CN101097278A - Optical fiber safety early warning phase control system - Google Patents

Abstract

The invention is an optic fiber safety prewarning phase control system of buried tube, construction or important establishment and area. It uses laser [101] to connected with wave splitter [203], output is connected with photoelectricity detector [309] and [310], then, scheme one is signal modulating circuit [312] and [313], A/D collecting card [314] and [315] are connected by wire and then connected with the input of the signal process and calculator [316], output is connected with phase modulator [206] of optic fiber [1] or [2] via phase controller [205]; scheme two is that A/D collecting card [314] and [315] are connected by wire and then connected with mixer [517] with signal generator [514], output of mixer [517] is connected with filter [518], signal processor [519], filter [520], signal demodulator [521], laser [101] is connected with signal generator [513], output of the signal generator [513] is connected with phase modulator [206] of optic fiber [1] or [2].

Description

Optical fiber safety early warning phase control system

Technical field

The present invention is the optical fiber safety early warning phase control system of the safeguard protection early warning in a kind of buried pipeline or structures or critical facility and zone, relates to the measurement of mechanical vibration, the measurement and the piping system technical field of impact.

Background technology

For materials such as oil, rock gas, product oil, coal slurry and water, pipeline transportation is a kind of safe, economic and means of transportation efficiently, in global carrier, bringing into play more and more important effect, especially at oil, finished product oil and gas these have inflammable and explosive and energy substance transportation that transaction value is high in occupy very important position, in our country, annual newly-built several thousand kilometers at least pipeline be we can say, pipeline is the main artery of energy transportation.The oil of pipeline transportation, the existing high transaction value of finished product oil and gas also have inflammable and explosive this characteristic, pipeline is in case leak, combustion explosion very easily takes place in leakage region, not only influence the safety in production of pipeline industry, cause enormous economic loss, and all edge line people's property and life security in serious threat.In addition, the pipeline leakage can't be estimated especially to the harm that peripheral ecologic environment causes.

Since pipeline has been arranged, the destruction that comes from the outside has just been arranged also.Especially in the last few years, rise of the oil price, under the driving of interests, the lawless person is possessed with a lust for gain, drilling hole of oil stolen, robber's gas on pipeline; The national basis construction starts in a large number, and pipeline construction site along the line is seen everywhere; In addition, disasteies such as landslide, rubble flow take place again and again, the production safety that these are all constantly threatening pipeline, and wherein drilling hole of oil stolen and illegal construction become the primary factor of threat tube safety in production.

According to incompletely statistics, only China destroys the pipe leakage that causes because of the external world or explode last over thousands of time every year, and direct economic loss reaches several hundred million yuan, and indirect losses such as environmental disruption and social influence can't be estimated especially.For preventing outer bound pair pipeline destroyed, the pipeline transportation industry has dropped into lot of manpower and material resources every year, but still can't effectively prevent and stop destruction.The safety in production form of pipeline transportation industry is very severe, and it is extremely urgent to seek means and the method for guaranteeing the pipeline transportation safety in production.

Along with the development of pipeline transportation industry, various pipeline transportation safety monitoring technologies are also in continuous development, and present existing pipe safety production monitoring technology mainly contains two classes.One: the monitoring technology after the pipe leakage incident takes place, this technology mainly contains " tube fluid mechanical state detection technique and distribution type fiber-optic temperature and stress monitoring technology ".Tube fluid mechanical state detection technique is to gather signals such as the flow of fluid in the pipeline, temperature and pressure in real time, carry out pipeline leakage testing and location, this technology is subjected to the effects limit such as performance of fluid behaviour, delivery technology and testing tool in the pipeline, sensitivity and bearing accuracy to line leakage are lower, and this class technology comprises: pressure gradient method, negative pressure wave method, flow equilibrium method.Distribution type fiber-optic temperature and stress monitoring technology are the positions that the medium that utilizes the nonlinear characteristic of optical fiber (Ramam effect and brillouin effect) to gather pipe leakage is in real time determined leakage point to the temperature effect and the shock stress of optical fiber, and this technology is subjected to the distance limit of the structure of optical cable and optical cable and leakage point and influences monitoring effect.They are two years old, prevention monitoring technology before the pipeline damage incident takes place, pipeline damage early warning technology just, existing such technology mainly is " technology of acoustic wave monitoring " at present, this technology is to utilize sound wave along the pipeline transmission principle, an active sensor is being installed every about 1 kilometer, picking up pipeline voice signal along the line is analyzed, determine event property, and then the incident of destroying pipeline found in advance, but each senser element must be equipped with a cover electric supply installation and a communicator, not only increases the investment and the maintenance cost of equipment, and these facilities are also destroyed easily itself, and device can not normally be moved.

