1、BRITISH STANDARDBS EN 60793-1-48:2007Optical fibres Part 1-48: Measurement methods and test procedures Polarization mode dispersionThe European Standard EN 60793-1-48:2007 has the status of a British StandardICS 33.180.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g4
2、4g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 60793-1-48:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2008 BSI 2008ISBN 978 0 580 55009 6Nation
3、al forewordThis British Standard is the UK implementation of EN 60793-1-48:2007. It is identical to IEC 60793-1-48:2007. It supersedes BS EN 60793-1-48:2003 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommittee GEL/86/1,
4、 Optical fibres and cables.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard c
5、annot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD EN 60793-1-48 NORME EUROPENNE EUROPISCHE NORM November 2007 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisc
6、hes Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2007 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60793-1-48:2007 E ICS 33.180.10 Supersedes EN 60793-1-48:2003English version
7、Optical fibres - Part 1-48: Measurement methods and test procedures - Polarization mode dispersion (IEC 60793-1-48:2007) Fibres optiques - Partie 1-48: Mthodes de mesure et procdures dessai - Dispersion du mode de polarisation (CEI 60793-1-48:2007) Lichtwellenleiter -Teil 1-48: Messmethoden und Prfv
8、erfahren - Polarisationsmodendispersion (IEC 60793-1-48:2007) This European Standard was approved by CENELEC on 2007-09-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard
9、 without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other l
10、anguage made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic,
11、 Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword The text of document 86A/1038/CDV, future e
12、dition 2 of IEC 60793-1-48, prepared by SC 86A, Fibres and cables, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel Unique Acceptance Procedure and was approved by CENELEC as EN 60793-1-48 on 2007-09-01. This European Standard supersedes EN 60793-1-48:2003. In EN 60793-1-48:2007
13、, reference to IEC/TR 61282-9 has resulted in the removal of Annexes E, F, G and H as well as the creation of a new Annex E. This standard is to be used in conjunction with EN 60793-1-1. The following dates were fixed: latest date by which the EN has to be implemented at national level by publicatio
14、n of an identical national standard or by endorsement (dop) 2008-06-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-09-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60793-1-48:2007 was app
15、roved by CENELEC as a European Standard without any modification. _ EN 60793-1-48:2007 2 CONTENTS INTRODUCTION.5 1 Scope.6 2 Normative references .6 3 Terms and definitions .7 4 General 7 4.1 Methods for measuring PMD .7 4.2 Reference test method 9 4.3 Applicability.9 5 Apparatus.10 5.1 Light source
16、 and polarizers .10 5.2 Input optics .10 5.3 Input positioner .11 5.4 Cladding mode stripper .11 5.5 High-order mode filter11 5.6 Output positioner.11 5.7 Output optics.11 5.8 Detector 11 5.9 Computer 11 6 Sampling and specimens11 6.1 General .11 6.2 Specimen length12 6.3 Deployment .12 7 Procedure
17、13 8 Calculation or interpretation of results 13 9 Documentation .13 9.1 Information required for each measurement 13 9.2 Information to be available 13 10 Specification information 14 Annex A (normative) Fixed analyser measurement method 15 Annex B (normative) Stokes evaluation method .26 Annex C (
18、normative) Interferometry method.31 Annex D (informative) Determination of RMS width from a fringe envelope 41 Annex E (informative) Glossary of symbols 45 Bibliography47 Figure A.1 Block diagrams for Method A 15 Figure A.2 Typical results from Method A.18 Figure A.3 PMD by Fourier analysis.21 Figur
19、e A.4 Cross-correlation and autocorrelation functions 25 EN 60793-1-48:2007 3 Annex ZA (normative) Normative references to international publications with their corresponding European publications 48 Figure B.1 Block diagram for Method B26 Figure B.2 Typical random-mode-coupling results from Method
20、B 28 Figure B.3 Typical histogram of DGD values 28 Figure C.1 Schematic diagram for Method C (generic implementation).31 Figure C.2 Other schematic diagrams for Method C .32 Figure C.3a Random mode-coupling using a TINTY-based measurement system with one I/O SOP 36 Figure C.3b Negligible mode-coupli
