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1、BRITISH STANDARD BS EN 60793-1-42: 2007 Optical fibres Part 1-42: Measurement methods and test procedures Chromatic dispersion The European Standard EN 60793-1-42:2007 has the status of a British Standard ICS 33.180.10 ? Licensed Copy: London South Bank University, London South Bank University, Sat
2、Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS EN 60793-1-42:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007 ISBN 978 0 580 54659 4 National foreword This British Standard is the UK implementation of
3、EN 60793-1-42:2007. It is identical to IEC 60793-1-42:2007. It supersedes BS EN 60793-1-42:2002 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommittee GEL/86/1, Optical fibres and cables. A list of organizations represen
4、ted 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 cannot confer immunity from legal obligations. Amendments
5、issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD EN 60793-1-42 NORME EUROPENNE EUROPISCHE NORM June 2007 CENELEC European Committee for Electrotec
6、hnical Standardization Comit Europen de Normalisation Electrotechnique Europisches 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. E
7、N 60793-1-42:2007 E ICS 33.180.10 Supersedes EN 60793-1-42:2002 English version Optical fibres - Part 1-42: Measurement methods and test procedures - Chromatic dispersion (IEC 60793-1-42:2007 + corrigendum 2007) Fibres optiques - Partie 1-42: Mthodes de mesure et procdures dessai - Dispersion chroma
8、tique (CEI 60793-1-42:2007 + corrigendum 2007) Lichtwellenleiter - Teil 1-42: Messmethoden und Prfverfahren - Chromatische Dispersion (IEC 60793-1-42:2007 + Corrigendum 2007) This European Standard was approved by CENELEC on 2007-05-01. CENELEC members are bound to comply with the CEN/CENELEC Intern
9、al Regulations which stipulate the conditions for giving this European Standard the status of a national standard 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 mem
10、ber. This European Standard exists in three official versions (English, French, German). A version in any other language 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. CENELE
11、C members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
12、Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: London South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60793-1-42:2007 2 Foreword The text of document 86A/1136/FDIS, future edition 2 of IEC 60793-1-42,
13、 prepared by SC 86A, Fibres and cables, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60793-1-42 on 2007-05-01. This European Standard supersedes EN 60793-1-42:2002. The main changes in EN 60793-1-42:2007 concern the addition of a new An
14、nex E on chromatic dispersion fitting and the applicability to A4 fibres. 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 publication of an identical national standard or by endorseme
15、nt (dop) 2008-02-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2010-05-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60793-1-42:2007 and its corrigendum June 2007 was approved by CENELEC as a
16、 European Standard without any modification. _ Licensed Copy: London South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 EN 60793-1-42:2007 CONTENTS Scope.5 2 Normative references .6 3 Overview of methods 6 3.1 Method A, phase shift6
17、3.2 Method B, spectral group delay in the time domain.6 3.3 Method C, differential phase shift.6 3.4 Method D, interferometry .7 4 Reference test methods7 4.1 Category A1 and category A4f, A4g and A4h multimode fibres7 4.2 Class B single-mode fibres 7 5 Apparatus.7 5.1 Launch optics 7 5.2 High-order
18、 mode filter (single-mode) 7 5.3 Input positioning apparatus8 5.4 Output positioning apparatus .8 5.5 Computation equipment .8 6 Sampling and specimens 8 6.1 Specimen length8 6.2 Specimen end face8 6.3 Reference fibre8 7 Procedure 8 8 Calculations .9 8.1 Category A1 and A4f, A4g, A4h multimode and B
19、1.1 and B1.3 single-mode fibres.9 8.2 Category B1.2 single-mode fibres 9 8.3 Category B2 single-mode fibres .9 8.4 Category B4 and B5 single-mode fibres10 9 Results.10 10 Specification information.10 Annex A (normative) Requirements specific to method A, phase-shift .11 Annex B (normative) Requireme
20、nts specific to method B, spectral group delay in the time domain16 Annex C (normative) Requirements specific to method C, differential phase-shift 20 Annex D (normative) Requirements specific to method D, interferometry.25 Annex E (normative) Chromatic dispersion fitting29 Annex ZA (normative) Norm
21、ative references to international publications with their corresponding European publications31 Figure A.1 Chromatic dispersion measurement set, multiple laser system (typical) 12 Figure A.2 Typical delay and dispersion curves 12 Figure A.3 Chromatic dispersion measurement set, LED system (typical)1
22、4 Figure B.1 Block diagram, fibre Raman laser system 17 Figure B.2 Block diagram, multiple laser diode system17 Licensed Copy: London South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60793-1-42:2007 4 Figure C.1 Chromatic differen
23、tial phase dispersion measurement set, multiple laser system .21 Figure C.2 Chromatic differential phase dispersion measurement set, LED system22 Figure C.3 Chromatic dispersion measurement set, differential phase by dual wavelength method.22 Figure C.4 Chromatic dispersion measurement set, differen
24、tial phase by double demodulation23 Figure D.1 Fibre chromatic dispersion test set Interferometry by fibre reference path27 Figure D.2 Fibre chromatic dispersion test set Interferometry by air reference path 27 Figure D.3 Examples of delay data.28 Table E.1 Definition of fit types and fit coefficien
25、ts; equations for group delay and dispersion coefficient 29 Table E.2 Slope equations .29 Table E.3 Zero-dispersion wavelength and slope equations 30 Licensed Copy: London South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 5 EN 60793-1
26、-42:2007 OPTICAL FIBRES Part 1-42: Measurement methods and test procedures Chromatic dispersion 1 Scope This part of IEC 60793 establishes uniform requirements for measuring the chromatic dispersion of optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. C
27、hromatic dispersion varies with wavelength. Some methods and implementations measure the group delay as a function of wavelength and the chromatic dispersion and dispersion slope are deduced from the derivatives (with respect to wavelength) of this data. This differentiation is most often done after
