in different layers of the concrete structure. When detecting the stress of the concrete structure, the optical switch 210 adjusts the transmission path of the laser signal to the first sensing optical fiber 220, and simultaneously outputs the nanosecond pulse signal and the swept frequency pulse signal to the first sensing optical fiber 220 to detect the stress of the concrete structure layer where the first sensing optical fiber 220 is laid. After a period of detection, the optical switch adjusts the transmission path of the laser signal to the second sensing optical fiber 230, and simultaneously outputs the nanosecond pulse signal and the swept frequency pulse signal to the second sensing optical fiber 230 to detect the stress of the concrete structure layer where the second sensing optical fiber 230 is laid.

[0083] In the embodiment of the present application, the first sensing optical fiber 220 and the second sensing optical fiber 230 are respectively connected through the optical switch 210. When the first sensing optical fiber 220 and the second sensing optical fiber 230 are located in the same optical cable, the nanosecond pulse signal and the swept frequency pulse signal can be transmitted in two different sensing optical fibers 200, thereby avoiding mutual interference between the two optical signals and improving the accuracy of detection. When the first sensing optical fiber 220 and the second sensing optical fiber 230 are in different optical cables, different optical cables are laid in different layers of the concrete structure, and multiple layers of the concrete structure can be detected, thereby improving the accuracy of detection.

[0084] In some examples, the distributed optical fiber sensing device also includes a first coupler 120 and a second coupler 150, the input end of the first coupler 120 is connected to the output end of the laser 110, the first output end of the first coupler 120 is connected to the input end of the first electro-optical modulation module 130, and the second output end of the first coupler 120 is connected to the input end of the second electro-optical modulation module 140.

[0085] The first input end of the second coupler 150 is connected to the output end of the first electro-optical modulation module 130 , the second input end of the second coupler 150 is connected to the output end of the second electro-optical modulation module 140 , and the output end of the second coupler 150 is connected to the sensing optical fiber 200 .

[0086] For example, the first coupler 120 and the second coupler 150 can both be configured as fiber couplers, wherein the first coupler 120 can be configured as a fiber coupler having one input end and two output ends, and the second coupler 150 can be configured as a fiber coupler having two input ends and one output end.

[0087] The embodiment of the present application can couple the laser signal output by the laser 110 into the first electro-optical modulation module 130 and the second electro-optical modulation module 140 respectively through the setting of the first coupler 120 and the second coupler 150 for modulation respectively, and then couple the laser signal output by the first electro-optical modulation module 130 and the laser signal output by the second electro-optical modulation module 140 to the sensing optical fiber 200.

[0088] Furthermore, the second electro-optical modulation module 140 includes a first electro-optical modulator 141 and a second electro-optical modulator 142 .

[0089] The first input end of the first electro-optical modulator 141 is connected to the second output end of the first coupler 120 , the output end of the first electro-optical modulator 141 is connected to the first input end of the second electro-optical modulator 142 , and the output end of the second electro-optical modulator 142 is connected to the second input end of the second coupler 150 .

[0090] The first electro-optic modulator 141 is configured to shift the frequency of the laser signal output by the laser 110 ; the second electro-optic modulator 142 is configured to modulate the shifted laser signal of the first electro-optic modulator 141 to output a swept frequency pulse signal.

[0091] For example, the laser signal passes through the first electro-optical modulator 141, and the frequency shift of the laser signal is realized in the first electro-optical modulator 141. The laser signal after the frequency shift enters the second electro-optical modulator 142, and the repetition frequency and pulse signal of the pulse signal after the frequency shift are adjusted in the second electro-optical modulator 142 to modulate and form a swept frequency pulse signal.

[0092] The embodiment of the present application can modulate the laser signal output by the laser 110 through the setting of the first electro-optic modulator 141 and the second electro-optic modulator 142, so as to modulate the laser signal output by the laser 110 into a swept-frequency pulse signal, so that the swept-frequency pulse signal generates temperature-sensitive Rayleigh scattered light in the sensing optical fiber 200.