At the problem that existing pipe safety monitoring technology exists, Australia has patent to propose based on Mach-Zehnder (Mach-Zehnder) fibre optic interferometer principle, with the technical scheme of optical fiber sense vibration.This invention is a breakthrough to the line target or the large-area appearance target safe early warning of long distance, but not enough be the light path system instability of this invention, have the signal blanking that causes because of phase fading and polarization decay, be difficult to effectively work.

Summary of the invention

The objective of the invention is to invent the optical fiber safety early warning phase control system of predispersed fiber alarm system light path stable phase angle of the safeguard protection early warning in a kind of buried pipeline or structures or critical facility and zone.

The present invention is directed to the problem that existing pipe safety monitoring technology exists, two Mach-Zehnders (Mach-Zehnder) the fibre optic interferometer principle of a kind of base with the phase fading control technology proposed, eliminated the signal blanking that causes because of phase fading, formed two-way and interfered laser modulation signal relatively transmission and light channel structure of picking up at the interferometer both-end on interferometer synchronously with stable phase angle.It is utilize with pipeline laying in one ditch or structures, critical facility and zone on every side the common communications optical fiber in the subterranean cable as the interference arm and the Transmission Fibers of interferometer, and then the soil vibration detecting sensor of formation continuous distribution formula, pick up near the vibration signal of soil along the line of pipeline.When connecing positioning system then, go out near the occurrence positions of soil the vibration event along the line pipeline according to the transmission time difference analytical calculation of two-way laser signal.Connect signal recognition system again and just can determine to cause the character and the classification of soil vibration event.On this basis, be equipped with each function system or module again, after local management system control, analyzing and handle, carry out data remote or local the warning by communication system or warning output system.

Realization principle of the present invention is:

Optical fiber safety early-warning system interferometer output intensity signal can be write as after opto-electronic conversion:

${\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="A20061009059200131.png"\; state="\{\{state\}\}">I</figure-callout>}}_0=I_1+I_2+2\sqrt{I_1{\mathrm{<figure-callout\; id="2"\; label="I"\; filenames="A20061009059200131.png"\; state="\{\{state\}\}">I</figure-callout>}}_2}\cos ({\mathrm{\&phi;}}_s+{\mathrm{\&phi;}}_n+{\mathrm{\&phi;}}_0)---\left(1\right)$

Wherein: I1, I2 are respectively the light intensity of two arms of interferometer, and I0 is synthetic total light intensity of output, φ _sThe phase change that expression soil vibration signal causes, φ _nRepresent various interference and noise, φ ₀Expression initial bit phase, three positions all refer to the phasic difference signal of interferometer two arms mutually above all.

The output intensity signal can be represented with following formula after photodetector converts electric signal to:

$V=V_1+{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="A20061009059200131.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+2\sqrt{V_1{V}_2}\cos ({\mathrm{\&phi;}}_s+{\mathrm{\&phi;}}_n{+\mathrm{\&phi;}}_0)---\left(2\right)$

Wherein, V is the voltage signal of output, V ₁, V ₂I1, I2 in the corresponding formula (1), V1, V2 are constants.Be the convenience of problem analysis, (2) formula can be write as:

V＝A+Bcos(φ _s+φ _n) (3)

Wherein, A=V ₁+ V ₂, $B=2\sqrt{V_1{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="A20061009059200131.png"\; state="\{\{state\}\}">V</figure-callout>}}_2},$ φ ₀Incorporate φ into _nGeneral external interference signal psi _nBe the low frequency large-signal, φ _sBe the high frequency small-signal, when signal has a subtle change amount Δ φ _sThe time:

ΔV≈Bsinφ _n·Δφ _s (4)

Because low-frequency disturbance φ _nRandom variation, and amplitude is big, the signal to noise ratio (S/N ratio) of being not difficult to draw system's output by (4) formula is changing, and as sin φ _n=0 o'clock, the complete blanking of signal.Interferometer output signal is called the phase fading phenomenon of interferometer with the signal random fluctuation phenomenon that the variation of external environment occurs.At this phenomenon, the present invention proposes two kinds of methods.

