CN203550977U - Injection-seeding BOTDR distributed optical fiber sensing system - Google Patents
Injection-seeding BOTDR distributed optical fiber sensing system Download PDFInfo
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- CN203550977U CN203550977U CN201320744610.3U CN201320744610U CN203550977U CN 203550977 U CN203550977 U CN 203550977U CN 201320744610 U CN201320744610 U CN 201320744610U CN 203550977 U CN203550977 U CN 203550977U
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Abstract
An injection-seeding BOTDR distributed optical fiber sensing system relates to the injection-seeding Brillouin optical time domain reflection technology and belongs to the technical field of non-scanning real-time distributed optical fiber sensing measurement, so as to solve the problems that according to the prior BOTDR system, the signal-to-noise ratio is low, the sensing distance is short, the structure of the BOTDA system is complicated, real-time measurement can not be carried out, and the fault detection is difficult. As broadband seed lights which cover the range of a Brillouin gain spectrum or a loss spectrum formed by pulse pumping lights in sensing optical fiber replace sweep frequency-type probing lights in the traditional BOTDA system, the sweep frequency process is avoided, real-time sensing can be realized, and fault detection can be completed under the condition of not increasing complexity of the system; and the structure is simple and concise, and in comparison with the single-end method of the BOTDR system, output of the sensing signals is more stable, the sensing precision is high, and the signal-to-noise ratio within 50 to 80km is improved to more than 10dB. The injection-seeding BOTDR distributed optical fiber sensing system is suitable for engineering application of the Brillouin fiber sensing.
Description
Technical field
The utility model relates to seed and injects Brillouin light time domain reflection technology, belongs to non-scanning type and measures in real time Distributed Optical Fiber Sensing Techniques field.
Background technology
In recent decades, the security and stability of national industry and energy supply comes into one's own all the more, and the health monitoring of infrastructure becomes a crucial ring.For this demand, possess the successional distributed optical fiber sensing system of the one-dimensional space and progressively grow up.Distributed optical fiber sensing system based on Brillouin scattering technology is monitored optical fiber temperature along the line and adaptability to changes is subject to extensive concern owing to possessing simultaneously.Current through engineering approaches comparatively proven technique is Brillouin light Time-Domain Technique: Brillouin light time domain reflection technology (BOTDR), Brillouin optical time domain analysis technology (BOTDA).
BOTDR system is based on spontaneous brillouin scattering principle, utilize back-scattering light and the time interval of pulsed light to extract the positional information (similar to the optical time domain reflectometer OTDR detecting for optical fiber) of event, utilize the frequency displacement of brillouin scattering signal and intensity to extract temperature and strain information.BOTDR system authority is simple, cost is lower, and measuring optical fiber temperature, stress information along the line possesses fault detection capability simultaneously in real time.Because the spontaneous brillouin scattering intensity as sensing channel in BOTDR system is extremely faint, signal to noise ratio (S/N ratio) lowly causes sensing accuracy lower, simultaneously distance sensing limited (common tens kilometers).
BOTDA system is based on stimulated Brillouin scattering (SBS) principle.Respectively injected pulse pump light and continuous probe light at optical fiber two ends, when both frequency differences are when in optical fiber, somewhere Brillouin shift equates,, there is energy transfer in generation stimulated Brillouin effect between the two.Frequency difference between continuous modulation two-laser, detects the detection light intensity being coupled out from one section of optical fiber simultaneously and is aided with OTDR technology, just can obtain each segment region of optical fiber corresponding frequency difference when energy shifts maximum, and then extract temperature and stress information.BOTDA system signal noise ratio is high, is easy to realize high precision, remote recording.
BOTDA system adopts double-end measurement and needs the polarized matching between pumping-detection or disturb inclined to one side processing, and complex structure, cost are higher; For mensuration brillouin gain, composing the necessary frequency sweep time causes BOTDA system to measure in real time; By spare system, cannot not complete fault detect.
Utility model content
The purpose of this utility model is in order to solve the exemplary shortcomings of the existing distributed optical fiber sensing system based on Brillouin: BOTDR system signal noise ratio is low, distance sensing is short; BOTDA system architecture is complicated, cannot measure in real time, fault detect difficulty.Provide a kind of seed to inject BOTDR distributed optical fiber sensing system.
