1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationFibre optic communication subsystem test procedures Part 1-4: General communication subsystems Light source encircled flux measurement methodBS EN 61280-1-4:2010National foreword
2、This British Standard is the UK implementation of EN 61280-1-4:2010. It isidentical to IEC 61280-1-4:2009. It supersedes BS EN 61280-1-4:2003 whichis withdrawn.The UK participation in its preparation was entrusted by Technical CommitteeGEL/86, Fibre optics, to Subcommittee GEL/86/3, Fibre optic syst
3、ems andactive devices.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 62538 1ICS 33.180.0
4、1Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 March 2010Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 61280-1-4:2010EUR
5、OPEAN STANDARD EN 61280-1-4 NORME EUROPENNE EUROPISCHE NORM February 2010 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: Avenue Marnix 17, B - 1000 Brussels 2010 CEN
6、ELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61280-1-4:2010 E ICS 33.180.01 Supersedes EN 61280-1-4:2003English version Fibre optic communication subsystem test procedures - Part 1-4: General communication subsystems - Light sourc
7、e encircled flux measurement method (IEC 61280-1-4:2009) Procdures dessai des sous-systmes de tlcommunication fibres optiques - Partie 1-4: Sous-systmes gnraux de tlcommunication - Mthode de mesure du flux inscrit de la source lumineuse (CEI 61280-1-4:2009) Lichtwellenleiter-Kommunikationsuntersyste
8、me - Grundlegende Prfverfahren - Teil 1-4: Allgemeine Kommunikationsuntersysteme - Verfahren zur Messung des begrenzten Lichtstroms einer Strahlungsquelle (IEC 61280-1-4:2009) This European Standard was approved by CENELEC on 2010-02-01. CENELEC members are bound to comply with the CEN/CENELEC Inter
9、nal 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 me
10、mber. 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. CENEL
11、EC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania,
12、Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61280-1-4:2010EN 61280-1-4:2010 - 2 - Foreword The text of document 86C/920/FDIS, future edition 2 of IEC 61280-1-4, prepared by SC 86C, Fibre optic systems and active devices, of IEC TC 86, Fibre optics, was submitted to t
13、he IEC-CENELEC parallel vote and was approved by CENELEC as EN 61280-1-4 on 2010-02-01. This European Standard supersedes EN 61280-1-4:2003. The significant technical changes with respect to EN 61280-1-4:2003 are described in the introduction. Attention is drawn to the possibility that some of the e
14、lements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national stand
15、ard or by endorsement (dop) 2010-11-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2013-02-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61280-1-4:2009 was approved by CENELEC as a European St
16、andard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 60793-1-20 NOTE Harmonized as EN 60793-1-20. IEC 60793-1-41 NOTE Harmonized as EN 60793-1-41. _ BS EN 61280-1-4:2010- 3 - EN 61280-1-4:2010 Annex ZA (norm
17、ative) Normative references to international publications with their corresponding European publications 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
18、referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60793-2-10 - Optical fibres - Part 2-10: Product specifications - Sectional
19、specification for category A1 multimode fibresEN 60793-2-10 - IEC 60825-1 - Safety of laser products - Part 1: Equipment classification and requirements EN 60825-1 - IEC 61745 1988 End-face image analysis procedure for the calibration of optical fibre geometry test sets - - BS EN 61280-1-4:2010 2 61
20、280-1-4 IEC:2009 CONTENTS 0 Introduction 6 0.1 General .6 0.2 Changes from previous edition 6 0.3 Assumptions applicable to the characterization of data sources 6 0.4 Assumptions applicable to the characterization of measurement sources 6 1 Scope.7 2 Normative references .7 3 Terms and definitions .
21、7 4 Symbols .8 5 Apparatus.9 5.1 Common apparatus .9 5.1.1 General .9 5.1.2 Computer 10 5.1.3 Image digitizer.10 5.1.4 Detector 10 5.1.5 Magnifying optics.11 5.1.6 Attenuation11 5.1.7 Micropositioner (optional) 11 5.1.8 Input port.12 5.1.9 Calibration light source12 5.2 Transmission source apparatus
22、.12 5.2.1 General .12 5.2.2 Test jumper assembly13 5.2.3 Fibre shaker 13 5.3 Measurement source apparatus 14 6 Sampling and specimens14 7 Geometric calibration .15 8 Measurement procedure.15 8.1 Safety .15 8.2 Image acquisition 15 8.2.1 Raw image acquisition.15 8.2.2 Dark image acquisition 16 8.2.3
23、Corrected image16 8.3 Optical centre determination16 8.3.1 General .16 8.3.2 Centroid image 16 8.3.3 Centroid computation 17 8.4 Test source image acquisition .17 9 Computation of encircled flux .17 9.1 Computation of radial data functions .17 9.2 Integration limit and baseline determination.19 9.2.
