CN2612938Y - Polarization resistant micro-vibration measurement and non-loss single mode optical fiber interferometer - Google Patents
Polarization resistant micro-vibration measurement and non-loss single mode optical fiber interferometer Download PDFInfo
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- CN2612938Y CN2612938Y CNU032218613U CN03221861U CN2612938Y CN 2612938 Y CN2612938 Y CN 2612938Y CN U032218613 U CNU032218613 U CN U032218613U CN 03221861 U CN03221861 U CN 03221861U CN 2612938 Y CN2612938 Y CN 2612938Y
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Abstract
Disclosed is an anti-polarizing influence micro-oscillation measuring and fidelity picking-up single mode fiber interferometer which is characterized in that the interferometer adopts a single mode fiber, uses a laser device as the light source, the laser is divided to two ways respectively via a reference arm and a signal arm by a single mode fiber coupling device, a generated interference signal is output as the frequency modulation electric signal in a photoelectric detector, a high-frequency signal driver, a piezoelectric ceramic phase modulation device which is used for generating the high-frequency signal, a collimator and a half-wave plate which controls the rotary angle via the feedback of peak values of high-frequency signals of the photoelectric detector and is used for adjusting a polarization state of the reference light. The utility model is a single mode fiber interferometer which has practical significances and relatively cheap price, is used for making the accurate measurement and fidelity picking-up to the micro-oscillation signals which amplitudes are less than the magnitude of 50 nanometers.
Description
Technical field:
The utility model relates to the interference-type optical fiber sensing technology, more particularly a kind ofly is used for the single-mode fiber interferometer that microvibration measuring and fidelity pick up.
Background technology:
Mechanical vibration are the important monitoring targets in a plurality of fields.At present, in the vibration more than 1 micron, can use the vibration measuring set of traditional piezoelectric type or magneto-electric to measure for amplitude; For the measurement of vibration amplitude, generally need to carry out with vibration measurement with laser instrument interfere type, the price comparison costliness at the micro-vibration signal below 1 micron.
For some specific occasion, as distributed vibration signal monitoring etc. in the measurement of the medium-and-large-sized fixture vibratory response of sound field, the buildings, its measured amplitude is usually less than 50 nanometers, and to the requirement of portable and cost performance, existing vibration measuring set is difficult to satisfy these requirements in addition.The single-mode fiber sensing technology is suitable selection from several respects such as sensitivity, portability and cost performance, but the using single mode fiber sensing technology must overcome two big technical barriers:
1, environmental perturbation causes the polarization state random variation and the signal dropout that causes:
When the temperature of environment and stress application change, birefringent change changes the propagation polarization state of light thereupon in the optical fiber, can cause interfering the fluctuating of line contrast (being the interference signal amplitude) this moment, when the interference signal amplitude descends, the sensitivity of input also can descend, the signal dropout that polarization state that Here it is causes.
2, environmental perturbation causes the phase place random variation and the signal dropout that causes:
Because the vibration signal that system detected is very faint, the fiber lengths that signal causes changes usually only to be had below the magnitude of per mille wavelength, and the fiber lengths that environmental perturbation causes variation usually can reach more than the wavelength magnitude, just can cause the interference signal decline this moment.
For overcoming above first difficult point, generally adopt methods such as polarization maintaining optical fibre or KDP polarization state High Speed Modulation.But the common fault of these methods not only is to cost an arm and a leg, but also exists some technology that are difficult to overcome to use difficult point.At second difficult point, generally adopt methods such as Phase Tracking, synthetic beat or phase carrier modulation.
According to prior art, because single-mode fiber can't keep transmitting polarized state of light, when environmental baseline changes, the change of its polarization state will cause the decline of interference signal, therefore, usually think the single-mode fiber interferometer, as not adding measures such as Polarization Control or polarization compensation, difficult with practical value.
Summary of the invention:
Technical problem to be solved in the utility model is to avoid existing weak point in the above-mentioned prior art, provides a kind of and has Practical significance, relative low price, is used for amplitude is accurately measured less than the micro-vibration signal of 50 nanometer scale and the microvibration measuring and the fidelity of the anti-polarization influence that fidelity picks up pick up the single-mode fiber interferometer.
