CN1227520C - Long-distance scatterer microvibrating signal measurement and fidelit pickup interferometer - Google Patents
Long-distance scatterer microvibrating signal measurement and fidelit pickup interferometer Download PDFInfo
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- CN1227520C CN1227520C CNB031134785A CN03113478A CN1227520C CN 1227520 C CN1227520 C CN 1227520C CN B031134785 A CNB031134785 A CN B031134785A CN 03113478 A CN03113478 A CN 03113478A CN 1227520 C CN1227520 C CN 1227520C
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Abstract
The present invention relates to a long-distance scatterer microvibration signal measurement and fidelity pickup interferometer which uses a fiber laser as a light source. After the output light beam of the light source passes through a polarization-preserving fiber and a collimator, the output light beam enters a polarizing beam splitter A. Subsequently, one path of the light beam is projected out of a telescoping system through a lambada/4 wave plate and is focused on a distant object, and the scattered light of the distant object is used as signal light. The other path of the light beam is used as local reference light and is reflected to the polarizing beam splitter A through the lambada/4 wave plate and a reflecting mirror. After the signal light collected by the telescoping system and the local reference light penetrate through the polarizing beam splitter A, the signal light and the local reference light respectively enter photoelectric detectors D1 and D2 forming interference signals through the half-wave plate firstly and a polarizing beam splitter B subsequently. The present invention has the advantages that the utilization efficiency of the power of the light source is effectively enhanced, system phase noise is reduced, and the measurement and the fidelity pickup of long distance microvibration signals without cooperated objects are realized.
Description
Technical field:
The present invention relates to non-contact laser vibration measuring technology, the measurement and the fidelity pick device of a kind of long distance scatter thing micro-vibration signal of more specifically saying so.
Background technology:
The measurement of vibration signal and fidelity pick up all can adopt Doppler (Doppler) interference technique.Closely contactless detection is generally adopted two-beam interference (two-beam interference) and is mixed (self-mixing) technology certainly, and the amplitude precision has reached inferior nanometer scale.When detecting distance when far away, generally adopt reference light Michelson (Michelson) interference technique, but, usually need install additional the cooperative target of the return light intensity of increase on the measured object surface when measuring distance when (as greater than 25 meters) far away.
In some practical applications, because environmental limit, measuring equipment must be away from measured object, and the measured object surface can't install cooperative target additional, and has necessarily and take measurement of an angle.Discover, in this environment for use, the requirement that the signal to noise ratio (S/N ratio) of traditional Doppler's vialog is difficult to satisfy to measure and fidelity picks up.Because when detect distance far away, take measurement of an angle big and when not having cooperative target, because the rapid decay of received signal luminous energy makes detected light signal extremely faint; In addition, when distance is far away, except the noise that the fevering sodium effect of the polarization drift of speckle interference, light source and scattering surface, environmental perturbation etc. are brought, when short distance detection, embodies the light source phase noise that does not come out and also become one of important source of noise.Caused the rapid reduction of interference system signal to noise ratio (S/N ratio) thus.
Traditional employed LASER Light Source of Doppler's vialog, its laser linewidth and luminous power can not satisfy the telemeasurement requirement simultaneously.
Summary of the invention:
Technical matters to be solved by this invention is to avoid existing weak point in the above-mentioned prior art, a kind of signal light power, reduction system phase noise of improving is provided, and final measurement of long distance scatter thing micro-vibration signal and the fidelity of realizing that remote no cooperative target micro-vibration signal is measured and fidelity picks up picks up interferometer.
The technical scheme that technical solution problem of the present invention is adopted is:
Design feature of the present invention is:
With the fiber laser is light source, light path is: the output of fiber laser after polarization maintaining optical fibre and collimating apparatus with parallel beam to polarization beam apparatus A, thereafter, the one tunnel projects telescopic system through λ/4 wave plates, focusing on the distant object thing, is flashlight with the scattered light of distant object thing; Another road is returned polarization beam apparatus A as local reference light via λ/4 wave plates and mirror reflects; After seeing through polarization beam apparatus A by telescope system collected signal light and local reference light, rotate the half-wave plate of 45 degree earlier simultaneously through the polarization direction that makes flashlight and reference light, process polarization beam apparatus B is respectively to photoelectric detector D1 that forms interference signal and photoelectric detector D2 again.
