CN220960115U - Distributed optical fiber temperature and acoustic wave sensing system - Google Patents
Distributed optical fiber temperature and acoustic wave sensing system Download PDFInfo
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- CN220960115U CN220960115U CN202323102237.4U CN202323102237U CN220960115U CN 220960115 U CN220960115 U CN 220960115U CN 202323102237 U CN202323102237 U CN 202323102237U CN 220960115 U CN220960115 U CN 220960115U
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Abstract
The invention relates to the technical field of distributed optical fiber sensing, and provides a distributed optical fiber temperature and sound wave sensing system which comprises a laser, a first optical fiber coupler, an acousto-optic modulator, an optical fiber amplifier, an optical fiber circulator, a sensing optical fiber, a second optical fiber coupler, a first detector, a third optical fiber coupler, a second detector, a third detector, a multi-channel acquisition card, a data processing unit and a main control and display unit. And the first optical fiber coupler and the second optical fiber coupler are used for coherent detection of the first detector, so that the sensing detection of the sound wave is realized. And sensing and detecting the temperature are realized through the detection of the third optical fiber coupler on the second detector and the third detector. The distributed optical fiber temperature and sound wave sensing system disclosed by the invention combines two sensing functions of temperature and sound wave, can meet different working requirements, effectively overcomes the defect that conventional distributed optical fiber sensing equipment only has single temperature or sound wave sensing, saves cost and is convenient to use.
Description
Technical Field
The invention relates to the technical field of distributed optical fiber sensing, in particular to a distributed optical fiber temperature and sound wave sensing system.
Background
The optical fiber sensing technology is widely applied to safety monitoring due to the advantages of long measurement distance, electromagnetic interference resistance, corrosion resistance and the like. The distributed optical fiber sensing system uses the optical fiber as a sensing sensitive element and a transmission signal medium, external disturbance (such as temperature, vibration, deformation and the like) at the sensing optical fiber can change the property (intensity, phase, polarization, frequency and the like) of the back scattered light of the sensing optical fiber, and the working environment of the transmission optical fiber can be judged according to the detected condition of the back scattered light. The existing distributed optical fiber sensing system only has single temperature or acoustic wave sensing, so that the optical fiber sensing monitoring frequency is low, and the response speed is low.
Disclosure of Invention
The present invention is directed to solving at least one of the technical problems existing in the related art. Therefore, the invention provides a distributed optical fiber temperature and sound wave sensing system, which solves the defect that the existing optical fiber sensing has only single temperature or sound wave sensing.
According to an embodiment of the invention, a distributed optical fiber temperature and acoustic wave sensing system comprises:
The device comprises a laser, a first optical fiber coupler, an acousto-optic modulator, an optical fiber amplifier, an optical fiber circulator, sensing optical fibers, a second optical fiber coupler, a first detector, a third optical fiber coupler, a second detector, a third detector, a multi-channel acquisition card, a data processing unit, a main control and display unit, wherein:
the laser is connected to the first optical fiber coupler;
The first optical fiber coupler comprises two output ends, a first output end of the first optical fiber coupler is connected with the acousto-optic modulator, and a second output end of the first optical fiber coupler is connected with the first detector;
the acousto-optic modulator is connected with the optical fiber amplifier;
The optical fiber amplifier, the sensing optical fiber and the second optical fiber coupler are sequentially connected to three ports of the optical fiber circulator;
The second optical fiber coupler comprises two output ends, a first output end of the second optical fiber coupler is connected with the first detector, and a second output end of the second optical fiber coupler is connected with the third optical fiber coupler;
The third optical fiber coupler comprises two output ends, a first output end of the third optical fiber coupler is connected with the second detector, and a second output end of the third optical fiber coupler is connected with the third detector;
The multi-channel acquisition card comprises four input ends, the first detector is connected with the first input end of the multi-channel acquisition card, the second detector is connected with the second input end of the multi-channel acquisition card, the third detector is connected with the third input end of the multi-channel acquisition card, and the main control and display unit is connected with the fourth input end of the multi-channel acquisition card;
The data processing unit is connected with the output end of the multichannel acquisition card;
the main control and display unit is connected with the output end of the data processing unit.
