CN109000712A - Cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method - Google Patents
Cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method Download PDFInfo
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- G—PHYSICS
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
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- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
The invention discloses cable tunnel multi-parameter distributed fiber-optic sensor measuring devices, it completes to monitor cable tunnel intrinsic parameter on-line, including laser emission element, laser datum signal element, Laser feedback signal element, control unit, distributed linear transducer array, the control terminal of laser emission element and the output end of control unit connect, the output end of laser emission element is connect with the input terminal of laser datum signal element all the way, another way is connect with the input terminal of distributed linear transducer array, the output end of distributed linear transducer array is connect with the input terminal of Laser feedback signal element, the output end of Laser feedback unit and the input terminal of control unit connect.Realize that temperature, humidity and gas concentration parameters whiles monitor on-line in cable tunnel, structure is simple, low in energy consumption and essential safety.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, are based especially on the multi-parameter distributed sensing of optical time-domain analysis technology
System is mainly used in the multiple spot Distributed Detection of temperature in cable tunnel, humidity and gas concentration.
Background technique
In recent years, with the growth of China's economic strength and the demand of Process of Urbanization Construction, State Grid Corporation of China increases defeated
Power grid cables dynamics of investment refreshes the total mileage of cable tunnel constantly.China has become cable tunnel in the world at present
At most, the most fast country of development.Consequent is that the demand of cable tunnel operation management is greatly increased, wherein right
It is essential in the detection of temperature, humidity and corresponding gas concentration in cable tunnel.However, for upper in current cable tunnel
The detection sensor for stating parameter still rests on the stage of a variety of detection means and relevant device assembling combination mostly, not only senses
Structure is complicated for device, and transducing signal is many and diverse, data transfer demands amount is big, apply at the scene in system power dissipation is big, stability is poor
And it is difficult to realize the essential safety of monitoring.Currently, simple structure, low in energy consumption, essential safety and can are still lacked in cable tunnel
With the system and device detected simultaneously to temperature, humidity and gas concentration, so that temperature, humidity and gas in cable tunnel
The on-line monitoring of bulk concentration parameter is difficult to effectively implement.
Summary of the invention
The object of the present invention is to provide cable tunnel multi-parameter distributed fiber-optic sensor measuring device and measuring method, realize
It is monitored on-line while temperature, humidity and gas concentration parameters in cable tunnel, structure is simple, low in energy consumption and essential safety.
To achieve the above object, the present invention adopts the following technical solutions:
First invention of the present invention provides a kind of cable tunnel multi-parameter distributed fiber-optic sensor measuring device, completes to electricity
Cable tunnel intrinsic parameter on-line monitoring, including laser emission element, laser datum signal element, Laser feedback signal element, control
Unit, distributed linear transducer array, the control terminal of laser emission element and the output end of control unit connect, laser emission element
Output end is connect with the input terminal of laser datum signal element all the way, and another way is connect with the input terminal of distributed linear transducer array,
The output end of distributed linear transducer array is connect with the input terminal of Laser feedback signal element, the output end of Laser feedback unit and control
The input terminal of unit processed connects.
Further, laser emission element includes first laser device and second laser, first laser device and second laser
The input terminal of device is electrically connected with laser high-frequency driving circuit/temperature control circuit respectively, laser high-frequency driving circuit/temperature control circuit
It is electrically connected with control unit；The pulse laser beam that first laser device and second laser issue enters the after the first beam splitter
Two beam splitters, a branch of after the second beam splitter beam splitting to enter laser datum signal element, another beam enters distributed linear transducer array.
Further, the laser datum signal element includes third wavelength division multiplexer, third photodetector and the 4th
Photodetector；Light into laser datum signal element is allocated as two beams after third wavelength division multiplexer, and first laser device goes out
It penetrates light and enters third photodetector, the emergent light of second laser enters the 4th photodetector；Third photodetector and
The photosignal that 4th photodetector responds is sent to control unit by the acquisition of multi-channel high-speed data Acquisition Circuit, makees
For the reference signal of optical signal analysis.
