1、 TIA/EIASTANDARDFOTP-196Guideline for Polarization-ModeMeasurement in Single-Mode FiberOptic Components and DevicesTIA/EIA-455-196NOVEMBER 1999TELECOMMUNICATIONS INDUSTRY ASSOCIATIONRepresenting the telecommunications industry inassociation with the Electronic Industries Alliance ANSI/TIA/EIA-455-19
2、6-1999Approved: November 9, 1999TIA/EIA-455-196Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICETIA/EIA Engineering Standards and Publications are designed to serve the pub
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6、ion whatever to parties adopting the Standard orPublication.This Standard does not purport to address all safety problems associated with its use or all applicableregulatory requirements. It is the responsibility of the user of this Standard to establish appropriatesafety and health practices and to
7、 determine the applicability of regulatory limitations before its use.(From Standards Proposal No. 4355-A, formulated under the cognizance of the TIA FO-6.3Subcommittee on Fiber Optic Interconnecting Devices.)Published byTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1999Standards and Technology Department
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12、/EIA-455-196AJB,TIA SC FO-6.3.5, 09-15-99 iFOTP-196Guideline for Polarization- Mode Dispersion Measurement in Single-ModeFiber Optic Components and DevicesContentsForewordiii1 Introduction. 12 Normative references. 23 Apparatus 24 Sampling and specimens 25 Procedure 36 Interpretation of Results and
13、Calculations . 47 Documentation 68 Specification information. 7Annex A (Informative) 8Annex B (Informative).13Annex C (Informative).13Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS
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15、e Dispersion Measurement in Single-ModeFiber Optic Components and DevicesForeword(This Foreword is informative only and is not part of this Standard.)From TIA Project No. 4355, formulated under the cognizance of TIA FO-6.3.5,Subcommittee on Passive Fiber Optic Devices.This FOTP is part of the series
16、 of test procedures included within RecommendedStandard EIA/TIA-455.There are three annexes, all of them informative.Key words: Polarization-mode Dispersion, Components, Isolators, Filters, PMDCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo re
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18、-6.3.5, 09-15-99 11 Introduction1.1 IntentThis document describes the measurement of Polarization-mode Dispersion (PMD)and Differential Group Delay (DGD) in fiber optic devices or components. ExistingFiber Optic Test Procedures, FOTP-113, FOTP-122 and FOTP-124 apply only tofiber and fiber cables, bu
19、t may be applied to components providing certainprecautions are observed. This document describes the application of theseprocedures to fiber component PMD measurement.1.2 ScopeThe document discusses the application of the pre-existing fiber test procedures forPMD measurement in fiber to the special
20、 case of fiber components. Specialprecautions are required to avoid several potential problems, and these problemsand precautions are described for each of the applicable procedures. Thisdocument does not describe the test procedures in detail, merely the variationsrequired for component measurement
21、s. In particular, for amplifiers and also narrow-band devices, specific precautions are given.This FOTP also does not apply to components that have in excess of 10 dB ofpolarization-dependent loss (PDL).1.3 BackgroundThere already exist three Test Procedures for PMD measurement in Fibers andfiber ca
22、bles. Two of these methods use a Polarimetric approach to PMDmeasurement and are typically referred to as frequency domain measurements,because the techniques rely on measuring the variation of birefringence andpolarized light transmission with wavelength to determine PMD. These are theJones Matrix
23、Eigenanalysis (JME) method (covered by FOTP-122) and the FixedAnalyzer (FA) technique (covered by FOTP-113). The latter is subdivided withExtrema Counting (FAEC) and Fourier Transform (FAFT) processing methods.The third Technique is Interferometry (covered by FOTP-124), where a broadband(e.g. LED) s
24、ource is used as a low-coherence source to examine the path lengthimbalance (time delay differences) caused by the PMD. For this reason it isreferred to as a time-domain PMD method.Any of the three methods referred to here may be applied. The user is particularlyreferred to Annex A where the possibl
25、e application issues of each method arediscussed.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-19622 Normative referencesTest or inspection requirements may includ
26、e, but are not limited to, the followingreferences:EIA/TIA-455-A, (Example: Standard Test Procedure for Fiber Optic Fibers, Cables,Transducers, Sensors, Connecting and Transmitting Devices, and Other Fiberoptic components.)FOTP-113 (EIA/TIA-113), (Polarization-mode Dispersion Measurement for Single-
27、Mode Optical Fibers by the Fixed Analyzer method.)FOTP-122 (EIA/TIA-122), (Polarization-mode Dispersion Measurement for Single-Mode Optical Fibers by Jones Matrix Eigenanalysis.)FOTP-124 (EIA/TIA-124), (Polarization-mode Dispersion Measurement for Single-Mode Optical Fibers by Interferometric Method
28、.)FOTP-157 (EIA/TIA-157), (Polarization-Dependent Loss Measurement in PassiveOptical Components)Users of these FOTPs are encouraged to specify the most recent edition.3 ApparatusUse apparatus dictated by the relevant selected FOTP.4 Sampling and specimensThe sample is typically a fiber-pigtailed dis
29、crete component, which is fusion-splicedor connected via suitable patch cords, pigtails etc. into the PMD test apparatus. Thespecimen may be in normal laboratory environments, or alternatively as required thecomponent may be placed in an environmental chamber to allow it to be subject tohigh or low