According to the distributed optical fiber temperature and acoustic wave sensing system provided by the embodiment of the invention, the sensing detection of acoustic waves is realized through the coherent detection of the first optical fiber coupler and the second optical fiber coupler in the first detector. And sensing and detecting the temperature are realized through the detection of the third optical fiber coupler on the second detector and the third detector. The distributed optical fiber temperature and acoustic wave sensing system disclosed by the invention combines two sensing functions of temperature and acoustic wave, can meet different working requirements, effectively overcomes the defect that conventional distributed optical fiber sensing equipment only has single temperature or acoustic wave sensing, saves cost, is convenient to use, and overcomes the problems of low monitoring frequency, low response speed and the like caused by the conventional system adopting a time division multiplexing mode based on an optical switch, and has the advantages of high detection frequency, quick response and the like.
According to one embodiment of the invention, the main control and display unit is connected to the input of the acousto-optic modulator.
According to one embodiment of the present invention, the optical fiber amplifier further comprises a first optical fiber filter, the optical fiber circulator comprises four ports, the output end of the optical fiber amplifier is connected to the first port of the optical fiber circulator, the second port of the optical fiber circulator is connected to the first optical fiber filter, the third port of the optical fiber circulator is connected to the sensing optical fiber, and the fourth port of the optical fiber circulator is connected to the input end of the second optical fiber coupler.
According to an embodiment of the present invention, a second optical fiber filter is disposed between the second optical fiber coupler and the first detector, a third optical fiber filter is disposed between the third optical fiber coupler and the second detector, and a fourth optical fiber filter is disposed between the third optical fiber coupler and the third detector.
According to one embodiment of the present invention, the first optical fiber filter is a reflective optical fiber grating filter, and the second optical fiber filter, the third optical fiber filter, and the fourth optical fiber filter are transmissive optical fiber filters.
According to one embodiment of the invention, the laser, the first optical fiber coupler, the acousto-optic modulator, the optical fiber amplifier, the optical fiber circulator, the first optical fiber filter, the sensing optical fiber, the second optical fiber coupler, the second optical fiber filter, the first detector, the third optical fiber coupler, the third optical fiber filter, the fourth optical fiber filter, the second detector and the third detector are connected through a single mode fiber;
The first detector, the second detector, the third detector, the multichannel acquisition card, the data processing unit, the main control unit, the display unit and the acousto-optic modulator are connected through a radio frequency signal line.
According to one embodiment of the present invention, the first fiber filter center wavelength is a laser emission laser center wavelength,
And/or the center wavelength of the second optical fiber filter is the backward Rayleigh scattering center wavelength of the sensing optical fiber,
And/or, the third optical fiber filter is the backward Stokes scattering center wavelength of the sensing optical fiber,
And/or the fourth optical fiber filter is the backward anti-stokes scattering center wavelength of the sensing optical fiber.
According to one embodiment of the invention, the first fiber coupler has a split ratio of 1:99, the optical energy transmitted to the acousto-optic modulator is 99%, and the optical energy transmitted to the first detector is 1%;
and/or the beam splitting ratio of the second optical fiber coupler to the third optical fiber coupler is 1:1.
According to one embodiment of the invention, the sensing fiber is a single mode fiber.
According to one embodiment of the invention, the first detector is a balanced detector and/or the second and third detectors are single pixel linear APD detectors.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
FIG. 1 is a schematic diagram of a distributed optical fiber temperature and acoustic wave sensing system according to an embodiment of the present invention.
Reference numerals:
1. A laser; 2. a first optical fiber coupler; 3. an acousto-optic modulator; 4. an optical fiber amplifier; 5. an optical fiber circulator; 6. a first optical fiber filter; 7. a sensing optical fiber; 8. a second fiber coupler; 9. a second optical fiber filter; 10. a first detector; 11. a third fiber coupler; 12. a third optical fiber filter; 13. a fourth optical fiber filter; 14. a second detector; 15. a third detector; 16. a multichannel acquisition card; 17. a data processing unit; 18. and a main control and display unit.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples. The following examples are illustrative of the invention but are not intended to limit the scope of the invention.