Further, another beam emergent light of the second beam splitter enters the second wavelength division multiplexer all the way after circulator, the
The emergent light of two wavelength division multiplexers is divided into two bundles: the emergent light of first laser device and the emergent light of second laser respectively enter point
Cloth linear transducer array；The reflected light of distributed linear transducer array is returned according to original route, and it is multiple that first wave point is entered after circulator
With device, the emergent light of the first wavelength division multiplexer is allocated as two beams, the reflected light pass of first laser device to the first photodetector, and
The reflected light pass of dual-laser device is to the second photodetector；The output photoelectric of first photodetector and the second photodetector
Signal is connect with multi-channel high-speed data Acquisition Circuit, and multi-channel high-speed data Acquisition Circuit is electrically connected with control unit.
Further, the distributed linear transducer array includes the probe of several series connections, is concatenated between adjacent two probe
There is the delayer for amplifying laser signal；The probe includes gas chamber, the first fiber grating, the second fiber grating and third light
Fine grating；First fiber grating and the second fiber grating characteristic wavelength are different, first laser device emergent light the first light of directive
Fine grating rear portion light is reflected along original route, a part of directive of emergent light after another part light the second fiber grating of directive
Delayer, another part are reflected along original route；The emergent light of second laser directive after gas chamber is absorbed by under test gas
Three fiber gratings, a part of directive delayer of emergent light, another part are reflected along original route.
Further, the plenum surface is provided with several holes, and gas chamber is connected by hole with external environment, completes
Extraneous environmental gas is detected.
Second aspect of the present invention provides cable tunnel multi-parameter distributed fiber-optic sensor measurement method, specific as follows:
The reflection echo signal of the different probes of distributed linear transducer array will reach the first photodetector in different moments
With the second photodetector, by being demodulated to the echo-signal in time domain, realize to temperature at different probes, humidity and
The demodulation of gas concentration information.
Further, first laser device outgoing light wavelength is scanned by short and length, and demodulation obtains distributed linear transducer array
In the first fiber grating reflection echo signal IT1’、IT2’、……、ITn' and the second fiber grating reflection echo signal IH1’、
IH2’、……、IHn'；By monitoring the drift of reflection echo signal wavelength, temperature and wet is completed according to fiber grating characteristic parameter
Spend the deduction of detection parameters.
Further, a beam intensity of second laser is IG0Pulse reach first probe, first probe in by gas
Intensity becomes I after gas in room absorbsG1, after the part reflection of the third fiber grating of the first probe, a part of pulse
Light beam is reflected, intensity IG1r31, another part pulsed light beam is transmitted through third fiber grating, and it is backward to pass through delayer
It pops one's head in and transmits, intensity IG1t31；Wherein r31For first probe in third fiber grating reflectivity, and transmit intensity
For IG1t31Pulsed light beam by second probe in gas indoor gas absorption after its intensity become IG2, reflect a part of pulse
Light beam, intensity IG2r31, transmit a part of pulsed light beam, intensity IG2t31；And so on, until the n that pops one's head in；
For the echo-signal I for 1 fiber grating 3 of popping one's head inG1',
Wherein, α1For constant related with gas chamber in the first probe and under test gas characteristic absorption wavelength, c1For gas Indoor Air
The concentration of body；
Similarly, for the echo-signal I for 2 fiber gratings 3 of popping one's head inG2',
And so on, for echo-signal IGn',
Based on formula (1)-(n), pass through the echo-signal I of acquisitionG1’、IG2’、……、IGn', may finally inverting obtain
The concentration value of under test gas at each probe.
The effect provided in summary of the invention is only the effect of embodiment, rather than invents all whole effects, above-mentioned
A technical solution in technical solution have the following advantages that or the utility model has the advantages that
1, the device of temperature, humidity and gas concentration parameters detection is serially connected on optical fiber by the present invention, to more ginsengs
When number is detected, the simple concatenation by multiple sensors is realized to the leap of system effective integration, really proposes one kind one
Multi-parameter (temperature, humidity, gas concentration) detection device of body；
2, system uses optical time-domain analysis technology, and beam of laser pulse can realize multiple spot while detect, and greatly improve light source
Utilization efficiency；
3, detection device uses distributed frame, only can be realized by two optical fiber to multiple to be measured within the scope of long range
The detection of point, greatly reduces the quantity of probe source, effectively reduces the power consumption of detection system, while price is cheaper；
4, in monitoring field, proposed detection device is the optical fiber transmission of optical signal, from the influence of electromagnetic interference, and
Detection process without hot line job, has essential safety attribute at the scene.