30、temperature or humidity etc during measurements. In the case ofamplifier components, energize the amplifier pump as required.Ensure the component has less than 10 dB PDL, and that its approximate spectralbandwidth (or gain bandwidth) is known.Copyright Telecommunications Industry Association Provide
31、d by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-196AJB,TIA SC FO-6.3.5, 09-15-99 3Certain devices, e.g. gratings, work in reflection. In these cases, it will benecessary to connect the device to the test apparatus via a 1x
32、2 directional coupleror circulator. The coupler/circulator used must have a known low PMD value.5 ProcedurePerform measurements as per the selected FOTP. Select the wavelength range tobe used, ensuring that the range set does not exceed the spectral range of thedevice under test. In the case of ampl
33、ifiers, the spectral range is interpreted as thegain bandwidth. In the case of Interferometry (FOTP-124), if the source bandwidth exceeds thecomponent bandwidth, do not proceed.Connect the component to the test apparatus and lay the fiber leads into and out ofthe device in large radii (e.g. radius10
34、0 mm) coils, without tight bends.Establish that the received signal level is within the correct range for the componentand instrumentation in use. In particular, when testing components containingamplifiers, look for evidence of excess ASE noise, in the form of incorrect signallevel, poor signal-noi
35、se ratio, or broad/flat interferograms/Fourier plots, and otherabnormal result outputs. If in doubt, do not proceed.Perform one measurement of the PMD in accordance with the relevant FOTP andthe instrumentation in use.Record the PMD results in accordance with the FOTP, and section 6.If required, rep
36、eat the measurement, with the fiber leads laid out in a differentpattern, to ensure a different polarization state is launched into, and collected from,the device under test. Record the PMD results in accordance with the FOTP, andsection 6.If required, repeat this procedure, with leads moved again,
37、up to three more times,according to requirements.Record the PMD results in accordance with the FOTP, and section 6.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-19
38、646 Interpretation of Results and CalculationsIn all of the methods, the key parameters that are required are typically:-The maximum DGD value within the wavelength range;The component PMD- defined as the average DGD over the specifiedmeasurement wavelength range.Both parameters (and any others) are
39、 determined with some manual interpretationfrom the measurement results.Refer to Annex A for further background on interpretation.6.1 Interpretation of ResultsCertain interpretations of the measurement results must be exercised; these differfor each measurement technique used, as shown below:For FAE
40、C (FOTP-113, Method A) : Examine the ratio plot for dual or multiple frequency of oscillations. If multiple-frequency oscillations are present proceed only after checking that the “cyclecounting” peak detection is correctly functioning. If not, select anothermeasurement method.For FAFT (FOTP-113, Me
41、thod B) : Examine the Fourier transform plot for dual or multiple peaks. Determinebaseband and intermodulation peaks as appropriate. Intermodulation peaks willbe at “sum and/or difference” DGD values. Eliminate or ignore theintermodulation peaks.For JME (FOTP-122) : Examine the DGD plot for oscillat
42、ions. If no oscillations present, average theDGD over the wavelength range. If oscillations above the expected noise leveloccur, determine the average DGD and the maximum DGD over the wavelengthrange used.For Interferometry (FOTP-124) : Examine the Interferogram plot for single or multiple peaks. De
43、termine if any of the peaks are not PMD related (i.e. do not change amplitudewith a new fiber lead configuration or input polarization state). Repeat themeasurement as many times as necessary to determine the true PMD peaks.Eliminate or ignore the “non-PMD” peaks.Copyright Telecommunications Industr
44、y Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-196AJB,TIA SC FO-6.3.5, 09-15-99 56.2 CalculationsPerform PMD calculations for each measurement taken as per the selected FOTPand following the procedure
45、 given below. Always use the case of low-modecoupling, where given.For FAEC (FOTP-113, Method A) : For each of the measurements taken, determine the mean DGD over thewavelength range, using low-mode coupling calculations (coupling factor, k =1.0). Average the mean DGD values obtained from each measu
46、rement taken. Report this average as the component PMD value, in ps. It is not generally possible to determine the maximum DGD from this method butthis corresponds to the maximum extrema density in the ratio plot. If this value isrequired, select another measurement method.For FAFT (FOTP-113, Method
47、 B) : For each of the measurements taken, and for each baseband peak, determinethe DGD value and height for each peak, using low-mode coupling calculations. Average the DGD values and heights of each peak over all the measurementstaken, to form a histogram of peaks. Identify which peak has the large
48、st DGD and determine that DGD value, as wellas the mean DGD of the histogram of peaks. Use the formula:Mean DGD = Si (Pi.xi) / Si (Pi)where Pi represents the peak height of the ith peak;xi is the DGD value of the ith peak;i is the total number of peaks;Si ( ) represents a summation over all the peaks from the first to the ith. Report the mean DGD determined above as the component PMD value, in ps. Report also the maximum DGD value, in ps.For JME (FOTP-122) : Average the DGD values foun
