CN101603857A - Phase carrier demodulation method in the Fabry-Perot interference type fibre optic hydrophone - Google Patents
Phase carrier demodulation method in the Fabry-Perot interference type fibre optic hydrophone Download PDFInfo
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- CN101603857A CN101603857A CNA2009100725325A CN200910072532A CN101603857A CN 101603857 A CN101603857 A CN 101603857A CN A2009100725325 A CNA2009100725325 A CN A2009100725325A CN 200910072532 A CN200910072532 A CN 200910072532A CN 101603857 A CN101603857 A CN 101603857A
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Abstract
The present invention is to provide the phase carrier demodulation method in a kind of Fabry-Perot interference type fibre optic hydrophone, it is characterized in that: incident light is divided into two bundles by beam intensity ratio at 1: 4, and the light intensity of one road direct sunshine electro-detection is I
0, fiber F-P cavity is injected through the three-dB coupler of cascade in another road, behind the formation multiple-beam interference, measures reflective light intensity I
R, make I
0, I
RBe output as 1/T=I by subtracter, divider hardware or software algorithm realization system
0/ (I
0-I
R), next carry out the PGC demodulation, output mutually must put in place.The present invention takes new light path design by the computing reciprocal to F-P chamber transmissivity, has proposed the method for utilization PGC demodulation techniques in F-P multiple-beam interference system.Widened the range of application of PGC demodulation.All need utilize the F-P interferometer of phase-detection all can use this method to realize the signal demodulation.
Description
(1) technical field
What invention related to is a kind of system's output detecting method of Fabry-Perot interference type fibre optic hydrophone, specifically adopts the inventive method can realize the utilization of phase modulation and demodulation of interferometric in Fabry-Perot interference type fibre optic hydrophone.
(2) background technology
Fibre optic hydrophone is highly sensitive, small and light, be not subjected to electromagnetic interference (EMI); Vector hydrophone has good low audio frequency and infra-acoustic frequency performance, itself does not produce tangible sound field distortion, can be considered as a receiver, so its directive property is good, and performance parameter is stable, can be used for accurately measuring or long-time the measurement.Both advantages are combined, will will produce significant effects the future development of underwater sound Detection Techniques.Current emphasis is the optical fiber vector hydrophone unit in the development towing line array sonar, utilizes high sensitivity and low noise optical fiber sound pressure nautical receiving set and optical fiber acceleration transducer to realize.This not only can fundamentally solve the problem that the port and starboard target is differentiated, and can improve the spatial gain of dragging linear array, help surveying long-range weak target, so fibre optic hydrophone will become one of optimal acoustical signal receiving device in the following marine technology.
In F-P interference type optical fiber hydrophone scheme, because of multiple-beam interference, phse sensitivity is higher.Because the sensing transmission is all finished on an optical fiber, light channel structure is simple, does not have double light path inherent defects such as polarization interference.But also owing to multiple-beam interference, ripe PGC detection technique can't be directly used in F-P and interfere.
(3) summary of the invention
The object of the present invention is to provide the phase carrier demodulation method in a kind of Fabry-Perot interference type fibre optic hydrophone that in the phase detection technique of the position of Fabry-Perot interference type fibre optic hydrophone, can use PGC modulation and demodulation technology.
The object of the present invention is achieved like this:
Incident light is divided into two bundles by beam intensity ratio at 1: 4, and the light intensity of one road direct sunshine electro-detection is I
0, fiber F-P cavity is injected through the three-dB coupler of cascade in another road, behind the formation multiple-beam interference, measures reflective light intensity I
R, make I
0, I
RBe output as by subtracter, divider hardware or software algorithm realization system
Next carry out the PGC demodulation, output mutually must put in place.
Or:
Incident light through three-dB coupler with light intensity I
0Inject fiber F-P cavity and interfere, carry the transmitted light I of measured signal
TThrough opto-electronic conversion, by being transformed to the inverse output of transmissivity behind divider hardware or the computer software algorithm
Next carry out the PGC demodulation, output mutually must put in place.
The present invention has proposed a kind of method that can use the PGC demodulation techniques in the F-P interference type optical fiber hydrophone on the basis of original double light path PGC detection technique.Expanded conventional P GC The Application of Technology scope.
