CN104180830A - Distributed optical fiber fizeau interferometer based on light time domain reflection principle - Google Patents
Distributed optical fiber fizeau interferometer based on light time domain reflection principle Download PDFInfo
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Abstract
The invention provides a distributed optical fiber fizeau interferometer based on light time domain reflection principle, used for distributed optical fiber sensing and measuring. The system is composed of a wide spectrum light source (1), a three-port optical fiber circulator (2), an non-equilibrium Mach-Zehnder interferometer (5) composed of a 2*2 fiber coupler (3) and (4),a sensing fiber (6), a photoelectric detector (9), a photoelectric detector (10) and a differential signal amplification processing circuit (11). In the system, distributed measurement is realized through the reflection characteristic of the light time domain characteristics; minute disturbance measurement is realized through interference patterns; mean intensity signals can be offset through the differential type signal detection characteristics, so as to redouble the interference signals; two optical pulse signals are in the same optical fiber, environment temperature can be regarded as the same, so temperature effect is automatically eliminated. Accordingly, the distributed optical fiber fizeau interferometer can be widely used for distributed disturbance measurement and perimeter safe monitoring.
Description
(1) technical field
A kind of distributed fizeau interferometer based on optical time domain reflection (OTDR) principle of the present invention, can be used for distributing optical fiber sensing and measurement, belongs to technical field of optical fiber sensing.
(2) background technology
Utilize backward Rayleigh scattering light in Transmission Fibers to carry the feature of the information such as fiber position, external disturbance, adopt white light interference technique with non-equilibrium Mach-Zehnder interferometer, single light pulse to be carried out the light-splitting method of former and later two pulses of the separated generation of light path, can construct a kind of distributed fizeau interferometer based on optical time domain reflection (OTDR) principle, this sensing that is distributed interference and measurement provide may.
1976, the optical time domain reflectometer (OTDR-Optical Time Domain Reflectmeter) of M.K.Barnoski and S.M.Jensen invention, by means of the detection of rear orientation light in optical fiber having been realized to the distribution measuring of fibre loss.When burst pulse light is injected to testing fiber, this system can check over time the continuity in optical fiber and measure its decay by measuring back scattering light intensity, thus the length of definite testing fiber and loss distribution situation along the line thereof.Because OTDR method of testing has non-destructive, only needs one end access and advantage fast directly perceived, become that optical fiber cable is produced, construction, safeguard in indispensable instrument.Yet traditional OTDR technology is only backscatter intensity signal due to what measure, thus only sensitiveer to end face, breakpoint or larger stationary curved loss ratio, for example, to the time dependent small sample perturbations of optical fiber: vibration signal is but not too sensitive.For this reason, the invention technical patent that publication number is CN101290235A has provided a kind of interfere type optical time domain reflectometer, on original OTDR basis, adopt 2 * 2 coupling mechanisms, increase Liao Yi road reference optical fiber, thereby realized on the basis of backscatter intensity signal, distributed interference information has superposeed.But due to one side, detection optical fiber is separated with reference optical fiber, temperature impact is difficult to overcome; On the other hand, less interference signal is superimposed upon on larger strength signal, causes the detection sensitivity of system not high.In order to solve the detection optical fiber shortcoming separated with reference optical fiber, publication number is that the invention technical patent of CN102809421A is on traditional OTDR basis, adopted polarising beam splitter, rear orientation light is carried out to the separation of polarization state quadrature and amplifies in differential mode.This has lost the feature of interferometry on the one hand; On the other hand, due to the impact of variation of ambient temperature on fiber birefringence, also can make the positioning precision of vibration detecting decline.
In order to overcome above-mentioned shortcoming and defect, the present invention proposes a kind of distributed fizeau interferometer based on optical time domain reflection (OTDR) principle.It adopts white light source, in same optical fiber, by a non-equilibrium Mach-Zehnder interferometer, single light pulse is carried out to the separated light-splitting method that produces former and later two pulses of light path, form the backward Rayleigh scattering signal of two-way light, via same non-equilibrium Mach-Zehnder interferometer, the light path of two pulsed lights is compensated, just formed the fizeau interferometer that can carry out distribution measuring.By means of two anti-phase features of detection port interference signal of 2 * 2 fiber coupler, carry out differential detection and the amplification of two signals, this has automatically eliminated the intensity backscatter signal not interfering on the one hand simultaneously; On the other hand, at the bottom of also having eliminated the backscatter intensity code book in coherent signal.In addition, also make interference signal realize multiplication.Because optical interferometry has highly sensitive, the advantage such as dynamic range is large, responsiveness is fast, long transmission distance, in addition under the condition of front and back two pulses in same optical fiber in common light path, temperature variation is identical on the light path impact of two pulses, and this has just realized the auto-compensation of temperature impact.Therefore, this territory scattering of novel light time fizeau interferometer is expected to realize the detection of long-distance distributed small sample perturbations and location.