Native system has two kinds of technical schemes, first scheme as shown in Figure 1, it is that laser instrument 101 is connect and channel join-splitting device 204 by optical fiber, optical fiber 1, optical fiber 2 is formed the channel join-splitting device 203 of Mach-Zehnder (Mach-Zehnder) fibre optic interferometer, channel join-splitting device 203 connects photoelectric detector 309 and photoelectric detector 310 respectively by two optical fiber, connect signal conditioning circuit 312 and signal conditioning circuit 313 by electric wire respectively after this two photoelectric detector 309 and the photoelectric detector 310, receive the input of signal Processing and arithmetical unit 316 behind A/D capture card 314 and the A/D capture card 315 jointly, and the output of signal Processing and arithmetical unit 316 through phase controller 205 to the phase-modulator 206 that is serially connected in optical fiber 1 or 2.

The electric principle of this programme as shown in Figure 3, channel join-splitting device 203 is connect the two-way optical input of photosignal reason circuit 309-1 by two optical fiber, its two-way electricity delivery outlet respectively connects an A/D capture card 314 and A/D capture card 315, the output of A/D capture card 314 and A/D capture card 315 connects phase controller main frame 205-1 input port, its delivery outlet meets phase controller 205-2, and the delivery outlet of phase controller 205-2 connects the input port of phase-modulator 206.Here realized the function of two-way photoelectric detector 309, photoelectric detector 310, signal conditioning circuit 312 and signal conditioning circuit 313 with photosignal modulate circuit 309-1, both realized the function of signal Processing and arithmetical unit 316 with phase controller main frame 205-1, also realized simultaneously the function of phase controller 205 jointly, but it is simpler just to seem with phase controller 205-2.

Wherein said laser instrument 101 is continuous mono-colour laser.

Described photoelectric detector 309, photoelectric detector 310, signal conditioning circuit 312, signal conditioning circuit 313, A/ D capture card 314 and 315, signal Processing and arithmetical unit 316, phase controller 205, phase-modulator 206 are city's pin product, and appropriate the selection gets final product.Photosignal modulate circuit 309-1, phase controller main frame 205-1 also are city's pin products.

This is the system of a kind of closed-loop control working point, is a kind of method of active phase compensation.The signal of optical fiber safety early-warning system output is quantized by the A/D capture card after opto-electronic conversion, can be write as:

V＝A+Bcos(φ _s+φ _n) (3)

General signal psi _sBe high frequency, external interference φ _nBe low frequency, (3) formula is averaged on certain hour length, can obtain this time period external interference amount φ _nMean value In interferometer one arm, add phase-modulator, on phase-modulator, add a FEEDBACK CONTROL voltage V then _F, produce control and differ φ _Press, the influence of offsetting external interference makes interferometer work determine on the working point one, as shown in the formula:

Work as φ _nDuring variation, φ _PressAlso change thereupon.We adjust it, and by so continuous circulation, the working point of interferometer can be stabilized near the pi/2, and we can obtain reliable, stable signal output.System works point perseverance is stabilized on the sensitiveest point, overcomes the phase fading of optical fiber safety early-warning system.