The present invention is high-power by adopting, and has single longitudinal mode, super narrow laser linewidth fiber laser, improve effectively flashlight power, reduced the phase noise in the interferometer; Adopt telescope that laser beam is focused on the vibrating object surface, and utilize telescope to collect back scattered flashlight; Utilize the balance detection method to reduce system noise, improve detection sensitivity.
Compared with the prior art, beneficial effect of the present invention is embodied in:
1, the present invention is by adopting the fiber laser of high-power narrow linewidth single longitudinal mode, and its laser linewidth is less than 5KHz, and luminous power is greater than 10mW, and optical maser wavelength is in the eye-safe wave band.Improve effectively flashlight power, reduced the phase noise in the interferometer when remote the detection, improve sensitivity limit.
2, the present invention effectively improves the utilization ratio of light source power by the laser beam projection transform optical system that polarization maintaining optical fiber collimator and telescopic system constitute.The final measurement and the fidelity of remote no cooperative target micro-vibration signal realized picks up.
3, the present invention is by utilizing telescope lock onto target thing, and is simple and practical.
Fig. 1 is a structural representation of the present invention.
Fig. 2 is circuit theory diagrams of the present invention.
Embodiment:
Referring to Fig. 1, present embodiment is a light source with fiber laser 1, utilize telescopic system 6 with laser focusing to the vibration object 13 on, its scattered light is a flashlight, is converged by 6 pairs of flashlights of telescopic system again.
Concrete light path is: the output of fiber laser 1 after polarization maintaining optical fibre 2 and collimating apparatus 3 with parallel beam to A polarization beam apparatus 4, thereafter, one the tunnel projects telescopic system 6 through λ/4 wave plates 5, another road as local reference light via λ/4 wave plates 8 and catoptron 7 reflected back A polarization beam apparatus 4; After flashlight of being collected by telescopic system 6 and local reference light see through A polarization beam apparatus 4, make the polarization direction of flashlight and reference light rotate 45 degree simultaneously through half-wave plate 9 earlier, on D1 photoelectric detector 11 and D2 photoelectric detector 12, form the interference signal that is convertible into the frequency modulation electric signal respectively through B polarization beam apparatus 10 again.
In this light channel structure, λ/4 wave plates 5 that are arranged in the signal light path perpendicular to the shoot laser polarization state, make the luminous power that arrives D1 photoelectric detector 11 and D2 photoelectric detector 12 the strongest the return signal polarization state of light; Be arranged in the light intensity that λ/4 wave plates 8 are used to regulate reference light of local reference path; Half-wave plate 9 is used for regulating arrival B polarization beam apparatus 10 flashlights and with reference to polarization state of light, makes the luminous power balance of D1 photoelectric detector 11 and D2 photoelectric detector 12, and only when balance, two-way balance detection method could effectively reduce noise and improve signal to noise ratio (S/N ratio).
In concrete the enforcement, collimating apparatus 3 is positioned at the imaging surface center of telescopic system 6.Polarization maintaining optical fibre 2 is used for the laser beam transformation that the angle of divergence is bigger with collimating apparatus 3 and becomes parallel beam.
For the power that improves flashlight effectively, reduce the phase noise in the interferometer, the fiber laser in the present embodiment be single longitudinal mode, laser linewidth less than 5KHz, side mode suppression ratio greater than 20dB, laser power greater than 10mW.
In addition, all surface optical devices all plate anti-reflection film; Wave plate all adopts the zero level quartz wave-plate; Photoelectric detector D1 and photoelectric detector D2 should be photoelectric tubes of the same race, the responsiveness unanimity of will trying one's best; Photoelectric detector D1 and photoelectric detector D2 position are on the imaging surface of telescopic system.
