阅读说明：本技术 一种光纤温度监测装置 (Optical fiber temperature monitoring device ) 是由 靳宝全 牛子健 高妍 王宇 张红娟 刘昕 白清 王鹏飞 于 2021-08-02 设计创作，主要内容包括：本发明一种光纤温度监测装置,属于光纤温度监测装置技术领域；所要解决的技术问题为：提供一种光纤温度监测装置硬件结构的改进；解决上述技术问题采用的技术方案为：包括第一激光器、第二激光器、第一波分复用器、比值调节模块、数据采集模块、数据处理模块,第一激光器、第二激光器的输出端分别连接至第一波分复用器的a、b输入端,第一波分复用器将接收到激光耦合到同一根光纤中,将耦合的激光输出到比值调节模块的输入端,比值调节模块将耦合的激光经过比值调节后输出至数据采集模块的输入端；数据采集模块将采集到的数据从数据采集模块的输出端输出至数据处理模块；数据处理模块将采集到的数据进行信号处理；本发明应用于光纤温度监测。(The invention relates to an optical fiber temperature monitoring device, belonging to the technical field of optical fiber temperature monitoring devices; the technical problem to be solved is as follows: the improvement of the hardware structure of the optical fiber temperature monitoring device is provided; the technical scheme for solving the technical problems is as follows: the device comprises a first laser, a second laser, a first wavelength division multiplexer, a ratio adjusting module, a data acquisition module and a data processing module, wherein the output ends of the first laser and the second laser are respectively connected to the input ends a and b of the first wavelength division multiplexer, the first wavelength division multiplexer couples received laser to the same optical fiber and outputs the coupled laser to the input end of the ratio adjusting module, and the ratio adjusting module adjusts the ratio of the coupled laser and outputs the laser to the input end of the data acquisition module; the data acquisition module outputs the acquired data to the data processing module from the output end of the data acquisition module; the data processing module carries out signal processing on the acquired data; the invention is applied to optical fiber temperature monitoring.)

1. An optical fiber temperature monitoring device, characterized in that: the device comprises a first laser (1), a second laser (2), a first wavelength division multiplexer (3), a ratio adjusting module, a data acquisition module (17) and a data processing module (18), wherein the output end of the first laser (1) is connected to the input end a of the first wavelength division multiplexer (3), the output end of the second laser (2) is connected to the input end b of the first wavelength division multiplexer (3), the first wavelength division multiplexer (3) couples the received laser of the first laser (1) and the second laser (2) into the same optical fiber, the c output end of the first wavelength division multiplexer (3) outputs the coupled laser to the input end of the ratio adjusting module, the ratio adjusting module is provided with ratio demodulation based on the ratio of backward scattering light to the backward scattering Stokes light intensity and ratio demodulation based on the coexistence of the ratio of the scattering Stokes light to the anti-Stokes light intensity, the ratio adjusting module is used for outputting the coupled laser to the input end of the data acquisition module (17) after the ratio adjustment;

the data acquisition module (17) acquires data at a set sampling rate and outputs the acquired data to the data processing module (18) from the output end of the data acquisition module (17);

the data processing module (18) carries out filtering, denoising, amplitude demodulation and phase demodulation signal processing on the acquired data, and displays the demodulated external signals in real time.

2. The optical fiber temperature monitoring device according to claim 1, wherein: the ratio adjusting module comprises a first optical fiber coupler (4), a second optical fiber coupler (5), an acousto-optic modulator (6), a signal generator (7), a semiconductor optical amplifier (8), an erbium-doped optical fiber amplifier (9), a circulator (10), a sensing optical fiber (11), a second wavelength division multiplexer (12), a first avalanche photodiode (13), a second avalanche photodiode (14), a photoelectric detector (15) and a balance photoelectric detector (16), and a specific optical path structure is as follows:

