CN102879082A - Acoustic frequency detector and acoustic frequency detecting system with multi-mode coupler - Google Patents
Acoustic frequency detector and acoustic frequency detecting system with multi-mode coupler Download PDFInfo
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- CN102879082A CN102879082A CN2012103743562A CN201210374356A CN102879082A CN 102879082 A CN102879082 A CN 102879082A CN 2012103743562 A CN2012103743562 A CN 2012103743562A CN 201210374356 A CN201210374356 A CN 201210374356A CN 102879082 A CN102879082 A CN 102879082A
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Abstract
The invention relates to an acoustic frequency detector and an acoustic frequency detecting system with a multi-mode coupler. The acoustic frequency detector comprises a multi-mode optical fiber coupler, an aluminum film and a metal block, the diameter of the circular aluminum film ranges from 30mm to 40mm, the thickness of the circular aluminum film ranges from 2.5 micrometers to 3.5 micrometers, the periphery of the circular aluminum film is flatly adhered on the metal block, two ends of the multi-mode optical fiber coupler are fixed, a middle coupling region of the multi-mode optical fiber coupler naturally droops to be in contact with the aluminum film, and the length of the middle coupling region ranges from 5mm to 10mm. The acoustic frequency detecting system with the multi-mode coupler comprises the acoustic frequency detector, an acoustic frequency signal generator, a loudspeaker, a wide-spectrum light source, a 1X2 optical fiber coupler, a high-speed photovoltaic conversion module and a frequency spectrum analyzer. Compared with the traditional acoustic frequency detector and the traditional acoustic frequency detecting system which are implemented in a capacitance detecting method, the acoustic frequency detector and the acoustic frequency detecting system have the advantages of high interference resistance and easiness in long-distance transmission owing to an optical fiber acoustic sensing mode.
Description
Technical field
The present invention relates to a kind of frequency of sound wave detector and multi-mode coupler frequency of sound wave detection system.
Background technology
Frequency of sound wave is surveyed very important in optical fiber communication and optical fiber sensing system accurately.
The most frequently used frequency of sound wave detection means is to use Electret Condencer Microphone, it has two metal polar plates, wherein surface scribbles electret film and with its ground connection, another pole plate is connected on the grid of field effect transistor, is connected to a diode between grid and the source electrode.When being vibrated or be subject to the friction of air-flow, because vibration changes the distance between two-plate, be that electric capacity changes, and electric weight is constant, will cause the variation of voltage, the size of change in voltage has reflected the power of extraneous acoustic pressure, this change in voltage frequency has reflected the frequency of external sound, the principle of work of Here it is Electret Condencer Microphone.The Electret Condencer Microphone electroacoustic property is fine.But its moisture resistance is poor, and physical strength is low, and price is slightly expensive, and uses slightly aobvious trouble.
Based on the novel device of optical fiber sound sensing technology because its volume is little, dynamic range is wide, anti-electromagnetic interference (EMI) can be worked under rugged surroundings, good stability and be easy to multiplexing etc. advantage and be subject to extensive concern.Optical fiber sound sensing technology can be summarised as three large method fields substantially: optical fibre device sonic transducer, fibre optic interferometer sonic transducer, fiber grating acoustic sensor.The stable performance of optical fibre device sonic transducer, but too rely on device performance, can only work in the specific occasion.For example 2004, the people such as R Chen proposed based on fused biconical taper monomode coupler ultrasonic sensor.This method is measured sensitivity can reach 5.6mV/Pa, and the survey frequency scope is at 10kHz-1mHz; Fibre optic interferometer sonic transducer frequency sonding scope can reach 40Hz-400kHz, and sensitivity is higher, but easily causes phase error.For example 2008, the people such as the Wu Dongfang of Fudan University did a series of research to Sagnac interference-type optical fiber microphone, and its experimental result shows that bandwidth reaches 10Hz-200kHz, and signal to noise ratio (S/N ratio) is up to more than the 60dB; Fiber grating acoustic sensor is highly sensitive, good stability, but only be suitable for the high frequency sound signal of look-in frequency more than 10kHz.For example 2010, the people such as Hiroshi Tsuda carried out comparative study to the method that the bragg grating of several structures is measured ultrasonic signal.
Summary of the invention
Technical matters to be solved by this invention provide a kind of look-in frequency scope wide, survey accurately frequency of sound wave detector and multi-mode coupler frequency of sound wave detection system.
For solving the problems of the technologies described above, the present invention at first provides a kind of frequency of sound wave detector, it is characterized in that, comprise multi-module optical fiber coupler, aluminium matter film and derby, the diameter of described aluminium matter circular membrane is that 30 ~ 40mm, thickness are 2.5 ~ 3.5um, smooth being pasted on the described derby around the described aluminium matter circular membrane, the two ends of described multi-module optical fiber coupler are fixed, and the coupled zone of middle long 5 ~ 10mm naturally droops with described aluminium matter film and contacts.
