CN104864911A - High-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement - Google Patents
High-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement Download PDFInfo
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Abstract
The invention relates to a high-speed demodulation device and method based on fiber fabry-perot cavity and fiber grating combined measurement. The high-speed demodulation device comprises a power supply module, a 3dB coupler, a circulator, a sensing unit and a demodulation unit. The high-speed demodulation method comprises that the relation among the demodulation error amount, the temperature variation and the pressure/strain variation of a fiber grating is obtained via calibration, and relation among the length variation of a fiber fabry-perot cavity, the temperature variation and the pressure/strain variation is obtained via calibration; the length variation of the fiber fabry-perot cavity and the drift amount of the wavelength of a reflection center of the fiber grating are modulated; and the temperature variation and the pressure/strain variation are solved. Compared with the prior art, double parameters can be measured via rapid demodulation on the basis of fiber fabry-perot cavity and fiber grating sensing, influence of fiber fabry-perot interference spectrum on temperature measurement caused by fiber grating modulation is compensated, and the cost is low.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, particularly relate to a kind of high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating and method.
Background technology
In recent years; based on Fibre Optical Sensor two parameters (temperature, pressure/strain) simultaneously sensing technology be a very active research field, this kind of sensing is mainly used in the structural health self diagnosis, environment self-adaption, damage self-healing etc. of compound substance, heavy construction structure, aerospace vehicle, war products etc.
Fabry-perot optical fiber chamber is by the long change obtaining external physical quantity in demodulation chamber as sensor, the advantages such as it has that structure is simple, volume is little, easy for installation, high reliability, high sensitivity, fast response, single fiber Signal transmissions, become one of focus of optical fiber sensing technology and applied research.Fiber grating is realized detection to be measured by the drift value of demodulating fiber bragg grating reflection kernel wavelength, and its sourceless characteristic, electromagnetism interference, corrosion-resistant and temperature tolerance etc. make fiber grating be adapted at carrying out health monitoring in some rugged surroundings.In recent years, Fabry-perot optical fiber chamber was combined with the characteristic of fiber grating, realized two parameter measurement, received the concern of scholars.
In prior art, to in the technology of Fabry-perot optical fiber chamber and the demodulation of fiber grating composite sensing [as document 1: Rao Yunjiang, Zeng Xiangkai, Zhu Yong etc., extrinsic Fabry-Perot interferometer optical fibre Bragg optical grating strain temperature sensor and application [J] thereof. Acta Optica, 2002,22 (1): 85-88; Document 2:Baochen Sun, Liping Yang, Yanliang Du, et al.Research onintegrated fibre Bragg grating/extrinsic Fabry-Perot sensor [C], Proceedings of the 6th WorldCongress on Intelligent Control and Automation, Dalian, China, 2006; ], general employing spectrometer scanning optical spectrum, by observing spectral information, utilize phase demodulating method to the chamber progress row demodulation in Fabry-perot optical fiber chamber, the amount of movement directly observing fiber bragg grating center wavelength in spectrum carries out demodulation to fiber grating reflection kernel wavelength.Existing this demodulation mode, demodulation speed is slow, can not meet the requirement of fast demodulation.
Summary of the invention
For the problem that existing demodulation speed is slow, the invention provides a kind of high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating and method.The high-speed demodulating apparatus of of the present invention pair of parameter combined measurement and method, be applicable to the measurement based on Fabry-perot optical fiber chamber and optical fiber Bragg grating sensing, can realize Quick Measurement to temperature, pressure/strain variation in environment.
A kind of high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating provided by the invention, comprising: light source module, three-dB coupler, circulator, sensing unit and demodulating unit.
Described light source module comprises three narrow-band light source and wide spectrum light source, the spectrum of three narrow-band light source and the spectrum non-overlapping copies of wide spectrum light source; Described sensing unit comprises Fabry-perot optical fiber chamber sensing arrangement and optical fiber grating sensing structure; Described demodulating unit comprises 1 × 3 dense wave division multiplexer (DWDM), 1 × 2 Coarse Wave Division Multiplexer (CWDM), photodetector, signal conditioning circuit, data collecting card and computing machine.
After the three beams laser of narrowband sent in light source module and a branch of wide spectrum optical are transferred to the three-dB coupler of 4 × 1 by four single-mode fibers simultaneously, four bundle light are mapped in circulator through being coupled into, and then import sensing unit into.