the c output end of the first wavelength division multiplexer (3) is connected to the a input end of the first optical fiber coupler (4); the output end b of the first optical fiber coupler (4) is connected to the input end a of the second optical fiber coupler (5), and the output end c of the first optical fiber coupler (4) is connected to the input end of the acousto-optic modulator (6);

the output end of the acousto-optic modulator (6) is connected to the input end a of the semiconductor optical amplifier (8); the output end of the signal generator (7) is connected to the b input end of the semiconductor optical amplifier (8); the output end c of the semiconductor optical amplifier (8) is connected to the input end of the erbium-doped optical fiber amplifier (9); the output end of the erbium-doped fiber amplifier (9) is connected to the input end a of the circulator (10);

the output end b of the circulator (10) is connected to the input end of the sensing optical fiber (11), and the output end c of the circulator (10) is connected to the input end a of the second wavelength division multiplexer (12); the b output end of the second wavelength division multiplexer (12) is connected to the b input end of the second optical fiber coupler (5), the c output end of the second wavelength division multiplexer (12) is connected to the input end of the first avalanche photodiode (13), the d output end of the second wavelength division multiplexer (12) is connected to the input end of the second avalanche photodiode (14), and the e output end of the second wavelength division multiplexer (12) is connected to the input end of the photodetector (15);

the c output end of the second optical fiber coupler (5) is connected to the a input end of the balanced photoelectric detector (16), and the d output end of the second optical fiber coupler (5) is connected to the b input end of the balanced photoelectric detector (16);

the c output end of the balanced photoelectric detector (16) is connected to the a input end of the data acquisition module (17); the output end of the first avalanche photodiode (13) is connected to the b input end of the data acquisition module (17); the output end of the second avalanche photodiode (14) is connected to the c input end of the data acquisition module (17); the output end of the photoelectric detector (15) is connected to the d input end of the data acquisition module (17).

3. An optical fiber temperature monitoring device according to claim 2, wherein: the first laser (1) specifically adopts a 1550nm laser, and emits continuous narrow-linewidth laser with the center wavelength of 1550nm to enter an a input end of the first wavelength division multiplexer (3);

the second laser (2) is a 1310nm laser, and emits pulse light with a central wavelength of 1310nm to enter the input end b of the first wavelength division multiplexer (3).

4. A fiber optic temperature monitoring device according to claim 3, wherein: a module for detecting the breakpoint of the optical fiber is arranged in the data processing module (18), specifically, OTDR fault detection and coherent detection vibration detection are adopted for breakpoint detection, the data processing module (18) demodulates the acquired signal with 1310nm wavelength, and finds the initial position of the breakpoint through the fei nieer reflection peak fed back;

if the breakpoint is detected, the influence of vibration is exerted on the optical fiber near the position, the data collected from the balanced photoelectric detector (16) are divided into two groups by the data processing module (18) according to different pulse widths, differential operation is carried out in a time domain, and a more accurate breakpoint position is further found according to the fact that the amplitude of the vibration signal restored before and after the breakpoint has a large difference, so that the optical fiber at the damaged position is repaired.

5. An optical fiber temperature monitoring device according to claim 2, wherein: the first optical fiber coupler (4) divides laser into two parts of 1% and 99%, the b output end of the first optical fiber coupler (4) outputs 1% of detection light to the a input end of the second optical fiber coupler (5), and the c output end of the first optical fiber coupler (4) outputs 99% of detection light to the input end of the acousto-optic modulator (6).

Technical Field

The invention discloses an optical fiber temperature monitoring device, and belongs to the technical field of optical fiber temperature monitoring devices.

Background

In recent years, many large-scale power failure and fire accidents caused by power equipment failure have occurred domestically due to lack of effective monitoring means. The distributed optical fiber Raman temperature sensing system (DTS) is wide in monitoring range, sensing optical fibers are easy to lay, and the distributed optical fiber Raman temperature sensing system has the characteristics of corrosion resistance, small size, no electromagnetic interference, electric insulation and the like, and is very suitable for solving the problems of real-time monitoring of temperature, fault location, hidden danger discovery and the like in cable transmission.