In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the embodiments of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected" and "connected" are to be construed broadly, and may be, for example, fixed or removable, wherein the fixed connection may include an integral connection; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in embodiments of the present utility model will be understood in detail by those of ordinary skill in the art.
In embodiments of the invention, unless expressly specified and limited otherwise, a first feature "up" or "down" on a second feature may be that the first and second features are in direct contact, or that the first and second features are in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the embodiments of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Referring to fig. 1, the distributed optical fiber temperature and acoustic wave sensing system according to the embodiment of the present invention includes a laser 1, a first optical fiber coupler 2, an acousto-optic modulator 3, an optical fiber amplifier 4, an optical fiber circulator 5, a sensing optical fiber 7, a second optical fiber coupler 8, a first detector 10, a third optical fiber coupler 11, a second detector 14, a third detector 15, a multi-channel acquisition card 16, a data processing unit 17, a main control and display unit 18,
Wherein the laser 1 is connected to a first fiber coupler 2; the first optical fiber coupler 2 comprises two output ends, a first output end of the first optical fiber coupler 2 is connected with the acousto-optic modulator 3, and a second output end of the first optical fiber coupler 2 is connected with the first detector 10; the acousto-optic modulator 3 is connected with the optical fiber amplifier 4; the optical fiber amplifier 4, the sensing optical fiber 7 and the second optical fiber coupler 8 are sequentially connected to three ports of the optical fiber circulator 5; the second optical fiber coupler 8 comprises two output ends, a first output end of the second optical fiber coupler 8 is connected with the first detector 10, and a second output end of the second optical fiber coupler 8 is connected with the third optical fiber coupler 11; the third optical fiber coupler 11 comprises two output ends, a first output end of the third optical fiber coupler 11 is connected with the second detector 14, and a second output end of the third optical fiber coupler 11 is connected with the third detector 15; the multi-channel acquisition card 16 comprises four input ends, the first detector 10 is connected to the first input end of the multi-channel acquisition card 16, the second detector 14 is connected to the second input end of the multi-channel acquisition card 16, the third detector 15 is connected to the third input end of the multi-channel acquisition card 16, and the main control and display unit 18 is connected to the fourth input end of the multi-channel acquisition card 1616; the data processing unit 17 is connected to the output end of the multichannel acquisition card 16; the main control and display unit 18 is connected to the output of the data processing unit 17.
According to the distributed optical fiber temperature and acoustic wave sensing system provided by the embodiment of the invention, the sensing detection of acoustic waves is realized through the coherent detection of the first optical fiber coupler 2 and the second optical fiber coupler 8 in the first detector 10. The third optical fiber coupler 11 detects the temperature in the second detector 14 and the third detector 15, so that the sensing detection of the temperature is realized. The distributed optical fiber temperature and acoustic wave sensing system disclosed by the invention combines two sensing functions of temperature and acoustic wave, can meet different working requirements, effectively overcomes the defect that conventional distributed optical fiber sensing equipment only has single temperature or acoustic wave sensing, saves cost, is convenient to use, and overcomes the problems of low monitoring frequency, low response speed and the like caused by the conventional system adopting a time division multiplexing mode based on an optical switch, and has the advantages of high detection frequency, quick response and the like.
It will be appreciated that the laser 1 provides a light source in a distributed optical fiber temperature and acoustic wave sensing system that generates and emits an optical signal of a specific wavelength and power that is modulated and transmitted by the optical fiber coupler and other components for ultimate use in sensing detection.
It will be appreciated that the optical fiber couplers (including the first optical fiber coupler 2, the second optical fiber coupler 8 and the third optical fiber coupler 11) achieve distribution and combination of optical signals in a distributed optical fiber temperature and acoustic wave sensing system. The input optical signals may be distributed to different output ports or the optical signals from different ports may be combined into one output port.
