CN102589593B - Phase sensitive type optical time domain reflection sensing system and method - Google Patents
Phase sensitive type optical time domain reflection sensing system and method Download PDFInfo
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Abstract
The invention provides a phase sensitive type optical time domain reflection sensing system which has double light sources and a large dynamic range, and a phase sensitive type optical time domain reflection sensing system method. The phase sensitive type optical time domain reflection sensing system comprises a first light source and a second light source; the first light source and the second light source are controlled by a main control unit to emit continuous narrow-line wide lasers with the wavelengths of lambda1 and lambda2; and the first light source emits a low-power light beam and the second light source emits a high-power light beam. Two beams of the light are combined into one beam by a coupler; and the continuous light is modulated by an acoustic optical modulator to be emitted into a sensing optical fiber in a pulse state. The lights with different wavelengths in a returned Rayleigh scattering signal are filtered through a filtering sheet and are detected by two detectors, respectively. A signal collecting and processing part is used for processing and calculating detected signals. According to the phase sensitive type optical time domain reflection sensing system and the phase sensitive type optical time domain reflection sensing method, a light signal detection difficulty in the large dynamic range can be better solved through detecting different distances by the light beams with different powers; and a detection distance of a distribution type optical fiber sensor is increased under the precondition of not increasing the processing time.
Description
Technical field
The present invention relates to a kind of sensory field of optic fibre, relate to especially and arrive phase sensitive type optical time domain reflection sensing system and the method for great dynamic range.
Background technology
Phase sensitive type optical time domain reflection instrument (Φ-OTDR) obtains disturbing signal by surveying the variation of the interference signal of backward Rayleigh scattering light, and by the echo time to state event location.The concern that it is continued abroad always and research, as far back as 1993, H.F.Taylor just proposed phase sensitive formula Φ-OTDR technology, by improving the interference effect of backward Rayleigh scattering light, the sensitivity that acquisition is higher than common OTDR, is suitable for surveying faint disturbing signal.Until 2005, the people such as J.C.Juarez adopt Er-doped fiber to form fiber laser in conjunction with F-P chamber, and Output of laser live width is less than 3KHz, can on the optical fiber of 12km, detect people's ground invasion situation and can locate, and monitoring for perimeter alarm.
In recent years, appearance along with super narrow-band light source technology, make Φ-OTDR technology be continued development, Φ-OTDR technology based on super narrow-band light source has that detection sensitivity is high, system signal process simple, measuring speed is fast, accurate positioning, measuring distance is long, signal to noise ratio (S/N ratio) is high, low cost and other advantages, therefore in safety protection technique, becomes a kind of competitive selection.
Relevant with the pulsed light power of injection fibre due to the distance sensing of Φ-OTDR system, the distance sensing that improve system will increase pulse power.But when distance sensing is long, the backward Rayleigh scattering signal of optical fiber has very large dynamic range, with general single mode fiber loss 0.2dB/km, calculate, when transmission range surpasses 100km, light intensity back and forth loss surpasses 40dB.This research with regard to the phase sensitive type optical time domain reflection sensing system for great dynamic range has brought many difficulties, how to improve its dynamic range and measures length, in some patent, proposes certain methods.For example in patent CN1330265A, by controlling light source, launch different capacity pulsed light, survey the scattered signal that different distance goes out.Each pulse of this method can only be surveyed a segment distance, complete light path has been surveyed, and needs a plurality of pulses, has greatly improved Measuring Time, to the not high occasion of requirement of real-time, is operable.A kind of method that has proposed timesharing reception in patent CN101660944A and CN101603856A improves the dynamic range of end of probe, both by the scattered light in the recurrence interval being divided into the different time periods, with different detectors, received, then by the signal integration receiving.This mode needs very accurate design and strict control, is also not suitable for practical application.
Summary of the invention
In order to solve deficiency of the prior art, the invention provides a kind of phase sensitive type optical time domain reflection sensing system and method for great dynamic range, can realize great dynamic range length apart from light signal collection and measurement.