[0093] It is feasible that the first acquisition module 320 includes a first detector 321 and a second detector 322, and the second acquisition module 330 includes a third detector 331. The input end of the first detector 321 is connected to the first output end of the wavelength selection filter 310, and the first detector 321 is configured to receive the Stokes light signal output from the first output end of the wavelength selection filter 310. The input end of the second detector 322 is connected to the second output end of the wavelength selection filter 310, and the second detector 322 is configured to receive the anti-Stokes light signal output from the second output end of the wavelength selection filter 310. The input end of the third detector 331 is connected to the third output end of the wavelength selection filter 310, and the third detector 331 is configured to receive the Rayleigh scattered light signal output from the third output end of the wavelength selection filter 310. The output end of the first detector 321, the output end of the second detector 322, and the output end of the third detector 331 are all connected to the input end of the control module 340.

[0094] It should be noted that Raman light includes Stokes light and anti-Stokes light. When demodulating Raman light, it is necessary to collect Stokes light and anti-Stokes light respectively, and after demodulating Stokes light and anti-Stokes light respectively, calculate the relationship between the demodulation data of Stokes light and the demodulation data of anti-Stokes light to obtain temperature data.

[0095] Exemplarily, the control module 340 includes a data acquisition card 341 and a controller 342. The output ends of the first detector 321, the second detector 322 and the third detector 331 are all connected to the input end of the data acquisition card 341. The first detector 321, the second detector 322 and the third detector 331 respectively output laser signals to different channels of the data acquisition card 341. The data acquisition card 341 then outputs the laser signal to the controller 342. The controller 342 processes the Raman light signal and the Rayleigh scattered light signal to obtain the stress data of the concrete structure.

[0096] The embodiment of the present application is connected to the first detector 321, the second detector 322 and the third detector 331 through the wavelength selection filter 310. The wavelength selection filter 310 can transmit the laser signal in the sensing optical fiber 200, according to different wavelengths, to transmit the Stokes light to the first detector 321, the anti-Stokes light to the second detector 322, and the Rayleigh scattered light to the third detector 331.

[0097] In some other implementations, the first electro-optical modulation module 130 includes a third electro-optical modulator 131 and a first function generator 132; the first input end of the third electro-optical modulator 131 is connected to the output end of the laser 110, the second input end of the third electro-optical modulator 131 is connected to the output end of the first function generator 132, and the output end of the third electro-optical modulator 131 is connected to the input end of the sensing optical fiber 200; the third electro-optical modulator 131 is configured to modulate the laser signal output by the laser 110 to form a nanosecond pulse signal; the first function generator 132 is configured to drive the third electro-optical modulator 131 to modulate the laser signal output by the laser 110 to form a nanosecond pulse signal.

[0098] In the embodiment of the present application, the first function generator 132 is configured to drive the third electro-optic modulator 131 to modulate the laser signal output by the laser 110 to form a nanosecond pulse signal, so that the nanosecond pulse signal forms a temperature-sensitive Raman signal in the sensing optical fiber 200.

[0099] Similarly, the second electro-optical modulation module 140 also includes a second function generator 143. The second input end of the first electro-optical modulator 141 is connected to the first output end of the second function generator 143. The second input end of the second electro-optical modulator 142 is connected to the second output end of the second function generator 143. The second function generator 143 is configured to drive the first electro-optical modulator 141 to shift the frequency of the laser signal output by the laser 110. The second electro-optical modulator 142 is also configured to drive the second electro-optical modulator 142 to modulate the laser signal after the shift of the first electro-optical modulator 141 to output a swept frequency pulse signal.

[0100] The embodiment of the present application can not only drive the first electro-optic modulator 141 to modulate the laser signal through the setting of the second function generator 143, but also drive the second electro-optic modulator 142 to modulate the laser signal, so as to modulate the laser signal output by the laser 110 into a swept frequency pulse signal, so that the swept frequency pulse signal forms a stress-sensitive Rayleigh scattered light signal in the sensing optical fiber 200.

[0101] In some other examples, the laser emitting assembly 100 also includes an erbium-doped fiber amplifier 160, the input end of the erbium-doped fiber amplifier 160 is connected to the output end of the second coupler 150, and the output end of the erbium-doped fiber amplifier 160 is connected to the input end of the sensing fiber 200; the erbium-doped fiber amplifier 160 is configured to amplify the Raman light signal and the Rayleigh scattered light signal output by the second coupler 150.

[0102] The embodiment of the present application can achieve power amplification of the nanosecond pulse signal output by the first electro-optical modulation module 130 and the swept-frequency pulse signal output by the second electro-optical modulation module by setting the erbium-doped fiber amplifier 160 .