1,2 and 3 is three optical fiber, and wherein optical fiber 1,2 is interference optical fiber, optical fiber 3 Transmission Fibers, Mach-Zehnder (Mach-Zehnder) fibre optic interferometer that channel join-splitting device 203, channel join-splitting device 204 and optical fiber 1,2 are formed.The one-wavelength laser of continuous mono-colour laser 101 emissions, be divided into two-way by optical fiber to the one-wavelength laser of channel join-splitting device 203: wherein one road laser is by the 203 end incidents of Mach-Zehnder (Mach-Zehnder) optical fiber channel join-splitting device, close ripple and form the interference light wave at channel join-splitting device 204 ends, interfere light wave to pass channel join-splitting device 203 back by optical fiber 3 again, wherein another road laser passes to channel join-splitting device 204 by optical fiber 3, by the 204 end incidents of Mach-Zehnder (Mach-Zehnder) interferometer channel join-splitting device, close ripple and form the interference light wave at channel join-splitting device 203 ends.

Among Fig. 1, interference signal is after photoelectric detector 309 and photoelectric detector 310 conversions, after process signal conditioning circuit 312 and signal conditioning circuit 313 carry out amplification filtering, quantize by A/D capture card 314 and A/D capture card 315, the phase place that is produced by the external interference amount is averaged on length on a period of time by signal Processing and arithmetical unit 316, come drive signal to handle and feedback voltage of arithmetical unit 316 generations according to the phase average that calculates, go control phase modulator 206 to produce compensation of phase, offset the influence of external interference, make interferometer work determine on the working point one.

Second kind of scheme is phase carrier (PGC) modulation, and as Fig. 2, this is a kind of passive demodulation techniques.Add the phase-modulator of interferometer or directly modulate optical frequency by modulation, in interferometer, added the phase differential that one-period changes, the output of optical fiber safety early-warning system is become:

V＝A+Bcos(Ccosω ₀t+φ _s+φ _n) (6)

Wherein C reflects depth of modulation, ω ₀It is modulating frequency.It is actually system works o'clock is changed in a very big scope, and system can not rest on the most highly sensitive district of phase response, also can not be trapped in the dead band, and there is an average stable phse sensitivity in the system that finally makes.

To (6) formula modulation signal ω ₀And frequency-doubled signal carries out obtaining after mixing and the low-pass filtering:

BJ ₁(C)sin(φ _s+φ _n) (7)

BJ ₂(C)cos(φ _s+φ _n) (8)

Wherein, J ₁, J ₂Expression single order, second order Bessel function.Last two formulas respectively differential and with differential before the opposing party multiply each other, end product subtracts each other, and obtains:

$B^2{J}_1\left(C\right)J_2\left(C\right)\frac{d({\mathrm{\&phi;}}_s+{\mathrm{\&phi;}}_n)}{\mathrm{dt}}---\left(9\right)$

Obtain behind the integration:

B ²J ₁(C)J ₂(C)(φ _s+φ _n) (10)

High-pass filtering, and system output carried out obtaining the soil vibration after the demodulation and the signal phase value φ that produces _s

The formation of alternative plan [seeing Fig. 2, Fig. 4] is that it receives channel join-splitting device 203 by laser instrument 101 usefulness optical fiber, channel join-splitting device 203 connects photoelectric detector 309 and photoelectric detector 310 respectively by two optical fiber, receive the frequency mixer 517 that signal generator 514 is imported jointly after connecing A/D capture card 314 and A/D capture card 315 by electric wire respectively after this two photoelectric detector 309 and the photoelectric detector 310, the following series filter 518 of frequency mixer 517 outputs, signal processor 519, wave filter 520, demodulator of PM signal PM 521 demodulate the soil vibration and the phase signal of generation; The laser instrument 101 usefulness optical fiber number of receiveing letter generators 513 connect the phase-modulator 206 that is connected in optical fiber 1 or 2 by signal generator 513 outputs more simultaneously; Interference signal is after photoelectric detector 309 and 310 conversions, quantize by A/ D capture card 314 and 315, it is the modulation signal of F for the A frequency that signal generator 513 produces an amplitude, phase-modulator 206 of interfering on the arm of modulated laser 101 or modulation interferometer, in interferometer, produce the phase differential that one-period changes, photoelectric detector 309 and 310 detects interferometer two-way output light and transfers electric signal to, after giving A/ D circuit 314 and 315 conversion, the signal of giving frequency that frequency mixer 517 and signal generator 514 produce and be F with and the frequency-doubled signal mixing, after wave filter 518 filtering, behind signal processor 519 process infinitesimal analysis and the plus and minus calculation, pass through wave filter 520 again, demodulate the soil vibration and the phase signal of generation by demodulator of PM signal PM 521 at last.