The light signal importing sensing unit into first enters to inject optical fiber grating sensing structure, the light wave meeting fiber grating reflection kernel wavelength is reflected, other light-wave transmission enters Fabry-perot optical fiber chamber sensing arrangement and multiple-beam interference occurs wherein, interference light returns optical fiber grating sensing structure and by its direct transmission, interference light is formed with the reflected light of fiber grating and superposes spectrum.
Superposition spectrum enters to inject 1 × 3DWDM and 1 × 2CWDM respectively through the three-dB coupler of 1 × 2, light signal is divided into five tunnels.1 × 3DWDM and three narrow-band light source matches, and the chamber that the three-beam exported by 1 × 3DWDM is used for demodulation Fabry-perot optical fiber chamber is long; The two-beam that 1 × 2CWDM exports is used for the demodulation of fiber grating reflection kernel wavelength.Five road light signals are converted to electric signal through photodetector and enter signal condition unit, and electric signal changes digital signal into through signal condition unit and is transferred to computing machine by data collecting card and stores.In a computer demodulation is carried out to electric signal, obtain the change of cavity length amount in Fabry-perot optical fiber chamber and the drift value of fiber grating reflection kernel wavelength.
Described sensing unit is the compound sensor that the fiber grating of Fabry-perot optical fiber chamber and Non-stress packaging forms, or the cascaded structure of Fabry-perot optical fiber pressure/strain transducer and fiber-optical grating temperature sensor.
According to the requirement of demodulation to light source, described narrow-band light source is Distributed Feedback Laser, and described wide spectrum light source adopts amplified spontaneous emission source (ASE) or the super-fluorescence light source (SFS) based on doped fiber.
Based on above-mentioned high-speed demodulating apparatus, present invention also offers a kind of high speed demodulation method based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating, comprise following concrete steps:
Step one: carry out calibration experiment, obtains the error drift amount Δ λ that demodulating fiber bragg grating reflection kernel wavelength causes
1and the relation between variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X, as follows:
Δλ
1＝K
1ΔT+K
2ΔX (1)
Obtain the change of cavity length amount Δ L in Fabry-perot optical fiber chamber and the relation between variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X:
ΔL＝K
3ΔT+K
4ΔX (2)
Step 2: the drift value of the change of cavity length amount in demodulation Fabry-perot optical fiber chamber and the reflection kernel wavelength of fiber grating;
Obtained the change of cavity length amount Δ L in Fabry-perot optical fiber chamber by three wavelength numeral phase demodulating method demodulation, obtained the drift value Δ λ of fiber grating reflection kernel wavelength by the demodulation of edge filter method; Wherein, Δ λ contains the demodulating error drift value Δ λ of fiber grating reflection kernel wavelength
1with the practical center wavelength shift Δ λ of fiber grating caused by temperature variation
2, the drift value Δ λ of fiber grating reflection kernel wavelength reality
2can be expressed as:
Δλ
2＝Δλ-Δλ
1(3)
Step 3: solve temperature variation Δ T and pressure/strain variation amount Δ X
Utilize formula (1), (2), (3), and the actual drift value Δ λ of integrated temperature variation delta T and fiber bragg grating center wavelength
2between relation, obtaining temperature variation Δ T can be expressed as:
The variation delta X of pressure/strain is:
In formula (4), (5), A is the temperature sensitive coefficient of fiber grating.Formula (4), (5) are utilized finally to obtain the variable quantity of temperature and pressure/strain in environment.
The present invention has following beneficial effect: the present invention is based on the advantage that the demodulation speed of intensity demodulation is fast, complete the demodulating equipment of Quick Measurement and the design of method simultaneously of two parameter (temperature, pressure/strain), make two parameter can Quick Measurement simultaneously; On the other hand, by calibration experiment, compensate for the impact that the interference spectum that returns due to Fabry-perot optical fiber chamber causes temperature survey demodulating fiber bragg grating, make measurement result more accurate; Demodulation scheme is avoided using traditional spectrometer high based on the price required for Fabry-perot optical fiber chamber and fiber grating two parameter measurement, and demodulation cost is declined greatly.