It will be appreciated that the acousto-optic modulator 3 is used to modulate an optical signal, modulate a continuous optical signal emitted by the laser 1 into a pulsed optical signal, and may modulate parameters such as frequency, width and frequency shift of the optical signal. In the distributed optical fiber temperature and acoustic wave sensing system, the acousto-optic modulator 3 is used for accurately modulating an optical signal so as to facilitate subsequent sensing detection and data processing.
It will be appreciated that the optical fibre amplifier 4 is used to amplify the optical signal to compensate for losses in the signal during transmission, ensuring that the optical signals detected by the first detector 10, the second detector 14 and the third detector 15 are accurate.
It will be appreciated that the fiber optic circulator 5 may provide a specific optical path for the optical signal.
It will be appreciated that the multi-channel acquisition card 16 may acquire optical signal data from different detectors, including the first detector 10, the second detector 14 and the third detector 15, and convert it into digital signals for processing and storage. Real-time and accurate acquisition of sensing signals can be realized, and basic data can be provided for subsequent data processing and analysis.
It will be appreciated that the data processing unit 17 is configured to process data acquired by the multi-channel acquisition card 16.
It will be appreciated that the master control and display unit 18 serves as the core control and information display in a distributed fiber optic temperature and acoustic wave sensing system. The main control unit is responsible for controlling and managing the whole system, and monitors and processes various states and events of the system, so that the normal operation and efficient operation of the system are ensured. Meanwhile, the main control unit is also responsible for processing and analyzing control data and communicating and coordinating with other components. The display unit is used for displaying the working state and various parameters of the system in real time. The method can intuitively display the acquired data in the modes of graphics, charts and the like, and is convenient for users to observe and analyze. Meanwhile, the display unit can also provide an operation interface so that a user can configure and control the system.
It will be appreciated that the second output of the first fibre-optic coupler 2 is connected to the first detector 10; the first output end of the second optical fiber coupler 8 is connected to the first detector 10, and the first detector 10 carries out coherent detection on two input signals to obtain acoustic wave sensing data of an optical signal. One of the second detector 14 and the third detector 15 is used for detecting the long wave of the optical signal, the other is used for detecting the short wave of the optical signal, and the long wave and short wave data obtained by the second detector 14 and the third detector 15 can be used for detecting the temperature sensing data of the optical signal.
It should be noted that the connection of the present invention may be direct or indirect through an intermediate medium, for example, the second optical fiber coupler 8 may be connected to the first detector 10 through the second optical fiber filter 9, the third optical fiber coupler 11 may be connected to the second detector 14 through the third optical fiber filter 12, and the third optical fiber coupler 11 may be connected to the third detector 15 through the fourth optical fiber filter 13.
In one embodiment, the fiber amplifier 4 may be an erbium doped fiber amplifier 4, in which rare earth erbium (Er) ions are doped.
According to one embodiment of the invention, the master control and display unit 18 is connected to the input of the acousto-optic modulator 3. It will be appreciated that the main control and display unit 18 may be used to control parameters such as frequency, width and frequency shift of the modulated optical signal of the acousto-optic modulator 3.
According to one embodiment of the present invention, the distributed optical fiber temperature and acoustic wave sensing system further comprises a first optical fiber filter 6, the optical fiber circulator 5 comprises four ports, the output end of the optical fiber amplifier 4 is connected to the first port of the optical fiber circulator 5, the second port of the optical fiber circulator 5 is connected to the first optical fiber filter 6, the third port of the optical fiber circulator 5 is connected to the sensing optical fiber 7, and the fourth port of the optical fiber circulator 5 is connected to the input end of the second optical fiber coupler 8.
It will be appreciated that the optical signals may flow sequentially along the paths of the four ports of the fibre optic circulator 5. The optical signal enters the first port of the optical fiber circulator 5 from the output end of the optical fiber amplifier 4, then enters the first optical fiber filter 6 through the second port of the optical fiber circulator 5, returns to the optical fiber circulator 5 after being filtered by the first optical fiber filter 6, further flows through the sensing optical fiber 7 through the third port of the optical fiber circulator 5 to obtain data of the sensing optical fiber 7, and finally is output to the input end of the second optical fiber coupler 8 through the fourth port of the optical fiber circulator 5.