The electric principle of this programme as shown in Figure 4, channel join-splitting device 203 is connect by two optical fiber has two-way photoelectric detector 309, photoelectric detector 310, the two-way optical input of the photoelectric signal processing circuit 309-1 of signal conditioning circuit 312 and signal conditioning circuit 313 functions, the two-way optical input of photoelectric signal processing circuit 309-1, its two-way electricity delivery outlet respectively connects an A/D capture card 314 and A/D capture card 315, the output of A/D capture card 314 and A/D capture card 315 connects has frequency mixer 517, signal generator 514, wave filter 518, signal processor 519, the signal demodulation main frame 521-1 input port of wave filter 520 and demodulator of PM signal PM 521 functions, signal generator 513 outputs meet phase controller 205-2, and phase controller 205-2 output connects the phase-modulator 206 that is connected in optical fiber 1 or 2.Here realize the function of two-way photoelectric detector 309, photoelectric detector 310, signal conditioning circuit 312 and signal conditioning circuit 313 with photosignal modulate circuit 309-1, realized the function of frequency mixer 517, signal generator 513, wave filter 518, signal processor 519, wave filter 520 and demodulator of PM signal PM 521 with signal demodulation main frame 521-1.

Wherein said laser instrument 101 is continuous mono-colour laser.

Described photoelectric detector 309, photoelectric detector 310, A/D capture card 314, A/D capture card 315, signal generator 513, signal generator 514, frequency mixer 517, wave filter 518, signal processor 519, wave filter 520, demodulator of PM signal PM 521, phase controller 205, phase-modulator 206 are city's pin product, can appropriately select, or a tractor serves several purposes.

Among Fig. 2, it is the modulation signal of F for the A frequency that signal generator 513 produces an amplitude, phase-modulator 206 of interfering on the arm of modulated light source 101 or modulation interferometer, in interferometer, produce the phase differential that one-period changes, photoelectric detector 309 and 310 detects interferometer two-way output light and transfers electric signal to, after giving A/ D circuit 312 and 313 conversion, the signal of giving frequency that frequency mixer 517 and signal generator 514 produce and be F with and the frequency-doubled signal mixing, after wave filter 518 filtering, behind signal processor 519 process infinitesimal analysis and the plus and minus calculation, through wave filter 520, demodulate the soil vibration and the phase signal of generation by demodulator of PM signal PM 521 at last.

Description of drawings

Fig. 1 optical fiber safety early warning phase control system theory diagram [scheme 1]

Fig. 2 optical fiber safety early warning phase control system theory diagram [scheme 2]

Fig. 3 optical fiber safety early warning phase control system electrical schematic diagram [scheme 1]

Fig. 4 optical fiber safety early warning phase control system electrical schematic diagram [scheme 2]