The distributed optical fiber Raman temperature sensing (DTS) has the basic principle that the temperature-sensitive characteristic of an anti-Stokes Raman scattering signal generated when pulse laser is transmitted in an optical fiber and a positioning method of an Optical Time Domain Reflectometry (OTDR) are combined to realize distributed temperature sensing detection along the optical fiber and accurate positioning of abnormal temperature points.

The traditional temperature demodulation scheme mainly comprises two demodulation methods, namely single-channel temperature demodulation and double-channel temperature demodulation, wherein the effect of the double-channel temperature demodulation is far better than that of the single-channel temperature demodulation. The traditional distributed optical fiber Raman temperature measurement sensing collection and processing is sensing information of backward Raman scattering light, the light intensity of the backward Raman scattering light is one ten-thousandth of that of incident light, the light intensity of Stokes scattering light is far greater than that of anti-Stokes scattering light, and the problems of difficulty in signal collection, poor temperature demodulation precision and the like are caused. Therefore, improving the real-time performance and optimizing the traditional dual-channel temperature demodulation scheme still remains the problem to be solved by the distributed fiber raman temperature sensing system.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to solve the technical problems that: an improvement of the hardware structure of the optical fiber temperature monitoring device is provided.

In order to solve the technical problems, the invention adopts the technical scheme that: an optical fiber temperature monitoring device comprises a first laser, a second laser, a first wavelength division multiplexer, a ratio adjusting module, a data acquisition module and a data processing module, the output end of the first laser is connected to the a input end of the first wavelength division multiplexer, the output end of the second laser is connected to the b input end of the first wavelength division multiplexer, the first wavelength division multiplexer couples the received laser light of the first laser and the second laser into the same optical fiber, the output end c of the first wavelength division multiplexer outputs the coupled laser to the input end of a ratio adjusting module, the ratio adjusting module is internally provided with ratio adjustment for realizing the coexistence of ratio demodulation of backward Rayleigh scattering light and backward Raman scattering-based anti-Stokes light intensity and ratio demodulation of Raman scattering-based Stokes light and anti-Stokes light intensity, and the ratio adjusting module outputs the coupled laser to the input end of a data acquisition module after the ratio adjustment;

the data acquisition module acquires data at a set sampling rate and outputs the acquired data to the data processing module from the output end of the data acquisition module;

the data processing module carries out filtering, denoising, amplitude demodulation and phase demodulation signal processing on the acquired data, and displays the demodulated external signals in real time.

The ratio adjusting module comprises a first optical fiber coupler, a second optical fiber coupler, an acousto-optic modulator, a signal generator, a semiconductor optical amplifier, an erbium-doped optical fiber amplifier, a circulator, a sensing optical fiber, a second wavelength division multiplexer, a first avalanche photodiode, a second avalanche photodiode, a photoelectric detector and a balanced photoelectric detector, and the specific optical path structure is as follows:

the c output end of the first wavelength division multiplexer is connected to the a input end of the first optical fiber coupler; the output end b of the first optical fiber coupler is connected to the input end a of the second optical fiber coupler, and the output end c of the first optical fiber coupler is connected to the input end of the acousto-optic modulator;

the output end of the acousto-optic modulator is connected to the a input end of the semiconductor optical amplifier; the output end of the signal generator is connected to the b input end of the semiconductor optical amplifier; the output end c of the semiconductor optical amplifier is connected to the input end of the erbium-doped optical fiber amplifier; the output end of the erbium-doped fiber amplifier is connected to the input end a of the circulator;

the output end b of the circulator is connected to the input end of the sensing optical fiber, and the output end c of the circulator is connected to the input end a of the second wavelength division multiplexer; the output end b of the second wavelength division multiplexer is connected to the input end b of the second optical fiber coupler, the output end c of the second wavelength division multiplexer is connected to the input end of the first avalanche photodiode, the output end d of the second wavelength division multiplexer is connected to the input end of the second avalanche photodiode, and the output end e of the second wavelength division multiplexer is connected to the input end of the photodetector;

