1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22959-7 SANS 62614:2009Edition 1IEC/PAS 62614:2009Edition 1SOUTH AFRICAN NATIONAL STANDARD Fibre optics Launch condition requirements for
4、measuring multimode attenuation This national standard is the identical implementation of IEC/PAS 62614:2009 and is adopted with the permission of the International Electrotechnical Commission. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001Tel: +27 1
5、2 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 62614:2009 Edition 1 IEC/PAS 62614:2009 Edition 1 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS TC 79, Fibre optics, in accordance with procedures of the SABS Stand
6、ards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in November 2009. IEC/PAS 62614Edition 1.0 2009-03PUBLICLY AVAILABLE SPECIFICATIONPRE-STANDARD Fibre optics - Launch condition requirements for measuring multimode attenuation INTERNATIONAL ELECTROTE
7、CHNICAL COMMISSION KICS 33.180.01 PRICE CODEISBN 2-8318-1035-3 Registered trademark of the International Electrotechnical Commission SANS 62614:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . 2 PAS 62614 IEC:2009(E) CONTENTS FOREWORD.3 1
8、 Scope.4 2 Normative references4 3 Background on multimode launch conditions .4 4 Terminology4 5 Test source launch .6 5.1 Encircled flux.6 5.2 Encircled flux template illustration6 5.3 Encircled flux target for attenuation measurement7 5.4 Limitations on multimode launch conditions8 5.5 Encircled f
9、lux limits8 Figure 1 EF template illustration .7 Table 1 EF target for 50 m core fibre at 850 nm 7 Table 2 EF target for 50 m core fibre at 1 300 nm .7 Table 3 EF target for 62,5 m fibre at 850 nm.8 Table 4 EF target for 62,5 m fibre at 1 300 nm8 Table 5 Tolerance threshold .8 SANS 62614:2009This s
10、tandard may only be used and printed by approved subscription and freemailing clients of the SABS .PAS 62614 IEC:2009(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTICS LAUNCH CONDITION REQUIREMENTS FOR MEASURING MULTIMODE ATTENUATION FOREWORD 1) The International Electrotechnical Commiss
11、ion (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 the electrical and electronic fields. To this end and in
12、addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee int
13、erested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance
14、with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all intereste
15、d IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible
16、for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence betwe
17、en any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All user
18、s should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or othe
19、r damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. U
20、se of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent
21、 rights. A PAS is a technical specification not fulfilling the requirements for a standard, but made available to the public. IEC-PAS 62614 has been processed by IEC technical committee 86: Fibre optics. The text of this PAS is based on the following document: This PAS was approved for publication b
22、y the P-members of the committee concerned as indicated in the following document Draft PAS Report on voting 86/320/PAS 86/324/RVD Following publication of this PAS, which is a pre-standard publication, the technical committee or subcommittee concerned may transform it into an International Standard
23、. This PAS shall remain valid for an initial maximum period of 3 years starting from the publication date. The validity may be extended for a single 3-year period, following which it shall be revised to become another type of normative document, or shall be withdrawn. SANS 62614:2009This s tandard m
24、ay only be used and printed by approved subscription and freemailing clients of the SABS . 4 PAS 62614 IEC:2009(E) FIBRE OPTICS LAUNCH CONDITION REQUIREMENTS FOR MEASURING MULTIMODE ATTENUATION 1 Scope This Publicly Available Specification (PAS) describes the launch condition requirements used for m
25、easuring multimode attenuation in passive components and installed cable plant. In this PAS, the fibre types that are addressed include category A1a (50/125 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. Thi
26、s PAS may be suitable for multimode 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
27、different types of test equipment 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 PAS describes launch condition requirements for optical attenuation usi
28、ng sources with a controlled 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 a
29、ny amendments) applies. IEC 60793-2-10, Optical Fibres Part 2-10: Product specifications Sectional specification for category A1 multimode fibres IEC 61280-1-4: Ed. 21, Fibre optic communication subsystem test procedures Part 1-4: General communication subsystems - Light source encircled flux measur
30、ement method IEC 61931, Fibre optic terminology 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. In this clause only specific terms for the purpose of this document are provided. For common fibre optic terms, reference is made to IEC 61931. 3.1 mu
31、ltimode attenuation attenuation pertaining to multimode fibres and/or multimode fibre components, systems and subsystems 1To be published. SANS 62614:2009This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .PAS 62614 IEC:2009(E) 5 3.2 encircled fl
32、ux 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 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
33、the same multimode fibre with the same launching conditions 3.4 mode power distribution MPD relative mode power in each of the mode groups of a multimode fibre, often shown graphically 3.5 reference grade termination connector plug with tightened tolerances terminated onto an optical fibre with tigh
34、tened 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 part of the reference grade termination where required by the test configuration). NOTE 1 As an
35、example, the core diameter tolerance may need to be 0,7 m(ffs). Other fibre tolerances are ffs. NOTE 2 This definition remains as a point under study. When a more complete definition is available in another document, this definition will be replaced by a reference. 3.6 reference grade launch cord la
36、unch cords constructed with a reference grade termination at the interface to the device under test 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 attenu
37、ation, 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 component
38、s. 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 evol
39、ved, 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 instruments
40、having the same standards compliant setup, produce measurement variations that are induced by their differing launch conditions. Experts have concluded that the launch condition should be expressed at the interface between the test instrument launch cord and the terminated fibre to be tested. That i
41、s, 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 SANS 62614:2009This s tandard may only be used and printed by approved subscription and freemailing clie
42、nts of the SABS . 6 PAS 62614 IEC:2009(E) constrain the range of power distribution at large radii so that all 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 direc
43、tly into variability of loss measurements. Smaller power variations enable more reproducible loss measurements. 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, h
44、ave been verified by the test equipment manufacturer to produce the specified launch measured per IEC 61280-1-4. For reference grade fibre, core diameter tolerances of 0,7m have been evaluated with some success. Variance of other parameters, such as numerical aperture and core concentricity, need mo
45、re study 5.2 Encircled flux (EF) The EF is determined from the near field measurement of the light coming from the end of the reference grade launch cord in accordance with IEC 61280-1-4 Ed.2.0. The measured near field result is a function of the near field profile, I(r), of radius, r, away from the
46、 optical centre of the core, and the edge of the near field profile, R, which is used to generate the EF function 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 p
47、oints is defined. Upper and lower limit of EF values for a set of particular radial control points may also be defined. A compliant launch is a launch that falls within the template at the particular radial control points. SANS 62614:2009This s tandard may only be used and printed by approved subscr
48、iption and freemailing clients of the SABS .PAS 62614 IEC:2009(E) 7 Figure 1 EF template illustration 5.4 Encircled flux target for attenuation measurement For the purpose of this PAS, the EF requirement is defined as a target EF value for a set of particular radial control points for each of four c
49、ombinations 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 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 0,1 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 0,65