101-laser instrument 203-channel join-splitting device wherein

204-channel join-splitting device 205-phase controller

The 206-phase-modulator

309-photoelectric detector 310-photoelectric detector

312-signal conditioning circuit 313-signal conditioning circuit

314-A/D capture card 315-A/D capture card

316-signal Processing and arithmetical unit

513-signal generator 514-signal generator

517-frequency mixer 518-wave filter

519-signal processor 520-wave filter

The 521-demodulator of PM signal PM

Embodiment

Embodiment 1. with this example the specific embodiment of the present invention is described and the present invention is further illustrated.This example is an experimental prototype, and it constitutes as shown in Figure 1 and Figure 2.Among the figure, thick connecting line is an optical fiber, and thin connecting line is an electric wire.Specifically constitute: mono-colour laser 101 connects channel join-splitting device 203 continuously, channel join-splitting device 203 connects three optical fiber 1 respectively, 2,3 to channel join-splitting device 204, channel join-splitting device 203, channel join-splitting device 204 and optical fiber 1, optical fiber 2 is formed Mach-Zehnder (Mach-Zehnder) fibre optic interferometer, channel join-splitting device 203 meets photoelectric signal processing circuit 309-1 respectively by two optical fiber, photoelectric signal processing circuit 309-1 output connects A/D capture card 314 and A/D capture card 315 by electric wire respectively, phase control main frame 205-1 is received in 315 outputs of A/D capture card 314 and A/D capture card respectively jointly by electric wire input, and the output of phase control main frame 205-1 through phase controller 205-2 to the phase-modulator 206 that is serially connected in optical fiber 1 or 2.Interference signal is after photoelectric signal processing circuit 309-1 conversion, through amplification filtering, quantize by A/D capture card 314 and 315,205-1 is averaged the phase place that is produced by the external interference amount on a period of time length by the phase control main frame, drive amplifying circuit according to the phase average that calculates and produce a feedback voltage, go control phase modulator 206 to produce compensation of phase, offset the influence of external interference, make interferometer work determine on the working point one.

Wherein single-frequency laser 101 selects model: select KOHERAS ADJUSTIK HP E15; Channel join-splitting device 203 and channel join-splitting device 204 models: the WDM-A-2 * 2-1550-1-FC/UPC-3*54 of Lang Guang company; Phase control main frame 205-1:NI PXI-1050, PXI/SCXI CPU:PXI-8187 P4M 2.5G PXI-6120 A/D 4channel 16bit, D/A2 channel 16-bit; Phase controller 205-2:OZ OPTICS FICEPZ-STD-FC/PC; Phase-modulator 206:OZ OPTICS FICE PZ-STD-FC/PC; Photoelectric signal processing circuit 309-1: universal circuit two optical fiber input ports; Input range :-20～-45dBm, output area :-3V～+ 3V; A/D314, A/D 315 converter model: PXI-6120 A/D 4 channel 16bit, D/A2 channel16-bit.

The one-wavelength laser of continuous mono-colour laser 101 emissions, pass to Mach-Zehnder (Mach-Zehnder) fibre optic interferometer by optical fiber, Mach-Zehnder (Mach-Zehnder) fibre optic interferometer picks up the vibration signal of pipeline soil along the line as continuous distribution formula vibration transducer, passes to photoelectric signal processing circuit 309-1 through optical fiber and is handled.Phase controller 205-1, phase controller 205-2, phase-modulator 206 formed phase fading closed-loop control ring with Mach-Zehnder (Mach-Zehnder) fibre optic interferometer, makes to propagate on Mach-Zehnder (Mach-Zehnder) fibre optic interferometer and form the two-way of interfering and interfere the phase difference value of light wave to be stabilized on the needed phase value of system.

Native system adds optical fiber safety early-warning system, through the actual use of certain pipeline, test, to ground break ground excavation, touch pipeline, welding on pipeline, punching all can predict, detection to the soil vibration signal has very high sensitivity, can effectively detect near the optical cable 3 meters with interior any soil vibration signal, and detection is stable, reliable, there is no omission.

Native system not only is applicable to the safety precaution and the early warning of pipeline; also be applicable to the safety precaution and the early warning of other critical facility and important area, such as: critical facilitys such as communications optical cable, means of transportation, historic reservation, armory, emphasis office and essential industry plant area and regional safeguard protection and strick precaution early warning.

2. examples of embodiment are industrial experiment model machines, and it constitutes as Fig. 2, shown in Figure 4.Among the figure, thick connecting line is an optical fiber, and thin connecting line is an electric wire.Specifically constitute: receive channel join-splitting device 203 by laser instrument 101 usefulness optical fiber, channel join-splitting device 203 is connect two optical inputs of photoelectric signal processing circuit 309-1 respectively by two optical fiber, the two electric delivery outlets of photoelectric signal processing circuit 309-1 are connect the input port of A/D capture card 314 and A/D capture card 315 respectively by electric wire, the delivery outlet of A/D capture card 314 and A/D capture card 315 is received signal demodulation main frame 521-1 jointly; Signal demodulation main frame 521-1 has replaced having frequency mixer 517, wave filter 518, signal processor 519, wave filter 520, the demodulator of PM signal PM 521 of signal generator 514 inputs; The laser instrument 101 usefulness optical fiber number of receiveing letter generators 513 are connect the input of phase controller 205-2 again by signal generator 513 outputs simultaneously, and the output of phase controller 205-2 connects the phase-modulator 205 that is connected in optical fiber 1 or 2.

