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 978-0-626-19389-8 SANS 61282-3:2007Edition 2 IEC TR 61282-3:2006Edition 2SOUTH AFRICAN NATIONAL STANDARD Fibre optic communication system design gui
4、des Part 3: Calculation of link polarization mode dispersion This national standard is the identical implementation of IEC TR 61282-3:2006 and is adopted with the permission of the International Electrotechnical Commission. Published by Standards South Africa 1 dr lategan road groenkloof private bag
5、 x191 pretoria 0001 tel: 012 428 7911 fax: 012 344 1568 international code + 27 12 www.stansa.co.za Standards South Africa SANS 61282-3:2007 Edition 2 IEC TR 61282-3:2006 Edition 2 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee
6、 StanSA SC 74A, Communication technology Fibre optics, in accordance with procedures of Standards South Africa, in compliance with annex 3 of the WTO/TBT agreement. This part of SANS 61282 was published in April 2007. This SANS edition supersedes SANS edition 1 (SANS 61282-3:2003). TECHNICAL REPORT
7、IECTR 61282-3Second edition2006-10Fibre optic communication system design guides Part 3: Calculation of link polarization mode dispersion PRICE CODE IEC 2006 Copyright - all rights reserved No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanica
8、l, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission, 3, rue de Varemb, PO Box 131, CH-1211 Geneva 20, SwitzerlandTelephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmailiec.ch Web: www.iec.ch V For price, se
9、e current catalogueCommission Electrotechnique InternationaleInternational Electrotechnical Commission SANS 61282-3:2007This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . 2 TR 61282-3 IEC:2006(E) CONTENTS FOREWORD.3 INTRODUCTION.5 1 Scope.6 2 B
10、asic design models for total system PMD performance6 2.1 Notation.6 2.2 Calculation of system PMD 7 3 Calculation of cabled fibre PMD 9 3.1 General .9 3.2 Method 1: Calculating PMDQ, the PMD link design value11 3.3 Method 2: Calculating the probability of exceeding DGDmax14 3.4 Equivalence of method
11、s.18 4 Calculation of optical component PMD 20 5 Summary of acronyms and symbols 20 Annex A (informative) PMD concatenation fundamentals 22 Annex B (informative) Combining Maxwell extrema from two populations26 Annex C (informative) Worked example30 Annex D (informative) Relationship of probability
12、to system performance 31 Annex E (informative) Concatenation experiment32 Bibliography34 Figure 1 Various passing distributions 15 Figure 2 Worst case approach assumption .17 Figure 3 Convolution of two Diracs .17 Figure 4 Equivalence envelopes for method 1/2 defaults.19 Figure A.1 Sum of randomly r
13、otated elements.25 Figure A.2 Sum of randomly rotated elements.25 Table 1 Probability based on wavelength average.9 Table 2 Acronyms and definitions .21 Table 3 Symbols and clause of definition 21 Table E.1 Concatenation math verification33 SANS 61282-3:2007This s tandard may only be used and printe
14、d by approved subscription and freemailing clients of the SABS .TR 61282-3 IEC:2006(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ FIBRE OPTIC COMMUNICATION SYSTEM DESIGN GUIDES Part 3: Calculation of link polarization mode dispersion FOREWORD 1) The International Electrotechnical Commission (IEC)
15、 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 addition
16、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 interested i
17、n 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 with cond
18、itions 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 interested IEC Nat
19、ional 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 for the w
20、ay 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 between any IE
21、C 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 users should
22、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 other damage
23、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. Use of the
24、 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 rights.