24、1 Integration limit19 9.2.2 Baseline determination 19 9.2.3 Baseline subtraction 19 BS EN 61280-1-4:201061280-1-4 IEC:2009 3 9.3 Computation of encircled flux 19 10 Results.20 10.1 Information available with each measurement .20 10.2 Information available upon request20 11 Specification information
25、20 Annex A (informative) Measurement sensitivity considerations 22 Annex B (informative) Theory of geometric calibration using the micropositioner .27 Annex C (normative) Procedure for geometric calibration using the micropositioner.32 Bibliography34 Figure 1 Apparatus block diagram10 Figure 2 Typic
26、al set-up for transmission source measurement .13 Figure 3 Fibre shaker example.14 Figure 4 Pixel and ring illustration18 Figure A.1 Core images from instrument A and instrument B .22 Figure A.2 Compressed core images from instrument A and instrument B22 Figure A.3 Intensity versus radius for Instru
27、ments A and B 23 BS EN 61280-1-4:2010 6 61280-1-4 IEC:2009 0 Introduction 0.1 General This part of IEC 61280 is used to measure the encircled flux of a multimode light source. Encircled flux is a measure, as a function of radius, of the fraction of the total power radiating from a multimode optical
28、fibres core. The basic approach is to collect 2D nearfield data using a calibrated camera, and to mathematically convert the 2D data into three normalized functions of radial distance from the fibres optical centre. The three functions are intensity, incremental flux and encircled flux. Intensity ha
29、s dimension optical power per area; incremental flux has dimension power per differential of radius; and encircled flux has dimension total optical power, all three being functions of radius. These three radial functions are intended to characterize fibre optic laser sources either for use in mathem
30、atical models predicting the minimum guaranteed length of a communications link, or to qualify a light source to measure insertion loss in multimode links. 0.2 Changes from previous edition This edition of the standard differs from its predecessor in both scope and content. Many of the content chang
31、es improve the measurement precision. Several changes have been made to the computation procedure: the integration methodology of the radial functions was simple summation, and is now specified to use trapezoidal integration or other higher-order techniques (see 9.3); a baseline subtraction step is
32、specified to improve immunity to DC drifts (see 9.2.2 and 9.2.3); the ring width parameter is explicitly specified (see 9.2.1); the integration limit is specified (see 9.3). The geometric calibration of the apparatus microscope now specifies either (depending on the application) the methodology of I
33、EC 61745 or the original technique using the micropositioning stage (see Clause 7). Pixel sensitivity uniformity correction is now optional. 0.3 Assumptions applicable to the characterization of data sources The 50-m or 62,5-m core near-parabolic graded-index multimode fibre used as the “test jumper
34、 assembly” is treated as if it possessed perfect circular symmetry about its optical centre, as asymmetries in the launched optical flux distributions will dominate any lopsidedness of the test jumper assembly. It is further assumed that all cladding modes will be stripped by passage through the spe
35、cified ten metres or more of fibre. The modes of a mode group need not carry equal flux. (In fact, with such short fibres, one thousand metres or less, unequal distribution of flux in the modes of a group is the norm, not the exception.) 0.4 Assumptions applicable to the characterization of measurem
36、ent sources Measurement sources are assumed to be sufficiently broadband and incoherent that speckle is not a problem, and to have a sufficiently symmetrical nearfield distribution that the truncated centroid of that nearfield indicates the location of the optical centre of the fibre with sufficient
37、 accuracy for the purposes of this standard. BS EN 61280-1-4:201061280-1-4 IEC:2009 7 FIBRE OPTIC COMMUNICATION SUBSYSTEM TEST PROCEDURES Part 1-4: General communication subsystems Light source encircled flux measurement method 1 Scope This part of IEC 61280 is intended to characterize the encircled
38、 flux of two types of light sources: transmission light sources, which are usually coherent and substantially under-excite the mode volume of a multimode fibre, and measurement light sources, which are incoherent and excite most of the mode volume of a multimode fibre. This part of IEC 61280 sets fo
39、rth a standard procedure for the collection of two-dimensional fibre optic nearfield greyscale data and subsequent reduction to one-dimensional data expressed as a set of three sampled parametric functions of radius from the fibres optical centre. This revision of IEC 61280-1-4 continues to fulfil i
40、ts original purpose, characterization of transmission light sources, which enables the accurate mathematical prediction of minimum guaranteed link length in 1 gigabit per second or greater fibre optic data communication systems. New to this revision is support for improved measurement precision of i
41、nsertion loss in multimode fibre optic links through the characterization of measurement light sources. Estimation of the fibre core diameter is not an objective of this standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For da
42、ted references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60793-2-10, Optical fibres Part 2-10: Product specifications Sectional specification for category A1 multimode fibres IEC 60825-1, Safety of l
43、aser products Part 1: Equipment classification and requirements IEC 61745:1988, End-face image analysis procedure for the calibration of optical fibre geometry test sets 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 calibration light source
44、 light source used to find the optical centre of a multimode fibre 3.2 centroid image image used to determine the optical centre of the multimode fibre core BS EN 61280-1-4:2010 8 61280-1-4 IEC:2009 3.3 corrected image image which has had a dark image subtracted from it and whose elements have had u
45、niformity correction applied 3.4 dark image image taken with the measured light source either turned off or not installed in the input port. Stray light and electrical signals of the detection system will remain in the dark image 3.5 image two-dimensional rectangular array of numbers whose elements
46、are pixels and whose pixel values linearly correspond to the optical power falling on the pixels 3.6 light source something that emits light that is coupled into a fibre, the output of which can be measured (can be a calibration light source, a transmission light source or a light source used for at
47、tenuation measurements) 3.7 measurement light source light source intended to be used in the measurement of attenuation 3.8 nominal core radius half the nominal core diameter of the multimode fibre to be measured 3.9 ring smoothing technique to reduce the two dimensional near field image into a 1-D
48、near field intensity profile while cancelling the effects of the periodic spacing of imager pixels of finite area 3.10 transmission light source light source used to transmit digital data over multimode fibre optic links 3.11 uniformity correction process to correct the sensitivity of a pixel so tha
49、t it performs substantially like an average pixel 3.12 valid pixel optical detection element in the detector matrix whose sensitivity, when corrected, is within 5 % of the mean sensitivity of the average conversion efficiency of the detector 4 Symbols B the baseline intensity. This value is determined from a region of the computed near field just outside the core boundary. D the distance from the centre of the centroid image to the nearest boundary of the imag
