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1、通过调相式载波消除外差干涉仪的非线性SergeDubovitsky,OliverP.Lay,andDavidJ.SeidelJetPropulsionLaboratory,M/S301-451,4800OakGroveDrive,Pasadena,California91109ReceivedOctober8,2001Accuracyinmeasuringdisplacementinopticalinterferometersislimitedbycyclicerrorsintroducedbyvariousleakagepat
2、hswithinthesystem.Existingtechniquestoreducethisnonlinearitydonotworkwhenthereislargeopticallossinthetargetpath,suchasforlong-rangemeasurements.Wedescribeanewapproachtoreducingnonlinearitythatovercomestheselimitations.Basedonphasemodulationofthelaserlight,andrequirin
3、gminimaladditionalcomponents,experimentshavedemonstratedrejectionoftheeffectsofleakageinthepresenceoflargeopticalloss.©2002OpticalSocietyofAmerica光学干涉仪测量位移的精确度受限于循环误差所引入的各种系统内泄漏路径(leakagepaths)。现有的技术来减少这种非线性在目标路径有大量光损耗如远程测量时不可行。我们描述了一种新的方式来减少非线性,克服这些局限性。基于相位调制的激光,并要求
4、最少组件,实验已证明拒绝泄漏影响的大量光损耗的存在。2002年美国©光学学会OCIScodes:120.3940,120.3180,120.5060.Opticalinterferometryisamethodofchoiceformeasurementsofsubmicrometerdisplacements.光学干涉是对亚微米级位移测量的一种选择方法。Mostpracticalinterferometersusedforprecisionsensingarebasedontheheterodyneinterferometer
5、,owingtoitshigh-precisionreadoutaffordedbyheterodynesignalprocessing.最实用的干涉仪用于精密感应是基于外差干涉仪,由于自身的高精度读出所给予的外差信号处理。However,atypicalopticalheterodyneinterferometerislimitedinitsresolutionbyparasiticleakageofopticalsignals,calledpolarizationleakageorpolarizationmixing,whi
6、chresultsinundesiredself-interferenceheterodynebeatsatthephotodetector.1–3然而,一个典型的光学外差干涉仪受限于它的分辨率通过无源泄漏的光信号,被称为极化泄漏或极化混合,结果是不期望的自干涉外差跳动在光电探测器上。Self-interference(SI)causesacyclicnonlinearityintheinterferometer’sphase-versus-displacementresponse.自干涉导致循环在干涉仪的phaseversus
7、-displacement非线性响应。ThemagnitudeoftheerrorisproportionaltotheratiooftheSIleveltothedesiredrange-relatedsignal.误差的大小是成正比的比值自干涉水平所需的range-related信号。Typicallythisratioisoftheorderofafewpercentandresultsinarangenonlinearityerrorofafewnanometers.通常这个比例为百分之几和结果在一系列几纳米的非线性误差
8、。Anumberofmethodsforcalibratingthenonlinearityandimprovingresolutiontothesubnanometerlevelhavebeenproposed.已经计划使用一些方法来校正非线性和改善亚纳米级的