Seed described in the utility model injects BOTDR distributed optical fiber sensing system and comprises narrow band fiber laser instrument 1, the first fiber coupler 2, pump light unit 3, optical fiber circulator 4, sensor fibre 5, fibre optic isolater 6, seed light module 7, Polarization Controller 8, the second fiber coupler 9, photodetector 10 and microwave lower frequency changer circuit 11, the output terminal of described narrow band fiber laser instrument 1 connects the input end of the first fiber coupler 2, the first output port 2-1 of the first fiber coupler 2 connects the input end of pump light unit 3, the output terminal of described pump light unit 3 connects the first port 4-1 of optical fiber circulator 4, the second port 4-2 of optical fiber circulator 4 connects one end of sensor fibre 5, the laser of seed light module 7 outputs enters the other end of sensor fibre 5 after fibre optic isolater 6, the 3rd port 4-3 of optical fiber circulator 4 connects the first input end mouth 9-1 of the second fiber coupler 9, the second output port 2-2 of the first fiber coupler 2 connects the optic fibre input end of Polarization Controller 8, the fiber-optic output of described Polarization Controller 8 connects the second input port 9-2 of the second fiber coupler 9, the laser of the output terminal output of the second fiber coupler 9 incides the input end of photodetector 10, the output terminal of photodetector 10 connects the input end of microwave lower frequency changer circuit 11, the signal output part of microwave lower frequency changer circuit 11 is the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system.
Described pump light unit 3 comprises Polarization Controller 3-1, intensity modulator 3-2, D.C. regulated power supply 3-3, arbitrary waveform signal generator 3-4 and Erbium-Doped Fiber Amplifier (EDFA) 3-5, the optic fibre input end of described Polarization Controller 3-1 connects the first output port 2-1 of the first fiber coupler 2, the light input end of the output terminal strength of joint modulator 3-2 of Polarization Controller 3-1, the light output end of described intensity modulator 3-2 connects the seed light input end of Erbium-Doped Fiber Amplifier (EDFA) 3-5, the output terminal of described Erbium-Doped Fiber Amplifier (EDFA) 3-5 is the output terminal of pump light unit 3, the power input of the electrical signal strength of joint modulator 3-2 of D.C. regulated power supply 3-3, the waveform signal input end of the waveform signal output terminal strength of joint modulator 3-2 of arbitrary waveform signal generator 3-4.
Described seed light module 7 comprises optical fiber filter 7-1 and wideband light source 7-2, and the laser of described wideband light source 7-2 output enters fibre optic isolater 6 through optical fiber filter 7-1 is laggard.
Described wideband light source 7-2 is C-band wideband light source.
Described sensor fibre 5 is standard single-mode fiber.
Described narrow band fiber laser instrument 1 is C-band Distributed Feedback Laser (distributed feedback laser).
Above-mentioned seed injects BOTDR distributed optical fiber sensing system and also comprises data acquisition and upper treatment circuit 12, and described data acquisition is connected the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system with the detectable signal input end of upper treatment circuit 12.
Seed described in the utility model injects BOTDR distributed optical fiber sensing system based on SBS principle, the brillouin gain spectrum forming in sensor fibre 5 with covering pulse pump light or the broadband seed light of loss spectra scope have replaced frequency sweep type in traditional B OTDA system and have surveyed light, thereby evaded frequency sweep process, can realize real-time sensing; Present embodiment is simple for structure, compare with single-ended method BOTDR system, can in the situation that not increasing system complexity, complete fault detect, and transducing signal output is more stable, can in 50-80km, provide the transducing signal of high s/n ratio, more than signal to noise ratio (S/N ratio) improves 10dB.Present embodiment combines the advantage of BOTDA and BOTDR, significant in the through engineering approaches application of Brillouin fiber optic sensing.
Accompanying drawing explanation
Fig. 1 is the structural representation that seed described in the utility model injects BOTDR distributed optical fiber sensing system.