28、 the data are fitted to a mathematical model. Other implementations can allow direct measurement (of the chromatic dispersion) at each of the required wavelengths. For some categories of fibre, the chromatic dispersion attributes are specified with the parameters of a specific model. In these cases,
29、 the relevant recommendation or standard defines the model appropriate for the definition of the specified parameters. For other fibre categories, the dispersion is specified to be within a given range for one or more specified wavelength intervals. In the latter case, either direct measurements may
30、 be made at the wavelength extremes or some fitting model may be used to allow either group delay measurement methods or implementations or storage of a reduced set of parameters that may be used to calculate the interpolated dispersion for particular wavelengths which may not have actual direct mea
31、surement values. Annex E gives a general description of chromatic dispersion fitting and outlines a number of fitting equations suitable for use with any of the measurement methods or fibre categories. This standard gives four methods for measuring chromatic dispersion: method A: phase shift; method
32、 B: spectral group delay in the time domain; method C: differential phase shift; method D: interferometry. Methods A, B, and C apply to the measurement of chromatic dispersion of the following fibres over a specified wavelength range: class A1 graded-index multimode fibres; category A4f, A4g and A4h
33、 multimode fibres; class B single-mode fibres (all categories). Method D applies to the measurement of chromatic dispersion values of single-mode fibres categories B1, B2, B4 and B5 over the 1 000 nm to 1 700 nm wavelength range. The methods can be applied to laboratory, factory and field measuremen
34、ts of chromatic dispersion, and the wavelength range of the measurements can be tailored as required. Measurements are made at temperature as stated in IEC 60793-1-1, Table 1 Standard range of atmospheric conditions (Temperature 23 C 5 C). Licensed Copy: London South Bank University, London South Ba
35、nk University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI EN 60793-1-42:2007 6 The methods are suitable for fibre or cable lengths greater than 1 km. They may also be applied to shorter lengths, but accuracy and repeatability may be compromised. Method D is the preferred method f
36、or shorter piece fibres (1 m to 10 m). Information common to all methods is contained in Clauses 1-8, and information pertaining to each individual method appears in Annexes A, B, C, and D, respectively. 2 Normative references The following referenced documents are indispensable for the application
37、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 60793-1-1:2002, Optical fibres Part 1-1: Measurement methods and test procedures General and guidance IEC 60793-1-41,
38、Optical Fibres Part 1-41: Measurement methods and test procedures Bandwidth 3 Overview of methods 3.1 Method A, phase shift This method describes a procedure for determining the chromatic dispersion of all categories of type B single-mode fibres, category A1 graded-index multimode fibres and categor
39、y A4f, A4g and A4h fibres, over a specified wavelength range using the relative phase shifts among sinusoidally modulated optical sources of different wavelengths. The sources are typically laser diodes or filtered light emitting diodes or filtered amplified spontaneous emission (ASE) sources. Relat
40、ive phase shifts are converted to relative time delays, and the resultant spectral group delay data are then fitted to an equation defined for each fibre type. 3.2 Method B, spectral group delay in the time domain This method describes a procedure for determining the chromatic dispersion of all cate
41、gories of type B single-mode fibres, category A1 graded-index multimode fibres and category A4f, A4g and A4h fibres with the use of a Nd:YAG/fibre Raman laser source or multiple laser diodes operating at a number of wavelengths both greater than and less than the typical zero- dispersion wavelength.
42、 In this method, the time difference of optical pulse delay through a known length of fibre at several wavelengths is measured. A reference set of measurements shall also be taken through a short reference fibre and data are subtracted from data taken from the fibre under test to obtain relative spe
43、ctral group delay. The resultant spectral group delay data are then fitted to an equation defined for each fibre type. 3.3 Method C, differential phase shift This method describes a procedure for determining the chromatic dispersion of all categories of type B single-mode fibres, category A1 graded-
44、index multimode fibres and category A4f, A4g and A4h fibres. The dispersion coefficient at a particular wavelength is determined from the differential group delay between two closely spaced wavelengths. In this procedure, a modulated light source is coupled into the fibre under test, and the phase o
45、f the light exiting the fibre at a first wavelength is compared with the phase of the light exiting at a second wavelength. Average chromatic dispersion over the interval between the two wavelengths is determined from differential phase shift, wavelength interval and fibre length. Licensed Copy: Lon
46、don South Bank University, London South Bank University, Sat Aug 18 09:43:23 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 7 EN 60793-1-42:2007 The chromatic dispersion coefficient at a wavelength medial to the two test wavelengths is assumed to be equal to the average chromatic dispersion over the int
47、erval between the two wavelengths. The resultant chromatic dispersion data are then fitted to an equation defined for each fibre type. 3.4 Method D, interferometry This method describes a procedure for determining the chromatic dispersion of single-mode fibres categories B1, B2, B4 and B5 over the 1
48、 000 nm to 1 700 nm wavelength range. By using this test method, the chromatic dispersion of a short piece of fibre can be measured. In this test method, the wavelength-dependent time delay between the test sample and the reference path is measured by Mach-Zehnder interferometer. The reference path
49、can be an air path or a single-mode fibre with known spectral group delay. It should be noted that extrapolation of the chromatic dispersion values derived from the interferometric test in fibres of a few metres length to long fibre sections assumes longitudinal homogeneity of the fibre. This assumption may not be applicable in every case. 4 Reference test methods 4.1 Category