Laser Beam Diameter Instruments

1 Page 1 NIST PUBUCAJJONil REFEflEMCE NISTSpecialPublication250-87 CalibrationServiceforInstruments thatMeasureLaserBeamDiameter ShaoYang 1^ll^^^^n NationalInstituteofStandardsandTechnology I^1^HilrI UnitedStatesDepartmentofComme... Open at page → 2 Page 2 rhe NationalInstituteofStandardsandTechnologywasestablishedin1988byCongressto"assistindustryinthe developmentoftechnology ...neededtoimproveproductquality,tomodernizemanufacturingprocesses,toensure productreliability ...... Open at page → 3 Page 3 NISTSpecialPublication250-87 CalibrationServiceforInstruments thatMeasureLaserBeamDiameter ShaoYang Optoelectronics Division NationalInstituteofStandardsandTechnology 325Broadway Boulder,CO80305-3337 July2010 U.S.DEPARTM... Open at page → 4 Page 4 Certaincommercialentities,equipment,ormaterialsmaybeindentifiedinthisdocumentinordertodescribean experimentalproceduralorconceptadequatetly.Suchidentification isnotintendedtoimplyrecommentionor endorsementbytheNationalIn... Open at page → 5 Page 5 CONTENTS 1. Introduction 1 2. CalibrationServiceSummary 1 3. TheoryofMeasurement 2 3.1 SystemBasicsandMeasurementPrinciple 2 3.2 MeasurementEquations 4 3.3 DataAnalysis 7 4. MeasurementSystem 7 4.1 TestBeam 7 4.2 Scannin... Open at page → 7 Page 7 CalibrationServiceforInstrumentsthatMeasureLaserBeam Diameter ShaoYang NationalInstituteofStandardsandtechnology OptoelectronicsDivision 325Broadway Boulder,CO80305 Thisdocumentdescribesthecalibrationserviceforinstrument... Open at page → 8 Page 8 4o)beamdiameterdefinedbyISO,butmayusedifferentmeasurementmethodsother thantheNISTmeasurement.Atthecompletionofthecahbrationmeasurements, the DUTandacahbrationreportaresenttothecustomer.Thecahbrationreportsummarizes there... Open at page → 9 Page 9 Currentsource &TEcontroller FC/PC connectors Monitor detector LD LDmount 0 Variablefiber attenuator 0 Fibersplitter B. FC/PC connectors Testbeam Collimator Detectionplane Slit&detector NISTbeamdiameter measurementsystem... Open at page → 10 Page 10 2 J-ooJ-cO OO (Ty= \ \ • -3.2 3.2MeasurementEquations ISOdefineslaserbeamdiameterbyuseofthesecondordermomentsofthebeampower densitydistribution I{x, [1 - 3]: rr{x-xfI{x,y)dxdy _2 J-ODJ-ao 1 CT= , 3.1 I{x,y)dxdy J-aoJ-QO... Open at page → 11 Page 11 f xP{x)dx x=— , 3.10 rP{x)dx J-00 y=— . 3.11 f Q^y)dy J-oO Equations3.5through3.11arethebasisofslitscanmeasurementofthe4f7laserbeam diameter.TheintegrationlimitsinEquations3.1to3.4and3.6to3.11arefromnegative topositivein... Open at page → 12 Page 12 3 WidthofIntegrationAreaWg{mm) Figure3.2Anintegrationareawithawidthofthreetimesthebeamdiameterdefinesmeasuredbeam diameterforthetestbeamandthebestfitGaussianbeam.Thesolidanddottedcurvesshowthemeasured beamdiameter, Df,,o... Open at page → 13 Page 13 3.3DataAnalysis IntheNISTslitscanmeasurementsystem,thewidthoftheshtis10|imandthelengthis 7mm.Foronesinglecompletemeasurement,theslitscansinboththehorizontal(x)and vertical(y)directionsatstepsof25[imforarangeof8mm.Usingit... Open at page → 14 Page 14 changeof0.002%inthefibermodefielddiameter,orachangeof0.05[iminthetest beamwidth. 4.2ScanningSlitMeasurementSystem Forthecharacterizationofthetestbeamdiameter,theNISTmeasurementsystemuses thescanningslitmethod.Thewidthoft... Open at page → 15 Page 15 specificsoftheDUT.Eachmeasurementrunmayalsoconsistofseveralmeasurements. EachNISTmeasurementincludesonescanineachofthexandydirections.Thescan takes25|imineachstepandcoversarangeof8mm.Eachscandatumisacquired simultaneousl... Open at page → 16 Page 16 wherethexvaluesrepresenttheindividualmeasurementsandNisthenumberofxvalues usedforaparticularTypeAerrorcomponent.Thestandarddeviationofthemeanis Sr/N'^,andthetotalstandarduncertaintyofthemean is[I(Sr^/N)] wherethe summati... Open at page → 17 Page 17 themonitordetector.Simulationresultsindicatedthatthisresultedinanuncertaintyof 0.1|iminthebeamwidthmeasurement. 6.1.2InterferencePattern(TypeA) Becauseofthenarrowspectralwidthofthelaserbeam,interferenceduetoreflections b... Open at page → 18 Page 18 6.2.5DetectorNonlinearity(TypeB) NonlinearitymeasurementoftheNISTdetectorshowedapositiveresponsenonHnearity ofupto2%occurredatthelowerendofthemeasurementrange.Simulationsindicated thatthisresultsinastandarduncertaintyof0... Open at page → 19 Page 19 7.QualityControl ThemeasurementservicesoftheOptoelectronicDivisionmakeuseofqualityassurance practicestoensurethevalidityofmeasurement resultsandtheiruncertainties.Such practicesinclude: •Repeatedmeasurements/calibrations... Open at page → 20 Page 20 service.Whenavailable,historicdatafrompreviousmeasurementsofthetestbeamshall beplacedintothetestfolderbytheMeasurement ServicesCoordinator afterthe preparationofthecalibrationreport.TheCalibrationLeaderandtheGroupLeaders... Open at page → 21 Page 21 References [1] ISO11146-1:2005,''Lasersandlaser-relatedequipment-Testmethodsforlaser beamwidths,divergenceanglesandbeampropagationratios-Part1:Stigmatic andsimpleastigmaticbeams,"2005. [2] ISO11146-2:2005,"Lasersandlaser... Open at page → 23 Page 23 TechnicalPublications Periodical JournalofResearchoftheNationalInstituteofStandardsandTechnology-ReportsNISTresearchand development inmetrologyandrelatedfieldsofphysicalscience,engineering,appliedmathematics, statistics,... Open at page → 24 Page 24 U.S.DepartmentofCommerce NationalInstituteofStandardsandTechnology 325Broadway Boulder,CO80305-3337 OfficialBusiness PenaltyforPrivateUse$300 Open at page →