According to one embodiment of the present invention, the distributed optical fiber temperature and acoustic wave sensing system further comprises a second optical fiber filter 9, a third optical fiber filter 12 and a fourth optical fiber filter 13, wherein the second optical fiber filter 9 is arranged between the second optical fiber coupler 8 and the first detector 10, the third optical fiber filter 12 is arranged between the third optical fiber coupler 11 and the second detector 14, and the fourth optical fiber filter 13 is arranged between the third optical fiber coupler 11 and the third detector 15.
According to one embodiment of the invention, the first optical fiber filter 6 is a reflective optical fiber grating filter, and the second optical fiber filter 9, the third optical fiber filter 12 and the fourth optical fiber filter 13 are transmissive optical fiber filters. It will be appreciated that the reflective fiber grating filter performs a filtering function by reflecting light signals of a particular wavelength, which may be selected or used to reject certain unwanted wavelengths, thereby improving the quality and clarity of the signal.
It will be appreciated that a transmissive optical fiber filter selects or filters an optical signal by transmission. The transmissive optical fiber filter allows light signals of a particular wavelength to pass while blocking other unwanted wavelengths. Such filters are typically used to further purify the optical signal, removing noise or other interference, to improve the signal-to-noise ratio and performance of the system. For example, the third optical fiber filter 12 may allow only a long wave with respect to temperature to pass therethrough, and the fourth optical fiber filter may allow only a short wave with respect to temperature to pass therethrough, achieving a good filtering effect. It should be noted that the present invention is by way of example only and not by way of limitation.
According to one embodiment of the invention, the laser 1, the first fiber coupler 2, the acousto-optic modulator 3, the fiber amplifier 4, the fiber circulator 5, the first fiber filter 6, the sensing fiber 7, the second fiber coupler 8, the second fiber filter 9, the first detector 10, the third fiber coupler 11, the third fiber filter 12, the fourth fiber filter 13, the second detector 14, and the third detector 15 are connected by a single mode fiber; the first detector 10, the second detector 14, the third detector 15, the multichannel acquisition card 16, the data processing unit 17, the main control unit 18 and the acousto-optic modulator 3 are connected through radio frequency signal lines.
It will be appreciated that single mode optical fibers have a single propagation mode and thus provide more stable signal transmission with reduced dispersion and mode noise. The optical fiber components (the laser 1, the first optical fiber coupler 2, the acousto-optic modulator 3, the optical fiber amplifier 4, the optical fiber circulator 5, the first optical fiber filter 6, the sensing optical fiber 7, the second optical fiber coupler 8, the second optical fiber filter 9, the first detector 10, the third optical fiber coupler 11, the third optical fiber filter 12, the fourth optical fiber filter 13, the second detector 14 and the third detector 15) are connected through a single-mode optical fiber, the transmission loss is lower, the bandwidth of the single-mode optical fiber is higher, and the optical fiber is suitable for high-speed and large-data transmission.
It can be understood that the radio frequency signal line has higher anti-interference capability, can effectively prevent the data error that electromagnetic interference leads to, and detector, acquisition card, processing unit etc. are connected through the radio frequency signal line, can effectively ensure the integrality and the fidelity of detection signal, improve data acquisition's accuracy.
According to one embodiment of the present invention, the first fiber filter 6 has a center wavelength that is the center wavelength of the lasing light emitted from the laser 1. It will be appreciated that when the center wavelength of the filter matches the emission wavelength of the laser 1, it is ensured that the optical signal emitted by the laser 1 passes through the filter to the maximum extent, thereby maximizing the use of the optical signal and avoiding waste of energy.