(3) summary of the invention
The present invention is directed to the deficiency that prior art exists, proposed a kind of distributed fizeau interferometer based on optical time domain reflection (OTDR) principle, can be used for distributing optical fiber sensing and measurement, as shown in Figure 1.It is characterized by, this system is by wide spectrum light source (1), three fiber port circulators (2), the non-equilibrium Mach-Zehnder interferometer (5) that 2 * 2 fiber couplers (3) and (4) form, sensor fibre (6), photodetector (9) and photodetector (10) and differential wave amplification treatment circuit (11) form.The light that wide general light source (1) sends enters system by three end optical fiber circulators (2), the other two-port of the bad shape device of three end optical fiber is connected with photodetector (9) with fiber coupler (3) respectively, the another port of fiber coupler (3) is connected with photodetector (10), photodetector (9) is connected with differential wave amplification treatment circuit (11) respectively with photodetector (10) again, and the output port of fiber coupler (4) is connected with sensor fibre (6).
The light pulse of being sent by wide spectrum light source (1), after three fiber port circulators (2), arrive at the non-equilibrium Mach-Zehnder interferometer (5) that the optical path difference being comprised of two 2 * 2 fiber couplers (3) and (4) is n Δ L, this pulsed light is evenly divided into former and later two pulses (7) and (8), and forms optical path difference n Δ L.There is Rayleigh scattering on the way in these two light pulses of transmitting forward along optical fiber, two backward Rayleigh scattering lights that produce will be passed back along same optical fiber, former and later two scattered light signals that reflect via non-equilibrium Mach-Zehnder interferometer (5) after, light path is compensated.Because two pulse incident light amplitudes are suitable, frequency is all identical with incident light, Rayleigh scattering light mechanism of production is identical, will produce interference meeting under the condition of phase matching, and coherent signal is received by two-way photodetector (9) and photodetector (10) respectively.Because the received two-way coherent signal of two detectors is to be exported by two ports of 2 * 2 fiber couplers, so its phase place is just the opposite, after differential wave amplification treatment circuit (11), backscatter signal and the direct current component in coherent signal irrelevant with interferometry have just automatically been cancelled, and measure coherent signal, obtain differential enhancing.In addition,, in the optical fiber of two interference signals in a common light path, this has just formed distributed back scattering fizeau interferometer, and has automatically eliminated the impact being brought by environment temperature.
This system both can adopt the single mode telecommunication optical fiber of standard, also can adopt various polarization maintaining optical fibres, as shown in Figure 2.When sensor-based system is selected polarization maintaining optical fibre, contribute to improve the interference performance of system.The Transmission Fibers length of the two-way receiving optical signals of this system should equate to guarantee that two-way rear orientation light is received simultaneously.In order to make the intensity equilibrium of two ways of optical signals to obtain larger dynamic range and higher detection sensitivity.Wherein a road light signal need to increase an optical attenuator (12) back scattering light signal strength is regulated, as shown in Figure 3.In order to improve the signal to noise ratio (S/N ratio) of system, the present invention also can adopt and light source or photosignal modulator are carried out to code modulated method reach this purpose.In addition,, without prejudice to spirit of the present invention, in system, can also increase a modulation signal generator (13) wide spectrum light source SLD is directly modulated.Also can adopt more high-power ASE wide spectrum light source, increase a photosignal modulator (14) simultaneously, modulation signal generator (13) carries out the modulation of light signal to photosignal modulator (14), improves the signal to noise ratio (S/N ratio) of system, as shown in Figure 4.In order to improve this system for the Discern and judge ability of disturbing signal, the present invention can also increase optical fiber end reverberator (15), as shown in Figure 6, former and later two light pulse signals that separate are reflected back successively in optical fiber end, formed the long-armed Feisuo interferometer of common optic fibre light path.The one,, this signal is optical fiber end reflected signal, and it is for rear orientation light, and signal amplitude is larger, can be used for compartment system whether to have completed the label signal of the dynamic interference scanning of an overall process; The 2nd,, the disturbance information of this signal is included in a certain group of back scattering interference signal before this signal, thereby this signal confirmation verification criterion signal that can whether occur as the disturbance event of recognition system.