Detailed description of the invention
Fig. 1 is cable tunnel multi-parameter distributed fiber-optic sensor measuring device structural schematic diagram of the present invention；
Fig. 2 is the distribution of optical signal and the explanation schematic diagram of echo-signal in each probe of the invention.
Specific embodiment
In order to clarify the technical characteristics of the invention, below by specific embodiment, and its attached drawing is combined, to this hair
It is bright to be described in detail.Following disclosure provides many different embodiments or example is used to realize different knots of the invention
Structure.In order to simplify disclosure of the invention, hereinafter the component of specific examples and setting are described.In addition, the present invention can be with
Repeat reference numerals and/or letter in different examples.This repetition is that for purposes of simplicity and clarity, itself is not indicated
Relationship between various embodiments and/or setting is discussed.It should be noted that illustrated component is not necessarily to scale in the accompanying drawings
It draws.Present invention omits the descriptions to known assemblies and treatment technology and process to avoid the present invention is unnecessarily limiting.
System and device proposed by the invention as shown in Figure 1, mainly by laser high-frequency driving circuit/temperature control circuit, swash
Light device 1, laser 2, beam splitter 1, beam splitter 2, circulator, wavelength division multiplexer 1, wavelength division multiplexer 2, wavelength division multiplexer 3, delay
Device, photodetector 1 (PD1), photodetector 2 (PD2), photodetector 3 (PD3), photodetector 4 (PD4), multichannel
High Speed Data Acquisition Circuit, microcontroller (MCU) and distributed linear transducer array.
Wherein distributed linear transducer array by probe 1, probe 2 ..., probe n forms.Each probe is by gas chamber, light
Fine grating 1, fiber grating 2 and fiber grating 3 form.Wherein fiber grating 1 is different from the characteristic wavelength of fiber grating 2, point
It Yong Yu not be to the perception of environment temperature and humidity, and with the variation of environment temperature and humidity, the characteristic wavelength of two fiber gratings
It will not be overlapped.Fiber grating 3 is chirp grating, and gas to be measured can be completely covered in characteristic wavelength wider range of reflection
The broadening of body absorption peak.
Laser 1 is electrically connected with laser high-frequency driving circuit/temperature control circuit respectively with laser 2, receives driving, temperature control
The control of circuit.Photodetector 1, photodetector 2, photodetector 3, photodetector 4 are adopted with multi-channel high-speed data
Collector electrical connection, multi-channel high-speed data Acquisition Circuit are electrically connected with MCU, and multi-channel high-speed data Acquisition Circuit is in microcontroller
The photosignal that acquisition photodetector generates under the control of device further will acquire signal feeding microcontroller and carry out calculating solution
It adjusts.Laser, beam splitter, circulator, wavelength division multiplexer, delayer, probe and fiber grating in probe, gas chamber is according to such as
Mode shown in FIG. 1 is connected by optical fiber.
Gas chamber is connected by punching thereon with external environment, for detecting to the gas in environment.Laser 1
It is corresponding with fiber grating 1, the fiber grating 2 in probe, the active probe light source as environment temperature, humidity.1 wave of laser
The characteristic wavelength of long scan range covering fiber grating 1 and fiber grating 2.Even if environment temperature and humidity change, light
The characteristic wavelength of fine grating 1 and fiber grating 2 is still within the scope of the scanning wavelength of laser 1.
Laser 2 is corresponding with the fiber grating 3 in probe, and as the active probe light source of gas concentration, wavelength is swept
It is consistent with the wavelength where the Absorption Characteristics spectrum of under test gas to retouch range.
Under laser high-frequency driving circuit/temperature control circuit drive control, laser 1 is launched respectively with laser 2
The pulse laser beam of length scanning.The pulse laser beam that two-laser is launched after beam splitter 1 enter same root optical fiber into
Row transmission.After 2 beam splitting of beam splitter, a part enters circulator, and another part enters wavelength division multiplexer 3.It is multiple into wavelength-division
It is divided into two beams according to wavelength difference after being divided with that a part of device 3, a branch of emergent light for laser 1, another beam is sharp
The emergent light of light device 2.Two pulses light arrives separately at photodetector 3 (PD3) and photodetector 4 (PD4) and responds out light
Electric signal.Gained photosignal is obtained by multi-channel high-speed data Acquisition Circuit and the reference signal as optical signal analysis.Through
It crosses another beam pulse light that beam splitter 2 separates and reaches wavelength division multiplexer 2 after circulator guides.
