CN108593089B - Optical vibration sensor based on birefringence resonance effect and sensing method - Google Patents
Optical vibration sensor based on birefringence resonance effect and sensing method Download PDFInfo
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- CN108593089B CN108593089B CN201810410240.7A CN201810410240A CN108593089B CN 108593089 B CN108593089 B CN 108593089B CN 201810410240 A CN201810410240 A CN 201810410240A CN 108593089 B CN108593089 B CN 108593089B
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- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
Abstract
The invention discloses an optical vibration sensor based on a birefringence resonance effect and an induction method. The optical vibration sensor comprises a laser emitting unit, a vibration sensing amplifying unit, a laser receiving unit and a standard waveform unit which are connected in sequence. The laser emission unit modulates light emitted by the light source; the vibration induction amplifying unit guides the modulated optical signal into a polarization maintaining ring cavity, and the optical signal resonates to obtain two intrinsic polarization states; the laser receiving unit converts the optical signal into an electric signal, obtains a resonance demodulation curve and slope characteristics of two intrinsic polarization states ESOPs, and realizes the induction of vibration by using the phase difference between the two polarization states; and the standard waveform unit performs unified modulation and demodulation on the transmission signal. The invention utilizes the birefringence resonance effect to amplify the sensitivity of light to vibration, thereby realizing vibration induction with high sensitivity and large measurement space range.
Description
Technical Field
The invention relates to a vibration sensor, in particular to an optical vibration sensor based on a birefringence resonance effect and an induction method.
Background
Over the past decades, optical vibration sensors have evolved rapidly due to their characteristics of high sensitivity, large measurement spatial range, electromagnetic insensitivity, and the like. Existing optical vibration sensors mainly include distributed vibration sensors and point vibration sensors. The distributed vibration sensor realizes continuous vibration field measurement on one optical fiber based on Rayleigh scattering effect in the optical fiber, has the advantage of large spatial range measurement, but has poor sensitivity and is not suitable for vibration measurement in high-sensitivity and extreme environments. The point vibration sensor has a small measurement space range, but has excellent vibration measurement capability. It is difficult for both conventional optical vibration sensors to achieve a balance between sensitivity and measurement spatial range.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides the optical vibration sensor based on the birefringence resonance effect, which amplifies the sensitivity of light to vibration by using the birefringence resonance effect, thereby realizing vibration induction with high sensitivity and large measurement space range.
In order to achieve the purpose, the invention adopts the specific scheme that:
an optical vibration sensor based on birefringence resonance effect comprises a laser emitting unit, a vibration induction amplifying unit, a laser receiving unit and a standard waveform unit which are connected in sequence; the laser emission unit comprises a laser and a phase modulator which are connected with each other; the vibration induction amplifying unit comprises a polarization-maintaining ring cavity, the input end of the polarization-maintaining ring cavity is connected with the output end of the phase modulator through a polarization-maintaining optical fiber, and the connection point adopts a 45-degree direction for rotary welding; the laser receiving unit comprises a photoelectric detector, a phase-locked amplifier and a signal processor which are sequentially connected, wherein the photoelectric detector is connected with the output end of the polarization-maintaining annular cavity, and the signal processor is connected with the laser; the standard waveform unit comprises a signal generator which is connected with the phase modulator and the phase-locked amplifier.
Preferably, the laser is connected to the phase modulator through an isolator.
Preferably, the polarization-maintaining ring cavity has a first input port, a second input port, a first output port and a second output port, wherein the second input port and the second output port are reflected into a ring by 0 ° fusion.
Preferably, the output end of the phase modulator is connected to the first input port.
Preferably, the signal generator outputs a sine wave or a square wave.
Preferably, the laser is configured as a narrow linewidth high coherence laser.
A sensing method of an optical vibration sensor based on a birefringence resonance effect comprises the following steps:
s1, outputting primary laser by the laser and transmitting the primary laser to the phase modulator, and simultaneously sending out a modulation waveform and a demodulation waveform by the signal generator and transmitting the modulation waveform and the demodulation waveform to the phase modulator;
s2, the phase modulator modulates the phase of the primary laser according to the modulation waveform, and the modulated laser is output to the polarization-maintaining ring cavity;
s3, exciting two ESOPs resonances with intrinsic polarization states in the polarization-maintaining annular cavity by primary laser;
s4, external vibration acts on the polarization-maintaining annular cavity to influence the phase difference between resonance points of two ESOPs resonances, and secondary laser is obtained;
s5, the polarization-maintaining ring cavity transmits the secondary laser to the photoelectric detector and the phase-locked amplifier in sequence, and the signal generator transmits the demodulation waveform to the phase-locked amplifier;
s6, demodulating the secondary laser by the photoelectric detector to obtain an electric signal and amplifying the electric signal by a phase-locked amplifier, wherein the electric signal comprises slope characteristics of two ESOPs resonances;
and S7, the phase-locked amplifier transmits the amplified electric signal to the signal processor, and the signal processor outputs the phase difference between the two ESOPs resonances, so that vibration information can be obtained according to the phase difference.