The object of the present invention is achieved like this:
The principle of work of the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle as shown in Figure 1, the light sending from light-pulse generator, after 2 * 2 coupling mechanisms that are 1: 1 through splitting ratio, be divided into the two bundle coherent lights that power equates, they form optical path difference n Δ L after non-equilibrium Mach-Zehnder interferometer.There is Rayleigh scattering on the way in these two light pulses of transmitting forward along optical fiber, two backward Rayleigh scattering lights that produce will be passed back along same optical fiber, former and later two scattered light signals that reflect via non-equilibrium Mach-Zehnder interferometer after, what at photodetector, detect is three groups of backscatter signal pulses, as shown in Figure 5.Two light pulses that wherein light path is compensated are interfered mutually, and the signal that does not obtain two light pulses of optical path compensation is backscatter intensity signal, and received light signal sequential chart as shown in Figure 5.
Through the backward Rayleigh scattering signal of former and later two pulsed lights of passing back along same optical fiber of optical path compensation after coupling mechanism, because the two frequency is all identical with incident light, two-way incident optical power equates, the mechanism that Rayleigh scattering light produces is identical, the phase differential of supposing two-way Rayleigh scattering light changes the frequency far below light wave electric field, and phase differential variation is relatively slowly.Therefore they will be equivalent to fizeau interferometer, at each self-forming interference signal of two ports of coupling mechanism, so arrive photo-detector PD
1and PD
2light signal be respectively S
1(z, t) and S
2(z, t).Distributed dynamic interference signal after differential amplification is S (z, t)=A[S
2(z, t)-S
1(z, t)], in formula, A is signal amplification factor.
Compare with original technology, this distributed fizeau interferometer based on optical time domain reflection (OTDR) principle disclosed in this invention has following outstanding feature: (1) optical time domain reflection characteristic---can realize distribution measuring; (2) interference pattern---can realize small sample perturbations and measure; (3) differential signal detection feature---when having offset mean intensity signal, make interference signal multiplication; (4) temperature self-compensation characteristic---because two light pulse signals are co-located in same optical fiber, it is identical that variation of ambient temperature can be considered, and automatically eliminated the impact of temperature.
(4) accompanying drawing explanation
Fig. 1 is the distributed fizeau interferometer system architecture schematic diagram based on optical time domain reflection (OTDR) principle;
Fig. 2 (a) is that typical standard single mode telecommunication optical fiber cross-sectional view, (b) are that panda type polarization-preserving fiber cross-sectional view, (c) are the cross-sectional views of bow-tie type polarization maintaining optical fibre;
Fig. 3 has increased the distributed fizeau interferometer system architecture schematic diagram that light source is carried out to direct signal coding demodulator;
Fig. 4 has increased high-power ASE light source, has increased the distributed fizeau interferometer system architecture schematic diagram that light pulse is carried out to code modulated electrooptic modulator and Signal coding modulator simultaneously;
Fig. 5 is that the distributed Fizeau interference instrument system based on optical time domain reflection (OTDR) principle receives signal timing diagram;
Fig. 6 (a) is the distributed Fizeau interference instrument system with optical fiber end reverberator; (b) be the interference signal schematic diagram that reflection end is corresponding.