[0103] In some other implementations, the distributed optical fiber sensing device also includes a circulator 170, an input end of the circulator 170 is connected to an output end of the erbium-doped fiber amplifier 160, a first output end of the circulator 170 is connected to the sensing optical fiber 200, and a second output end of the circulator 170 is connected to a wavelength selective filter 310.

[0104] In the embodiment of the present application, the circulator 170 is provided so that the circulator 170 can provide a plurality of ports, so that the Raman light signal and the Rayleigh scattered light signal in the sensing optical fiber 200 are transmitted to the wavelength selective filter 310 via the circulator 170 .

[0105] It is easy to understand that those skilled in the art can combine, split, reorganize, etc. the embodiments of the present application to obtain other embodiments based on the several embodiments provided in the present application, and these embodiments do not exceed the protection scope of the present application.

[0106] The above specific implementation methods further explain in detail the purpose, technical solutions and beneficial effects of the embodiments of the present application. It should be understood that the above are only specific implementation methods of the embodiments of the present application and are not used to limit the protection scope of the embodiments of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.

Claims

1. A distributed optical fiber sensing device for concrete structure, characterized in that: It comprises a laser emission component (100), a sensing optical fiber (200) and a collection component (300); The laser emitting assembly (100) comprises a laser (110) for outputting a laser signal, a first electro-optical modulation module (130) and a second electro-optical modulation module (140), wherein the output end of the laser (110) is respectively connected to the first input end of the first electro-optical modulation module (130) and the first input end of the second electro-optical modulation module (140); The first electro-optical modulation module (130) is configured to modulate the laser signal output by the laser (110) to form a nanosecond pulse signal; The second electro-optical modulation module (140) is configured to modulate the laser signal output by the laser (110) to form a swept frequency pulse signal; The sensing optical fiber (200) is laid in the concrete structure, the input end of the sensing optical fiber (200) is respectively connected to the output ends of the first electro-optical modulation module (130) and the second electro-optical modulation module (140), and the sensing optical fiber (200) is configured to receive and transmit the nanosecond pulse signal and the swept frequency pulse signal, the nanosecond pulse signal forms a Raman light signal in the sensing optical fiber (200), and the swept frequency pulse signal forms a Rayleigh scattered light signal in the sensing optical fiber (200); The acquisition component (300) comprises a wavelength selection filter (310), a first acquisition module (320), a second acquisition module (330) and a control module (340); the input end of the wavelength selection filter (310) is connected to the output end of the sensing optical fiber (200); the first output end of the wavelength selection filter (310) is connected to the input end of the first acquisition module (320); the second output end of the wavelength selection filter (310) is connected to the input end of the second acquisition module (330); the wavelength selection filter (310) is configured to select the laser signal output by the sensing optical fiber (200) to output the Raman light signal to the first acquisition module (320) and output the Rayleigh scattered light signal to the second acquisition module (330); The input end of the control module (340) is respectively connected to the output end of the first acquisition module (320) and the output end of the second acquisition module (330), and the control module (340) is configured to process the Raman light signal and the Rayleigh scattered light signal to obtain stress data of the concrete structure.

2. The distributed optical fiber sensing device for concrete structure according to claim 1, characterized in that: The distributed optical fiber sensing device further comprises an optical switch (210), and the sensing optical fiber (200) comprises a first sensing optical fiber (220) and a second sensing optical fiber (230); The input end of the optical switch (210) is respectively connected to the output end of the first electro-optical modulation module (130) and the output end of the second electro-optical modulation module (140); The output end of the optical switch (210) is connected to the input end of the first sensing optical fiber (220) and the input end of the second sensing optical fiber (230) respectively; The optical switch (210) is configured to switch the transmission path of the laser signal; The first sensing optical fiber (220) is configured to transmit at least one of the nanosecond pulse signal or the swept frequency pulse signal; The second sensing optical fiber (230) is configured to transmit at least one of the nanosecond pulse signal or the swept frequency pulse signal.