the output end c of the second optical fiber coupler is connected to the input end a of the balanced photoelectric detector, and the output end d of the second optical fiber coupler is connected to the input end b of the balanced photoelectric detector;

the output end c of the balanced photoelectric detector is connected to the input end a of the data acquisition module; the output end of the first avalanche photodiode is connected to the b input end of the data acquisition module; the output end of the second avalanche photodiode is connected to the c input end of the data acquisition module; and the output end of the photoelectric detector is connected to the d input end of the data acquisition module.

The first laser specifically adopts a 1550nm laser, and emits continuous narrow-linewidth laser with the central wavelength of 1550nm to enter an a input end of the first wavelength division multiplexer;

the second laser is a 1310nm laser, and pulse light with 1310nm center wavelength is emitted to enter the b input end of the first wavelength division multiplexer.

The data processing module is internally provided with a module for detecting the breakpoint of the optical fiber, and specifically adopts OTDR fault detection and coherent detection vibration detection to detect the breakpoint, demodulates the acquired 1310nm wavelength signal, and finds the initial position of the breakpoint through the feedback Fresnel reflection peak;

if the breakpoint is detected, the influence of vibration is exerted on the optical fiber near the position, the data acquired from the balanced photoelectric detector are divided into two groups by the data processing module according to different pulse widths, differential operation is carried out in a time domain, and a more accurate breakpoint position is further found according to the fact that the amplitude of the vibration signal restored before and after the breakpoint has a larger difference, so that the optical fiber at the damaged position is repaired.

The first optical fiber coupler divides laser into two parts of 1% and 99%, the output end b of the first optical fiber coupler outputs 1% of detection light to the input end a of the second optical fiber coupler, and the output end c of the first optical fiber coupler outputs 99% of detection light to the input end of the acousto-optic modulator.

Compared with the prior art, the invention has the beneficial effects that: the invention improves the traditional double-channel temperature demodulation scheme, and adopts a demodulation scheme based on the ratio of the anti-Stokes light intensity of backward Rayleigh scattering light and Raman scattering. By means of the characteristic that the proportion of the Rayleigh scattered light in backward scattered light is large and the Rayleigh scattered light is insensitive to temperature, the sensitivity and the precision of the system are effectively improved.

The invention adopts a scheme that the ratio demodulation of the anti-Stokes light intensity based on the backward Rayleigh scattering light and the backward Raman scattering coexists with the traditional ratio demodulation of the Stokes light and the anti-Stokes light intensity based on the Raman scattering. Because Rayleigh scattering light is sensitive to vibration, under the condition of no external disturbance, an improved demodulation scheme of the ratio of the backward Rayleigh scattering light to the backward Raman scattering anti-Stokes light intensity is adopted for temperature demodulation; and in the presence of external disturbance, demodulating by adopting a traditional Raman scattering-based Stokes light and anti-Stokes light intensity ratio demodulation scheme. In practical application, a proper scheme can be selected according to the situation of the external environment.

The invention integrates the traditional OTDR fault detection technology and the coherent detection vibration monitoring technology, realizes the rapid detection and accurate positioning of the fiber breakage damage fault, and further finds more accurate breakpoint position through the larger difference of the vibration signal amplitude restored before and after the breakpoint. The system provides direct reference for diagnosing, positioning and effectively repairing fault points, and has the advantages of simple structure, convenience in operation, strong anti-electromagnetic interference capability and distributed detection.