According to one embodiment of the invention, the second fiber filter 9 has a center wavelength that is the center wavelength of the backward Rayleigh scattering of the sensing fiber 7. It will be appreciated that when the central wavelength of the second optical fiber filter 9 is matched to the backward rayleigh scattering central wavelength of the sensing optical fiber 7, the filter is able to selectively pass the rayleigh scattering signal, and the receiving and processing capacity of the sensing system for the rayleigh scattering signal can be improved, thereby improving the sensing performance, including sensitivity, resolution and dynamic range.
According to one embodiment of the invention, the third fiber filter 12 is a backward stokes scattering center wavelength of the sensing fiber 7. It will be appreciated that when the central wavelength of the third optical fiber filter 12 matches the backward stokes scattering central wavelength of the sensing optical fiber 7, the backward stokes scattering signal can be selectively passed and enhanced, and the signal-to-noise ratio of the backward stokes scattering signal can be improved.
According to one embodiment of the invention, the fourth fiber filter 13 is the backward anti-stokes scattering center wavelength of the sensing fiber 7. It will be appreciated that the fourth optical filter 13 is able to selectively pass the anti-stokes scatter signal when its central wavelength matches the backward anti-stokes scatter central wavelength of the sensing optical fiber 7.
According to one embodiment of the invention, the first fiber coupler 2 has a splitting ratio of 1:99, and the light energy transmitted to the acousto-optic modulator 3 is 99% and the light energy transmitted to the first detector 10 is 1%. It will be appreciated that the first fibre coupler 2 distributes the incoming optical signal to the first detector 10 and the acousto-optic modulator 3 in a ratio of 1:99. A small portion of the optical signal is isolated for monitoring or testing while the majority of the signal continues to be transmitted to other components.
According to one embodiment of the invention, the splitting ratio of the second fiber coupler 8 to the third fiber coupler 11 is 1:1. It can be understood that the 1:1 beam splitting ratio enables the optical signal intensities of the two output ports to be equal, plays a role in equally distributing optical signals, and provides flexible optical path configuration and function implementation for the system.
According to one embodiment of the invention, the sensing fiber 7 is a single mode fiber. It will be appreciated that single mode optical fibers allow only one mode (fundamental mode HE 11) to propagate therein, thus avoiding the problem of modal dispersion and ensuring stable transmission of optical signals. Because the fiber core diameter is very small, the transmission loss of the single-mode fiber is relatively low, and the optical signal of the sensing fiber 7 can still have enough strength after long-distance transmission.
According to one embodiment of the invention, the first detector 10 is a balanced detector. It will be appreciated that balanced detectors may eliminate common mode noise and improve the accuracy of signal detection. In one embodiment, the balanced detector consists of two identical photodiodes, which are connected to the amplifier inputs of opposite polarity. When two photodiodes receive the same optical signal, common mode noise is cancelled by an amplifier, and a differential signal is amplified and output.
According to one embodiment of the invention, the second detector 14, the third detector 15 are single pixel linear APD (avalanche photodiode) detectors. It will be appreciated that the use of single pixel linear APD detectors as the second detector 14 and the third detector 15 can provide high sensitivity, fast response and linear photoelectric conversion, ensure accurate detection of weak signals, and improve dynamic range and linearity of the system.
Finally, it should be noted that the above-mentioned embodiments are merely illustrative of the invention, and not limiting. While the invention has been described in detail with reference to the embodiments, those skilled in the art will appreciate that various combinations, modifications, or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and it is intended to be covered by the scope of the claims of the present invention.