Accompanying drawing explanation
Fig. 1 is the high-speed demodulating apparatus structural representation based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating of the present invention;
Fig. 2 is that in the present invention, wide spectrum optical superposes spectrum schematic diagram through the emulation that Fabry-perot optical fiber chamber returns after fiber grating;
Fig. 3 is the experimental provision schematic diagram of relation between the demodulating error drift value of demarcation optical fiber optical grating reflection centre wavelength provided by the invention and temperature variation;
When Fig. 4 is without pressure/effects of strain, what wide spectrum optical returned after fiber grating through Fabry-perot optical fiber chamber superposes the emulation superimposed light spectrogram of spectrum before and after variation of ambient temperature;
Fig. 5 is the experimental provision schematic diagram of relation between the demodulating error drift value of demarcation optical fiber optical grating reflection centre wavelength provided by the invention and pressure/strain variation amount;
When Fig. 6 is without temperature variation, what wide spectrum optical returned after fiber grating through Fabry-perot optical fiber chamber superposes the emulation superimposed light spectrogram of spectrum before and after environmental pressure/strain variation;
When Fig. 7 is without temperature variation, the detailed schematic superposing fiber grating part in the emulation superimposed light spectrogram of spectrum before and after environmental pressure/strain variation that wide spectrum optical returns after fiber grating through Fabry-perot optical fiber chamber;
Fig. 8 is the experimental provision schematic diagram of relation between the change of cavity length amount in demarcation Fabry-perot optical fiber chamber provided by the invention and temperature variation, pressure/strain variation amount;
Fig. 9 is the experimental provision schematic diagram demarcating optical fiber grating temperature sensitivity in the present invention.
Wherein:
1-light source module, 2-first Distributed Feedback Laser, 3-second Distributed Feedback Laser, 4-the 3rd Distributed Feedback Laser, 5-wide spectrum light source, 6-single-mode fiber, the three-dB coupler of 7-4 × 1, 8-circulator, the three-dB coupler of 9-1 × 2, 10-optical fiber grating sensing structure, 11-Fabry-perot optical fiber chamber sensing arrangement, 12-sensing unit, 13-1 × 3DWDM, 14-1 × 2CWDM, 15-photodetector, 16-signal conditioning circuit, 17-data collecting card, 18-computing machine, 19-demodulating unit, 20-fiber grating reflectance spectrum, 21-Fabry-perot optical fiber chamber interference spectum, 22-temperature charger, the 23-joints of optical fibre, 24-ring flange, 25-spectrometer, 26-pressure/strain loading device, 27-temperature, pressure/strain loading device, 28-SM125 (FBG) demodulator.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in detail.
The present invention by the change of sensory-perceptible ambient temperature, pressure/strain, by while the change of cavity length amount in demodulation Fabry-perot optical fiber chamber and the reflection kernel wavelength shift of fiber grating, realize the measurement to temperature, pressure/strain variation amount.The present invention by based on intensity demodulation three wavelength numeral phase demodulating methods and edge filter method be integrated in a set of demodulation scheme, respectively demodulation is carried out to Fabry-perot optical fiber chamber and fiber grating, and no longer adopt the mode of spectral scan, substantially increase the speed of demodulation like this.On the other hand, carried out calibration experiment before measuring, compensate for due to Fabry-perot optical fiber chamber return interference spectum on demodulating fiber bragg grating cause on thermometric impact, thus make measurement result more accurate.
As shown in Figure 1, the high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating of the present invention, comprises light source module 1, three-dB coupler, circulator 8, sensing unit 12 and demodulating unit 19.Single-mode fiber is adopted to carry out optical signal transmission between each parts.
Light source module 1 comprises three Distributed Feedback Lasers and a wide spectrum light source 5, three Distributed Feedback Lasers are the first Distributed Feedback Laser 2, second Distributed Feedback Laser 3 and the 3rd Distributed Feedback Laser 4.The spectrum of described three narrow-band light source and the spectrum non-overlapping copies of described wide spectrum light source.According to the requirement of demodulation to light source, narrow-band light source is DFB (Distributed Feed Back) laser instrument, and described wide spectrum light source adopts amplified spontaneous emission source (ASE) or the super-fluorescence light source (SFS) based on doped fiber.
Sensing unit 12 comprises optical fiber grating sensing structure 10 and Fabry-perot optical fiber chamber sensing arrangement 11.Sensing unit 12 is the compound sensor that the fiber grating of Fabry-perot optical fiber chamber and Non-stress packaging forms, or the cascaded structure of Fabry-perot optical fiber pressure/strain transducer and fiber-optical grating temperature sensor.