Drawings

The invention is further described below with reference to the accompanying drawings:

FIG. 1 is a schematic structural view of the present invention;

in the figure: 1. a first laser; 2. a second laser; 3. a first wavelength division multiplexer; 4. a first fiber coupler; 5. a second fiber coupler; 6. an acousto-optic modulator; 7. a signal generator; 8. a semiconductor optical amplifier; 9. an erbium-doped fiber amplifier; 10. a circulator; 11. a sensing optical fiber; 12. a second wavelength division multiplexer; 13. a first avalanche photodiode; 14. a second avalanche photodiode; 15. a photodetector; 16. a balanced photodetector; 17. a data acquisition module; 18. and a data processing module.

Detailed Description

As shown in fig. 1, the optical fiber temperature monitoring device of the present invention includes: the device comprises a 1550nm first laser 1, a 1310nm second laser 2, a first wavelength division multiplexer 3, a first optical fiber coupler 4, a second optical fiber coupler 5, an acousto-optic modulator 6, a signal generator 7, a semiconductor optical amplifier 8, an erbium-doped optical fiber amplifier 9, a circulator 10, a sensing optical fiber 11, a second wavelength division multiplexer 12, a first avalanche photodiode 13, a second avalanche photodiode 14, a photodetector 15, a balanced photodetector 16, a data acquisition module 17 and a data processing module 18. Fig. 1 is a schematic structural diagram of an optical fiber temperature monitoring device according to the present invention, and an embodiment of the present invention is described below with reference to fig. 1.

The 1550nm first laser 1 emits continuous narrow linewidth laser with the central wavelength of 1550nm, and the continuous narrow linewidth laser enters an a input end of the first wavelength division multiplexer 3; the 1310nm second laser 2 emits pulse light with a central wavelength of 1310nm, and the pulse light enters the input end b of the first wavelength division multiplexer 3; the first wavelength division multiplexer 3 couples the received 1550nm and 1310nm laser to the same optical fiber, and the c output end of the first wavelength division multiplexer 3 outputs the coupled laser to the a input end of the first optical fiber coupler 4; the first optical fiber coupler 4 divides laser into two parts of 1% and 99%, the output end b of the first optical fiber coupler 4 outputs 1% of detection light 1 to the input end a of the second optical fiber coupler 5, and the output end c of the first optical fiber coupler 4 outputs 99% of detection light 2 to the input end of the acousto-optic modulator 6; the acousto-optic modulator 6 makes the continuous detection light generate frequency shift, and the modulated detection light is output to the a input end of the semiconductor optical amplifier 8 from the output end of the acousto-optic modulator 6; the signal generator 7 is connected with the b input end of the semiconductor optical amplifier 8 and provides a driving pulse signal for the semiconductor optical amplifier, and the pulse light which is modulated and amplified into pulse light with the pulse width of 100ns enters the a input end of the circulator 10 after being subjected to power amplification through the erbium-doped optical fiber amplifier 9; the detection pulse light is output to the sensing optical fiber 11 through a port b of the circulator 10; the backward scattered light returning light generated by the sensing optical fiber 11 passes through a port b of the circulator 10 and is output to an input end a of the second wavelength division multiplexer 12 through an output end c of the circulator 10; the b output end of the second wavelength division multiplexer 12 outputs the filtered laser light with 1310nm wavelength to the b input end of the second optical fiber coupler 5, the c output end of the second wavelength division multiplexer 12 outputs the filtered laser light with 1450nm wavelength to the input end of the first avalanche photodiode 13, the d output end of the second wavelength division multiplexer 12 outputs the filtered laser light with 1660nm wavelength to the input end of the second avalanche photodiode 14, and the e output end of the second wavelength division multiplexer 12 outputs the filtered laser light with 1550nm wavelength to the input end of the photodetector 15; the second optical fiber coupler 5 divides the laser into two parts of 50% and 50%, the c output end of the second optical fiber coupler 5 outputs one 50% of detection light to the a input end of the balanced photoelectric detector 16, and the d output end of the second optical fiber coupler 5 outputs the other 50% of detection light to the b input end of the balanced photoelectric detector 16; the first avalanche photodiode 13 converts the optical signal into an electrical signal and outputs the electrical signal to the b input end of the data acquisition module 17; the first avalanche photodiode 14 converts the optical signal into an electrical signal and outputs the electrical signal to the c input end of the data acquisition module 17; the photoelectric detector 15 converts the optical signal into an electrical signal and outputs the electrical signal to the d input end of the data acquisition module 17; the balanced photoelectric detector 16 converts the optical signal into an electrical signal and outputs the electrical signal to an input end a of the data acquisition module 17; the data acquisition module 17 acquires data at a sampling rate of 100MSPS, and outputs the acquired data from an e output end of the data acquisition module 17 to the data processing module 18; the data processing module 18 performs signal processing such as filtering, denoising, amplitude demodulation and phase demodulation on the acquired data, and displays the demodulated external signal in real time.