It is emitted from two-laser and the pulse laser beam with different wave length is divided into two beams by wavelength division multiplexer 2, wherein one
The light beam that beam is emitted by laser 1 is transmitted into probe 1 and towards fiber grating 1 and fiber grating 2；Another beam is sharp
The light beam that light device 2 is emitted is transmitted into probe 1 and towards gas chamber, fiber grating 3.The laser beam-wave that laser 1 is launched
The long ascending characteristic wavelength for being initially coated with fiber grating 1, passes through the variation of the drift sense ambient temperature of its characteristic wavelength；
The characteristic wavelength of further covering fiber grating 2 is passed through into its characteristic wavelength then as the red shift of laser beam-wave long scan
The variation of drift perception ambient humidity.After the light beam that laser 1 is emitted enters probe 1, in the short-wave band section of scanning by optical fiber
1 part of grating reflection, another part energy transmission, and fiber grating 2 for this wave band without any reflection effect, light beam is completely saturating
It penetrates；In the long-wave band section of scanning, laser beam is reflected by 2 part of fiber grating, another part energy transmission, and fiber grating 1
For this wave band without any reflection effect, light beam is wholly transmissive.After the light beam that laser 2 is emitted enters probe 1, gas is first passed around
Room is simultaneously partially absorbed by under test gas, and remaining beam energy is further to fiber grating 3 and is partially reflected, another part light
Beam transmission.
The light beam of reflection is returned along incident original route, and the light beam by corresponding to two-laser after wavelength division multiplexer 2 closes
Two is are transmitted to circulator together, and reach wavelength division multiplexer 1 by the guidance of circulator.Pulsed light beam passes through wavelength division multiplexer
1 light splitting is again broken down into two beams, wherein a branch of correspond to laser 1, and is transmitted to photodetector 1 and causes photosignal, should
Photosignal has reacted the response message of fiber grating 1 and fiber grating 2 in probe, to carry temperature and humidity at probe
Information；Another beam corresponds to laser 2, and is transmitted to photodetector 2 and causes photosignal, and the photosignal is by optical fiber light
Grid 3 reflect and reflect gas indoor gas in probe, and it is dense to carry gas at probe to the absorbing state of 2 outgoing beam of laser
Spend information.In probe 1, the light beam transmitted will all continue to be transmitted to spy either from laser 1 or laser 2
Delayer between first 1 and probe 2.Delayer increases the light path of pulse laser beam transmission, to extend the time of its transmission.Through
Light beam continues to be transmitted in probe 2 after crossing delayer, and repeats its circulation way in probe 1.And so on, correspond to two
The detection light beam of sublaser will each probe occur part reflection and fractional transmission, transmitted light beam will successively from probe 1 by
It is a to be transmitted to probe n.At probe n, fiber grating 1, fiber grating 2 and fiber grating 3 are to corresponding reflected waveband
It is totally reflected.
For photodetector 1 and photodetector 2, the echo-signal of difference probe will successively be reached in different moments,
A series of echo-signals are formed with identical interval in the time domain.By being demodulated to the echo-signal in time domain, will realize
Demodulation to temperature, humidity and gas concentration information at different probes.
The wavelength of 1 outgoing pulse light beam of laser is scanned by short and length, and probe inner fiber grating 1 can be completely covered
With the reflectance signature wavelength of fiber grating 2.Temperature, humidity in the reflectance signature wavelength of grating and probe in environment to be measured is at line
Sexual intercourse, by detect two gratings reflectance signature wavelength and its drift can to the temperature and humidity parameter in each probe into
Row inverting demodulation.
As shown in Fig. 2, obtaining the reflection echo signal I of fiber grating 1 in each probe in demodulationT1’、IT2’、……、
ITn' and fiber grating 2 reflection echo signal IH1’、IH2’、……、IHn'.By monitoring the drift of echo-signal wavelength, root
According to the characteristic parameter of fiber grating, the inverting of relevant temperature and humidity parameter can be fast implemented.
