1、 TECHNICAL REPORT IECTR 61292-5First edition 2004-07Optical amplifiers Part 5: Polarization mode dispersion parameter General information Reference number IEC/TR 61292-5:2004(E) Publication numbering As from 1 January 1997 all IEC publications are issued with a designation in the 60000 series. For e
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7、formation. Customer Service Centre If you have any questions regarding this publication or need further assistance, please contact the Customer Service Centre: Email: custserviec.ch Tel: +41 22 919 02 11 Fax: +41 22 919 03 00 TECHNICAL REPORT IEC TR 61292-5First edition 2004-07Optical amplifiers Par
8、t 5: Polarization mode dispersion parameter General information PRICE CODE IEC 2004 Copyright - all rights reserved No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fro
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10、nal Electrotechnical Commission 2 TR 61292-5 IEC:2004(E) CONTENTS FOREWORD.3 1 Scope.5 2 Normative references.5 3 Acronyms and abbreviations.5 4 General Information6 4.1 Principal states of polarization and mode coupling 6 4.2 Differential group delay and polarization mode dispersion .6 5 Test metho
11、d calculations7 6 Measurement issues.7 6.1 Source degree of polarization and amplified spontaneous emission.7 6.2 The use of a broadband source .9 6.3 Coherence interference effects and multiple path interferences.9 Annex A (informative) Applicability of various PMD test methods to different applica
12、tions 11 Bibliography12 TR 61292-5 IEC:2004(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ OPTICAL AMPLIFIERS Part 5: Polarization mode dispersion parameter General information FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprisin
13、g 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 to other activities, IEC publishes International Standards
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23、nternational 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 the art“. IEC 61292-5, which is a Technical Report, has be
24、en prepared by subcommittee 86C: Fibre optic systems and active devices, of IEC technical committee 86: Fibre optics. The text of this Technical Report is based on the following documents: Enquiry draft Report on voting 86C/579A/DTR 86C/608/RVC Full information on the voting for the approval of this
25、 Technical Report can be found in the report on voting indicated in the above table. 4 TR 61292-5 IEC:2004(E) IEC 61292 consists of the following parts, under the new general title Optical amplifiers: Part 1: Parameters of amplifier components Part 2: Theoretical background for noise figure evaluati
26、on using the electrical spectrum analyzer Part 3: Classification, characteristics and applications. Part 4: Maximum permissible optical power for the damage-free and safe use of optical amplifiers, including Raman amplifiers 1)Part 5: Polarization mode dispersion parameter General information Future
27、 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 the next edition. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of
28、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 v
29、ersion of this publication may be issued at a later date. 1)To be published. TR 61292-5 IEC:2004(E) 5 OPTICAL AMPLIFIERS Part 5: Polarization mode dispersion parameter General information 1 Scope This part of IEC 61292, which is a Technical Report, applies to all commercially available optical ampli
30、fiers (OAs) including those using fibres (OFAs), semiconductors (SOAs), and waveguides (POWA), as classified in IEC 61292-3. This Technical Report presents general information about polarization mode dispersion (PMD), related to the application of the two commonly used methods to test PMD in OAs, th
31、e Jones matrix eigenanalysis (JME) and the Poincar sphere analysis (PSA), which have been demonstrated to be formalistically equivalent 4,5 2) . This report is complementary to the International Standards describing the JME procedure (IEC 61290-11-1) and the PSA procedure (IEC 61290-11-2). 2 Normati
32、ve references The following referenced documents are indispensable for the understanding 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 61290-11-1, Optical amplifier
33、 test methods Part 11-1: Polarization mode dispersion Jones matrix eigenanalysis method (JME) IEC 61290-11-2, Optical fibre amplifier test methods Part 11-2: Polarization mode dispersion Poincar sphere analysis method 3)IEC 61292-3, Optical amplifiers Part 3: Classification, characteristics and appl
34、ications 3 Acronyms and abbreviations ASE amplified spontaneous emission BBS broadband source DGD differential group delay DOP degree of polarization JME Jones matrix eigenanalysis OA optical amplifier OFA optical fibre amplifier OSA optical spectrum analyser PDG polarization dependent gain PDL pola