21、ng using a TINTY-based measurement system with one I/O SOP 36 Figure C.3 Fringe envelopes for negligible and random polarization mode-coupling.36 Figure C.4a Random mode-coupling using a GINTY-based measurement system with I/O-SOP scrambling.37 Figure C.4b Negligible mode-coupling using a GINTY-base
22、d measurement system with I/O-SOP scrambling.37 Figure C.4c Mixed mode-coupling using a GINTY-based measurement system with I/O-SOP scrambling 38 Figure C.4 Fringe envelopes for negligible and random polarization mode-coupling (Ginty procedure)38 Figure D.1 Parameters for interferogram analysis 41 T
23、able A.1 Cosine transform calculations 24 EN 60793-1-48:2007 4 INTRODUCTION Polarization mode dispersion (PMD) causes an optical pulse to spread in the time domain. This dispersion could impair the performance of a telecommunications system. The effect can be related to differential phase and group
24、velocities and corresponding arrival times of different polarization components of the signal. For a sufficiently narrow band source, the effect can be related to a differential group delay (DGD), , between pairs of orthogonally polarized principal states of polarization (PSP) at a given wavelength.
25、 For broadband transmission, the delays bifurcate and result in an output pulse that is spread out in the time domain. In this case, the spreading can be related to the average of DGD values. In long fibre spans, DGD is random in both time and wavelength since it depends on the details of the birefr
26、ingence along the entire fibre length. It is also sensitive to time-dependent temperature and mechanical perturbations on the fibre. For this reason, a useful way to characterize PMD in long fibres is in terms of the expected value, , or the mean DGD over wavelength. In principle, the expected value
27、 does not undergo large changes for a given fibre from day to day or from source to source, unlike the parameters or . In addition, is a useful predictor of lightwave system performance. The term “PMD“ is used both in the general sense of two polarization modes having different group velocities, and
28、 in the specific sense of the expected value . The DGD or pulse broadening can be averaged over wavelength, yielding , or time, yielding t, or temperature, yielding T. For most purposes, it is not necessary to distinguish between these various options for obtaining . The coupling length lcis the len
29、gth of fibre or cable at which appreciable coupling between the two polarization states begins to occur. If the fibre length L satisfies the condition L scales with fibre length. The corresponding PMD coefficient is “short-length“ PMD coefficient = /L. Fibres in practical systems are nearly always i
30、n the L lc, regime and mode coupling is random. If mode coupling is also found to be random, scales with the square root of fibre length, and “long-length“ PMD coefficient = / L EN 60793-1-48:2007 5 OPTICAL FIBRES Part 1-48: Measurement methods and test procedures Polarization mode dispersion 1 Scop
31、e This part of IEC 60793 applies to three methods of measuring polarization mode dispersion (PMD), which are described in Clause 4. It establishes uniform requirements for measuring the PMD of single-mode optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes
32、. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60793-1-1, Optical f
33、ibres Part 1-1: Measurement methods and test procedures General and guidance IEC 60793-1-44, Optical fibres Part 1-44: Measurement methods and test procedures Cut-off wavelength IEC 60793-2-50, Optical fibres Part 2-50: Product specifications Sectional specification for class B single-mode fibres IE
34、C 60794-3, Optical fibre cables Part 3: Sectional specification Outdoor cables IEC 61280-4-4, Fibre optic communication subsystem test procedures Part 4-4: Cable plants and links Polarization mode dispersion measurement for installed links IEC/TR 61282-3, Fibre optic communication system design guid
35、es Part 3: Calculation of link polarization mode dispersion IEC/TR 61282-9, Fibre optic communication system design guides Part 9: Guidance on polarization mode dispersion measurements and theory IEC 61290-11-1, Optical amplifier test methods Part 11-1: Polarization mode dispersion Jones matrix eige