The technical scheme that the utility model technical solution problem is adopted is:
Design feature of the present utility model is to adopt the single-mode fiber light path, is light source with the laser instrument, by single-mode optical-fibre coupler laser is divided into two-way, the one tunnel through reference arm to half anti-mirror; The signal arm of another road through being provided with collimating apparatus A is to half anti-mirror, and formed interference signal is exported with the frequency modulation electric signal in photoelectric detector;
Design feature of the present utility model also is in described reference arm, set gradually with the high-frequency signal driver drives, serve as piezoelectric ceramic phase, the collimating apparatus A that produces the high frequency interference signal, and by the high frequency interference signal FEEDBACK CONTROL anglec of rotation of photoelectric detector, in order to adjust the half-wave plate of reference light polarization state.
Theoretical analysis and experimental study show that in the environment for use of this product, the phase place random variation that environmental perturbation causes is a low frequency signal, and the polarization state random variation that environmental perturbation the causes lower slow varying signal that is frequency.At these characteristics, the utility model adopts the modulation of high frequency phase carrier to cooperate follow-up demodulator circuit, to eliminate the signal dropout that the phase place random variation causes, and utilize the amplitude size of this interference signal simultaneously, the automatic rotation of FEEDBACK CONTROL half-wave plate is adjusted with reference to polarization state of light, makes the amplitude maximum of interference signal, lock this state by signal Processing and control circuit, suppressed the signal dropout that the polarization state random variation causes with this.This method makes the single-mode fiber interferometer have good practicability.
Compared with the prior art, the beneficial effects of the utility model are embodied in:
1, the utility model adopts common single mode optical fibres, rotation by the FEEDBACK CONTROL half-wave plate, the locking interference signal has suppressed the signal dropout that the polarization state random variation causes at the maximum amplitude place, has obtained practical and cheap microvibration measuring and fidelity and has picked up the single-mode fiber interferometer.
2, the utility model is by driving piezoelectric ceramic phase with high-frequency signal, make the laser between reference arm and the signal arm produce the high frequency interference signal, this interference signal cooperates follow-up demodulator circuit can eliminate that environmental perturbation causes the phase place random variation and the signal dropout that causes, again can be according to the size of its amplitude, the rotation of control half-wave plate, its amplitude is locked in maximum, and this is with regard to having suppressed environmental perturbation and causing the polarization state random variation and the signal dropout that causes.
Accompanying drawing is the utility model structural representation.
Embodiment:
Referring to accompanying drawing, present embodiment is to adopt single-mode fiber, is light source with laser instrument 1, by single-mode optical-fibre coupler 2 laser is divided into two-way, and one tunnel signal arm 6 through being provided with A collimating apparatus 11 is to half anti-mirror 10; Another road through reference arm 3 to half anti-mirror 10; The formed interference signal of flashlight and reference light is exported with the frequency modulation electric signal in photoelectric detector 12.
Shown in the figure, in reference arm 3, set gradually with 4 drivings of high-frequency signal driver, serve as piezoelectric ceramics phaser modulator 5, the B collimating apparatus 7 that produces the high frequency interference signal, and by the high frequency interference signal FEEDBACK CONTROL anglec of rotation of photoelectric detector, in order to adjust the half-wave plate 8 of reference light polarization state.
In concrete the enforcement, control motor 9 is set, can adopts stepper motor,, and then control half-wave plate 8 rotations automatically with the FM signal of stepper motor acceptance from signal processing control circuit 13.
In addition, when using semiconductor laser as light source, the light path of signal arm and reference arm is answered basically identical; Twine the length of optical fiber and driving voltage on the piezoelectric ceramics and should cooperate in the lump and consider, guarantee to produce the above phase differential of one-period; Half-wave plate can adopt the zero level quartz wave-plate; Each surface optical device plating anti-reflection film.