Demodulating unit 19 comprises 1 × 3 dense wave division multiplexer (DWDM) 13,1 × 2 Coarse Wave Division Multiplexer (CWDM) 14, photodetector 15, signal conditioning circuit 16, data collecting card 17 and computing machine 19.
The three beams laser of narrowband sent in light source module 1 and a branch of wide spectrum optical are coupled in four single-mode fibers 6 simultaneously, and four bundle light, by after the three-dB coupler 7 of 4 × 1, incide in circulator 8, then import sensing unit 12 into.Light signal first enters to inject optical fiber grating sensing structure 10, the light wave meeting fiber grating reflection kernel wavelength is reflected, other light-wave transmission enters Fabry-perot optical fiber chamber sensing arrangement 11 and multiple-beam interference occurs wherein, interference light returns optical fiber grating sensing structure 10 and by its direct transmission, this interference light is formed with the reflected light of fiber grating and superposes spectrum, and superposition spectrum as shown in Figure 2.Wherein, Fabry-perot optical fiber chamber sensing arrangement 11 is for pressure/strain measurement, and optical fiber grating sensing structure 10 is for temperature survey.
Superposition spectrum as shown in Figure 2, the three-dB coupler 9 through 1 × 2 enters to inject 1 × 3DWDM13 and 1 × 2CWDM14 respectively, thus light signal is divided into five tunnels.Described 1 × 3DWDM13 and three narrow-band light source matches, and the chamber that the three-beam passed through is used for demodulation Fabry-perot optical fiber chamber is long; Light through described 1 × 2CWDM14 is used for the demodulation of fiber grating reflection kernel wavelength.Via photodetector 15, five road light signals are converted to electric signal and enter signal condition unit 16.Electric signal changes digital signal into through signal condition unit 16 and is transferred to computing machine 18 by data collecting card 17 and stores.Pass through signal handler, stored digital signal is analyzed, utilize three wavelength numeral phase demodulating methods and edge filter method to carry out fast demodulation to the change of cavity length amount in Fabry-perot optical fiber chamber and the drift value of fiber grating reflection kernel wavelength respectively, thus realize two parameter (temperature, pressure/strain) combined measurement.
Due to three beams laser of narrowband and wide spectrum optical separate, make the three beams of laser for demodulation Fabry-perot optical fiber chamber long message can not be subject to the impact of wide spectrum optical.But when utilizing the wide spectrum optical returned from fiber grating to carry out demodulation to fiber grating, the impact of the interference spectrum in Fabry-perot optical fiber chamber is subject to owing to returning wide spectrum optical, making to produce error drift amount during demodulating fiber bragg grating reflection kernel wavelength, needing to compensate by demarcating.On the other hand, the change of cavity length amount due to Fabry-perot optical fiber chamber is the double influence due to temperature variation and pressure/strain variation, therefore also needs to compensate.
Based on above-mentioned high-speed demodulating apparatus, the high speed demodulation method based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating provided by the invention, specific implementation step is as follows:
Step one: carry out calibration experiment.
1. calibration experiment one: the demodulating error drift value Δ λ obtaining fiber grating reflection kernel wavelength
1and the relation between variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X, as follows:
Δλ
1＝K
1ΔT+K
2ΔX (1)
K
1acquisition pattern: adopt standardization experimental apparatus as shown in Figure 3 in the embodiment of the present invention, utilizes temperature charger 22 pairs of sensing units 12 to load temperature, given temperature variation Δ T.As shown in Figure 4, temperature variation Δ T not only makes fiber grating reflection kernel wavelength create drift value Δ λ to the superposition spectrum that before and after temperature variation, sensing unit 12 returns, and also makes Fabry-perot optical fiber chamber length there occurs Δ L
tchange, detect superimposed light by the light intensity change information obtained after 1 × 2CWDM, utilize the demodulation of edge filter method to obtain comprising the drift value of the fiber grating reflection kernel wavelength of error demodulation amount.Spectrometer 25 is adopted to obtain the actual drift value of fiber grating reflection kernel wavelength.By the difference between actual drift value and demodulation drift value, can obtain because temperature variation causes the error demodulation drift value of fiber grating reflection kernel wavelength, thus demarcate and obtain K
1.