Embodiment
Embodiment one: present embodiment is described in conjunction with Fig. 1, seed described in present embodiment injects BOTDR distributed optical fiber sensing system and comprises narrow band fiber laser instrument 1, the first fiber coupler 2, pump light unit 3, optical fiber circulator 4, sensor fibre 5, fibre optic isolater 6, seed light module 7, Polarization Controller 8, the second fiber coupler 9, photodetector 10 and microwave lower frequency changer circuit 11, the output terminal of described narrow band fiber laser instrument 1 connects the input end of the first fiber coupler 2, the first output port 2-1 of the first fiber coupler 2 connects the input end of pump light unit 3, the output terminal of described pump light unit 3 connects the first port 4-1 of optical fiber circulator 4, the second port 4-2 of optical fiber circulator 4 connects one end of sensor fibre 5, the laser of seed light module 7 outputs enters the other end of sensor fibre 5 after fibre optic isolater 6, the 3rd port 4-3 of optical fiber circulator 4 connects the first input end mouth 9-1 of the second fiber coupler 9, the second output port 2-2 of the first fiber coupler 2 connects the optic fibre input end of Polarization Controller 8, the fiber-optic output of described Polarization Controller 8 connects the second input port 9-2 of the second fiber coupler 9, the laser of the output terminal output of the second fiber coupler 9 incides the input end of photodetector 10, the output terminal of photodetector 10 connects the input end of microwave lower frequency changer circuit 11, the signal output part of microwave lower frequency changer circuit 11 is the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system.
Seed described in present embodiment injects BOTDR distributed optical fiber sensing system, and the laser of narrow band fiber laser instrument 1 output is divided into two-way through the first fiber coupler 2, and a road forms pulse pump light behind pump light unit 3; Described pulse pump light enters one end of sensor fibre 5 through optical fiber circulator 4, its power is controlled at below stimulated Brillouin scattering threshold value; Another road laser, after Polarization Controller 8, enters the second input port of the second fiber coupler 9 as local oscillator light.Seed light module 7 produces broad band laser, and described broad band laser, as seed light, enters the other end of sensor fibre through fibre optic isolater 6, and its spectral bandwidth covers brillouin gain spectrum or the loss spectra scope that pulse pump light forms in sensor fibre.Host computer in data acquisition and upper treatment circuit 12 sends trigger pip, and the pulse pump light that pump light unit 3 produces enters sensor fibre, data acquisition and 12 collections of timing simultaneously of upper treatment circuit; Spectral components frequency in the seed light that seed light module 7 produces is lower than the centre frequency of pulse pump light, frequency difference is the Brillouin shift of sensor fibre, and when polarization state is identical, this part spectral components in this seed light will obtain energy generation excited Brillouin and amplify, and produce enhancement mode transducing signal; Spectral components frequency in seed light is higher than the centre frequency of pulse pump light, the Brillouin shift that frequency difference is sensor fibre, and polarization state is when identical, and this part spectral components in seed light, by off-energy, produces loss-type transducing signal; Described enhancement mode or loss-type transducing signal, through the 3rd port output of optical fiber circulator, enter the first input end mouth of the second fiber coupler; Stokes brillouin scattering signal and local oscillator light close bundle through the second fiber coupler 9, by the second fiber coupler 9 output terminals, are exported, and enter photodetector 10; The high frequency electrical signal of photodetector 10 outputs is exported to data acquisition and treatment facility after 11 frequency conversions of microwave down conversion module, to obtain temperature and the strain information of a certain position of sensor fibre.
Seed described in present embodiment injects BOTDR distributed optical fiber sensing system based on SBS principle, the brillouin gain spectrum forming in sensor fibre 5 with covering pulse pump light or the broadband seed light of loss spectra scope have replaced frequency sweep type in traditional B OTDA system and have surveyed light, thereby evaded frequency sweep process, can realize real-time sensing; Present embodiment is simple for structure, compare with single-ended method BOTDR system, can in the situation that not increasing system complexity, complete fault detect, and transducing signal output is more stable, can in 50-80km, provide the transducing signal of high s/n ratio, more than signal to noise ratio (S/N ratio) improves 10dB.Present embodiment combines the advantage of BOTDA and BOTDR, significant in the through engineering approaches application of Brillouin fiber optic sensing.
