1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58procedures Part 2-11: Digital systems Averaged Q-factor determination using amplitude histogram eva
2、luation for optical signal quality monitoringThe European Standard EN 61280-2-11:2006 has the status of a British StandardICS 33.180.10Fibre optic communication subsystem test BRITISH STANDARDBS EN 61280-2-11:2006Incorporating Corrigendum No. 1BS EN 61280-2-11:2006This British Standard was published
3、 under the authority of the Standards Policy and Strategy Committee on 31 May 2006 BSI 2006ISBN 0 580 48381 9request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the
4、section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application
5、.Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pages 2 to 34, an inside back cover and a back cover.The BSI copyright notice displayed in this document indi
6、cates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments16489 Corrigendum No. 130 June 2006 Correction to formatting errors at printing stageA list of organizations represented on this subcommittee can be obtained on present to the responsible international/E
7、uropean committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.National forewordThis British Standard is the official English language version of EN 61280-2-11:2006.
8、 It is identical with IEC 61280-2-11:2006.The UK participation in its preparation was entrusted by Technical Committee GEL/86, Fibre optics, to Subcommittee GEL/86/3, Fibre optic systems and active devices, which has the responsibility to: aid enquirers to understand the text;EUROPEAN STANDARD EN 61
9、280-2-11 NORME EUROPENNE EUROPISCHE NORM April 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2006 CENELEC - All rights of
10、 exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61280-2-11:2006 E ICS 33.180.10 English version Fibre optic communication subsystem test procedures Part 2-11: Digital systems - Averaged Q-factor determination using amplitude histogram evaluation for opt
11、ical signal quality monitoring (IEC 61280-2-11:2006) Procdures dessai des sous-systmes de tlcommunications fibres optiques Partie 2-11: Systmes numriques - Dtermination du facteur de qualit moyenn par lvaluation dhistogramme damplitude pour la surveillance de la qualit des signaux optiques (CEI 6128
12、0-2-11:2006) Prfverfahren fr Lichtwellenleiter-Kommunikationsuntersysteme Teil 2-11: Digitale Systeme - Bestimmung des mittleren Q-Faktors durch Auswertung des Amplitudenhistogramms zur Qualittsberwachung optischer Signale (IEC 61280-2-11:2006) This European Standard was approved by CENELEC on 2006-
13、02-01. 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 concerning such national standards may be ob
14、tained 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 its own language and notified to the Ce
15、ntral Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, th
16、e Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Foreword The text of document 86C/682FDIS, future edition 1 of IEC 61280-2-11, prepared by SC 86C, Fibre optic systems and active devices, of IEC TC 86, Fibre optics, was submitte
17、d to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61280-2-11 on 2006-02-01. 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) 2006-11-01 latest date by which
18、the national standards conflicting with the EN have to be withdrawn (dow) 2009-02-01 The International Electrotechnical Commission (IEC) and CENELEC draw attention to the fact that it is claimed that compliance with this document may involve the use of a patent concerning the averaged Q-factor measu
19、rement. The IEC and CENELEC take no position concerning the evidence, validity and scope of this patent right. The holder of this patent right has assured the IEC that he is willing to negotiate licences under reasonable and non-discriminatory terms and conditions with applicants throughout the worl
20、d. In this respect, the statement of the holder of this patent right is registered with the IEC. Information may be obtained from: NTT Corporation Tokyo Japan Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights other than those identif
21、ied above. IEC and CENELEC shall not be held responsible for identifying any or all such patent rights. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 61280-2-11:2006 was approved by CENELEC as a European Standard without any modification. _ EN 61
22、280-2-11:2006 2 3 EN 61280-2-11:2006 CONTENTS 0 INTRODUCTION 5 0.1 Background .5 0.2 Averaged Q-factor formula.6 1 Scope 7 2 Normative references .7 3 Terms and definitions .8 4 Abbreviated terms 8 5 Apparatus.8 5.1 Optical bandpass filter .9 5.2 Receiver9 5.3 Clock oscillator10 5.4 Electrical pulse
23、 generator 10 5.5 Sampling module.10 5.6 Signal processing circuit 11 5.7 Monitoring system parameters .11 6 Procedure 11 6.1 Equipment connections11 6.2 Threshold level definitions .11 7 Calculations .12 Annex A (normative) Measurement accuracy, reliability, and sensitivity.16 Annex B (informative)
24、 Crosstalk and frequency detuning of optical bandpass filter 19 Annex C (normative) Highest limit of Qavg23 Annex D (informative) Bit rate dependence.25 Annex E (informative) Format dependence .26 Annex F (informative) Dependence of Qavg,1,avg,|1,avg 0,avg|, and Q on chromatic dispersion and OSNR .2
25、8 Annex G (informative) Relationship between Qaveand Q with PMD impairment.30 Annex ZA (normative) Normative references to international publications with their corresponding European publications34 Bibliography .32 Figure 1 Asynchronous eye-pattern and amplitude histogram6 Figure 2 Averaged Q-facto