The pulsed light beam energy that laser 2 is emitted is equally divided into two beams by beam splitter 2, and a branch of arrival photodetection 4 causes
Intensity is IG0Photosignal.Another beam intensity is IG0Pulse reach probe 1.It is absorbed in probe 1 by the gas in gas chamber
Intensity becomes I afterwardsG1, after the reflection of the part of fiber grating 3, a part of pulsed light beam is reflected, intensity IG1r31, separately
A part of pulsed light beam transmits, intensity I transmitted through grating, and after delayer to probeG1t31.Wherein r31To visit
The reflectivity of fiber grating 3 in first 1.And the intensity transmitted is IG1t31Pulsed light beam by probe 2 in gas indoor gas suction
Its intensity becomes I after receiptsG2, the process being similar in probe 1 then occurs, reflects a part of pulsed light beam, intensity is
IG2r31, transmit a part of pulsed light beam, intensity IG2t31.This process and so on, until the n that pops one's head in.For 1 optical fiber of popping one's head in
The echo-signal I of grating 3G1',
Wherein α1For constant related with gas chamber in probe 1 and under test gas characteristic absorption wavelength, c1For gas indoor gas
Concentration.Similarly, for the echo-signal I for 2 fiber gratings 3 of popping one's head inG2',
And so on, for echo-signal IGn',
Based on formula (1)-(n), pass through the echo-signal I of acquisitionG1’、IG2’、……、IGn' may finally inverting obtain respectively
The concentration value of under test gas at a probe.
By taking the detection of temperature, humidity and methane gas in cable tunnel as an example.Choose laser 1 central wavelength be
1530nm, scanning range are 1528nm to 1532nm.The central wavelength for choosing laser 2 is 1653.7, scanning range 1nm, first
Alkane gas has significant Absorption Characteristics peak in this wave band.Microcontroller is using certain time interval T as the period, to laser driving circuit
Stair-stepping digital signal is sent, i.e. digital signal value is sequentially increased over time, shows ladder-like, but each side
The period of wave signal is T；In bigger time range T0, microcontroller is repeated the above process, and repetition exports above-mentioned ladder
The discrete signal of shape.Laser driving circuit, which converts this stair-stepping periodic digital signal to using time T0 as modulus of periodicity, to be intended
Sawtooch sweep current signal, and its lasting control electric current input for being injected into laser 1 and laser 2 is drawn respectively
Foot.Two-laser swashs in the lasting output wavelength pulse from short to long of the control periodical of this sawtooch sweep current signal
Light beam.
The pulse laser beam of two-laser outgoing enters an optical fiber by beam splitter 1 and is split by beam splitter 2.
A part, by being further divided into two beams by wave band after wavelength division multiplexer 3, respectively the emergent light of laser 1 and swashs as reference light
The emergent light of light device 2.Two pulsed light beams cause the response of photodetector 3 Yu photodetector 4 respectively, generate final reference
Signal.Another beam pulse that beam splitter 2 separates enters wavelength division multiplexer 2 under the guidance of circulator and is divided.With above-mentioned wave
Situation in division multiplexer 3 is similar, and pulsed light beam is divided into two beams, a branch of to be emitted by laser 1, and another beam is laser 2
It is emitted.Two pulses are transmitted along two optical fiber respectively, successively by probe 1, probe 2 ..., probe n and probe
Between delayer.In each probe, when the outgoing pulse light beam scanning wave band of laser 1 is located at 1528nm to 1530nm wave
Duan Shi, the outgoing pulse part from laser 1 are reflected by fiber grating 1, remaining transmission, and fiber grating 2 is for the wave
Section pulse without any reflex, completely through.The pulsed light in this wave band by by the fiber grating 1 in each probe successively
Reflection, and different moments in the time domain eventually arrive at photodetector 1.By each moment in 1 gained time domain of photodetector
Acquired echo-signal takes ratio for removing the shake of laser 1 with 3 gained reference signal of photodetector respectively, thus
It is accurately obtained the wavelength of reflected light signal.Relationship based on fiber grating reflectance signature wavelength and environment temperature, when passing through demodulation
The detection to environment temperature at each probe positions may be implemented in the wavelength of the reflected light signal at each moment on domain.Similar,
When 1 outgoing pulse light beam of laser scanning wave band is in 1530nm to 1532nm wave band, the fiber grating 1 in each probe is right
Pulsed light beam is without any reflex, and fiber grating 2 has part reflex for pulsed light beam.Arteries and veins in this wave band
Washing off will successively be reflected by the fiber grating 2 in each probe, and different moments in the time domain eventually arrive at photodetector
1.It is same as described above, by echo-signal acquired in each moment in 1 gained time domain of photodetector respectively with photodetector 3