Embodiment two: present embodiment is described in conjunction with Fig. 1, present embodiment is the seed described in embodiment one to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described pump light unit 3 comprises Polarization Controller 3-1, intensity modulator 3-2, D.C. regulated power supply 3-3, arbitrary waveform signal generator 3-4 and Erbium-Doped Fiber Amplifier (EDFA) 3-5, the optic fibre input end of described Polarization Controller 3-1 connects the first output port 2-1 of the first fiber coupler 2, the light input end of the output terminal strength of joint modulator 3-2 of Polarization Controller 3-1, the light output end of described intensity modulator 3-2 connects the seed light input end of Erbium-Doped Fiber Amplifier (EDFA) 3-5, the output terminal of described Erbium-Doped Fiber Amplifier (EDFA) 3-5 is the output terminal of pump light unit 3, the power input of the electrical signal strength of joint modulator 3-2 of D.C. regulated power supply 3-3, the waveform signal input end of the waveform signal output terminal strength of joint modulator 3-2 of arbitrary waveform signal generator 3-4.
Embodiment three: present embodiment is described in conjunction with Fig. 1, present embodiment is seed described in embodiment one to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described seed light module 7 comprises optical fiber filter 7-1 and wideband light source 7-2, and the laser of described wideband light source 7-2 output enters fibre optic isolater 6 through optical fiber filter 7-1 is laggard.
Embodiment four: present embodiment is the seed described in embodiment three to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described wideband light source 7-2 is C-band wideband light source.
In present embodiment, wideband light source 7-2 is that low degree of polarization, C-band and bandwidth are the light source of 1nm～40nm; The transmission of optical fiber filter 7-1 or reflectance spectrum are flat-top, and its transmission wave band is C-band, and bandwidth is 0.2GHz～3GHz.
The degree of polarization of the seed light that wideband light source 7-2 sends is 0%～5%, thereby has evaded the inclined to one side problem of disturbing.
Embodiment five: present embodiment is the seed described in embodiment one to four to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described sensor fibre 5 is standard single-mode fiber.
Embodiment six: present embodiment is the seed described in embodiment one to four to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described narrow band fiber laser instrument 1 is C-band Distributed Feedback Laser.
The bandwidth range of the laser that described C-band Distributed Feedback Laser sends is 1KHz～10MHz.
Embodiment seven: present embodiment is the seed described in embodiment one to be injected to the further restriction of BOTDR distributed optical fiber sensing system: described seed injects BOTDR distributed optical fiber sensing system and also comprises data acquisition and upper treatment circuit 12, and described data acquisition is connected the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system with the detectable signal input end of upper treatment circuit 12.
Data acquisition and upper treatment circuit 12 send trigger pip, and the pulse pump light that pump light unit 3 produces enters sensor fibre, data acquisition and 12 collections of timing simultaneously of upper treatment circuit; The high frequency electrical signal of photodetector 10 outputs is exported to data acquisition and upper treatment circuit 12 after 11 frequency conversions of microwave lower frequency changer circuit, signal after 12 pairs of frequency conversions of data acquisition and upper treatment circuit is processed, and obtains temperature and the strain information of a certain position of sensor fibre.
Claims (7)
1. seed injects BOTDR distributed optical fiber sensing system, it is characterized in that: it comprises narrow band fiber laser instrument (1), the first fiber coupler (2), pump light unit (3), optical fiber circulator (4), sensor fibre (5), fibre optic isolater (6), seed light module (7), Polarization Controller (8), the second fiber coupler (9), photodetector (10) and microwave lower frequency changer circuit (11), the output terminal of described narrow band fiber laser instrument (1) connects the input end of the first fiber coupler (2), first output port (2-1) of the first fiber coupler (2) connects the input end of pump light unit (3), the output terminal of described pump light unit (3) connects first port (4-1) of optical fiber circulator (4), second port (4-2) of optical fiber circulator (4) connects one end of sensor fibre (5), the laser of seed light module (7) output enters the other end of sensor fibre (5) after fibre optic isolater (6), the 3rd port (4-3) of optical fiber circulator (4) connects the first input end mouth (9-1) of the second fiber coupler (9), second output port (2-2) of the first fiber coupler (2) connects the optic fibre input end of Polarization Controller (8), the fiber-optic output of described Polarization Controller (8) connects second input port (9-2) of the second fiber coupler (9), the laser of the output terminal output of the second fiber coupler (9) incides the input end of photodetector (10), the output terminal of photodetector (10) connects the input end of microwave lower frequency changer circuit (11), the signal output part of microwave lower frequency changer circuit (11) is the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system.