36、nanalysis method (JME) IEC 61290-11-2, Optical amplifiers Test methods Part 11-2: Polarisation mode dispersion parameter Poincar sphere analysis method IEC/TR 61292-5, Optical amplifiers Part 5: Polarization mode dispersion parameter General information IEC 61300-3-32, Fibre optic interconnecting de
37、vices and passive components Basic test and measurement procedures Part 3-32: Examinations and measurements Polarization mode dispersion measurement for passive optical components ITU-T Recommendation G.650.2, Definitions and test methods for statistical and non-linear related attributes of single-m
38、ode fibre and cable EN 60793-1-48:2007 6 3 Terms and definitions For the purposes of this document, the terms and definitions contained in ITU-T Recommendation G.650.2 apply. NOTE Further explanation of their use in this document is provided in IEC 61282-9. 4 General 4.1 Methods for measuring PMD Th
39、ree methods are described for measuring PMD (see Annexes A, B and C for more details). The methods are listed below in the order of their introduction. For some methods, multiple approaches of analyzing the measured results are also provided. Method A Fixed analyser (FA) Extrema counting (EC) Fourie
40、r transform (FT) Cosine Fourier transform (CFT) Method B Stokes parameter evaluation (SPE) Jones matrix eigenanalysis (JME) Poincar sphere analysis (PSA) State of polarization (SOP) Method C Interferometry (INTY) Traditional analysis (TINTY) General analysis (GINTY) The PMD value is defined in terms
41、 of the differential group delay (DGD), , which usually varies randomly with wavelength, and is reported as one or another statistical metric. Equation (1) is a linear average value and is used for the specification of optical fibre cable. Equation (2) is the root mean square value which is reported
42、 by some methods. Equation (3) can be used to convert one value to the other if the DGDs are assumed to follow a Maxwell random distribution. =AVGPMD (1) 212RMS/=PMD (22/12/138 = (3) NOTE Equation (3) applies only when the distribution of DGDs is Maxwellian, for instance when the fibre is randomly m
43、ode coupled. The generalized use of Equation (3) can be verified by statistical analysis. A Maxwell distribution may not be the case if there are point sources of elevated birefringence (relative to the rest of the fibre), such as a tight bend, or other phenomena that reduce the mode coupling, such
44、as a continual reduced bend radius with fibre in tension. In these cases, the distribution of the DGDs will begin to resemble the square root of a non-central Chi-square distribution with three degrees of freedom. For these cases, the PMDRMSvalue will generally be larger relative to the PMDAVGthat i
45、s indicated in Equation (3). Time domain methods such as Method C and Method A, cosine Fourier transform, which are based on PMDRMS, can use Equation (3) to convert to PMDAVG. If mode coupling is reduced, the resultant reported PMD value from these methods may exceed those that can be reported by th
46、e frequency domain measurements that report PMDAVG, such as Method B. EN 60793-1-48:2007 7 The PMD coefficient is the PMD value normalized to the fibre length. For normal transmission fibre, for which random mode coupling occurs and for which the DGDs are distributed as Maxwell random variables, the
47、 PMD value is divided by the square root of the length and the PMD coefficient is reported in units of ps/km1/2. For some fibres with negligible mode coupling, such as polarization maintaining fibre, the PMD value is divided by the length and the PMD coefficient is reported in units of ps/km. All me
48、thods are suitable for laboratory measurements of factory lengths of optical fibre and optical fibre cable. For all methods, changes in the deployment of the specimen can alter the results. For installed lengths of optical fibre cable that may be moving or vibrating, either Method C or Method B (in
49、an implementation capable of millisecond measurement time scales) is appropriate. All methods require light sources that are controlled at one or more states of polarization (SOPs). All methods require injecting light across a broad spectral region (i.e. 50 nm to 200 nm wide) to obtain a PMD value that is characteristic of the region (i.e. 1 300 nm or 1 550 nm). The methods differ in: a) the wavelen