Physical circuit is: PD1 and PD2 are the photoelectric detector (InGaAs/InP PIN detector) of parameter symmetry, and A1 and A2 are the same model low noise operational amplifiers, and PD1, A1 and feedback resistance Rf1 have constituted transimpedance formula low-noise preamplifier; PD2, A2 and feedback resistance Rf2 have constituted the transimpedance formula low-noise preamplifier of same parameter.Constitute balance detection circuit by these the two groups subtracters that have in same parametric preamplifier and the follow-up circuit, wherein adjustable resistance Rt1 and Rt2 are used for further finely tuning the two-way equilibrium state, serve as zero with the DC quantity that guarantees subtracter output.The bandwidth of bandpass filter needs to be adjusted according to the vibration frequency and the amplitude of measurand.Separating the phase device is used for vibration signal is restored from FM signal.
Claims (2)
1, measurement of long distance scatter thing micro-vibration signal and fidelity pick up interferometer, it is characterized in that:
With fiber laser (1) is light source, light path is: the output of fiber laser (1) after polarization maintaining optical fibre (2) and collimating apparatus (3) with parallel beam to polarization beam apparatus A (4), thereafter, one the tunnel projects telescopic system (6) through λ/4 wave plates (5), focus on the distant object thing (13), and be flashlight with the scattered light on the distant object thing (13); Another road as local reference light via λ/4 wave plates (8) and catoptron (7) reflected back polarization beam apparatus A (4); After flashlight of being collected by telescopic system (6) and local reference light see through polarization beam apparatus A (4), rotate the half-wave plate (9) of 45 degree earlier through the polarization direction that makes flashlight and reference light simultaneously, pass through polarization beam apparatus B (10) more respectively to photoelectric detector D1 (11) that forms interference signal and photoelectric detector D2 (12).
2, long distance scatter thing micro-vibration signal measurement according to claim 1 and fidelity pick up interferometer, and the output laser that it is characterized in that described fiber laser is single longitudinal mode, and its laser linewidth is less than 5KHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031134785A CN1227520C (en) | 2003-05-14 | 2003-05-14 | Long-distance scatterer microvibrating signal measurement and fidelit pickup interferometer |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB031134785A CN1227520C (en) | 2003-05-14 | 2003-05-14 | Long-distance scatterer microvibrating signal measurement and fidelit pickup interferometer |
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| CN1548936A CN1548936A (en) | 2004-11-24 |
| CN1227520C true CN1227520C (en) | 2005-11-16 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB031134785A Expired - Lifetime CN1227520C (en) | 2003-05-14 | 2003-05-14 | Long-distance scatterer microvibrating signal measurement and fidelit pickup interferometer |
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Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101465052B (en) * | 2007-12-21 | 2011-05-11 | 上海光亮光电科技有限公司 | Safety monitoring system and method for circumference |
| CN101620764B (en) * | 2009-06-15 | 2012-11-07 | 上海华魏光纤传感技术有限公司 | Distributed optical fiber vibration sensing system based on polarization beam splitting detection and sensing method |
| US9261800B2 (en) * | 2011-03-30 | 2016-02-16 | Mapper Lithography Ip B.V. | Alignment of an interferometer module for use in an exposure tool |
| 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 |
| CN105092013B (en) * | 2015-05-12 | 2019-01-11 | 清华大学 | Sound recognition system and sound identification method |
| CN108534986B (en) * | 2018-04-12 | 2020-03-31 | 安徽大学 | Multi-longitudinal-mode laser resonant cavity FSR measuring device and measuring method |
| CN112556820A (en) * | 2020-11-10 | 2021-03-26 | 华电电力科学研究院有限公司 | Detection method of laser interference detection vibration device for tile vibration transverse vibration acceleration of wind turbine generator |
| CN112684461A (en) * | 2020-12-21 | 2021-04-20 | 武汉光目科技有限公司 | Anti-vibration type area array frequency sweep measuring device and method |
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2003
- 2003-05-14 CN CNB031134785A patent/CN1227520C/en not_active Expired - Lifetime
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Effective date of registration: 20180319 Address after: 230088 A seat 4-5 layers of the two phase G4 building of the Innovation Industrial Park in Hefei hi tech Zone, Anhui Patentee after: ANHUI ZHIBO OPTOELECTRONIC TECHNOLOGY CO.,LTD. Address before: 230039 Hefei West Road, Anhui, No. 3 Patentee before: Anhui University |
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