1, F-P interferes the mathematical expression form of output intensity
As Fig. 1, incident light is injected the fiber F-P cavity that fineness is F by three-dB coupler, and order treats that location is mutually
, the reflective light intensity in F-P chamber is I
R, reflection coefficient is R, then
2, PGC technology
In the input treatment technology of interference type optical fiber hydrophone, generally adopt the disposal route of PGC, can adopt software algorithm to realize, algorithm is reliable and stable and to be convenient to digitizing integrated.As Fig. 2, the phase modulation (PM) frequency of establishing light source or PZT generation is ω
c, the output signal of typical two-beam interference is
Links such as the expansion of process Bessel's function, mixing, low-pass filtering, differentiate multiplication cross are subtracted each other, integration, high-pass filtering obtain measured signal
Linearity output.Because F-P is a multiple-beam interference, output intensity (1) formula does not satisfy the mathematical expression form of typical two-beam interference---(2) formula, thereby ripe PGC technology can't adopt.
Make the phase modulation (PM) frequencies omega
c, F-P chamber transmissivity
Can get by formula (1) conversion
As seen, if measure
Order
Then (3) formula is identical with (2) formula in form, and the technology of PGC just can realize in F-P interferes.
Method of the present invention has solved the intensity of light source and has risen and fallen to the influence of fibre optic hydrophone PGC demodulation, has promptly solved the parastic modulation problem.
Conventional P GC demodulation is to realize the phase carrier modulation by modulation PZT or light source injection current.The modulated light source injection current will unavoidably exert an influence to light source output power, i.e. parastic modulation.In (2) formula, A, B are the functions of incident intensity, and this just makes conventional P GC technology face this influence.And by (3) formula, A=1+F/2, B=-F/2 and incident intensity are irrelevant, only are the functions of F-P chamber fineness F, thereby follow-uply carry out the influence that the PGC demodulation is not risen and fallen by the intensity of light source.
Method of the present invention can extend to all phase-detection that adopt the various systems of Fabry-Perot interference formation.
It is typical multiple-beam interference that F-P interferes, and the phse sensitivity height is all finished in an optical fiber owing to interfere with transmission course, thereby the influence that not disturbed by asymmetry.Constitute the interfere type Fibre Optical Sensor with it and have distinct advantages.But carry out because conventional P GC demodulation is interfered at typical double light path, can't be directly used in F-P and interfere.The present invention takes new light path design by the computing reciprocal to F-P chamber transmissivity, has proposed the method for utilization PGC demodulation techniques in F-P multiple-beam interference system.Widened the range of application of PGC demodulation.All need utilize the F-P interferometer of phase-detection all can use this method to realize the signal demodulation.
(4) description of drawings
The theory diagram that Fig. 1 F-P interferes;
Fig. 2 PGC theory diagram;
The PGC demodulation principle block diagram of the F-P interference type optical fiber hydrophone of the reflective detection of Fig. 3;
The PGC demodulation principle block diagram of the F-P interference type optical fiber hydrophone that Fig. 4 transmission-type detects;
F-P interference type optical fiber hydrophone unit outward appearance and experimental system that Fig. 5 transmission-type detects;
The sound pressure sensitivity measured curve of Fig. 6 F-P interference type optical fiber hydrophone;
Fig. 7 F-P interference type optical fiber hydrophone acceleration sensitivity measured curve.
(5) embodiment
For example the present invention is done description in more detail below in conjunction with accompanying drawing:
In conjunction with Fig. 3, first kind of embodiment of the present invention is: incident light is divided into two bundles by beam intensity ratio at 1: 4, and one tunnel direct photoelectricity is converted to output intensity I
0, fiber F-P cavity is injected through the three-dB coupler of cascade in another road, and behind the formation multiple-beam interference, the reflected light that carries measured signal detects reflective light intensity I through opto-electronic conversion
RMake I
0, I
RBe output as by subtracter, divider hardware or software algorithm realization system
Next carry out the PGC demodulation, output mutually must put in place.