The object of the invention is to be achieved by the following technical programs:
Phase sensitive type optical time domain reflection sensing system, comprises light source, sensor fibre; Described sensor-based system further comprises:
The first light source, described the first light source is λ for emission wavelength
1, power is P
1light,
Secondary light source, described secondary light source is λ for emission wavelength
2, λ
2≠ λ
1, power is P
2, P
2≠ P
1light;
The first coupling mechanism, described the first coupling mechanism enters described sensor fibre for the optically-coupled that described the first light source and secondary light source are sent;
The second coupling mechanism, described coupling mechanism is for being coupled into spectral module by the scattered light signal of sensor fibre;
Spectral module, described spectral module is for isolating and correspond respectively to wavelength X from the light signal receiving
2, λ
2the scattered light signal of incident light, and be sent to detector module;
Detector module, described detector module is used for the scattered light signal after separation to be converted to first signal, secondary signal, and is sent to signal processing module;
Signal processing module, described signal processing module is for the treatment of the first signal receiving and secondary signal, thereby knows the perception information of described sensor fibre.
According to above-mentioned distributed optical fiber sensing system, preferably, described spectral module is grating or wave filter or prism.
According to above-mentioned distributed optical fiber sensing system, preferably, the light wavelength λ that described the first light source sends
1for 1310nm, the light wavelength λ that secondary light source sends
2for 1550nm.
According to above-mentioned distributed optical fiber sensing system, preferably, described light source is light-pulse generator.
According to above-mentioned distributed optical fiber sensing system, alternatively, described sensor-based system further comprises:
Photomodulator, described photomodulator is modulated to pulsed light for the continuous light that described light source is sent;
Driver module, the output terminal of described driver module connects described photomodulator;
Described light source is continuous light source.
Object of the present invention is also achieved by the following technical programs:
Phase sensitive type optical time domain reflection method for sensing, said method comprising the steps of:
(A1) the different incident pulse light of two of different capacity, different wave length bundles enters in the sensor fibre of perception external information, and the scattered light of generation enters coupling mechanism;
(A2) coupling mechanism is coupled into spectral module by described scattered light;
(A3) spectral module is isolated and is corresponded respectively to described different incident pulse scattering of light light signal, and is converted to first signal and secondary signal by detector module;
(A4) signal processing module is processed first signal and the secondary signal receiving, thereby knows the perception information of described sensor fibre.
According to above-mentioned method, alternatively, described method is further comprising the steps:
(B1) continuous light that light source sends is modulated to pulsed light.
According to above-mentioned method, preferably, described light source is narrow linewidth laser.
According to above-mentioned method, preferably, described different incident pulse light wavelengths are respectively: λ
1for 1310nm, λ
2for 1550nm.
According to above-mentioned method, alternatively, described method is further comprising the steps:
(C1) judge module judges whether vibration and/or temperature that described signal processing module sends exceed threshold value, if surpass threshold value, prompting is reported to the police.
Compared with prior art, the present invention has following beneficial effect:
The present invention adopts two light source combinations, solves the long distance measurement difficult problem of high dynamic range, for detection range reaches hundred kilometers of above distributed optical fiber vibration sensor development and production, provides foundation and reference.
Accompanying drawing explanation
With reference to accompanying drawing, disclosure of the present invention will be easier to understand.Those skilled in the art hold intelligible: these accompanying drawings are only for illustrating technical scheme of the present invention, and are not intended to protection scope of the present invention to be construed as limiting.In figure:
Fig. 1 is the basic block diagram of the distributed optical fiber sensing system of the embodiment of the present invention 1;
Fig. 2 is the process flow diagram of the method for the embodiment of the present invention 1;
Fig. 3 is the basic block diagram of the distributed optical fiber sensing system of the embodiment of the present invention 2;
Fig. 4 is the process flow diagram of the method for the embodiment of the present invention 2.
