1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationFibre optics Launch conditionrequirements for measuring multimode attenuationBS EN 62614:2010National forewordThis British Standard is the UK implementation of EN 62614:2010. It
2、is identical to IEC 62614:2010.The UK participation in its preparation was entrusted to Technical CommitteeGEL/86, Fibre optics.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 o
3、f acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 67890 5ICS 33.180.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 30 Novem
4、ber 2010.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 62614:2010EUROPEAN STANDARD EN 62614 NORME EUROPENNE EUROPISCHE NORM October 2010 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches K
5、omitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2010 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62614:2010 E ICS 33.180.01 English version Fibre optics - Launch condition requirement
6、s for measuring multimode attenuation (IEC 62614:2010) Fibres optiques - Exigences des conditions dinjection pour la mesure de laffaiblissement en multimodal (CEI 62614:2010) Lichtwellenleiter -Anforderungen an die Anregungsbedingungen fr Mehrmoden-Dmpfungsmessungen (IEC 62614:2010) This European St
7、andard was approved by CENELEC on 2010-10-01. 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 without any alteration. Up-to-date lists and bibliographical references conce
8、rning 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 language made by translation under the responsibility of a CENELEC member into
9、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, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland
10、, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN 62614:2010 - 2 - Foreword The text of document 86/367/FDIS, future edition 1 of IEC 62614, prepared by IEC TC 86, Fibr
11、e optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62614 on 2010-10-01. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or a
12、ll 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 standard or by endorsement (dop) 2011-07-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow
13、) 2013-10-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 62614:2010 was approved by CENELEC as a European Standard without any modification. _ BS EN 62614:2010- 3 - EN 62614:2010 Annex ZA (normative) Normative references to international public
14、ations 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 referenced document (including any amendments) appl
15、ies. 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 specification for category A1 multimode fibresEN 60
16、793-2-10 - IEC 61280-1-4 - Fibre optic communication subsystem test procedures - Part 1-4: General communication subsystems - Light source encircled flux measurement method EN 61280-1-4 - IEC 61280-4-1 2009 Fibre optic communication subsystem test procedures - Part 4-1: Installed cable plant - Multi
17、mode attenuation measurement EN 61280-4-1 2009 BS EN 62614:2010 62614 IEC:2010 CONTENTS 1 Scope.1H5 2 Normative references2H5 3 Terms and definitions .3H5 4 Background on multimode launch conditions .4H6 5 Test source launch .5H7 5.1 General .6H7 5.2 Encircled flux.7H7 5.3 Encircled flux template il
18、lustration8H7 5.4 Encircled flux target for attenuation measurement9H8 5.5 Harmonisation of multimode launch conditions to eliminate wavelength bias.10H9 5.6 Limitations on multimode launch conditions 11H10 5.7 Encircled flux limits 12H10 5.8 Practical limitations of multimode launch conditions . 13
19、H10 Bibliography 14H12 Figure 1 EF template illustration .15H8 Figure 2 Wavelength comparison .16H9 Table 1 EF target for 50 m core fibre at 850 nm 17H8 Table 2 EF target for 50 m core fibre at 1 300 nm .18H8 Table 3 EF target for 62,5 m fibre at 850 nm.19H9 Table 4 EF target for 62,5 m fibre at 1 3
20、00 nm20H9 Table 5 Tolerance threshold . 21H10 BS EN 62614:2010462614 IEC:2010 5 FIBRE OPTICS LAUNCH CONDITION REQUIREMENTS FOR MEASURING MULTIMODE ATTENUATION 1 Scope This International Standard describes the launch condition requirements used for measuring multimode attenuation in passive component
21、s and in installed cable plants. In this standard, the fibre types that are addressed include category A1a (50 m /125 m) and A1b (62,5 m /125 m) multimode fibres, as specified in IEC 60793-2-10. The nominal test wavelengths detailed are 850 nm and 1 300 nm. This standard may be suitable for multimod
22、e attenuation measurements for other multimode categories and/or other wavelengths, but the source condition for other categories and wavelengths are not defined here. The purpose of these requirements is as follows: to ensure consistency of field measurements when different types of test equipment
23、are used; to ensure consistency of factory measurements when different types of test equipment are used; to ensure consistency of field measurements when compared with factory measurements. This standard describes launch condition requirements for optical attenuation using sources with a controlled
24、encircled flux (EF). 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 6
25、0793-2-10, Optical fibres Part 2-10: Product specifications Sectional specification for category A1 multimode fibres IEC 61280-1-4, Fibre optic communication subsystem test procedures Part 1-4: General communication subsystems Light source encircled flux measurement method IEC 61280-4-1:2009, Fibre
26、optic communication subsystem test procedures Part 4-1: Installed cable plant Multimode attenuation measurement 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. NOTE In this clause only specific terms and definitions for the purposes of this docum
27、ent are provided. For common fibre optic terms, reference is made to IEC/TR 61931. BS EN 62614:2010 6 62614 IEC:2010 3.1 coupled power ratio CPR difference, expressed in dB, between the power exiting a multimode fibre and the power exiting a single-mode fibre concatenated to the same multimode fibre
28、 with the same launching conditions 3.2 encircled flux EF fraction of cumulative near-field power to the total output power as a function of radial distance from the optical centre of the core 3.3 mode power distribution MPD relative mode power in each of the mode groups of a multimode fibre, often