As shown in Figure 3, sensing unit 12 in high-speed demodulating apparatus of the present invention is inserted in temperature charger 22, the output terminal of the circulator 8 in high-speed demodulating apparatus of the present invention arranges the joints of optical fibre 23 and ring flange 24, can be connected spectrometer 25 by the joints of optical fibre 23 with ring flange 24.Temperature charger 22 pairs of sensing units 12 carry out temperature loading, light signal in sensing unit 12 after temperature modulation, detected by demodulating unit 19, finally utilize linear filtering method demodulation to obtain the drift value Δ λ of fiber grating reflection kernel wavelength in a computer.Δ λ contains the demodulating error drift value Δ λ of fiber grating reflection kernel wavelength
1with the practical center wavelength shift Δ λ of fiber grating caused by temperature variation
2.Utilize the joints of optical fibre 23, ring flange 24 is connected with spectrometer 25, light signal in the sensing unit 12 after temperature modulation, is detected by spectrometer 25, obtains the actual drift value Δ λ of fiber grating reflection kernel wavelength
2.Thus the demodulating error drift value Δ λ of fiber grating reflection kernel wavelength can be obtained
1.By the difference between demodulation drift value and actual drift value, can obtain because temperature variation causes the demodulating error drift value of fiber grating reflection kernel wavelength, thus demarcate and obtain K
1.
K
2acquisition pattern: standardization experimental apparatus schematic diagram as shown in Figure 5, in the immovable situation of environment temperature, utilize the 26 pairs of sensing unit 12 on-load pressures/strains of pressure/strain loading device, pressure/strain causes the long variable quantity producing Δ L in Fabry-perot optical fiber chamber, before and after superposition spectrum, comparison diagram as shown in Figure 6, and the detail view of the fiber grating part of its correspondence as shown in Figure 7.When this superposition spectrum is by after 1 × 3CWDM, will the variable quantity of light intensity be detected, demodulation can obtain the error drift amount of fiber grating reflection kernel wavelength by linear filtering method, thus demarcate and obtain K
2.
As shown in Figure 5, sensing unit 12 in high-speed demodulating apparatus of the present invention is inserted in pressure/strain loading device 26, stress/strain charger 26 pairs of sensing units 12 carry out stress/strain loading, light signal in sensing unit 12 demodulated unit 19 after stress/strain modulation detects, the error demodulation drift value of the fiber grating reflection kernel wavelength utilizing linear filtering method demodulation acquisition to cause due to stress/strain, thus demarcate acquisition K
2.
2. calibration experiment two: the relation between the change of cavity length amount Δ L in Fabry-perot optical fiber chamber and variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X:
ΔL＝K
3ΔT+K
4ΔX (2)
K
3, K
4acquisition pattern: caliberating device as shown in Figure 8, utilizes temperature, pressure/strain loading device 27 pairs of sensing units 12 loads temperature and pressure/strain, utilize SM125 (FBG) demodulator 28 to demarcate chamber, Fabry-perot optical fiber chamber long, thus demarcates K
3, K
4value.
As shown in Figure 8, sensing unit 12 of the present invention is put into separately temperature, pressure/strain loading device 27, sensing unit 12 output terminal is connected with SM125 (FBG) demodulator 28, and SM125 (FBG) demodulator 28 is connected to computing machine 18.The light that SM125 (FBG) demodulator 28 built-in light source sends enters sensing unit 12, utilize temperature, pressure/strain loading device 27 pairs of sensing units 12 load temperature and pressure/strain, light signal after being modulated by temperature and stress/strain returns SM125 (FBG) demodulator 28, open the demodulation process of the SM125 on computing machine, run the demarcation chamber long value that demodulation process obtains Fabry-perot optical fiber chamber.Utilize SM125 (FBG) demodulator 28, demarcate chamber, Fabry-perot optical fiber chamber long, thus demarcate K
3, K
4.
Calibration experiment in step one, completes before carrying out two parameter measurement, and formula (1) compensates the impact that temperature survey causes for causing demodulating fiber bragg grating to the interference spectum returned by Fabry-perot optical fiber chamber.
Step 2: the drift value of the change of cavity length amount in demodulation Fabry-perot optical fiber chamber and the reflection kernel wavelength of fiber grating.