Gained reference signal takes ratio for removing the shake of laser 1, to be accurately obtained the wavelength of reflected light signal.Based on optical fiber
The relationship of optical grating reflection characteristic wavelength and ambient humidity, can be with by the wavelength of the reflected light signal at each moment in demodulation time domain
Realize the detection to ambient humidity at each probe positions.Laser 2 be emitted pulse laser scanning wavelength be with 1653.7nm
Central wavelength, using 1nm as scanning range.It, can be in entire 2 outgoing pulse of laser since fiber grating 3 belongs to chirp grating
There is part reflex to pulsed light in optical scanning wavelength band.In each probe, corresponding pulsed light passes through gas chamber
When partially absorbed by the under test gas in it.The echo signal intensity of each probe and the concentration of gas chamber in each probe are showed
For example described formula (the 1)-formula (n) of relationship stated.Photodetector 2 will successively respond 2 outgoing pulse light beam of laser
Echo-signal, and acquired in multi-channel high-speed data Acquisition Circuit.It is closed according to recursion described in formula (1)-formula (n)
It is that the processing routine in microcontroller successively demodulation inverting will obtain the concentration value of methane gas in gas chamber.Laser 1 and laser
Device 2 respectively works independently, and due to using wavelength division multiplexer, two-laser outgoing pulse light beam is mutually noiseless, in time domain
Echo-signal is responded by two photodetectors respectively and is sent into multi-channel high-speed data Acquisition Circuit system.It is demodulated in signal
Cheng Zhong, the two are mutually indepedent.Only one wavelength of the pulsed light that laser is emitted every time, and each outgoing over time
The wavelength of pulse gradually increases, and until entire scan period T0 terminates, restarts new one and discusses scanning process.Although laser 1
Both for being also used for the detection to humidity to the detection of temperature, but due to the mode of laser pulse output, for temperature
The echo-signal that the detection of degree is reflected using fiber grating 1 reflects the detection of humidity using fiber grating 2
Echo-signal.Two groups of echo-signals are completely independent separation in the time domain, and same nothing interferes with each other.
Above-mentioned, although the foregoing specific embodiments of the present invention is described with reference to the accompanying drawings, not protects model to the present invention
The limitation enclosed, those skilled in the art should understand that, based on the technical solutions of the present invention, those skilled in the art are not
Need to make the creative labor the various modifications or changes that can be made still within protection scope of the present invention.
Claims (9)
1. cable tunnel multi-parameter distributed fiber-optic sensor measuring device is completed to monitor cable tunnel intrinsic parameter on-line, special
Sign is, including laser emission element, laser datum signal element, Laser feedback signal element, control unit, distributed probe battle array
The output end of column, the control terminal of laser emission element and control unit connects, the output end of laser emission element all the way with laser
The input terminal of reference signal unit connects, and another way is connect with the input terminal of distributed linear transducer array, distributed linear transducer array
Output end is connect with the input terminal of Laser feedback signal element, and the output end of Laser feedback unit and the input terminal of control unit connect
It connects.
2. multi-parameter distributed fiber-optic sensor measuring device in cable tunnel as described in claim 1, characterized in that Laser emission
Unit includes first laser device and second laser, the input terminal of first laser device and second laser respectively with laser high-frequency
Driving circuit/temperature control circuit electrical connection, laser high-frequency driving circuit/temperature control circuit are electrically connected with control unit；First laser
The pulse laser beam that device and second laser issue enters the second beam splitter after the first beam splitter, after the second beam splitter beam splitting
A branch of to enter laser datum signal element, another beam enters distributed linear transducer array.
3. multi-parameter distributed fiber-optic sensor measuring device in cable tunnel as claimed in claim 2, characterized in that the laser
Reference signal unit includes third wavelength division multiplexer, third photodetector and the 4th photodetector；Into laser-based definite message or answer
The light of number unit is allocated as two beams after third wavelength division multiplexer, and the emergent light of first laser device enters third photodetector, and
The emergent light of dual-laser device enters the 4th photodetector；The light that third photodetector and the 4th photodetector respond
Electric signal is sent to control unit by the acquisition of multi-channel high-speed data Acquisition Circuit, the reference signal as optical signal analysis.