(5) embodiment
Below in conjunction with accompanying drawing, the present invention is described in more detail:
Embodiment 1:
In conjunction with Fig. 1, embodiments of the present invention are, the light pulse of being sent by wide spectrum light source, and pulse width is τ, the recurrence interval is
take in the optical fiber that to guarantee in length be L, after the back scattering light signal producing can be received, then send second inquiry light pulse in first light pulse.The light pulse being sent by light source is after three fiber port circulators, the 3dB fiber coupler that is 1: 1 by splitting ratio is divided into two luminous powers light signal about equally, respectively after non-equilibrium Mach-Zehnder interferometer, form optical path difference n Δ L, because two pulsed optical signals that transmit forward along optical fiber all Rayleigh scattering can occur, the backward Rayleigh scattering light of these two pulsed lights will be passed non-equilibrium Mach-Zehnder interferometer back along optical fiber, the light amplitude of two back scattering light pulses that obtains optical path compensation is suitable, frequency is all identical with incident light, Rayleigh scattering light mechanism of production is identical, will produce interference meeting under the condition of phase matching.Wherein Yi road after three fiber port circulators (the about 1dB of loss) by photoelectric detector PD
1receive; Meanwhile, another road through after optical attenuator decay directly by photoelectric detector PD
2receive; Because the received two-way coherent signal of two detectors is to be exported by two ports of 2 * 2 fiber couplers, so its phase place is just the opposite, regulate optical attenuator, make two ways of optical signals size reach balance, at this moment after difference amplifier, the mean intensity signal irrelevant with interferometry is cancelled, and two-way interference signal obtains differential multiplication.Meanwhile, because two pulsed optical signals share same optical fiber, the change in optical path length that variation of ambient temperature causes is basic identical, and the phase differential causing thus remains unchanged.This has just eliminated the impact being brought by environment temperature automatically.
Embodiment 2:
By reference to the accompanying drawings 2, the difference of the second embodiment of the present invention and the first embodiment is, in order to improve signal to noise ratio (S/N ratio), on the basis of the first embodiment, to increase a modulation signal generator (13) wide spectrum light source SLD is carried out to direct coding and modulation.For example, with mutual-complementing code light pulse, as direct impulse, improve the detection performance of this distributed fizeau interferometer based on optical time domain reflection, under the prerequisite that does not affect range resolution, can improve effective measuring distance, reduce and measure the required time.
Embodiment 3:
By reference to the accompanying drawings 3, the difference of the third embodiment of the present invention and the first embodiment is, in order further to expand detection range, improve signal to noise ratio (S/N ratio), on the basis of the first embodiment, adopt more high-power ASE wide spectrum light source, increased a photosignal modulator (14) simultaneously, paired pulses light signal is encoded, and modulation signal generator (13) carries out the modulation of light signal to optical fiber signal modulator (14).For example: by pseudo-random code, realize the encoding and decoding of paired pulses light signal, improve the inhibition of signal to noise.
Claims (9)
1. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle, it is characterized in that, this system is by wide spectrum light source (1), three fiber port circulators (2), the non-equilibrium Mach-Zehnder interferometer (5) that 2 * 2 fiber couplers (3) and (4) form, sensor fibre (6), photodetector (9) and photodetector (10) and differential wave amplification treatment circuit (11) form, the light that wide general light source (1) sends enters system by three end optical fiber circulators (2), the other two-port of three end optical fiber circulators is connected with photodetector (9) with fiber coupler (3) respectively, the another port of fiber coupler (3) is connected with photodetector (10), photodetector (9) is connected with differential wave amplification treatment circuit (11) respectively with photodetector (10) again, the output port of fiber coupler (4) is connected with sensor fibre (6).
2. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: this system can be used standard single mode telecommunication optical fiber, also can use various polarization maintaining optical fibres.
3. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: the Transmission Fibers of the two-way receiving optical signals of this system is equal in length.
4. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: at photodetector (9) or the front optical attenuator (12) that adds of photodetector (10), carry out preconditioning.
5. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: increase a modulation signal generator (13) wide spectrum light source SLD is directly modulated.
6. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: adopt more high-power ASE wide spectrum light source.
7. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: at wide spectrum light source (1) and three fiber port circulators (2), increase a photosignal modulator (14).
8. photosignal modulator according to claim 7, is characterized in that: modulation signal generator (13) carries out the modulation of light signal to photosignal modulator (14).
9. the distributed fizeau interferometer based on optical time domain reflection (OTDR) principle according to claim 1, is characterized in that: at sensor fibre (6) art end, increase reverberator (15).
