ANSI TIA EIA 455-132-A-2001 Measurement of Effective Area of Single-Mode Optical Fiber《单模光纤有效面积测量》.pdf

1、 TIA/EIA STANDARD FOTP-132 Measurement of the Effective Area of Single-Mode Optical Fiber TIA/EIA-455-132A (Revision of TIA/EIA-455-132) JUNE 2001 TELECOMMUNICATIONS INDUSTRY ASSOCIATION The Telecommunications Industry Association represents the Communications Sector of ANSI/TIA/EIA-455-132A-2001 Ap

2、proved: May 16, 2001 TIA/EIA-455-132ACopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE TIA/EIA Engineering Standards and Publications are designed to serve the public inter

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7、nd to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 4835, formulated under the cognizance of the TIA FO-6.6 Subcommittee on Fibers and Materials.) Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION 2001 Standards and Technology Department 2500 W

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12、m IHS-,-,-iFOTP-132Measurement of the effective area of single-mode optical fiberContents Page1 Introduction .12 Normative references . 23 Apparatus .34 Sampling and specimens .45 Procedure .46 Calculations or interpretation of results . 47 Documentation .58 Specification information . 6Annex A Dire

13、ct far-field method measurement specifics .7Annex B Variable aperture in the far-field measurement specifics . 12Annex C Near-field method measurement specifics 17Annex D Sample data and calculations .20Annex E Comparison between this method and IEC or ITU Standards 23Annex F Treatment of side lobes

14、 in Far-Field Data 24Annex G A Method for Computing Effective Area from VariableAperture Data. 25Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132AiiThis page left

15、 blank.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132AiiiFOTP-132Measurement of the effective area of single-mode optical fiberForewordThis document comes from

16、TIA Project No. 3631, and was formulated under thecognizance of TIA FO-6.6, Subcommittee on Optical Fibers and Materials.This FOTP is part of the series of test procedures included within RecommendedStandard EIA/TIA-455.There are three normative annexes and two informative annexes.Key words: Nonline

17、ar refractive index, effective areaCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132AivThis page left blank.Copyright Telecommunications Industry Association Provi

18、ded by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1FOTP-132Measurement of effective area of single-mode optical fiber1 Introduction1.1 IntentThis is intended to document the methods for measuring the effective area (Aeff) ofsingle-mod

19、e fiber.1.2 ScopeThis document defines three methods of measuring Aeff. Information common to all themethods is found in the body of this document. Information specific to each method isfound in a normative annex. The three methods are:A Direct far-field (DFF)B Variable aperture in the far-field (VA

20、MFF)C Near-field (NF)The reference method, used to resolve disputes, is Method A, direct far-field.1.3 BackgroundEffective area is an optical attribute that is specified for single-mode fibers and used insystem designs that may be affected by the nonlinear refractive index coefficient, n2.There is a

21、greement in both national and international Standards bodies for thedefinition used in this document. Methods A, B, and C have been recognized asproviding equivalent results, provided that good engineering is used in implementation.The direct far-field is the reference method because it is the most

22、direct method and isnamed as the reference method for mode field diameter in the ITU.1.4 MappingA mapping function is a formula by which the measured results of one attribute are used topredict the value of another attribute on a given fiber. For a given fiber type and design, themode field diameter

23、 (MFD) can be used to predict the effective area with a mappingfunction. A mapping function is specific to a particular fiber type and design. Mappingfunctions are generated by doing an experiment in which a sample of fiber is chosen torepresent the spectrum of values of both MFD and for the fiber t

24、ype and in which the fibersCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132A2in the sample are measured for both MFD and Aeff. Linear regression can be used todet

25、ermine the fitting coefficient, k, as defined by the following:AkMFDeff=Ge6Ge8Ge7Gf6Gf8Gf722(1)Note: Other mathematical models may be used if they are more generally accurate.2 Normative referencesFOTP-57 (TIA/EIA-455-57B) Preparation and Examination of Optical Fiber Endfacefor Testing PurposesFOTP-

26、59 (TIA/EIA-455-59A), Measurement of Fiber Point Discontinuities using an OTDRFOTP-61 (TIA/EIA-455-61A), Measurement of Fiber or Cable Attenuation using an OTDRFOTP-77 (TIA/EIA-455-77), Procedures to Qualify a Higher-Order Mode Filter forMeasurements on Single-Mode FiberFOTP-80 (TIA/EIA-455-80), Mea

27、surement of Cutoff Wavelength of Uncabled Single-Mode Fiber by Transmitted PowerFOTP-170 (TIA/EIA-455-170), Cable Cutoff Wavelength of Single-Mode Fiber by Transmitted PowerCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networ

28、king permitted without license from IHS-,-,-TIA/EIA-455-132A33. ApparatusAnnexes A, B, and C include schematics for each method.3.1 Light sourceUse a suitable coherent or noncoherent light source, such as a semiconductor laser ora sufficiently powerful filtered white light or LED source. The source

29、shall be stable inintensity and wavelength over a time period sufficient to perform the measurement.The wavelength of the source shall be specified in the Detail Specification. Unlessotherwise specified in the Detail Specification, the spectral line width shall be less thanor equal to 10 nm Full Wid