Utilize device schematic diagram as shown in Figure 1, sensing unit 12 perception ambient temperature, pressure/strain, utilize the change of cavity length amount Δ L in three wavelength numeral phase demodulation algorithm demodulation Fabry-perot optical fiber chambeies, utilize the variation delta λ of edge filter method demodulating fiber bragg grating reflection kernel wavelength.Wherein, Δ λ contains the demodulating error drift value Δ λ of fiber grating reflection kernel wavelength
1with fiber grating due to temperature change caused by the drift value Δ λ of reflection kernel wavelength reality
2, the drift value Δ λ of fiber grating reflection kernel wavelength reality
2can be expressed as:
Δλ
2＝Δλ-Δλ
1(3)
Step 3: solve temperature variation Δ T and pressure/strain variation amount Δ X.
The actual drift value Δ λ of temperature variation Δ T and fiber grating reflection kernel wavelength
2between pass be:
Δλ
2＝AΔT (4)
Wherein A is constant, is called the temperature sensitive coefficient of fiber grating, and for bare optical fibers and bare optical gratings sensing arrangement, its value is A=λ
b(α+ξ), α is the thermal expansivity of fiber grating optical fiber used; ξ is the thermo-optical coeffecient of fiber grating optical fiber used; λ
bfor reflection kernel wavelength during fiber grating free state.It should be noted that, one is different due to doping composition and doping content, and thermal expansivity and the thermo-optical coeffecient of various optical fiber have bigger difference, thus cause the difference of A value; Two is due to the making of fiber grating and the different of annealing process condition, also can cause the difference of A value.Therefore in actual applications, need could be used for actual temperature measurement by demarcating.Experimental provision schematic diagram as shown in Figure 9, the light that wide spectrum light source 5 sends imports sensing unit 12 into by the three-dB coupler 9 of 1 × 2, sensing unit 12 is inserted in temperature charger 22, temperature charger 22 pairs of sensing units 12 carry out temperature loading, light signal in sensing unit 12 after temperature modulation, the three-dB coupler 9 through 1 × 2 returns and is detected by spectrometer 25.Utilize spectrometer 25 to detect the reflection kernel wavelength of optical fiber grating sensing structure under relevant temperature, thus demarcate and obtain A value.
Utilize formula (1), (2), (3), (4), obtaining temperature variation Δ T can be expressed as:
The variation delta X of pressure/strain is:
Formula (5), (6) are utilized finally to obtain the variable quantity of temperature and pressure/strain in environment.
Claims (5)
1., based on a high-speed demodulating apparatus for the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating, it is characterized in that, this device comprises: light source module, three-dB coupler, circulator, sensing unit and demodulating unit; Single-mode fiber is adopted to carry out optical signal transmission between each parts;
Described light source module comprises three narrow-band light source and a wide spectrum light source, the spectrum of three narrow-band light source and the spectrum non-overlapping copies of wide spectrum light source; Described sensing unit comprises Fabry-perot optical fiber chamber sensing arrangement and optical fiber grating sensing structure; Described demodulating unit comprises 1 × 3 dense wave division multiplexer (DWDM), 1 × 2 Coarse Wave Division Multiplexer (CWDM), photodetector, signal conditioning circuit, data collecting card and computing machine;
After the three beams laser of narrowband sent in light source module and a branch of wide spectrum optical are transferred to the three-dB coupler of 4 × 1 by four single-mode fibers simultaneously, four bundle light are mapped in circulator through being coupled into, and then import sensing unit into;
The light signal importing sensing unit into first enters to inject optical fiber grating sensing structure, the light wave meeting fiber grating reflection kernel wavelength is reflected, other light-wave transmission enters Fabry-perot optical fiber chamber sensing arrangement and multiple-beam interference occurs wherein, interference light returns optical fiber grating sensing structure and by its direct transmission, interference light is formed with the reflected light of fiber grating and superposes spectrum;
Superposition spectrum enters to inject 1 × 3DWDM and 1 × 2CWDM respectively through the three-dB coupler of 1 × 2, light signal is divided into five tunnels; 1 × 3DWDM and three narrow-band light source matches, and the chamber that the three-beam exported by 1 × 3DWDM is used for demodulation Fabry-perot optical fiber chamber is long; The two-beam that 1 × 2CWDM exports is used for the demodulation of fiber grating reflection kernel wavelength; Five road light signals are converted to electric signal through photodetector and enter signal condition unit, electric signal changes digital signal into through signal condition unit and is transferred to computing machine by data collecting card and stores, by carrying out demodulation to electric signal, obtain the change of cavity length amount in Fabry-perot optical fiber chamber and the drift value of fiber grating reflection kernel wavelength.