Light path basic comprising of the present utility model is optical fiber mach a---Zehnder interferometer, and reference arm wherein and signal arm are common single mode optical fibres.The signal dropout of adopting high frequency phase carrier modulation eliminating phase place random variation to cause, and utilize the amplitude size of this interference signal, determine the polarization state state, and further control motor rotation half-wave plate, adjust reference arm output polarization state of light, make the amplitude maximum of interference signal, lock this state, suppress the signal dropout that the polarization state random variation causes with this by signal Processing and control circuit.
Claims (2)
1, the microvibration measuring and the fidelity of anti-polarization influence pick up the single-mode fiber interferometer, it is characterized in that adopting the single-mode fiber light path, with laser instrument (1) is light source, by single-mode optical-fibre coupler (2) laser is divided into two-way, one tunnel signal arm (6) through being provided with collimating apparatus A (11) is to half anti-mirror (10); Another road is through the extremely described half anti-mirror (10) of reference arm (3); The formed interference signal of flashlight and reference light is exported with the frequency modulation electric signal in photoelectric detector (12);
In described reference arm (3), set gradually with high-frequency signal driver (4) and drive, serve as piezoelectric ceramic phase (5), the collimating apparatus B (7) that produces the high frequency interference signal, and by the high frequency interference signal FEEDBACK CONTROL anglec of rotation of photoelectric detector (12) and follow-up signal processing control circuit (13) output thereof, in order to the half-wave plate (8) of adjustment reference light polarization state.
2, the microvibration measuring and the fidelity of anti-polarization influence according to claim 1 pick up the single-mode fiber interferometer, it is characterized in that being provided with the drive motor (9) that rotates automatically in order to control half-wave plate (8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU032218613U CN2612938Y (en) | 2003-05-14 | 2003-05-14 | Polarization resistant micro-vibration measurement and non-loss single mode optical fiber interferometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU032218613U CN2612938Y (en) | 2003-05-14 | 2003-05-14 | Polarization resistant micro-vibration measurement and non-loss single mode optical fiber interferometer |
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| CN2612938Y true CN2612938Y (en) | 2004-04-21 |
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| CNU032218613U Expired - Fee Related CN2612938Y (en) | 2003-05-14 | 2003-05-14 | Polarization resistant micro-vibration measurement and non-loss single mode optical fiber interferometer |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487133A (en) * | 2013-09-23 | 2014-01-01 | 安徽大学 | Method and device for improving signal to noise ratio of laser micro-vibration sensing system |
| CN105911022A (en) * | 2016-06-06 | 2016-08-31 | 安徽大学 | Hazardous chemical substance remote sensing detection method and device based on wide tuning external cavity quantum cascade laser |
| CN110095177B (en) * | 2019-04-24 | 2021-08-03 | 上海传输线研究所（中国电子科技集团公司第二十三研究所） | System and method for suppressing fiber grating hydrophone phase demodulation polarization fading |
-
2003
- 2003-05-14 CN CNU032218613U patent/CN2612938Y/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103487133A (en) * | 2013-09-23 | 2014-01-01 | 安徽大学 | Method and device for improving signal to noise ratio of laser micro-vibration sensing system |
| CN103487133B (en) * | 2013-09-23 | 2015-08-19 | 安徽大学 | Improve method and the device of the micro-vibration sensing system signal to noise ratio (S/N ratio) of laser |
| CN105911022A (en) * | 2016-06-06 | 2016-08-31 | 安徽大学 | Hazardous chemical substance remote sensing detection method and device based on wide tuning external cavity quantum cascade laser |
| CN105911022B (en) * | 2016-06-06 | 2019-01-18 | 安徽大学 | Harmful influence remote detecting method and device based on broad tuning external cavity type quantum cascade laser |
| CN110095177B (en) * | 2019-04-24 | 2021-08-03 | 上海传输线研究所（中国电子科技集团公司第二十三研究所） | System and method for suppressing fiber grating hydrophone phase demodulation polarization fading |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20040421 Termination date: 20100514 |