30、th at Half-Maximum (FWHM).3.2 Input opticsUse an optical lens system or fiber pigtail to excite the test fiber. Couple the power intothe test fiber so it is insensitive to the position of the input end face. This can be donewith a launch beam that spatially and angularly overfills the test fiber. If

31、 a butt splice isused, use index matching fluid to avoid interference effects. The coupling shall bestable for the duration of the test.3.3 Cladding mode stripperUse a device that extracts cladding modes. The fiber coating will typically perform thisfunction.3.4 High order mode filterUse a method to

32、 remove higher order modes whenever they are capable ofpropagating. (Refer to the procedures in FOTP-77 for guidance). For example, a one-turn bend of diameter 30 mm in the test fiber is generally sufficient.3.5 ComputerOptionally, use a computer to control the apparatus, take intensity measurements

33、, andcompute the final result.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132A44 Sampling and specimens4.1 Specimen lengthPrepare the single-mode fiber test spec

34、imen to a length of, typically, 2.0 0.2 m.4.2 Specimen end facesPrepare flat end faces at the input and output ends of the specimen, as described inFOTP-57.For the input end, any of the conditions in table 1 of FOTP-57 are acceptable. For theoutput end, “Always Acceptable” or “Usually Acceptable” ar

35、e acceptable (except for1G). Poor output end quality can produce erroneous measurements.5. ProcedureSee annexes A, B, or C for methods A, B, and C, respectively.6. Calculation or interpretation of resultsThe following equations define the Aefffor the methods in terms of the electromagneticfield emit

36、ted from the end of the specimen. Calculation procedures are given in theannexes.6.1 Near-fieldEffective area, Aeff, is defined from the near-field intensity distribution, I(r), r being theradial distance from the center of the mode field profile, through the following equation:()()AIrrdrIr rdreff=G

37、e9GebGeaGeaGf9GfbGfaGfaGf2Gf220220(2)Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132A56.2 Direct far-fieldThe zero-order Bessel function, J0, is used to determin

38、e the near-field intensitydistribution pattern, I(r), from the far-field power distribution, ()Pff :() ()()()202/1sinsin2)(GfaGfaGfbGf9GeaGeaGebGe9Gf7Gf8Gf6Ge7Ge8Ge6=Gf2 drJPrIff(3)Note - The units of the measured wavelength, , shall be the same as those ofthe radial coordinate, r. Typically these a

39、re measured in m.Note If side lobes are observed, odd lobes are to be changed in sign(reference to sign in equation) before integration. (See Annex F for moreinformation).The resultant near-field intensity distribution derived from Equation 3 is then used withequation 2 to determine Aeff.6.3 Variabl

40、e aperture in the far-fieldThe power detected through an aperture of radius v is ()Pvv. The direct far field poweris related to the aperture power as:=Ge6Ge8Ge7Gf6Gf8Gf7tan1vD; () sin2= (4)()ddPPvff2)(= (5)Use equation 5 to convert )(vPvto ()ffP . Use equation 3 to convert to the near-fieldintensity

41、 pattern and then equation 2 to calculate the effective area.7. Documentation7.1 Report the following with each measurement:7.1.1 The FOTP number used.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without

42、 license from IHS-,-,-TIA/EIA-455-132A67.1.2 Identification for each test specimen7.1.3 Effective area (Aeff), in squared micrometers (m2)7.1.4 Wavelength7.2 The following information shall be available upon request:7.2.1 Test method7.2.2 Description of the test equipment including: light sources, s

43、canning or translationmethod, launch optics, cladding mode stripper, detection optics, and recordingtechniques.7.2.3 Date and results for the most recent instrument calibration.7.2.4 Data on measurement reproducibility.7.3 United States military applications require that the following information al

44、so bereported for each test. For other (nonmilitary) applications, this information need not bereported for each test.7.3.1 Name(s) of test personnel.7.3.2 Test equipment and date of latest calibration.8 Specification informationThe following shall be part of the Detail Specification:8.1 Fiber type8

45、.2 This FOTP (FOTP-132)8.3 Nominal measurement wavelength8.4 Failure or acceptance criteriaCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-132A7Annex A (normative)An

46、nex A - Direct far-field method measurement specificsThis annex documents the apparatus, procedure, and calculation for the direct far-fieldmethod.A.1 ApparatusA schematic of the apparatus is given in figure 1.XLight SourcePigtailTest FiberJointRotation StagePIN DetectorLock-inAmplifierComputerRefer

47、enceFigure 1 - Test set-up for the direct far-field measurementA.1.1 Detector and apertureUse a detector, such as a PIN diode, that has enough dynamic range, i.e, 50 dB downfrom the maximum power at zero degrees, and that is linear over the range ofintensities that are encountered. The “detection fl

48、oor” or “baseline noise” of thedetector should be minimized so as to maximize the usable dynamic range of thesystem. A minimum of 50 dB of usable dynamic range is recommended. The detectorshall be placed a distance of at least 100 2wfrom the test fiber end face, where 2w isthe nominal mode field diameter of the test fiber and is the nominal measurementwavelength. The angle subtended by the aperture in front of the detector shall be lessthan or equal to 0.5 degree in either dimension.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for Resal