2. a kind of high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating according to claim 1, it is characterized in that, described sensing unit is the compound sensor that the fiber grating of Fabry-perot optical fiber chamber and Non-stress packaging forms, or is the cascaded structure of Fabry-perot optical fiber pressure/strain transducer and fiber-optical grating temperature sensor.
3. a kind of high-speed demodulating apparatus based on the two parameter combined measurement of Fabry-perot optical fiber chamber and fiber grating according to claim 1, it is characterized in that, described narrow-band light source is distributed feedback laser, and described wide spectrum light source adopts amplified spontaneous emission source or the super-fluorescence light source based on doped fiber.
4. based on the high speed demodulation method of high-speed demodulating apparatus according to claim 1, it is characterized in that, this high speed demodulation method performing step is as follows:
Step one: carry out calibration experiment;
Obtain the error drift amount Δ λ that demodulating fiber bragg grating reflection kernel wavelength causes
1and the relation between variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X, as follows:
Δλ
1＝K
1ΔT+K
2ΔX (1)
Obtain the change of cavity length amount Δ L in Fabry-perot optical fiber chamber and the relation between variation of ambient temperature amount Δ T, pressure/strain variation amount Δ X:
ΔL＝K
3ΔT+K
4ΔX (2)
K
1, K
2, K
3and K
4be four coefficients, obtained by rating test;
Step 2: the drift value of the change of cavity length amount in demodulation Fabry-perot optical fiber chamber and the reflection kernel wavelength of fiber grating;
Utilize high-speed demodulating apparatus to carry out light signal measurement, utilize three wavelength numeral phase demodulating method demodulation to obtain the change of cavity length amount Δ L in Fabry-perot optical fiber chamber in a computer, utilize the demodulation of edge filter method to obtain the drift value Δ λ of fiber grating reflection kernel wavelength; The actual drift value Δ λ of fiber grating reflection kernel wavelength
2be expressed as:
Δλ
2＝Δλ-Δλ
1(3)
Step 3: solve temperature variation Δ T and pressure/strain variation amount Δ X;
Temperature variation Δ T is obtained according to formula (4):
The variation delta X of pressure/strain is obtained according to formula (5):
Wherein, A is the temperature sensitive coefficient of fiber grating;
Formula (4), (5) are utilized finally to obtain the variable quantity of temperature and pressure/strain in environment.
5. high speed demodulation method according to claim 4, is characterized in that, in described step one, determines K by calibration experiment below
1, specifically:
Sensing unit in described high-speed demodulating apparatus is inserted in temperature charger, temperature charger carries out temperature loading to sensing unit, light signal in sensing unit after temperature modulation, demodulated unit detection, utilizes linear filtering method demodulation to obtain the drift value Δ λ of fiber grating reflection kernel wavelength in a computer; Δ λ comprises the demodulating error drift value Δ λ of fiber grating reflection kernel wavelength
1with the practical center wavelength shift of fiber grating caused by temperature variation;
Connect spectrometer, the light signal in sensing unit after temperature modulation at the output terminal of the circulator of high-speed demodulating apparatus, by spectrometer detection, obtain the actual drift value of fiber grating reflection kernel wavelength; By the difference between demodulation drift value and actual drift value, obtain because temperature variation causes the error demodulation drift value Δ λ of fiber grating reflection kernel wavelength
1, thus demarcate acquisition K
1.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4596925A (en) * | 1982-10-27 | 1986-06-24 | The Foxboro Company | Fiber optic displacement sensor with built-in reference |
| CN2605705Y (en) * | 2003-04-03 | 2004-03-03 | 南开大学 | High-speed optical-fiber grating sensing-multiplexing-demodulating apparatus |