Before temperature monitoring, in order to prevent the optical fiber from being damaged and broken, the system uses OTDR fault detection technology and coherent detection vibration detection technology to detect the breakpoint, the data processing module 18 demodulates the acquired 1310nm wavelength signal, and finds the approximate position of the breakpoint through the feedback fresnel reflection peak. If the breakpoint is detected, a vibration influence is exerted on the optical fiber near the position, the data processing module 18 divides the data collected from the balanced photoelectric detector 16 into two groups according to different pulse widths, differential operation is performed in a time domain, and a more accurate breakpoint position is further found according to the fact that the amplitude of the vibration signal restored before and after the breakpoint has a large difference, so that the optical fiber at the damaged position is repaired in time.

And after the self-diagnosis of the system is finished, adopting different schemes to detect the temperature according to different external environments.

Under the condition of external disturbance, the system adopts a traditional dual-channel temperature demodulation scheme, and the data processing module 18 demodulates and denoises the acquired Raman Stokes signals with the wavelength of 1660nm and the acquired Raman anti-Stokes signals with the wavelength of 1450nm to obtain the real-time temperature.

Under the condition of no external disturbance, the system adopts an improved dual-channel temperature demodulation scheme, and the data processing module 18 carries out temperature demodulation and denoising processing on the collected Rayleigh signal with the wavelength of 1550nm and the collected Raman anti-Stokes signal with the wavelength of 1450nm, so that the temperature measurement precision and the stability of the system are improved.

The optical fiber temperature monitoring device improves the system on the basis of the traditional double-channel demodulation, and adopts a demodulation scheme based on the ratio of the intensity of the backward Rayleigh scattering light to the intensity of the anti-Stokes light of Raman scattering. The demodulation method demodulates the anti-Stokes curve of Raman scattering by adopting the Rayleigh scattering curve in the optical fiber, the Rayleigh scattering accounts for a large proportion of backward scattering light, and Rayleigh signals are not sensitive to temperature, so that the power at the reference temperature and the power at the demodulation temperature are approximately the same. The temperature demodulation is carried out by replacing the Stokes reflected light of the backward Raman scattering in the traditional scheme with the backward Rayleigh scattering light, so that the system is more stable, and the sensitivity and the precision are more accurate. And the traditional OTDR fault detection technology and the coherent detection vibration monitoring technology are fused, pulsed light is continuously emitted in a detection mode, the distance between the fiber break point and the joint is measured according to the calculation result of a backscattering curve, and a more accurate break point position is further found according to the fact that the amplitude of the vibration signal restored before and after the break point has larger difference. Therefore, the optical fiber temperature monitoring device can provide direct reference for solving the problems of real-time temperature monitoring, fault location, hidden danger discovery and the like in cable transmission, and has the advantages of simple structure, simplicity and convenience in operation, strong anti-electromagnetic interference capability and distributed detection.

It should be noted that, regarding the specific structure of the present invention, the connection relationship between the modules adopted in the present invention is determined and can be realized, except for the specific description in the embodiment, the specific connection relationship can bring the corresponding technical effect, and the technical problem proposed by the present invention is solved on the premise of not depending on the execution of the corresponding software program.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.