35、rization dependent loss 2) Numbers in brackets refer to the Bibliography. 3)To be published. 6 TR 61292-5 IEC:2004(E) PMD polarisation mode dispersion PMF polarization-maintaining fibre POWA planar optical waveguide amplifier PSA Poincar sphere analysis PSP principal states of polarization RBW resol
36、ution bandwidth RMS root mean square SMSR side mode suppression ratio SOA semiconductor optical amplifier SOP state of polarization TLS tuneable laser source 4 General Information PMD refers to how the polarized light and in particular the principal states of polarization (PSPs) from a short pulse o
37、f a narrowband light source are modified when going through a device such as an OA. This process is mathematically explained by the concepts of polarization transfer function, the Jones vector and the polarization dispersion matrix, the Stokes vector and the Poincar sphere, the PSPs and their mode c
38、oupling, the polarization dispersion vector and the differential group delay (DGD). The following clauses will discuss some of these concepts as specifically applied to OAs. 4.1 Principal states of polarization and mode coupling OAs are usually defined by a combination of optical components (passive
39、 or active gain medium); in some cases, an optical fibre is used as the active gain medium (see IEC 61292-3). Some components have a deterministic behaviour while others behave stochastically, depending on their complexity and design. An optical fibre is deterministic if its length is short or if it
40、s birefringence axis is fixed, such as in the case of a polarization-maintaining fibre (PMF). The fibre will have a stochastic behaviour if it has a long length such as the fibre installed in cable plant. The length from which the fibre behaves stochastically is still under investigation. Most OAs a
41、re expected to behave in semi-random mode coupling. 4.2 Differential group delay and polarization mode dispersion In OAs, the DGD may vary as a function of wavelength (or frequency) even if this variation is smooth, small or sometimes predictable. In that case, the concept of PMD expressed as the RM
42、S value or average value of the variation of the DGD as a function of wavelength (or optical frequency) and the concept of maximum value of that DGD variation can be used. For OAs the DGD and PMD are reported in ps. In OAs, PMD together with polarization dependent loss (PDL) and polarization depende
43、nt gain (PDG) may introduce waveform distortion, leading to unacceptable bit error rate increase. Figure 1 illustrates the case where at the output of the DUT the bits are not only broadened (in absence of PDL/PDG) but also distorted (in presence of PDL/PDG). In presence of PDL, there is a loss of d
44、egree of polarization (DOP) for one PSP. TR 61292-5 IEC:2004(E) 7 Key t time z direction of propogation along the fibre Figure 1 Effect of PMD on transmission of an information bit pulse in a device 5 Test method calculations The mathematical formulation, as well as examples of calculation of JME an
45、d PSA, are found in IEC 61290-11-1 and IEC 61290-11-2, respectively. 6 Measurement issues The following clauses pertain specifically to PMD measurement issues for OAs 6.1 Source degree of polarization and amplified spontaneous emission The test methods require a polarized signal at the input of the
46、polarimeter. Although the test source is highly polarized, the DOP at the output of the OA may be significantly reduced by the unpolarized amplified spontaneous emission (ASE). The source DOP and measured signal DOP should be at least 25 % within the optical bandwidth of the SOP measurement. This is
47、 of particular concern when using a tuneable laser source (TLS) without a tracking optical filter at the OA output, because the total ASE power out of the OA, i.e. the ASE spectrum integrated over all wavelengths, impinges on the photodetectors whatever the selected wavelength. In this case, proper
48、saturation conditions must be ensured in order for the DOP at the output port of the DUT to be high enough, e.g. 30 %, for accurate measurement. Figure 2 shows a typical OFA output spectrum from a TLS input as viewed on an optical spectrum analyser (OSA) with a resolution bandwidth (RBW) of 0,5 nm (
49、65 GHz around 1 550 nm). Fast axis Slow axis z,t t IEC 1064/04 8 TR 61292-5 IEC:2004(E) Figure 2 Spectrum of optical fibre amplifier output The source DOP requirement is less of a concern when using a BBS and spectral analysis (which acts as a narrowband filter centred about the selected wavelength, such as with a typical implementation of the PSA method shown in IEC 61290-11-2), or a TLS with a tracking narrowba