As a preferable scheme, in S7, the method for the signal processor to obtain the phase difference between two espps resonances includes:
s7.1, the signal processor outputs sawtooth waves to scan the laser;
s7.2, the signal processor obtains slope characteristics of two ESOPs resonances from the lock-in amplifier;
and S7.3, calculating the phase difference between the two ESOPs resonances according to the slope characteristics of the two resonances by the signal processor.
Preferably, in S7, the vibration information is calculated by
Where Δ A is vibration information, k0Is the wave number under vacuum, l is the length of the transmission waveguide,
is the vibration coefficient of birefringence difference, phi is the phase difference of the resonance point.
Has the advantages that: the invention adopts the resonance effect of multi-turn transmission in the polarization-preserving annular cavity to amplify and detect the birefringence vibration, thereby greatly improving the sensitivity to the vibration. Two orthogonal polarization modes are transmitted in the same waveguide, and much noise is eliminated due to reciprocity (common mode), so that vibration detection with extremely high sensitivity is realized.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic structural diagram of a polarization maintaining ring cavity of the present invention;
FIG. 3 is a graph of the resonance demodulation of two ESOPs in the present invention;
FIG. 4 is a graphical representation of the resonance characteristics of two ESOPs as a function of the intra-cavity transmission cycle birefringence contrast, which is 0;
FIG. 5 is a graphical representation of the resonance characteristics of two ESOPs as a function of the intra-cavity transmission cycle birefringence contrast, which is 0.5 π;
FIG. 6 is a graphical representation of the resonance characteristics of two ESOPs as a function of the intra-cavity transmission cycle birefringence contrast, which is π;
FIG. 7 is a graphical representation of the resonance characteristics of two ESOPs as a function of the intra-cavity transmission cycle birefringence contrast, which is 1.5 π;
FIG. 8 is a schematic diagram showing the relationship between the phase difference between two resonance points and the phase difference of one-circle birefringence during transmission in a cavity, wherein the phase difference of birefringence ranges from 0 pi to 2 pi;
FIG. 9 is a schematic diagram showing the relationship between the phase difference between two resonance points and the phase difference of one-cycle birefringence during intracavity transmission, wherein the birefringence phase difference ranges from 0 pi to 0.07 pi.
Reference numerals: 1. a first input port, 2, a second input port, 3, a first output port, 4, a second output port, 5, a coupler.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 to 9, fig. 1 is a schematic diagram of the overall structure of the present invention, fig. 2 is a schematic diagram of the structure of a polarization-maintaining ring cavity of the present invention, fig. 3 is a resonance demodulation curve of two espps of the present invention, fig. 4 is a schematic diagram of the relationship between the resonance characteristics of two espps and the difference between the birefringence of one cycle of transmission in the cavity, the birefringence difference is 0, fig. 5 is a schematic diagram of the relationship between the resonance characteristics of two espps and the difference between the birefringence of one cycle of transmission in the cavity, the birefringence difference is pi, fig. 6 is a schematic diagram of the relationship between the resonance characteristics of two espps and the difference between the birefringence of one cycle of transmission in the cavity, fig. 7 is a schematic diagram of the relationship between the resonance characteristics of two espps and the difference between the birefringence of one cycle of transmission in the cavity, the birefringence difference is 1.5 pi, fig. 8 is a schematic diagram of the relationship between the, FIG. 9 is a schematic diagram showing the relationship between the phase difference between two resonance points and the phase difference of one-cycle birefringence during intracavity transmission, wherein the birefringence phase difference ranges from 0 pi to 0.07 pi.
An optical vibration sensor based on birefringence resonance effect comprises a laser emitting unit, a vibration sensing amplifying unit, a laser receiving unit and a standard waveform unit which are sequentially connected.