Based on above-mentioned frequency of sound wave detector, the present invention also provides a kind of multi-mode coupler frequency of sound wave detection system, it is characterized in that, comprise described frequency of sound wave detector, also comprise audio signal generator, loudspeaker, wide spectrum light source, 1 * 2 fiber coupler, the high speed optoelectronic modular converter, spectrum analyzer, described audio signal generator connects described loudspeaker, described loudspeaker are near described frequency of sound wave detector, the output terminal of described frequency of sound wave detector connects described high speed optoelectronic modular converter, and described high speed optoelectronic modular converter connects described spectrum analyzer.
Further optimize, described multi-mode coupler frequency of sound wave detection system also comprises 1 * 2 fiber coupler, the optics oscillograph, the output terminal of described frequency of sound wave detector connects described 1 * 2 fiber coupler, an output terminal of described 1 * 2 fiber coupler connects the optics oscillograph, and another output terminal connects described high speed optoelectronic modular converter.
Preferably, in the described multi-mode coupler frequency of sound wave detection system, the coupling ratio of described 1 * 2 fiber coupler is 50%, the coupling mechanism input end is connected by the welding mode with multi-module optical fiber coupler, and two output terminals are connected with the high speed optoelectronic modular converter with the optics oscillograph respectively that to be connected be to dock by the FC/APC fibre-optical splice.
The coupling ratio approximate range of the multi-module optical fiber coupler of described un-encapsulated is at 20%-30%.
Beneficial effect of the present invention is:
1, the present invention compares with traditional condenser type detection method, utilizes optical fiber sound sensing mode, and antijamming capability is strong, is easy to long Distance Transmission;
2, the present invention utilizes the optics oscillograph to come the time domain waveform of detectable signal by the spectral image of spectrum analyzer tracking signal simultaneously, has guaranteed the accuracy of measuring.
3, sensing head of the present invention is the multi-module optical fiber coupler that utilizes fused biconical taper technique to make, and cost is low, is easy to quick production in enormous quantities.
Description of drawings
Below in conjunction with the drawings and specific embodiments technical scheme of the present invention is further described in detail.
Fig. 1 is multi-mode coupler frequency of sound wave detection system structural drawing of the present invention;
Fig. 2 is the structural drawing of frequency of sound wave detector of the present invention;
Fig. 3 is multi-mode coupler preparation technology structural drawing of the present invention.
Embodiment
Fig. 1 has provided multi-mode coupler frequency of sound wave detection system structural drawing, and virtual instrument software audio signal generator 4 sends specific single-frequency acoustic signals by connecting loudspeaker 5.Wide spectrum light source 1 connects frequency of sound wave detector 2 by general single mode fiber, when the characteristic frequency acoustic signals acts on the frequency of sound wave detector, causes frequency of sound wave detector resonance, and the frequency of sound wave signal is converted into the variation of light signal.The output terminal that the output terminal of frequency of sound wave detector connects 1 * 2 fiber coupler, 3,1 * 2 fiber couplers 3 connects optics oscillograph 8, and dynamic scan is by the time domain fluctuation of the light signal of frequency of sound wave detector in real time.After changing into electric signal, another output terminal connection high speed optoelectronic modular converter 6 of 1 * 2 fiber coupler 3 accesses in the spectrum analyzer 7, the frequency domain spectra shape of display frequency detector resonance, thus demodulate the frequency of sound wave that acts on the frequency of sound wave detector 2.Optics oscillograph 8 output time-domain signals, the frequency-region signal of time-domain signal on gained signal after the Fourier transform and spectrum analyzer 7 contrasts, and guarantees the accuracy of demodulation frequency of sound wave.
1 * 2 fiber coupler 3 is the general single mode fiber coupling mechanism among Fig. 1, and its splitting ratio is 50:50.
Fig. 2 has provided the structural drawing of the used frequency of sound wave detector 2 of detection system, and it is comprised of multi-module optical fiber coupler 9, aluminium matter film 10 and the support metal piece 11 of un-encapsulated.The coupling ratio of multi-module optical fiber coupler 9 is about 20%-30%, and its two ends are fixed, and the centre naturally droops, and only length is that the coupled zone of 5 ~ 10mm contacts with aluminium matter film 10.Aluminium matter film 10 is diameter 30 ~ 40mm, the circular membrane of thick 2.5～3.5um, and smooth being pasted on the support metal piece 11 all around, support metal piece 11 is ring-like, internal diameter is slightly less than the diameter of aluminium matter circular membrane, thick approximately 20mm.Sound wave effect causes the resonance of aluminium matter film 10 on aluminium matter film 10, drive is positioned over the corresponding vibration of the multi-module optical fiber coupler coupled zone above the film, thereby so that Coupling power than the variation that occurs with the sound wave same frequency, has so just been realized based on the conversion to frequency of light wave of the frequency of sound wave of intensity modulation.