Photosignal modulate circuit 309-1 wherein: universal circuit two optical fiber input ports; Input range :-20～-45dBm, output area :-3V～+ 3V; A/D capture card 312 and A/D capture card 313 models: PXI-5112,2 channel, 100MHz, 32MB/Channel, 8-bit; Signal demodulation main frame 521-1 model: NIPXI-1042 8-Slot 3U CPU:PXI-8186 P4 2.2 I/O:NI; Signal generator 513 models: Agilent33250A; Phase controller 205-2:OZ OPTICS FICE PZ-STD-FC/PC; Phase-modulator: OZ OPTICS FICE PZ-STD-FC/PC.

Interference signal is after photoelectric signal processing circuit 309-1 conversion, quantize by A/ D capture card 314 and 315, it is the modulation signal of F for the A frequency that signal generator 513 produces an amplitude, phase-modulator 206 of interfering on the arm of modulated laser 101 or modulation interferometer, in interferometer, produce the phase differential that one-period changes, photoelectric signal processing circuit 309-1 detects interferometer two-way output light and transfers electric signal to, after giving A/ D circuit 314 and 315 conversion, the signal of giving frequency that signal demodulation main frame 521-1 produces and be F with and the frequency-doubled signal mixing, through filtering, behind infinitesimal analysis and the plus and minus calculation, pass through filtering again, demodulate the soil vibration at last and the phase signal of generation.

Native system adds optical fiber safety early-warning system, through the actual use of certain pipeline, test, to ground break ground excavation, touch pipeline, welding on pipeline, punching all can stablize and predict, detection to the soil vibration signal has very high sensitivity, can effectively detect near the optical cable 3 meters with interior any soil vibration signal; And detection is stable, reliable, no omission.

Native system not only is applicable to the safety precaution and the early warning of pipeline, also is applicable to the safety precaution and the early warning of other critical facility and important area.

Therefore the present invention can effectively detect near the optical cable 3 meters with interior any soil vibration signal and accurate decision event character; Event detection bearing accuracy height, bearing accuracy can reach ± and 10 meters, monitoring distance is long, and the monitoring distance of single cover system can reach about 120 kilometers; And monitoring is stable, reliable, no omission; Fundamentally eliminated be used for buried pipeline, structures or ground structures, critical facility and zone optical fiber safety early-warning system because of the signal blanking problem that phase fading causes, make optical fiber safety early-warning system stable, reliable.

Claims (6)

1. the optical fiber safety early warning phase control system of the safeguard protection early warning in buried pipeline or structures or critical facility and zone, comprise with the pipeline laying in one ditch or spread on the three piece optical fiber [1] of structures under peripherally, [2], [3] reach by channel join-splitting device [203], channel join-splitting device [204] and optical fiber [1], [2] form Mach-Zehnder (Mach-Zehnder) fibre optic interferometer and laser instrument [101], it is characterized in that laser instrument [101] is connect and channel join-splitting device [204] by optical fiber, optical fiber [1], optical fiber [2] is formed the channel join-splitting device [203] of Mach-Zehnder (Mach-Zehnder) fibre optic interferometer, channel join-splitting device [203] connects photoelectric detector [309] and photoelectric detector [310] respectively by two optical fiber, this two photoelectric detector [309] and photoelectric detector [310] connect signal conditioning circuit [312] and signal conditioning circuit [313] by electric wire respectively afterwards, receive the input of signal Processing and arithmetical unit [316] behind A/D capture card [314] and the A/D capture card [315] jointly, and the output of signal Processing and arithmetical unit [316] through phase controller [205] to the phase-modulator [206] that is serially connected in optical fiber [1] or [2]; Interference signal is after photoelectric detector [309] and [310] conversion, carry out amplification filtering through signal conditioning circuit [312] and [313], quantize by A/D capture card [314] and A/D capture card [315], the phase place that is produced by the external interference amount is averaged on a period of time length by signal Processing and arithmetical unit [316], drive amplifying circuit according to the phase average that calculates and produce a feedback voltage, go control phase modulator [206] to produce compensation of phase, offset the influence of external interference, make interferometer work determine on the working point one.