2. seed according to claim 1 injects BOTDR distributed optical fiber sensing system, it is characterized in that: described pump light unit (3) comprises Polarization Controller (3-1), intensity modulator (3-2), D.C. regulated power supply (3-3), arbitrary waveform signal generator (3-4) and Erbium-Doped Fiber Amplifier (EDFA) (3-5), the optic fibre input end of described Polarization Controller (3-1) connects first output port (2-1) of the first fiber coupler (2), the light input end of the output terminal strength of joint modulator (3-2) of Polarization Controller (3-1), the light output end of described intensity modulator (3-2) connects the seed light input end of Erbium-Doped Fiber Amplifier (EDFA) (3-5), the output terminal of described Erbium-Doped Fiber Amplifier (EDFA) (3-5) is the output terminal of pump light unit (3), the power input of the electrical signal strength of joint modulator (3-2) of D.C. regulated power supply (3-3), the waveform signal input end of the waveform signal output terminal strength of joint modulator (3-2) of arbitrary waveform signal generator (3-4).
3. seed according to claim 1 injects BOTDR distributed optical fiber sensing system, it is characterized in that: described seed light module (7) comprises optical fiber filter (7-1) and wideband light source (7-2), the laser of described wideband light source (7-2) output enters fibre optic isolater (6) through optical fiber filter (7-1) is laggard.
4. seed according to claim 3 injects BOTDR distributed optical fiber sensing system, it is characterized in that: described wideband light source (7-2) is C-band wideband light source.
5. according to the seed described in claim 1,2,3 or 4, inject BOTDR distributed optical fiber sensing system, it is characterized in that: described sensor fibre (5) is standard single-mode fiber.
6. according to the seed described in claim 1 or 4, inject BOTDR distributed optical fiber sensing system, it is characterized in that: described narrow band fiber laser instrument (1) is C-band Distributed Feedback Laser.
7. seed according to claim 1 injects BOTDR distributed optical fiber sensing system, it is characterized in that: it also comprises data acquisition and upper treatment circuit (12), described data acquisition is connected the detectable signal output terminal that described seed injects BOTDR distributed optical fiber sensing system with the detectable signal input end of upper treatment circuit (12).
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604450A (en) * | 2013-11-22 | 2014-02-26 | 哈尔滨理工大学 | Seed injection BOTDR distributed optical fiber sensing system |
| CN103955028A (en) * | 2014-04-29 | 2014-07-30 | 中国科学院半导体研究所 | Broadband tunable single-passband microwave photon filter generating system |
| CN105444794A (en) * | 2015-12-15 | 2016-03-30 | 中国电子科技集团公司第四十一研究所 | High spatial resolution Brillouin optical time-domain reflectometer(BOTDR) and working method thereof |
-
2013
- 2013-11-22 CN CN201320744610.3U patent/CN203550977U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103604450A (en) * | 2013-11-22 | 2014-02-26 | 哈尔滨理工大学 | Seed injection BOTDR distributed optical fiber sensing system |
| CN103955028A (en) * | 2014-04-29 | 2014-07-30 | 中国科学院半导体研究所 | Broadband tunable single-passband microwave photon filter generating system |
| CN105444794A (en) * | 2015-12-15 | 2016-03-30 | 中国电子科技集团公司第四十一研究所 | High spatial resolution Brillouin optical time-domain reflectometer(BOTDR) and working method thereof |
| CN105444794B (en) * | 2015-12-15 | 2018-02-06 | 中国电子科技集团公司第四十一研究所 | A kind of high spatial resolution Brillouin optical time-domain reflectometer and method of work |
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