Method of the present invention can also take to detect the method for F-P chamber transmitted light intensity except that the method for the detection F-P cavity reflection light intensity of taking above-mentioned embodiment, realize the PGC demodulation of Fabry-Perot interference type fibre optic hydrophone.In conjunction with Fig. 4, second kind of embodiment of the present invention is: incident light through three-dB coupler with light intensity I
0Inject fiber F-P cavity and interfere, carry the transmitted light I of measured signal
TThrough opto-electronic conversion, by being transformed to the inverse output of transmissivity behind divider hardware or the computer software algorithm
Next carry out the PGC demodulation, output mutually must put in place.
With F-P interference type optical fiber hydrophone example effect of the present invention is made aid illustration below in conjunction with accompanying drawing.F-P interference type optical fiber hydrophone with Fig. 3 light path formation, its basic mechanical structure is to twine the fiber F-P resonator cavity on elasticity post shell, acoustic pressure makes post shell generation deformation drive the long variation in F-P chamber in the water, produce the variation of phasic difference, through the present invention---the PGC method of F-P realizes the sound pressure signal demodulation.Nautical receiving set physical dimension is seen Fig. 5 much smaller than the wavelength of measured sound wave.
F-P interference type optical fiber hydrophone sensitivity measure carries out in national defence underwater sound metering first order station.In calibrating device, carry out during 63Hz～2kHz, press GB4310-84 " low frequency hydrophone calibration method " and implement; In anechoic tank,, carry out during 2kHz～5kHz, press GB7965-87 " acoustics-underwater acoustic transducer is measured " and implement.The sensitivity index of three nautical receiving sets of actual measurement: the range of sensitivity-130dB～-115dB (the corresponding 1V/ μ of 0dB Pa).During working band 20Hz～2kHz, rise and fall in the band less than ± 5dB; When working band was 2kHz～5kHz, rising and falling in the band was not more than ± 3dB.Acceleration sensitivity is measured frequency range 20Hz～200Hz, carries out the acceleration during according to the confirmed test of experiment situation, the acceleration sensitivity when converting out 1g: 26-30dB (the corresponding 1V/g of 0dB) on shaking table.
Claims (2)
1, the phase carrier demodulation method in a kind of Fabry-Perot interference type fibre optic hydrophone, it is characterized in that: incident light is divided into two bundles by beam intensity ratio at 1: 4, and the light intensity of one road direct sunshine electro-detection is I
0, fiber F-P cavity is injected through the three-dB coupler of cascade in another road, behind the formation multiple-beam interference, measures reflective light intensity I
R, make I
0, I
RBe output as by subtracter, divider hardware or software algorithm realization system
Next carry out the PGC demodulation, output mutually must put in place.
2, the phase carrier demodulation method in a kind of Fabry-Perot interference type fibre optic hydrophone is characterized in that: incident light through three-dB coupler with light intensity I
0Inject fiber F-P cavity and interfere, carry the transmitted light I of measured signal
TThrough opto-electronic conversion, by being transformed to the inverse output of transmissivity behind divider hardware or the computer software algorithm
Next carry out the PGC demodulation, output mutually must put in place.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009100725325A CN101603857B (en) | 2009-07-17 | 2009-07-17 | Method for demodulating phase carrier in Fabry-Perot interference type optical fiber hydrophon |
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| CN2009100725325A CN101603857B (en) | 2009-07-17 | 2009-07-17 | Method for demodulating phase carrier in Fabry-Perot interference type optical fiber hydrophon |