25、The main task of IEC technical committees is to prepare International Standards. However, a technical committee may propose 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 t
26、he art“. IEC 61282-3, which is a technical report, has been prepared by subcommittee 86C: Fibre optic systems and active devices, of IEC technical committee 86: Fibre optics. This second edition cancels and replaces the first edition published in 2002. It is a technical revision that includes the fo
27、llowing significant changes: a) the title has been changed to better reflect its applicability to links; b) Equations (1) and (2) were simplified in order to align with agreements in the ITU-T. SANS 61282-3:2007This s tandard may only be used and printed by approved subscription and freemailing clie
28、nts of the SABS . 4 TR 61282-3 IEC:2006(E) The text of this technical report is based on the following documents: Enquiry draft Report on voting 86C/701/DTR 86C/720/RVC Full information on the voting for the approval of this technical report can be found in the report on voting indicated in the abov
29、e table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts of the IEC 61282 series, published under the general title Fibre optic communication system design guides, can be found on the IEC website. The committee has decided that the contents of
30、 this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. A bilingual
31、version of this publication may be issued at a later date. SANS 61282-3:2007This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .TR 61282-3 IEC:2006(E) 5 INTRODUCTION Polarization mode dispersion (PMD) is usually described in terms of a differenti
32、al group delay (DGD), which is the time difference between the principal states of polarization of an optical signal at a particular wavelength and time. PMD in cabled fibres and optical components causes an optical pulse to spread in the time domain, which may impair the performance of a fibre opti
33、c telecommunication system, as defined in IEC 61281-1. SANS 61282-3:2007This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS . 6 TR 61282-3 IEC:2006(E) FIBRE OPTIC COMMUNICATION SYSTEM DESIGN GUIDES Part 3: Calculation of link polarization mode dis
34、persion 1 Scope This part of IEC 61282 provides guidelines for the calculation of polarization mode dispersion (PMD) in fibre optic systems to accommodate the statistical variation of PMD and differential group delay (DGD) in optical fibre cables and components. This technical report describes metho
35、ds for calculating PMD due to optical fibre cables and optical components in an optical link. The calculations are compatible with those documented in the outdoor optical fibre cable specification IEC 60794-3. Example calculations are given to illustrate the methods for calculating total optical lin
36、k PMD from typical cable and optical component data. The calculations include the statistics of concatenating individual optical fibre cables drawn from a specified distribution. The calculations assume that all components have PMD equal to the maximum specified value. The calculations described cov
37、er first order PMD only. The following subject areas are currently beyond the scope of this technical report, but remain under study: calculation of second and higher order PMD; accommodation of components with polarization dependent loss (PDL) if it is assumed that PDL is negligible in optical fibr
38、e cables; system impairments (power penalty) due to PMD; interaction with chromatic dispersion and other nonlinear effects. Measurement of PMD is beyond the scope of this technical report. Methods of measurement of PMD of optical fibre and cable are given in IEC 60793-1-48. The measurement of optica
39、l amplifier PMD is in IEC 61290-11-1. The measurement of component PMD is in IEC 61300-3-32. Measurement of link PMD is given in 61280-4-4. A general theory and guidance on measurements is given in 61282-9. 2 Basic design models for total system PMD performance 2.1 Notation For cabled fibre and comp
40、onents with randomly varying DGD, the PMD frequency domain measurement is based on averaging the individual DGD values for a range of wavelengths. The probability density function of DGD values is known to be Maxwell for fibre, and is assumed to be Maxwell, in effect, for components. The single para
41、meter for the Maxwell distribution scales with the PMD value. For long fibre and cable (typically longer than 500 m to 1 000 m), the PMD value is divided by the square root of the length to obtain the PMD coefficient. For components, the PMD value is reported without normalization. The following ter
42、ms and meanings will be used to distinguish the various expressions: DGD value The differential group delay at a time and wavelength (ps) PMD value The wavelength average of DGD values (ps) PMD coefficient The length normalised PMD (ps/sqrt(km) DGD coefficient The length normalised DGD (ps/sqrt(km)
43、SANS 61282-3:2007This s tandard may only be used and printed by approved subscription and freemailing clients of the SABS .TR 61282-3 IEC:2006(E) 7 NOTE The term “DGD coefficient” is used only in some of the calculations. The physical square root length dependence of the PMD value does not apply to
44、DGD. Deterministic components are those for which the DGD may vary with wavelength, but not appreciably with time. The variation in wavelength may be complex, depending on the number and characteristics of the sub-components within. For these types of components, either the maximum DGD is reported o
45、r the wavelength average is reported as the PMD value. For components with multiple paths, such as an optical demultiplexer, the maximum DGD of the different paths should be reported as the PMD value. 2.2 Calculation of system PMD PMD values of randomly varying elements can be added in quadrature. A
46、nnex A shows the basis of this, as well as one basis for concluding that the Maxwell distribution is appropriate to describe the distribution of DGD values. Annex A describes the concatenation in terms of the addition of rotated polarization dispersion vectors (pdv) which are, for randomly varying c
47、omponents, assumed to be random in magnitude and direction over both time and wavelength. For deterministic components, the evolution of the pdv with wavelength may be quite complex, but for each wavelength, there is a value that does not vary appreciably with time. Analysis of the relationships in
48、Annex A shows that deterministic components that are randomly aligned in combination with random elements behave like random components. For randomly varying components such as fibre, the statistics of DGD variation imply that there is little wavelength dependence of the PMD value. This leads to an
49、equivalence between PMD measurement methods such as Jones Matrix Eigenanalysis (JME) and interferometric methods (IT) where the wavelength ranges of the two are different. For deterministic elements, there can be distinct dependence of both the DGD and PMD on the wavelength range. Therefore for these elements, when doing calculations which combine both randomly varying and deterministic elements, the combined values are only representative of the