The laser, the isolator and the phase modulator are sequentially connected with the laser emitting unit, the laser is a narrow-linewidth high-coherence laser which specifically can be a YAG laser, a gas laser, a semiconductor laser or a fiber laser, and the laser is connected with the phase modulator through the isolator.
The vibration sensing amplification unit comprises a polarization-maintaining annular cavity, wherein the polarization-maintaining annular cavity is provided with a first input port 1, a second input port 2, a first output port 3 and a second output port 4, and the second input port 2 and the second output port 4 are reflected into a ring through 0-degree welding. The first input port 1 of the polarization-maintaining ring cavity is connected with the output end of the phase modulator through a polarization-maintaining optical fiber, and the connection point adopts 45-degree direction rotation welding.
The laser receiving unit comprises a photoelectric detector, a photoelectric detector and a signal processor which are sequentially connected, wherein the photoelectric detector is connected with the output end of the polarization-maintaining annular cavity, and the signal processor is connected with the laser.
The standard waveform unit comprises a signal generator, the signal generator is connected with the phase modulator and the photoelectric detector, and the standard waveform output by the signal generator is a sine wave or a square wave.
All devices can be integrated on a semiconductor or can be realized by a combination of discrete components.
Based on the optical vibration sensor, the invention also provides a sensing method of the optical vibration sensor based on the birefringence resonance effect, which comprises S1-S7.
And S1, outputting primary laser by the laser and transmitting the primary laser to the phase modulator, and sending out a modulation waveform and a demodulation waveform by the signal generator and transmitting the modulation waveform and the demodulation waveform to the phase modulator.
And S2, modulating the phase of the primary laser by the phase modulator according to the modulation waveform, and outputting the modulated laser to the polarization maintaining ring cavity.
S3, exciting two resonances with intrinsic polarization states in the polarization-preserving annular cavity by the primary laser.
And S4, the external vibration acts on the polarization-maintaining annular cavity to influence the phase difference between the resonance points of the two ESOPs resonances, and secondary laser is obtained.
And S5, the polarization-maintaining ring cavity transmits the secondary laser to the photoelectric detector and the phase-locked amplifier in sequence, and the signal generator transmits the demodulation waveform to the phase-locked amplifier.
And S6, demodulating the secondary laser by the photoelectric detector to obtain an electric signal, and amplifying the electric signal by the lock-in amplifier, wherein the electric signal comprises slope characteristics of two ESOPs resonances.
And S7, the phase-locked amplifier transmits the amplified electric signal to the signal processor, and the signal processor outputs the phase difference between the two ESOPs, so that the vibration information can be obtained according to the phase difference. The vibration information is calculated by
Where Δ A is vibration information, k0Is the wave number under vacuum, l is the length of the transmission waveguide,
is the vibration coefficient of birefringence difference, phi is the phase difference of the resonance point.
The specific method for obtaining the phase difference between the resonance points of the two ESOPs resonances by the signal processor comprises S7.1-S7.3.
And S7.1, outputting a sawtooth wave scanning laser by the signal processor.
S7.2, the signal processor obtains the slope characteristics of the two ESOPs from the lock-in amplifier.
S7.3, the signal processor calculates the phase difference between the two ESOPs according to the slope characteristics of the two resonances.
The working principle of the invention is as follows.
Firstly, a primary laser is input into a polarization-maintaining ring cavity from a first input port 1, then enters the polarization-maintaining ring cavity from a second output port 4 after passing through a coupler 5, and a matrix transmitted for one circle in the polarization-maintaining ring cavity is as follows:
α is the loss of light transmitted in cavity, which mainly includes the transmission loss of optical waveguide and the insertion loss of coupler, k is coupling coefficient, β and Delta β are the difference between average propagation constant and birefringence-induced propagation constant, and thetatRepresenting equivalent angular alignment errors to describe the polarization crosstalk of the straight end of the coupler; and l is the length of the waveguide ring cavity.
Eigenvalue λmAnd eigenvectors vmAre 2 key parameters of the matrix S, which satisfy
Svm＝λmvm(m＝1,2)； (2)
Wherein the eigenvectors vmSuch polarization states are represented: after the light is transmitted in the cavity for one circle from the second output port 4 of the coupler 5, the polarization state is restored to the original state, which is the eigenpolarization state espps that we often say; and the eigenvalue λmThe transmission coefficient, eigenvalue lambda, of one cycle of ESOPs resonance transmission in the cavity is shownmIs a complex number, not a matrix, which greatly reduces the polarization componentThe difficulty of the analysis.