| US7224465B2 (en) * | 2002-10-15 | 2007-05-29 | University Of Maryland | Fiber tip based sensor system for measurements of pressure gradient, air particle velocity and acoustic intensity |
| US20090091765A1 (en) * | 2005-10-18 | 2009-04-09 | The Australian National University | Apparatus for Interferometric Sensing |
| CN101458100A (en) * | 2009-01-13 | 2009-06-17 | 冉曾令 | Demodulation system of FBG sensor and demodulation method thereof |
| CN101476901A (en) * | 2009-01-20 | 2009-07-08 | 电子科技大学 | Demodulation system and method for optical fiber Fabry-Perot sensor |
| CN102322894A (en) * | 2011-06-08 | 2012-01-18 | 东华大学 | Allfiber type long period fiber grating solution multi-parameter sensing system |
| CN102589588A (en) * | 2012-02-17 | 2012-07-18 | 南京师范大学 | Method for demodulating cavity length of Fabry-Perot cavity by utilizing fiber Bragg gratings |
| CN102778242A (en) * | 2012-07-12 | 2012-11-14 | 顾杨 | Demodulation method for Bragg grating |
| CN103115636A (en) * | 2013-02-06 | 2013-05-22 | 天津大学 | Optical fiber Fabry-Perot sensor multiplexing method and device based on multi-wavelength and low-coherence light source |
| CN103344277A (en) * | 2013-06-26 | 2013-10-09 | 华中科技大学 | Fabry-Perot sensor capable of simultaneously detecting double parameters and detection device |
| CN103697923A (en) * | 2013-12-20 | 2014-04-02 | 北京航空航天大学 | Method for demodulating extrinsic fiber Fabry-Perot interferometer cavity length |
-
2015
- 2015-05-29 CN CN201510288899.6A patent/CN104864911B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4596925A (en) * | 1982-10-27 | 1986-06-24 | The Foxboro Company | Fiber optic displacement sensor with built-in reference |
| US7224465B2 (en) * | 2002-10-15 | 2007-05-29 | University Of Maryland | Fiber tip based sensor system for measurements of pressure gradient, air particle velocity and acoustic intensity |
| CN2605705Y (en) * | 2003-04-03 | 2004-03-03 | 南开大学 | High-speed optical-fiber grating sensing-multiplexing-demodulating apparatus |
| US20090091765A1 (en) * | 2005-10-18 | 2009-04-09 | The Australian National University | Apparatus for Interferometric Sensing |
| CN101458100A (en) * | 2009-01-13 | 2009-06-17 | 冉曾令 | Demodulation system of FBG sensor and demodulation method thereof |
| CN101476901A (en) * | 2009-01-20 | 2009-07-08 | 电子科技大学 | Demodulation system and method for optical fiber Fabry-Perot sensor |
| CN102322894A (en) * | 2011-06-08 | 2012-01-18 | 东华大学 | Allfiber type long period fiber grating solution multi-parameter sensing system |
| CN102589588A (en) * | 2012-02-17 | 2012-07-18 | 南京师范大学 | Method for demodulating cavity length of Fabry-Perot cavity by utilizing fiber Bragg gratings |
| CN102778242A (en) * | 2012-07-12 | 2012-11-14 | 顾杨 | Demodulation method for Bragg grating |
| CN103115636A (en) * | 2013-02-06 | 2013-05-22 | 天津大学 | Optical fiber Fabry-Perot sensor multiplexing method and device based on multi-wavelength and low-coherence light source |
| CN103344277A (en) * | 2013-06-26 | 2013-10-09 | 华中科技大学 | Fabry-Perot sensor capable of simultaneously detecting double parameters and detection device |
| CN103697923A (en) * | 2013-12-20 | 2014-04-02 | 北京航空航天大学 | Method for demodulating extrinsic fiber Fabry-Perot interferometer cavity length |
Non-Patent Citations (2)
| Title |
|---|
| 杨广学等: "光纤F-P和FBG传感器通用解调系统的研究", 《光电技术应用》 * |
| 饶云江等: "非本征型法布里-珀罗干涉仪光纤布拉格光栅应变温度传感器及其应用", 《光学学报》 * |
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| CN112595945A (en) * | 2021-01-05 | 2021-04-02 | 西安理工大学 | FBG temperature compensation optical fiber partial discharge detection device and method |
| CN113607196A (en) * | 2021-07-13 | 2021-11-05 | 中国航空工业集团公司北京长城计量测试技术研究所 | Fiber grating and Fabry-Perot cavity composite sensing signal decoupling method |
| CN113804247A (en) * | 2021-08-03 | 2021-12-17 | 西安理工大学 | Fabry-Perot cavity and fiber bragg grating-based transformer oil temperature and oil pressure multi-parameter monitoring system |
| CN113670359A (en) * | 2021-08-26 | 2021-11-19 | 中国核动力研究设计院 | High-speed demodulation system and method for optical fiber Fabry-Perot sensor |
| CN117109465A (en) * | 2023-08-31 | 2023-11-24 | 交通运输部天津水运工程科学研究所 | Decoupling calibration method for multi-physical-field strain sensing signals |
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