3. The distributed optical fiber sensing device for concrete structure according to claim 1, characterized in that: It also includes a first coupler (120) and a second coupler (150), wherein the input end of the first coupler (120) is connected to the output end of the laser (110), the first output end of the first coupler (120) is connected to the input end of the first electro-optical modulation module (130), and the second output end of the first coupler (120) is connected to the input end of the second electro-optical modulation module (140); The first input end of the second coupler (150) is connected to the output end of the first electro-optical modulation module (130), the second input end of the second coupler (150) is connected to the output end of the second electro-optical modulation module (140), and the output end of the second coupler (150) is connected to the sensing optical fiber (200).

4. The distributed optical fiber sensing device for concrete structure according to claim 3, characterized in that: The second electro-optical modulation module (140) comprises a first electro-optical modulator (141) and a second electro-optical modulator (142); The first input end of the first electro-optical modulator (141) is connected to the second output end of the first coupler (120), the output end of the first electro-optical modulator (141) is connected to the first input end of the second electro-optical modulator (142), and the output end of the second electro-optical modulator (142) is connected to the second input end of the second coupler (150); The first electro-optic modulator (141) is configured to shift the frequency of the laser signal output by the laser (110); The second electro-optic modulator (142) is configured to modulate the laser signal shifted by the first electro-optic modulator (141) to output a swept frequency pulse signal.

5. The distributed optical fiber sensing device for concrete structure according to any one of claims 1 to 4, characterized in that: The first acquisition module (320) includes a first detector (321) and a second detector (322), and the second acquisition module (330) includes a third detector (331); The input end of the first detector (321) is connected to the first output end of the wavelength selection filter (310), and the first detector (321) is configured to receive the Stokes light signal output by the first output end of the wavelength selection filter (310); The input end of the second detector (322) is connected to the second output end of the wavelength selection filter (310), and the second detector (322) is configured to receive the anti-Stokes optical signal output by the second output end of the wavelength selection filter (310); The input end of the third detector (331) is connected to the third output end of the wavelength selective filter (310), and the third detector (331) is configured to receive the Rayleigh scattered light signal output by the third output end of the wavelength selective filter (310); The output end of the first detector (321), the output end of the second detector (322), and the output end of the third detector (331) are all connected to the input end of the control module (340).

6. The distributed optical fiber sensing device for concrete structure according to any one of claims 1 to 4, characterized in that: The first electro-optical modulation module (130) comprises a third electro-optical modulator (131) and a first function generator (132); The first input end of the third electro-optic modulator (131) is connected to the output end of the laser (110), the second input end of the third electro-optic modulator (131) is connected to the output end of the first function generator (132), and the output end of the third electro-optic modulator (131) is connected to the input end of the sensing optical fiber (200); The third electro-optic modulator (131) is configured to modulate the laser signal output by the laser (110) to form a nanosecond pulse signal; The first function generator (132) is configured to drive the third electro-optic modulator (131) to modulate the laser signal output by the laser (110) to form a nanosecond pulse signal.

7. The distributed optical fiber sensing device for concrete structure according to claim 4, characterized in that: The laser emission assembly (100) further comprises an erbium-doped fiber amplifier (160), the input end of the erbium-doped fiber amplifier (160) being connected to the output end of the second coupler (150), and the output end of the erbium-doped fiber amplifier (160) being connected to the input end of the sensing optical fiber (200); The erbium-doped fiber amplifier (160) is configured to amplify the Raman optical signal and the Rayleigh scattered optical signal output by the second coupler (150).

8. The distributed optical fiber sensing device for concrete structure according to claim 4, characterized in that: The second electro-optical modulation module (140) further includes a second function generator (143); The second input end of the first electro-optic modulator (141) is connected to the first output end of the second function generator (143); The second input end of the second electro-optic modulator (142) is connected to the second output end of the second function generator (143); The second function generator (143) is configured to drive the first electro-optical modulator (141) to shift the frequency of the laser signal output by the laser (110); The second electro-optic modulator (142) is also configured to drive the second electro-optic modulator (142) to modulate the laser signal shifted by the first electro-optic modulator (141) to output a swept frequency pulse signal.

9. The distributed optical fiber sensing device for concrete structure according to claim 7, characterized in that: The laser emitting assembly (100) further comprises a circulator (170), wherein an input end of the circulator (170) is connected to an output end of the erbium-doped fiber amplifier (160), a first output end of the circulator (170) is connected to the sensing optical fiber (200), and a second output end of the circulator (170) is connected to the wavelength selection filter (310).

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