1、 IEC TR 62614-2 Edition 1.0 2015-07 TECHNICAL REPORT Fibre optics Multimode launch conditions Part 2: Determination of launch condition requirements for measuring multimode attenuation IEC TR 62614-2:2015-07(en) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2015 IEC, Geneva, Switzerland All righ
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11、ion of launch condition requirements for measuring multimode attenuation INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.180.01 ISBN 978-2-8322-2794-7 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distr
12、ibutor. 2 IEC TR 62614-2:2015 IEC 2015 CONTENTS FOREWORD . 4 INTRODUCTION . 6 1 Scope 7 2 Normative references 7 3 Terms and definitions 7 4 Background and history . 8 5 Metrics for multimode launch conditions 9 5.1 General . 9 5.2 Metrics no longer in use 9 5.2.1 General . 9 5.2.2 Coupled power rat
13、io (CPR) 9 5.2.3 Mode power distribution/relative power distribution (MPD/RPD) . 9 5.3 Encircled flux (EF) 10 6 Uncertainties . 11 7 Encircled flux envelope Theory and assumptions 11 7.1 Mode field eigenfunctions (MFE) . 11 7.2 Connections, attenuation and the encircled flux template 13 7.3 Target w
14、eights 15 7.4 Coupling matrix calculations . 18 8 Wavelength bias correction to EF targets/limits with spectrally broad sources . 19 8.1 General . 19 8.2 Modified spectrum assumptions 20 8.3 Determining the EF targets . 20 8.4 Determining the EF limits 22 8.5 Validating the EF limits . 23 Annex A (i
15、nformative) IEC international standards related to multimode launch conditions . 25 A.1 Introductory remarks . 25 A.2 Specification . 25 A.3 Measurement 25 A.4 Calibration 26 Annex B (informative) Coupled power ratio measurement for fibre optic sources 27 B.1 Introductory remarks . 27 B.2 Object . 2
16、7 B.3 Source 27 B.4 Apparatus . 27 B.5 Procedure . 28 Annex C (informative) Limits on RPD and MPD 29 C.1 Introductory remarks . 29 C.2 Modal transfer function . 29 C.3 Relative power distribution (RPD) . 30 C.4 MPD (modal power distribution) 32 C.4.1 General . 32 C.4.2 Requirements 33 Bibliography 3
17、5 IEC TR 62614-2:2015 IEC 2015 3 Figure 1 Comparison of target weights . 16 Figure 2 Encircled flux limit of 10 Gigabit Ethernet VCSELs . 16 Figure 3 Incremental attenuation using OFL . 17 Figure 4 Incremental attenuation using target launch . 18 Figure 5 Measured attenuation values showing the wave
18、length bias between 850 nm and 1 300 nm results 19 Figure 6 Measured attenuation values after correction of 850 nm target . 24 Figure C.1 Example of a characteristic MTF . 30 Figure C.2 Relative power distribution (RPD) specification . 32 Figure C.3 Example of a characteristic MPD 33 Figure C.4 MPD
19、(modal power distribution) specification 34 Table 1 Per cent variation for best fit against target to derive adjustment for encircled flux for 50 mm MMF . 21 Table 2 Encircled flux adjustment at 850 nm for 50 mm multimode fibre . 21 Table 3 Encircled flux adjustment at 1 300 nm for 50 mm multimode f
20、ibre 22 Table 4 Calculated encircled flux limits for 50 mm multimode fibre at 850 nm and 1 300 nm 23 Table A.1 Standards for multimode launch conditions 25 Table B.1 Light source characteristics 27 Table B 2 Light source categorization by CPR value (850 nm wavelength, CPR values in decibels) 28 Tabl
21、e B 3 Light source categorization by CPR value (1 300 nm wavelength, CPR values in decibels) 28 4 IEC TR 62614-2:2015 IEC 2015 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTICS MULTIMODE LAUNCH CONDITIONS Part 2: Determination of launch condition requirements for measuring multimode attenuati
22、on FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in
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33、the publication of a Technical Report when it has collected data of a different kind from that which is normally published as an International Standard, for example “state of the art“. IEC TR 62614-2, which is a Technical Report, has been prepared by subcommittee 86C: Fibre optic systems and active
34、devices, of IEC technical committee 86: Fibre optics. This first edition cancels and replaces IEC TR 61282-11 published in 2012. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: IEC TR 62614-2:2015
35、IEC 2015 5 significant reduction to the clause on uncertainties; technical edits throughout in addition to updates to key normative references; incorporation of additional figures related to the wavelength bias between 850 nm and 1 300 nm as well as the encircled flux limit of 10 Gigabit Ethernet VC
36、SELs. This publication contains an attached file titled, “TR 62614-2 Supplemental Data”, in the form of an Excel spreadsheet. This file is intended to be used as a complement and does not form an integral part of this Technical Report. The text of this Technical Report is based on the following docu
37、ments: Enquiry draft Report on voting 86C/1265/DTR 86C/1276A/RVC Full information on the voting for the approval of this Technical Report can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of
38、all parts in the IEC 62614 series, published under the general title Fibre optics Multimode launch conditions, can be found on the IEC website. Future standards in this series will carry the new general title as cited above. Titles of existing standards in this series will be updated at the time of
39、the next edition. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC website under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, r
40、eplaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date. 6 IEC TR 62614-2:2015 IEC 2015 INTRODUCTION At the meeting of IEC TC86 and its subcommittees and working groups in Cape Town in 2005, there were numerous discussions regarding measurement
41、s on multimode fibres, cables, passive components and cable plants. Liaisons were also received from ISO/IEC JTC1 SC25 WG3 that reported on the requirements of ISO/IEC14763-3 for testing fibre optic cabling in premises cabling. This Technical Report used a mode power distribution template in an atte
42、mpt to control the launch conditions at the location of the reference connector to improve measurement accuracy and reduce uncertainty when testing the attenuation of multimode fibre optic cabling. IEC SC86B had also adopted the metric. It was decided to set up a “Multimode Launch Co-ordinating Grou
43、p” referred to as MMLCG. This would be set up directly reporting to IEC TC86 and include representatives from interested persons in subcommittees 86A, 86B and 86C as well as ISO/IEC JTC1 SC25 WG3. The scope of the MMLCG was defined as: “To coordinate the harmonization of the variety of multimode mod
44、al launch conditions that exist within the documents being prepared and published by the subcommittees of IEC TC86 for the purpose of attenuation and return loss measurements.” The intent of this Technical Report is to keep available the key technical aspects issued by the MMLCG. The key documents u
45、sed in the developmental of this Technical Report have been retained and are stored on the IEC collaboration tools for reference. IEC TR 62614-2:2015 IEC 2015 7 FIBRE OPTICS MULTIMODE LAUNCH CONDITIONS Part 2: Determination of launch condition requirements for measuring multimode attenuation 1 Scope
46、 IEC TR 62614-2, which is a Technical Report, is intended to show the background of encircled flux for the characterization of multimode launch conditions. This includes the selection of the encircled flux and the definition of the encircled flux requirements in conjunction with the implied variatio
47、n for all multimode attenuation and return loss measurement methods on graded index multimode fibre products. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edi
48、tion 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 61280-1-4:2009, Fibre optic communication subsys
49、tem test procedures Part 1-4: General communication subsystems Light source encircled flux measurement method IEC 61280-4-1, 2009, Fibre optic communication subsystem test procedures Part 4-1: Installed cable plant Multimode attenuation measurement IEC TR 61282-14, Fibre optic communication system design guides Part 14: Determination of the uncertainties of the attenuation measurement of cabling 1IEC 61300-1, Fibre optic interconnecting devices and p