Claims (10)
1. A distributed fiber temperature and acoustic wave sensing system, comprising:
The device comprises a laser, a first optical fiber coupler, an acousto-optic modulator, an optical fiber amplifier, an optical fiber circulator, sensing optical fibers, a second optical fiber coupler, a first detector, a third optical fiber coupler, a second detector, a third detector, a multi-channel acquisition card, a data processing unit, a main control and display unit, wherein:
the laser is connected to the first optical fiber coupler;
The first optical fiber coupler comprises two output ends, a first output end of the first optical fiber coupler is connected with the acousto-optic modulator, and a second output end of the first optical fiber coupler is connected with the first detector;
the acousto-optic modulator is connected with the optical fiber amplifier;
The optical fiber amplifier, the sensing optical fiber and the second optical fiber coupler are sequentially connected to three ports of the optical fiber circulator;
The second optical fiber coupler comprises two output ends, a first output end of the second optical fiber coupler is connected with the first detector, and a second output end of the second optical fiber coupler is connected with the third optical fiber coupler;
The third optical fiber coupler comprises two output ends, a first output end of the third optical fiber coupler is connected with the second detector, and a second output end of the third optical fiber coupler is connected with the third detector;
The multi-channel acquisition card comprises four input ends, the first detector is connected with the first input end of the multi-channel acquisition card, the second detector is connected with the second input end of the multi-channel acquisition card, the third detector is connected with the third input end of the multi-channel acquisition card, and the main control and display unit is connected with the fourth input end of the multi-channel acquisition card;
The data processing unit is connected with the output end of the multichannel acquisition card;
the main control and display unit is connected with the output end of the data processing unit.
2. The distributed fiber optic temperature and acoustic wave sensing system of claim 1, wherein the master control and display unit is connected to an input of the acousto-optic modulator.
3. The distributed optical fiber temperature and acoustic wave sensing system of claim 1, further comprising a first optical fiber filter, the optical fiber circulator comprising four ports, the output of the optical fiber amplifier being connected to the first port of the optical fiber circulator, the second port of the optical fiber circulator being connected to the first optical fiber filter, the third port of the optical fiber circulator being connected to the sensing optical fiber, the fourth port of the optical fiber circulator being connected to the second optical fiber coupler input.
4. The distributed optical fiber temperature and acoustic wave sensing system of claim 3, further comprising a second optical fiber filter, a third optical fiber filter, and a fourth optical fiber filter, wherein the second optical fiber filter is disposed between the second optical fiber coupler and the first detector, the third optical fiber filter is disposed between the third optical fiber coupler and the second detector, and the fourth optical fiber filter is disposed between the third optical fiber coupler and the third detector.
5. The distributed optical fiber temperature and acoustic wave sensing system of claim 4, wherein the first optical fiber filter is a reflective optical fiber grating filter, and the second optical fiber filter, the third optical fiber filter, and the fourth optical fiber filter are transmissive optical fiber filters.
6. The distributed optical fiber temperature and acoustic wave sensing system of claim 4, wherein the laser, the first optical fiber coupler, the acousto-optic modulator, the optical fiber amplifier, the optical fiber circulator, the first optical fiber filter, the sensing optical fiber, the second optical fiber coupler, the second optical fiber filter, the first detector, the third optical fiber coupler, the third optical fiber filter, the fourth optical fiber filter, the second detector, the third detector are connected by a single mode fiber;
The first detector, the second detector, the third detector, the multichannel acquisition card, the data processing unit, the main control unit, the display unit and the acousto-optic modulator are connected through a radio frequency signal line.
7. The distributed optical fiber temperature and acoustic wave sensing system of claim 4, wherein the first optical fiber filter center wavelength is a laser emission laser center wavelength,
And/or the center wavelength of the second optical fiber filter is the backward Rayleigh scattering center wavelength of the sensing optical fiber,
And/or, the third optical fiber filter is the backward Stokes scattering center wavelength of the sensing optical fiber,
And/or the fourth optical fiber filter is the backward anti-stokes scattering center wavelength of the sensing optical fiber.
8. The distributed optical fiber temperature and acoustic wave sensing system of any one of claims 1 to 7, wherein the first optical fiber coupler has a split ratio of 1:99, the optical energy transmitted to the acousto-optic modulator is 99%, the optical energy transmitted to the first detector is 1%;
and/or the beam splitting ratio of the second optical fiber coupler to the third optical fiber coupler is 1:1.
9. The distributed optical fiber temperature and acoustic wave sensing system of any of claims 1-7, wherein the sensing optical fiber is a single mode optical fiber.
10. The distributed optical fiber temperature and acoustic wave sensing system of any of claims 1-7, wherein the first detector is a balanced detector and/or the second and third detectors are single pixel linear APD detectors.
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