4. multi-parameter distributed fiber-optic sensor measuring device in cable tunnel as claimed in claim 2, characterized in that the second beam splitting
Another beam emergent light of device enters the second wavelength division multiplexer all the way after circulator, and the emergent light of the second wavelength division multiplexer is divided into two
Beam: the emergent light of first laser device and the emergent light of second laser respectively enter distributed linear transducer array；Distribution probe battle array
The reflected light of column is returned according to original route, and first wave division multiplexer, the outgoing of the first wavelength division multiplexer are entered after circulator
Light is allocated as two beams, the reflected light pass of first laser device to the first photodetector, the reflected light pass of second laser to
Two photodetectors；The output photoelectric signal of first photodetector and the second photodetector and multi-channel high-speed data acquire
Circuit connection, multi-channel high-speed data Acquisition Circuit are electrically connected with control unit.
5. multi-parameter distributed fiber-optic sensor measuring device in cable tunnel as claimed in claim 4, characterized in that the distribution
Formula linear transducer array includes the probe of several series connections, and the delay for amplifying laser signal is serially connected between adjacent two probe
Device；The probe includes gas chamber, the first fiber grating, the second fiber grating and third fiber grating；First fiber grating
Different with the second fiber grating characteristic wavelength, first laser device emergent light directive the first fiber grating rear portion light is along former road
Diameter reflects, and a part of directive delayer of emergent light after another part light the second fiber grating of directive, another part is along original route
Reflection；The emergent light of second laser directive third fiber grating after gas chamber is absorbed by under test gas, emergent light a part
Directive delayer, another part are reflected along original route.
6. multi-parameter distributed fiber-optic sensor measuring device in cable tunnel as claimed in claim 4, characterized in that the gas chamber
Surface is provided with several holes, and gas chamber is connected by hole with external environment, and completion detects extraneous environmental gas.
7. cable tunnel multi-parameter distributed fiber-optic sensor measurement method, characterized in that specific as follows:
The reflection echo signals of the different probes of distributed linear transducer array will reach the first photodetector and the in different moments
Two photodetectors are realized by demodulating to the echo-signal in time domain to temperature, humidity and gas at different probes
The demodulation of concentration information.
8. multi-parameter distributed fiber-optic sensor measurement method in cable tunnel as claimed in claim 7, characterized in that first laser
Device outgoing light wavelength is scanned by short and length, and demodulation obtains the first fiber grating reflection echo signal in distributed linear transducer array
IT1’、IT2’、……、ITn' and the second fiber grating reflection echo signal IH1’、IH2’、……、IHn'；It is reflected by monitoring
The deduction of temperature and humidity detection parameters is completed in the drift of echo-signal wavelength according to fiber grating characteristic parameter.
9. multi-parameter distributed fiber-optic sensor measurement method in cable tunnel as claimed in claim 7, characterized in that second laser
One beam intensity of device is IG0Pulse reach first probe, first probe in by gas chamber gas absorb after intensity become
IG1, after the part reflection of the third fiber grating of the first probe, a part of pulsed light beam is reflected, intensity IG1r31,
Another part pulsed light beam transmits, intensity I transmitted through third fiber grating, and after delayer to probeG1t31；
Wherein r31For first probe in third fiber grating reflectivity, and transmit intensity be IG1t31Pulsed light beam pass through second
Its intensity becomes I after the absorption of gas indoor gas in probeG2, reflect a part of pulsed light beam, intensity IG2r31, transmission one
Partial pulse light beam, intensity IG2t31；And so on, until the n that pops one's head in；
For the echo-signal I for 1 fiber grating 3 of popping one's head inG1',
Wherein, α1For constant related with gas chamber in the first probe and under test gas characteristic absorption wavelength, c1For gas indoor gas
Concentration；
Similarly, for the echo-signal I for 2 fiber gratings 3 of popping one's head inG2',
And so on, for echo-signal IGn',
Based on formula (1)-(n), pass through the echo-signal I of acquisitionG1’、IG2’、……、IGn', may finally inverting obtain it is each
The concentration value of under test gas at probe.
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