Embodiment:
Fig. 1-4 and following declarative description optional embodiment of the present invention to instruct those skilled in the art how to implement and to reproduce the present invention.In order to instruct technical solution of the present invention, simplified or omitted some conventional aspects.Those skilled in the art should understand that be derived from the modification of these embodiments or replace will be within the scope of the invention.Those skilled in the art should understand that following characteristics can combine to form a plurality of modification of the present invention in every way.Thus, the present invention is not limited to following optional embodiment, and only by claim and their equivalent, is limited.
Embodiment 1:
Fig. 1 has schematically provided the basic block diagram of the phase sensitive type optical time domain reflection sensing system of the embodiment of the present invention, and as shown in Figure 1, described sensor-based system comprises:
The first light source and secondary light source, for launching the pulsed light of different wave length, different capacity, described light source can adopt laser instrument, as the pulse type semiconductor laser of narrow linewidth; Preferably, the outgoing wavelength X of the first light source
1for 1310nm, power is lower, in 10dBm left and right, for surveying short distance signal; The outgoing wavelength X of secondary light source
2for 1550nm, power is higher, surpasses 30dBm, for surveying long distance signal;
The first coupling mechanism, described the first coupling mechanism enters described sensor fibre for the optically-coupled that described the first light source and secondary light source are sent;
The second coupling mechanism, described coupling mechanism is for entering spectral module by the Rayleigh scattering light signal coupling of sensor fibre; Preferably, in the present embodiment, the first coupling mechanism and the second coupling mechanism are merged into a coupling mechanism.
Spectral module, described spectral module is for isolating and correspond respectively to wavelength X from the light signal receiving
2, λ
2the Rayleigh scattering light signal of incident light, and be sent to detector module; Preferably, described spectral module is grating or wave filter or prism, and the present embodiment adopts two wave filters to realize light splitting.
Detector module, described detector module is used for the Rayleigh scattering light signal after separation to be converted to first signal, secondary signal, and is sent to signal processing module;
Signal processing module, described signal processing module is for the treatment of the first signal receiving and secondary signal, thereby knows the perception information of described sensor fibre, as vibration, temperature.
Fig. 2 has schematically provided and has utilized above-mentioned sensor-based system to carry out phase sensitive type optical time domain reflection method for sensing, as shown in Figure 2, said method comprising the steps of:
(A1) the different incident pulse light of two of different capacity, different wave length bundles enters in the sensor fibre of perception external information, and the Rayleigh scattering light of generation enters coupling mechanism;
(A2) coupling mechanism is coupled into spectral module by described Rayleigh scattering light;
(A3) spectral module is isolated the Rayleigh scattering light signal that corresponds respectively to described different incident pulse light, and is converted to first signal and secondary signal by detector module;
(A4) signal processing module is processed first signal and the secondary signal receiving, thereby knows the perception information of described sensor fibre.
The benefit reaching according to embodiment 1 is: power, the wavelength of the first light source and secondary light source are different, and the method that this segmentation receives can solve the too high problem of dynamic range in long distance measurement, also can not make Measuring Time slack-off.
Embodiment 2:
Fig. 3 has schematically provided the basic block diagram of the phase sensitive type optical time domain reflection sensing system of the embodiment of the present invention, and as shown in Figure 3, described sensor-based system comprises:
The first light source and secondary light source, for launching the continuous light of different wave length, different capacity, described light source can adopt laser instrument, as the semiconductor laser of narrow linewidth; Preferably, the outgoing wavelength X of the first light source
1for 1310nm, power is lower, in 10dBm left and right, for surveying short distance signal; The outgoing wavelength X of secondary light source
2for 1550nm, power is higher, surpasses 30dBm, for surveying long distance signal;
The first coupling mechanism, described the first coupling mechanism enters photomodulator for the optically-coupled that described the first light source and secondary light source are sent;
Photomodulator, photomodulator is used for continuous light to be modulated into pulsed light, and is sent to the second coupling mechanism; Alternatively, described photomodulator adopts acousto-optic modulator; In the present embodiment, the extinction ratio of photomodulator requires to be greater than 55dB;
The second coupling mechanism, described coupling mechanism is used for described pulsed light to be coupled into sensor fibre, and the Rayleigh scattering light signal coupling in sensor fibre is entered to spectral module;
Spectral module, described spectral module is for isolating and correspond respectively to wavelength X from the light signal receiving
2, λ
2the Rayleigh scattering light signal of incident light, and be sent to detector module; Preferably, described spectral module is grating or wave filter or prism, and the present embodiment adopts two wave filters to realize light splitting.