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| CN101603857B CN101603857B (en) | 2011-01-26 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102072761A (en) * | 2010-12-06 | 2011-05-25 | 中国船舶重工集团公司第七一五研究所 | General calibration system and method of phase shift sensitivity based on optical phase demodulator |
| CN102359797A (en) * | 2011-07-08 | 2012-02-22 | 清华大学 | System and method for reducing noise of phase generated carrier (PGC) system in optical fiber hydrophone |
| CN103575468A (en) * | 2013-11-22 | 2014-02-12 | 武汉理工大学 | Dynamic phase demodulation and calibration method for high-reflectance optical fiber F-P chamber hydrophone |
| CN104197968A (en) * | 2014-09-18 | 2014-12-10 | 中国人民解放军国防科学技术大学 | PGC (phase generated carrier) and inverse scattering combined demodulation method for inhibiting signal crosstalk |
| CN107063435A (en) * | 2017-06-21 | 2017-08-18 | 中国人民解放军国防科学技术大学 | A kind of fibre optic hydrophone probe internally provided based on the full light carrier modulator of micro-nano fiber |
| CN109141264A (en) * | 2018-10-19 | 2019-01-04 | 西安交通大学 | A kind of method and device thereof demodulating three-dimensional tip clearance |
| CN111141432A (en) * | 2019-12-24 | 2020-05-12 | 中天科技光纤有限公司 | Optical fiber pressure sensor and testing method thereof |
| WO2023159395A1 (en) * | 2022-02-23 | 2023-08-31 | 北京佰为深科技发展有限公司 | Demodulation system for optical fiber fabry‑perot sensor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101852645B (en) * | 2010-06-25 | 2012-05-09 | 北京奥普科达科技有限公司 | Precise positioning type optical fiber distributed vibration sensor |
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2009
- 2009-07-17 CN CN2009100725325A patent/CN101603857B/en not_active Expired - Fee Related
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102072761B (en) * | 2010-12-06 | 2012-04-18 | 中国船舶重工集团公司第七一五研究所 | General calibration system and method of phase shift sensitivity based on optical phase demodulator |
| CN102072761A (en) * | 2010-12-06 | 2011-05-25 | 中国船舶重工集团公司第七一五研究所 | General calibration system and method of phase shift sensitivity based on optical phase demodulator |
| CN102359797B (en) * | 2011-07-08 | 2014-05-07 | 清华大学 | System and method for reducing noise of phase generated carrier (PGC) system in optical fiber hydrophone |
| CN102359797A (en) * | 2011-07-08 | 2012-02-22 | 清华大学 | System and method for reducing noise of phase generated carrier (PGC) system in optical fiber hydrophone |
| CN103575468B (en) * | 2013-11-22 | 2015-05-27 | 武汉理工大学 | Dynamic phase demodulation and calibration method for high-reflectance optical fiber F-P chamber hydrophone |
| CN103575468A (en) * | 2013-11-22 | 2014-02-12 | 武汉理工大学 | Dynamic phase demodulation and calibration method for high-reflectance optical fiber F-P chamber hydrophone |
| CN104197968A (en) * | 2014-09-18 | 2014-12-10 | 中国人民解放军国防科学技术大学 | PGC (phase generated carrier) and inverse scattering combined demodulation method for inhibiting signal crosstalk |
| CN104197968B (en) * | 2014-09-18 | 2017-03-15 | 中国人民解放军国防科学技术大学 | For suppressing the PGC of signal cross-talk to mix demodulation method with reversion delamination |
| CN107063435A (en) * | 2017-06-21 | 2017-08-18 | 中国人民解放军国防科学技术大学 | A kind of fibre optic hydrophone probe internally provided based on the full light carrier modulator of micro-nano fiber |
| CN107063435B (en) * | 2017-06-21 | 2019-04-16 | 中国人民解放军国防科学技术大学 | A kind of fibre optic hydrophone probe internally provided based on the full light carrier modulator of micro-nano fiber |
| CN109141264A (en) * | 2018-10-19 | 2019-01-04 | 西安交通大学 | A kind of method and device thereof demodulating three-dimensional tip clearance |
| CN109141264B (en) * | 2018-10-19 | 2019-11-08 | 西安交通大学 | A kind of method and device thereof demodulating three-dimensional tip clearance |
| CN111141432A (en) * | 2019-12-24 | 2020-05-12 | 中天科技光纤有限公司 | Optical fiber pressure sensor and testing method thereof |
| CN111141432B (en) * | 2019-12-24 | 2021-08-10 | 中天科技光纤有限公司 | Optical fiber pressure sensor and testing method thereof |
| WO2023159395A1 (en) * | 2022-02-23 | 2023-08-31 | 北京佰为深科技发展有限公司 | Demodulation system for optical fiber fabry‑perot sensor |
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