29、shown graphically 3.4 multimode attenuation attenuation pertaining to multimode fibres and/or multimode fibre components, systems and subsystems 3.5 reference grade launch cord launch cords constructed with a reference grade termination at the interface to the device under test 3.6 reference grade t
30、ermination connector plug with tightened tolerances terminated onto an optical fibre with tightened tolerances such that the expected loss of a connection formed by mating two such assemblies is less than or equal to 0,1 dB (an adapter, required to ensure this performance, may be considered to be pa
31、rt of the reference grade termination where required by the test configuration) NOTE 1 As an example, the core diameter tolerance may need to be 0,7 m (under consideration). Other fibre tolerances are also under consideration. NOTE 2 This definition remains under study. When a more complete definiti
32、on is available in another standard, this definition will be replaced by a reference to that standard. 4 Background on multimode launch conditions There have been a wide range of launch conditions used for testing multimode fibre components and systems. Light sources, typically used in measuring att
33、enuation, may produce varying modal distributions when launched into multimode fibre. These differing modal distributions, combined with the differential mode attenuation (DMA) inherent in most multimode components, commonly cause measurement variations when measuring attenuation of multimode compon
34、ents. For example, attenuation measurement variations can occur when two similar light sources or different launch cords are used. Legacy (LED based) applications had a wide power budget which in most cases masked the variance in results between the factory and field measurement. As technology has e
35、volved, the system requirements for attenuation have become more stringent. Demanding application requirements are driving the need for accurate and reproducible multimode attenuation measurements over a variety of field-test instruments. Attenuation measurement experiments, with different instrumen
36、ts having the same standards compliant set up, produce measurement variations that are induced by their differing launch conditions. BS EN 62614:201062614 IEC:2010 7 Experts have concluded that the launch condition should be expressed at the interface between the test instrument launch cord and the
37、terminated fibre to be tested. That is, the launch condition should be based in part on the measured near field at the output of the launch cord. The key to making reproducible loss measurements across various sources is to narrowly constrain the range of power distribution at large radii so that al
38、l compliant sources produce closely agreeing loss measurement results. This is because the variation in the allowed power distribution at large radii across different sources translates directly into variability of loss measurements. Smaller power variations enable more reproducible loss measurement
39、s. 5 Test source launch 5.1 General The source launch conditions are described at the output of the reference grade launch cord. It is expected that the source and launch cord, as supplied, have been verified by the test equipment manufacturer to produce the specified launch measured according to IE
40、C 61280-1-4. For reference grade fibre, core diameter tolerances of 0,7 m have been evaluated with some success. Variance of other parameters, such as numerical aperture and core concentricity, need more study. 5.2 Encircled flux The EF is determined from the near field measurement of the light comi
41、ng from the end of the reference grade launch cord in accordance with IEC 61280-1-4. The measured near field result is a function of the near field profile, I(r), of radius, r, away from the optical centre of the core, and the edge of the near field profile, R, which is used to generate the EF funct
42、ion as ()()()=RrdxxxIdxxxIrEF00(1) 5.3 Encircled flux template illustration An illustration of an EF template is shown in Figure 1. A target EF value for a set of particular radial control points is defined. Upper and lower limit of EF values for a set of particular radial control points may also be
43、 defined. A compliant launch is a launch that falls within the template at the particular radial control points. BS EN 62614:2010 8 62614 IEC:2010 Figure 1 EF template illustration 5.4 Encircled flux target for attenuation measurement For the purposes of this standard, the EF requirement is defined
44、as a target EF value for a set of particular radial control points for each of four combinations of fibre core diameter and wavelength, as tabulated in Table 1 through Table 4. Table 1 EF target for 50 m core fibre at 850 nm Radial offset m Target 10 0,335 0 15 0,655 0 20 0,919 3 22 0,975 1 Table 2
45、EF target for 50 m core fibre at 1 300 nm Radial offset m Target 10 0,336 6 15 0,656 7 20 0,918 6 22 0,972 8 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 EF template Radius (m)EF Target Template Radial offset (m) Target 10 0,3350 15 0,6550 20 0,9200 22 0,9751 I
46、EC 1746/10BS EN 62614:201062614 IEC:2010 9 Table 3 EF target for 62,5 m fibre at 850 nm Radial offset m Target 10 0,210 9 15 0,439 0 20 0,692 3 26 0,935 0 28 0,978 3 Table 4 EF target for 62,5 m fibre at 1 300 nm Radial offset m Target 10 0,211 9 15 0,440 9 20 0,694 5 26 0,935 7 28 0,978 2 5.5 Harmo
47、nization of multimode launch conditions to eliminate wavelength bias Efforts were taken to harmonize the expected component losses at 850 nm and 1 300 nm wavelengths for a given fibre core diameter. This was accomplished by adjustment of the 850 nm and 1 300 EF targets to produce comparable extrinsi
48、c component losses. An example of matching the attenuation characteristics at the two wavelengths is illustrated in Figure 2. This elimination of bias provides an opportunity to ensure dual wavelength compliance of a passive component or short cable plant link using a single source condition. 2.001.
49、751.501.251.000.750.500.250.002.001.751.501.251.000.750.500.250.00850 nm Attenuation (dB)1 300 nmAttenuation(dB)2,1,1,1,1,0,0,0,0,0, 0,25 0, 0,75 1, 1, 1, 1, 2,ActualIdeal2,00 1,75 1,50 25 00 75 50 0,25 0,00 0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 850 nm attenuation (dB) 1 300 nmattenuation (dB)Actual Ideal IEC 1747/10Figure 2 Wavelength comparison BS EN 62614:2010 10 62614 IEC:2010 5.6 Limitations on multimode launc