Detector module, described detector module is used for the scattered light signal after separation to be converted to first signal, secondary signal, and is sent to signal processing module;
Signal processing module, described signal processing module is for the treatment of the first signal receiving and secondary signal, thereby knows the perception information of described sensor fibre, as vibration, temperature;
Judge module, described judge module judges whether vibration and/or temperature that described signal processing module sends exceed threshold value; Described judge module can adopt circuit or software to realize, and specific implementation is the state of the art, does not repeat them here.
Alarm module, when judgment result is that of described judge module is, the prompting of described alarm module is reported to the police, can employing sound, the pattern of light or electricity reports to the police.
Fig. 4 has schematically provided and has utilized above-mentioned sensor-based system to carry out phase sensitive type optical time domain reflection method for sensing, as shown in Figure 4, said method comprising the steps of:
(B1) together with the continuous light that the first light source sends with secondary light source is coupling in, and be modulated to pulsed light;
(A1) the different incident pulse light of two of different capacity, different wave length bundles enters in the sensor fibre of perception external information, and the Rayleigh scattering light of generation enters coupling mechanism;
(A2) coupling mechanism is coupled into spectral module by described Rayleigh scattering light;
(A3) spectral module is isolated the Rayleigh scattering light signal that corresponds respectively to described different incident pulse light, and is converted to first signal and secondary signal by detector module;
(A4) signal processing module is processed first signal and the secondary signal receiving, thereby knows the perception information of described sensor fibre;
(C1) judge module judges whether vibration and/or temperature that described signal processing module sends exceed threshold value, if surpass threshold value, points out alarm module to report to the police.
The benefit reaching according to embodiment 2 is: power, the wavelength of the first light source and secondary light source are different, and the method that this segmentation receives can solve the too high problem of dynamic range in long distance measurement, also can not make Measuring Time slack-off.
Claims (10)
1. a phase sensitive type optical time domain reflection sensing system, comprises light source, sensor fibre; It is characterized in that: described sensor-based system further comprises:
The first light source, described the first light source is λ for emission wavelength
1, power is P
1light,
Secondary light source, described secondary light source is λ for emission wavelength
2, λ
2≠ λ
1, power is P
2, P
2≠ P
1light;
The first coupling mechanism, described the first coupling mechanism is coupled into described sensor fibre for the light that described the first light source and secondary light source are sent simultaneously;
The second coupling mechanism, described coupling mechanism is for being coupled into spectral module by the scattered light signal of sensor fibre;
Spectral module, described spectral module is for isolating and correspond respectively to wavelength X from the light signal receiving
2, λ
2the scattered light signal of incident light, and be sent to detector module;
Detector module, described detector module is used for the scattered light signal after separation to be converted to first signal, secondary signal, and is sent to signal processing module;
Signal processing module, described signal processing module is for the treatment of the first signal receiving and secondary signal, thereby knows the perception information of described sensor fibre.
2. distributed optical fiber sensing system according to claim 1, is characterized in that: described spectral module is grating or wave filter or prism.
3. distributed optical fiber sensing system according to claim 1, is characterized in that: the light wavelength λ that described the first light source sends
1for 1310nm, the light wavelength λ that secondary light source sends
2for 1550nm.
4. distributed optical fiber sensing system according to claim 1, is characterized in that: described light source is light-pulse generator.
5. distributed optical fiber sensing system according to claim 1, is characterized in that: described sensor-based system further comprises:
Photomodulator, described photomodulator is modulated to pulsed light for the continuous light that described light source is sent;
Driver module, the output terminal of described driver module connects described photomodulator;
Described light source is continuous light source.