The eigenvalues λ are obtained from the equations (1) and (2)mThe calculating method of (2):
wherein ξ satisfies:
generally, the polarization extinction ratio of a waveguide coupler is high, i.e., θtSmaller, therefore when Δ βl＜θtThen, the above formula (4) can be simplified as:
assuming that the optical field of the primary laser is E1, it is injected from the first input port 1 of the coupler 5 and then coupled to the second output port 4, and the emitted optical field is E4, and projected onto two espps respectively:
wherein a, b are the amplitudes of the intrinsic polarization states v1 and v2, respectively; v is a combinatorial matrix of espps, V ═ V1, V2; ckIs a coupling matrix:
wherein, thetakTo describe the equivalent angular alignment error at the cross-over end of the coupler.
Incident light is transmitted in the cavity for multiple circles, and the accumulated light fields of 2 ESOPs are respectively as follows:
as shown in the equations (8) and (3), two resonance states are excited in the cavity, and the difference between the resonance points is ═ 2 ξ (9)
From the formula (5), when Δ β is reachedl＞＞θtWhen the temperature of the water is higher than the set temperature,
φ＝Δβl。(10)
from the equation (10), the phase difference between the two resonance points is the birefringence phase difference of the polarization-maintaining ring cavity transmitting one turn.
When the vibration changes, the birefringence vibration effect of the polarization-maintaining optical waveguide is as follows:
where Δ A is vibration information, k0Is the wave number under vacuum, l is the length of the transmission waveguide,
is the vibration coefficient of the birefringence difference. Therefore, by detecting the phase difference (birefringence phase difference) of the two resonance points, the vibration can be detected:
according to the above theoretical analysis, the relationship between the resonance characteristic and the difference between the birefringence of the transmission in the cavity for one cycle is shown in fig. 4 to 7. In order to excite 2 ESOPs resonance in the cavity simultaneously, the linearly polarized light is incident to the polarization-maintaining ring cavity at 45 degrees to the slow axis. When the birefringence difference in the intracavity transmission for one revolution is zero, the resonances of the two ESOPs are very close, and the distance between the two resonance points increases with the increase of the difference.
The phase difference between the two resonance points is related to the phase difference of the one-round birefringence transmitted in the cavity as shown in fig. 8 and 9. When the birefringence difference is large (>0.1 π rad), the two are approximately linear, this region can be used to measure the change in vibration; however, when the birefringence phase difference is small, the two do not have a linear relationship, and the phase difference between the two resonance points tends to 2 θ as the birefringence phase difference decreasestThe region being unable to measure variations in vibrationAnd (4) transforming.
The invention adopts the resonance effect of multi-turn transmission of light in the annular polarization-maintaining annular cavity to amplify and detect the birefringence vibration, thereby greatly improving the sensitivity of vibration, realizing continuous vibration field measurement on one optical fiber and having wide measurement space range. Two orthogonal polarization modes are transmitted in the same waveguide, and much noise is eliminated due to reciprocity (common mode), so that vibration detection with extremely high sensitivity is realized.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. An optical vibration sensor based on birefringence resonance effect, characterized in that: the vibration sensing and amplifying device comprises a laser emitting unit, a vibration sensing and amplifying unit, a laser receiving unit and a standard waveform unit which are connected in sequence;
the laser emission unit comprises a laser and a phase modulator which are connected with each other;
the vibration induction amplifying unit comprises a polarization-maintaining ring cavity, the input end of the polarization-maintaining ring cavity is connected with the output end of the phase modulator through a polarization-maintaining optical fiber, and the connection point adopts a 45-degree direction for rotary welding;
the laser receiving unit comprises a photoelectric detector, a phase-locked amplifier and a signal processor which are sequentially connected, wherein the photoelectric detector is connected with the output end of the polarization-maintaining annular cavity, and the signal processor is connected with the laser;
the standard waveform unit comprises a signal generator which is connected with the phase modulator and the phase-locked amplifier; the sensing method of the optical vibration sensor based on the birefringence resonance effect comprises the following steps:
s1, outputting primary laser by the laser and transmitting the primary laser to the phase modulator, and simultaneously sending out a modulation waveform and a demodulation waveform by the signal generator and transmitting the modulation waveform and the demodulation waveform to the phase modulator;
s2, the phase modulator modulates the phase of the primary laser according to the modulation waveform, and the modulated laser is output to the polarization-maintaining ring cavity;
s3, exciting two ESOPs resonances with intrinsic polarization states in the polarization-maintaining annular cavity by primary laser;
s4, external vibration acts on the polarization-maintaining annular cavity to influence the phase difference between resonance points of two ESOPs resonances, and secondary laser is obtained;
s5, the polarization-maintaining ring cavity transmits the secondary laser to the photoelectric detector and the phase-locked amplifier in sequence, and the signal generator transmits the demodulation waveform to the phase-locked amplifier;
s6, demodulating the secondary laser by the photoelectric detector to obtain an electric signal and amplifying the electric signal by a phase-locked amplifier, wherein the electric signal comprises slope characteristics of two ESOPs resonances;
s7, the phase-locked amplifier transmits the amplified electric signal to the signal processor, and the signal processor outputs the phase difference between two ESOPs resonances, so that vibration information can be obtained according to the phase difference;
s7.1, the signal processor outputs sawtooth waves to scan the laser;
s7.2, the signal processor obtains slope characteristics of two ESOPs resonances from the lock-in amplifier;
s7.3, calculating the phase difference between the two ESOPs resonances by the signal processor according to the slope characteristics of the two resonances;
s7.4, the calculation method of the vibration information comprises
Where Δ A is vibration information, k0Is the wave number under vacuum, l is the length of the transmission waveguide,
is the vibration coefficient of birefringence difference, phi is the phase difference of the resonance point.
2. An optical vibration sensor based on birefringence resonance effect as claimed in claim 1, wherein: the laser is connected with the phase modulator through an isolator.
3. An optical vibration sensor based on birefringence resonance effect as claimed in claim 1, wherein: the polarization-maintaining ring cavity is provided with a first input port (1), a second input port (2), a first output port (3) and a second output port (4), wherein the second input port (2) and the second output port (4) are reflected into a ring through 0-degree welding.
4. An optical vibration sensor based on birefringence resonance effect as set forth in claim 3, wherein: the output end of the phase modulator is connected with the first input port (1).
5. An optical vibration sensor based on birefringence resonance effect as claimed in claim 1, wherein: the signal generator outputs a sine wave or a square wave.
6. An optical vibration sensor based on birefringence resonance effect as claimed in claim 1, wherein: the laser is configured as a narrow linewidth, high coherence laser.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20100004318A (en) * | 2008-07-03 | 2010-01-13 | 창원대학교 산학협력단 | Depolarized fiber-optic gyroscope |
| CN103528666A (en) * | 2013-09-29 | 2014-01-22 | 中国电子科技集团公司第四十一研究所 | Long-distance optical fiber vibration detection device and method on basis of Sagnac interference |
| CN104121983A (en) * | 2014-07-14 | 2014-10-29 | 南京林业大学 | Birefringence optical fiber environment based vibration dynamic monitoring system and method |
| WO2016135289A1 (en) * | 2015-02-27 | 2016-09-01 | Nils Schopohl | Sensor device for tires |
| CN106200015A (en) * | 2016-08-01 | 2016-12-07 | 天津理工大学 | Microwave photon filter based on high double-refraction photon crystal fiber multiple-wavelength laser Yu dispersion cascode device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2009103015A2 (en) * | 2008-02-14 | 2009-08-20 | Bergh Ralph A | An interferometer employing a multi-waveguide optical loop path and fiber optic rotation rate sensor employing same |
| US9587945B2 (en) * | 2014-06-23 | 2017-03-07 | Honeywell International Inc. | Symmetric three-laser resonator fiber optic gyroscope |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR20100004318A (en) * | 2008-07-03 | 2010-01-13 | 창원대학교 산학협력단 | Depolarized fiber-optic gyroscope |
| CN103528666A (en) * | 2013-09-29 | 2014-01-22 | 中国电子科技集团公司第四十一研究所 | Long-distance optical fiber vibration detection device and method on basis of Sagnac interference |
| CN104121983A (en) * | 2014-07-14 | 2014-10-29 | 南京林业大学 | Birefringence optical fiber environment based vibration dynamic monitoring system and method |
| WO2016135289A1 (en) * | 2015-02-27 | 2016-09-01 | Nils Schopohl | Sensor device for tires |
| CN106200015A (en) * | 2016-08-01 | 2016-12-07 | 天津理工大学 | Microwave photon filter based on high double-refraction photon crystal fiber multiple-wavelength laser Yu dispersion cascode device |
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