Fig. 3 has provided multi-mode coupler preparation technology structural drawing, the single wavelength light source 12 of 1550nm connects the general single mode fiber Output of laser, general single mode fiber connects one section multimode optical fiber 14 by the welding mode, multimode optical fiber 14 again with the parallel placement of another root multimode fiber, zone line approximately 25mm is all divested coat, then divest the two ends knotting of part, multimode optical fiber is fixed in respectively anchor clamps 13 and anchor clamps 15 to two ends, and anchor clamps 15 multimode optical fiber out is connected in detector 16 and detector 17 by naked fine adapter respectively again. Detector 16,17 is connected in computer 18, the power coupling information that detects is passed to computer 18, computer 18 is controlled the operation of anchor clamps by the driving circuit of electric wire jockey 13, anchor clamps 15 again, and computer 18 connects hydrogen duration and degree of heating 19 simultaneously, the motion of control duration and degree of heating.When computer 18 control duration and degree of heatings 19 move to hydrogen flame envelope heating multimode optical fiber to 14 the time, symmetrical disengaging movement when beginning to control anchor clamps 13, anchor clamps 15, multimode optical fiber is realized that to 14 the limit heating edge stretches, thereby the realization multimode optical fiber is to 14 power cross-couplings, stop to draw cone when reaching predetermined splitting ratio, so just carried out the preparation of multi-module optical fiber coupler 9.
Multimode optical fiber is the known multimode optical fiber of refractive index to 14 among Fig. 3, and its core diameter is 105um, cladding diameter 125um.Hydrogen duration and degree of heating 19 is to be supplied with hydrogen and controlled its hydrogen flowing quantity size by the hydrogen generator brine electrolysis.
It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although with reference to preferred embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.
Claims (5)
1. frequency of sound wave detector, it is characterized in that, comprise multi-module optical fiber coupler, aluminium matter film and derby, the diameter of described aluminium matter circular membrane is that 30 ~ 40mm, thickness are 2.5 ~ 3.5um, smooth being pasted on the described derby around the described aluminium matter circular membrane, the two ends of described multi-module optical fiber coupler are fixed, and the coupled zone of middle long 5 ~ 10mm naturally droops with described aluminium matter film and contacts.
2. multi-mode coupler frequency of sound wave detection system, it is characterized in that, comprise the described frequency of sound wave detector of claim 1, also comprise audio signal generator, loudspeaker, wide spectrum light source, 1 * 2 fiber coupler, the high speed optoelectronic modular converter, spectrum analyzer, described audio signal generator connects described loudspeaker, described loudspeaker are near described frequency of sound wave detector, the output terminal of described frequency of sound wave detector connects described high speed optoelectronic modular converter, and described high speed optoelectronic modular converter connects described spectrum analyzer.
3. multi-mode coupler frequency of sound wave detection system according to claim 2, it is characterized in that, also comprise 1 * 2 fiber coupler, the optics oscillograph, the output terminal of described frequency of sound wave detector connects described 1 * 2 fiber coupler, an output terminal of described 1 * 2 fiber coupler connects the optics oscillograph, and another output terminal connects described high speed optoelectronic modular converter.
4. multi-mode coupler frequency of sound wave detection system according to claim 3, it is characterized in that, the coupling ratio of described 1 * 2 fiber coupler is 50%, the coupling mechanism input end is connected by the welding mode with multi-module optical fiber coupler, and two output terminals are connected with the high speed optoelectronic modular converter with the optics oscillograph respectively that to be connected be to dock by the FC/APC fibre-optical splice.
5. multi-mode coupler frequency of sound wave detection system according to claim 1 is characterized in that, the coupling ratio approximate range of the multi-module optical fiber coupler of described un-encapsulated is at 20%-30%.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105277269A (en) * | 2014-07-22 | 2016-01-27 | 中国石油化工股份有限公司 | Phase shift fiber grating probe and manufacture method thereof |
| CN110236500A (en) * | 2019-06-19 | 2019-09-17 | 深圳市矽赫科技有限公司 | Detection device for vital signs |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1145669A (en) * | 1994-02-18 | 1997-03-19 | 南安普敦大学 | Optical device |
| US20020131713A1 (en) * | 2001-01-22 | 2002-09-19 | Yihlih Peng | Tapered fiber holder |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1145669A (en) * | 1994-02-18 | 1997-03-19 | 南安普敦大学 | Optical device |
| US20020131713A1 (en) * | 2001-01-22 | 2002-09-19 | Yihlih Peng | Tapered fiber holder |
Non-Patent Citations (3)
| Title |
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| JUN CHANG ET AL.: "Fiber optic vibration sensor based on over-coupled fused coupler", 《PROC. OF SPIE》, vol. 6595, 31 December 2007 (2007-12-31), pages 65954 * |
| R.C. TURNER ET AL.: "Materials for high temperature acoustic and vibration sensors:A review", 《APPLIED ACOUSTICS》, no. 41, 31 December 1994 (1994-12-31), pages 299 - 324, XP002579340 * |
| 胡正良: "耦合型声/振动光纤传感器", 《中国优秀硕士学位论文全文数据库》, no. 1, 31 December 2003 (2003-12-31), pages 140 - 37 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105277269A (en) * | 2014-07-22 | 2016-01-27 | 中国石油化工股份有限公司 | Phase shift fiber grating probe and manufacture method thereof |
| CN110236500A (en) * | 2019-06-19 | 2019-09-17 | 深圳市矽赫科技有限公司 | Detection device for vital signs |
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