6. utilize distributed optical fiber sensing system to detect a method for vibration and temperature simultaneously, said method comprising the steps of:
(A1) the different incident pulse light of two of different capacity, different wave length bundles enters in the sensor fibre of perception external information simultaneously, and the scattered light of generation enters coupling mechanism;
(A2) coupling mechanism is coupled into spectral module by described scattered light;
(A3) spectral module is isolated and is corresponded respectively to described different incident pulse scattering of light light signal, and is converted to first signal and secondary signal by detector module;
(A4) signal processing module is processed first signal and the secondary signal receiving, thereby knows the perception information of described sensor fibre.
7. method according to claim 6, is characterized in that: described method is further comprising the steps:
(B1) continuous light that light source sends is modulated to pulsed light.
8. method according to claim 7, is characterized in that: described light source is narrow linewidth laser.
9. method according to claim 6, is characterized in that: described different incident pulse light wavelengths are respectively: λ
1for 1310nm, λ
2for 1550nm.
10. method according to claim 6, is characterized in that: described method is further comprising the steps:
(C1) judge module judges whether vibration and/or temperature that described signal processing module sends exceed threshold value, if surpass threshold value, prompting is reported to the police.
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| CN104422512B (en) * | 2013-09-02 | 2018-01-05 | 中国石油天然气集团公司 | Method for detecting vibration based on coherent light time domain reflection |
| CN104390693B (en) * | 2013-12-20 | 2018-08-21 | 上海波汇科技股份有限公司 | Link self diagnosis long-distance distributed optical fiber vibration monitors system |
| CN103808339B (en) * | 2014-02-13 | 2017-01-11 | 一诺仪器（中国）有限公司 | OTDR (optical time domain reflectometry) device and method based on multi-wavelength pulse optical signals |
| CN104457808A (en) * | 2014-12-24 | 2015-03-25 | 北京奥普科达科技有限公司 | Method and system for achieving phi-OTDR system long-distance monitoring |
| CN104897301A (en) * | 2015-06-10 | 2015-09-09 | 贵州电网公司信息通信分公司 | Distributed optical fiber temperature alarm |
| GB2547520B (en) * | 2015-12-18 | 2020-04-29 | Schlumberger Technology Bv | Non-linear interactions with backscattered light |
| US10359302B2 (en) | 2015-12-18 | 2019-07-23 | Schlumberger Technology Corporation | Non-linear interactions with backscattered light |
| CN107436175B (en) * | 2017-07-26 | 2019-05-10 | 南京大学 | Continuously distributed formula optical fiber vibration sensing device and method with wideband sensing function |
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| CN108507662B (en) * | 2018-03-14 | 2021-07-09 | 中国人民解放军国防科技大学 | Optical fiber distributed sensing method and device based on multi-wavelength double-optical pulse |
| CN108519147A (en) * | 2018-04-25 | 2018-09-11 | 浙江杰昆科技有限公司 | Multiple light courcess phase sensitive optical time domain reflectometer and its method |
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| CN109210385B (en) * | 2018-06-08 | 2020-10-20 | 王超凡 | Phase-OTDR (optical time Domain reflectometer) -based distributed optical fiber sensing system and method |
| CN108809411B (en) * | 2018-09-27 | 2024-01-26 | 国网河南省电力公司洛阳供电公司 | Double-light source emission structure of optical time domain emission instrument |
| CN110136375B (en) * | 2019-05-31 | 2020-12-15 | 太原理工大学 | Distributed optical fiber zone warning system |
| CN110793616A (en) * | 2019-10-25 | 2020-02-14 | 深圳第三代半导体研究院 | All-fiber distributed cable safety and reliability monitoring system |
| CN110986814B (en) * | 2019-12-11 | 2021-10-08 | 安捷光通科技成都有限公司 | Phase sensitive optical time domain reflection system with improved dynamic strain measurement range |
| CN111879436B (en) * | 2020-06-29 | 2022-05-13 | 太原理工大学 | Distributed optical fiber Raman temperature demodulation device and method based on double-pulse modulation |
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