2. optical fiber safety early warning phase control system according to claim 1, it is characterized in that channel join-splitting device [203] is connect by two optical fiber and has two-way photoelectric detector [309], photoelectric detector [310], the two-way optical input of the photoelectric signal processing circuit [309-1] of signal conditioning circuit [312] and signal conditioning circuit [313] function, the two-way electricity delivery outlet of photoelectric signal processing circuit [309-1] respectively connects an A/D capture card [314] and A/D capture card [315], the output of A/D capture card [314] and A/D capture card [315] connects phase controller main frame [205-1] input port, phase controller main frame [205-1] delivery outlet connects phase controller [205-2], and the delivery outlet of phase controller [205-2] connects the input port of the phase-modulator [206] that is serially connected in optical fiber [1] or [2].

3. optical fiber safety early warning phase control system according to claim 1 and 2 is characterized in that described laser instrument [101] is continuous mono-colour laser.

4. the optical fiber safety early warning phase control system of the safeguard protection early warning in buried pipeline or structures or critical facility and zone, comprise with the pipeline laying in one ditch or spread on the three piece optical fiber [1] of structures under peripherally, [2], [3] reach by channel join-splitting device [203], channel join-splitting device [204] and optical fiber [1], [2] form Mach-Zehnder (Mach-Zehnder) fibre optic interferometer and laser instrument [101], it is characterized in that receiving channel join-splitting device [203] with optical fiber by laser instrument [101], channel join-splitting device [203] connects photoelectric detector [309] and photoelectric detector [310] respectively by two optical fiber, this two photoelectric detector [309] and photoelectric detector [310] are received the frequency mixer [517] that signal generator [514] is imported after connecing A/D capture card [314] and A/D capture card [315] by electric wire respectively afterwards jointly, frequency mixer [517] is exported the following series filter [518], signal processor [519], wave filter [520], demodulator of PM signal PM [521, demodulate the soil vibration and the phase signal of generation; Laser instrument [101] connects the phase-modulator [206] that is connected in optical fiber [1] or [2] by signal generator [513] output again with the optical fiber number of receiveing letter generator [513] simultaneously; Interference signal is after photoelectric detector [309] and [310] conversion, quantize by A/D capture card [314] and [315], it is the modulation signal of F for the A frequency that signal generator [513] produces an amplitude, phase-modulator [206] of interfering on the arm of modulated laser [101] or modulation interferometer, in interferometer, produce the phase differential that one-period changes, photoelectric detector [309] and [310] detect interferometer two-way output light and transfer electric signal to, after giving A/D circuit [314] and [315] conversion, the signal of giving frequency that frequency mixer [517] and signal generator [514] produce and be F with and the frequency-doubled signal mixing, after wave filter [518] filtering, behind signal processor [519] process infinitesimal analysis and the plus and minus calculation, pass through wave filter [520] again, demodulate the soil vibration and the phase signal of generation by demodulator of PM signal PM [521] at last.

5. optical fiber safety early warning phase control system according to claim 4, it is characterized in that channel join-splitting device [203] is connect by two optical fiber and has two-way photoelectric detector [309], photoelectric detector [310], the two-way optical input of the photoelectric signal processing circuit [309-1] of signal conditioning circuit [312] and signal conditioning circuit [313] function, its two-way electricity delivery outlet respectively connects an A/D capture card [314] and A/D capture card [315], the output of A/D capture card [312] and A/D capture card [313] connects has frequency mixer [517], signal generator [514], wave filter [518], signal processor [519], signal demodulation main frame [521-1] input port of wave filter [520] and demodulator of PM signal PM [521] function, signal generator [513] output connects phase controller [205-2], and phase controller [205-2] output connects the phase-modulator [206] that is connected in optical fiber [1] or [2].

6. according to claim 4 or 5 described optical fiber safety early warning phase control systems, it is characterized in that described laser instrument [101] is continuous mono-colour laser.

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