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105806789A (en) * | 2016-03-10 | 2016-07-27 | 哈尔滨工程大学 | Optical fiber white light interferometry difference spectrometer |
| CN105865751A (en) * | 2016-05-26 | 2016-08-17 | 上海交通大学 | System and method for monitoring optical fiber fuse effect |
| CN106643841A (en) * | 2016-12-30 | 2017-05-10 | 中国科学院深圳先进技术研究院 | Weak reflection-FIZEAU sensing device |
| CN110440901A (en) * | 2019-08-13 | 2019-11-12 | 郑州信大先进技术研究院 | A kind of distributed optical fiber vibration sensing localization method and device based on pulse accumulation |
| CN113834508A (en) * | 2021-07-20 | 2021-12-24 | 上海大学 | Distributed optical fiber sensing system based on mutual injection semiconductor laser and unbalanced Mach-Zehnder interferometer and positioning method thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1444019A (en) * | 2002-03-08 | 2003-09-24 | 电子科技大学 | Optical fibre Michelson interferometer with optic circulator |
| CN101441092A (en) * | 2008-10-16 | 2009-05-27 | 北京邮电大学 | Perimeter protection sensing positioning system based on coherent light time domain reflection |
| US20090147808A1 (en) * | 2006-04-18 | 2009-06-11 | Pyrophotonics Lasers Inc. | Method and system for tunable pulsed laser source |
| CN101598884A (en) * | 2008-06-03 | 2009-12-09 | 电子科技大学 | The all-optical logic gate of Mechelson, A. A. structure |
| CN101692628A (en) * | 2009-09-10 | 2010-04-07 | 复旦大学 | Single-sideband modulated single carrier frequency-domain equalization technology-based fiber communication system |
| CN202182702U (en) * | 2011-08-01 | 2012-04-04 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer using chaotic laser method |
| CN102620857A (en) * | 2012-03-27 | 2012-08-01 | 南京大学 | Brillouin optical time domain reflectometer for single-photon detection based on edged filter method |
-
2013
- 2013-05-24 CN CN201310195672.8A patent/CN104180830A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1444019A (en) * | 2002-03-08 | 2003-09-24 | 电子科技大学 | Optical fibre Michelson interferometer with optic circulator |
| US20090147808A1 (en) * | 2006-04-18 | 2009-06-11 | Pyrophotonics Lasers Inc. | Method and system for tunable pulsed laser source |
| CN101598884A (en) * | 2008-06-03 | 2009-12-09 | 电子科技大学 | The all-optical logic gate of Mechelson, A. A. structure |
| CN101441092A (en) * | 2008-10-16 | 2009-05-27 | 北京邮电大学 | Perimeter protection sensing positioning system based on coherent light time domain reflection |
| CN101692628A (en) * | 2009-09-10 | 2010-04-07 | 复旦大学 | Single-sideband modulated single carrier frequency-domain equalization technology-based fiber communication system |
| CN202182702U (en) * | 2011-08-01 | 2012-04-04 | 杭州欧忆光电科技有限公司 | Brillouin optical time domain analyzer using chaotic laser method |
| CN102620857A (en) * | 2012-03-27 | 2012-08-01 | 南京大学 | Brillouin optical time domain reflectometer for single-photon detection based on edged filter method |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105806789A (en) * | 2016-03-10 | 2016-07-27 | 哈尔滨工程大学 | Optical fiber white light interferometry difference spectrometer |
| CN105806789B (en) * | 2016-03-10 | 2018-12-07 | 哈尔滨工程大学 | A kind of optical fiber white light interference differential spectroscopy |
| CN105865751A (en) * | 2016-05-26 | 2016-08-17 | 上海交通大学 | System and method for monitoring optical fiber fuse effect |
| CN106643841A (en) * | 2016-12-30 | 2017-05-10 | 中国科学院深圳先进技术研究院 | Weak reflection-FIZEAU sensing device |
| CN106643841B (en) * | 2016-12-30 | 2019-06-25 | 中国科学院深圳先进技术研究院 | A kind of weak inverted-F BG-FIZEAU sensing device |
| CN110440901A (en) * | 2019-08-13 | 2019-11-12 | 郑州信大先进技术研究院 | A kind of distributed optical fiber vibration sensing localization method and device based on pulse accumulation |
| CN110440901B (en) * | 2019-08-13 | 2021-08-17 | 郑州信大先进技术研究院 | Distributed optical fiber vibration sensing positioning method and device based on pulse accumulation |
| CN113834508A (en) * | 2021-07-20 | 2021-12-24 | 上海大学 | Distributed optical fiber sensing system based on mutual injection semiconductor laser and unbalanced Mach-Zehnder interferometer and positioning method thereof |
| CN113834508B (en) * | 2021-07-20 | 2023-11-17 | 上海大学 | Distributed optical fiber sensing system based on mutual injection semiconductor laser and unbalanced Mach-Zehnder interferometer and positioning method thereof |
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