26、r measurement configuration9 Figure 3 Dependence of Qavgon Q for different , when Tr = 1/4 Tslots, Bre = 0,75 B Hz, Bopt = 4 B Hz, Tres = 1/256 Tslot s, Nsamp = 16 384 (214) 14 Figure 4 Dependence of R on , when Tr= 1/4 Tslot s, Bre = 0,7 B Hz, Bopt = 4 B Hz, Tres = 1/256 Tslot s, Nsamp = 16 384 (21
27、4) .14 Figure 5 Dependence of optimum value of on Bopt, when Tr = 1/4 Tslots, Bre = 0,75 B Hz, Tres = 1/64 Tslot s, Nsamp = 16 384(214)15 EN 61280-2-11:2006 4 Figure A.1 Definition of Qavgand Q 16Figure A.2 Dependence of the standard deviation of Qavgon Nsamp: Tr= 1/4 Tslots, Bre = 0,7 B Hz, Bopt =
28、4 B Hz, Tres = 1/256 Tslots, = 0,3, Q = 16 dB (BER1010) 17 Figure A.3 Dependence of linear fitting slope of Qavgversus Q on Bopt: Tr = 1/4 Tslots, Bre = 0,7 B Hz, Tres = 1/256 Tslot s, = 0,3.18 Figure A.4 Dependence of the standard deviation of eight measurement points of Qavgon Tres: Tr = 1/4 Tslot
29、 s, Bre = 0,75 B Hz, Bopt = 4 B Hz, Nsamp = 16 384(214), = 0,3, Q = 16 dB (BER 1010) 18 Figure B.1 Definition of WDM signal and OBPF frequency response19 Figure B.2 fobpfdependence of Q and Qavgfor fWDMof 100 GHz(a), 50 GHz(b), and 25 GHz(c) 20 Figure B.3 Definition of OBPF central frequency detunin
30、g fc21 Figure B.4 fcdependence of Qavgfor fWDMof 100 GHz(a), 50 GHz(b), and 25 GHz(c).22 Figure C.1 Dependence of Qavgon Q when B is 10 Gbit/s: Tr= 1/4 Tslots, Bre= 0,75 x B Hz, Bopt = 4 x B GHz, Tres = 1/256 Tslots, Nsamp = 16 384(214), = 0,323 Figure C.2 Dependence of the highest limit of Qavgon r
31、ise time after O/E converter 24 Figure D.1 Example of relationship between Qavgand Q for different bit rates .25 Figure E.1 Dependence of Qavgon Qwhen D = 0 ps/nm, Rduty= 0,4, Bre = 0,6 B Hz, Bopt= 240 GHz, Tres = 1/64 Tslot s, Nsamp = 16 384(214) and = 0,2 or 0,326 Figure E.2 Dependence of Qavgon Q
32、when D = 1 020 ps/nm, Rduty= 0,4, Bre= 0,6 B Hz,Bopt= 240 GHz, Tres = 1/64 Tslot s, Nsamp = 16 384(214) and = 0,2 or 0,327 Figure F.1 (a) Chromatic dispersion dependence and (b) OSNR dependence of 1, 1-0and Qavgfor 10-Gbit/s NRZ optical signals when Boptis 40 GHz and is 0,3 .28 Figure F.2 (a) Chroma
33、tic dispersion dependence and (b) OSNR dependence of 1, 1-0and Qavgfor 10-Gbit/s NRZ optical signals when Boptis 240 GHz and is 0,2 .28 Figure G.1 Dependence of Qavgon Qwhen mean DGD = 30 ps.30 Figure G.2 Histogram of Qavgwhen Q ranges from 18,5 dB to 18,7dB .31 Table 1 Monitoring system parameters
34、.11 Table D.1 Values of Tr, Bre, Bopt and Tres25 5 EN 61280-2-11:2006 0 INTRODUCTION 0.1 Background Signal quality monitoring is an important issue for operation and maintenance of optical transport networks (OTN). From the network operators point of view, monitoring techniques are required to estab
35、lish connections, protection, restoration, and/or service level agreements. In order to establish these functions, the monitoring techniques used should satisfy some general requirements: in-service (non-intrusive) measurement, signal deterioration detection (both SNR degradation and waveform distor
36、tion), fault isolation (localize impaired sections or nodes), transparency and scalability (irrespective of the signal bit rate and signal formats), and simplicity (small size and low cost). There are several approaches, both analog and digital techniques, that make it possible to detect various imp
37、airments: bit error rate (BER) estimation 1,2, error block detection, optical power measurement, optical SNR evaluation with spectrum measurement 3, 4, pilot tone detection 5,6, Q-factor monitoring 7, pseudo BER estimation using two decision circuits 8,9, and histogram evaluation with synchronous ey
38、e diagram measurement 10. A fundamental performance monitoring parameter of any digital transmission system is its end-to-end BER. However, the BER can be correctly evaluated only with outside service BER measurements, using a known test bit pattern in place of the real signal. On the other hand, in
39、-service measurement can only provide rough estimates through the measurement of digital parameters (e.g., BER estimation, error block detection, and error count in forward error correction) or analog parameters (e.g., optical SNR and Q-factor). What has been much desired and studied is some methods
40、 for signal quality monitoring that will provide a good measure of signal quality without the complexity of termination. When the system BER is too low to be measured within a reasonable length of time, it is useful to adopt Q-factor measurements. However, all sampling-based methods require synchron
41、ization and then some analysis, which makes them similar to protocol-aware termination in terms of cost and complexity. In fact, synchronous sampling requires timing extraction by complex equipment that is specific to each BER and each format. The above situation has, fortunately, very recently begu
42、n to change. A simple, asynchronous histogram method was developed for Q-factor measurement 11,12. Different degradation types (i.e., SNR degradation and wavelength distortion due to chromatic dispersion) can be monitored 13, thus providing information about the origin of the degradations 14. Asynch
43、ronous sampling allows bit-rate independent Q-factor monitoring, and the same equipment covers bit rates of up to 160 Gbit/s 15. Moreover, the monitoring is applied to both NRZ and RZ optical signals 11, and is independent of the bit rate and signal format used by the wavelength division multiplexed
44、 (WDM) channel 16. Performance monitoring can be performed at different monitoring points such as optical line repeaters, regenerators, or optical switching nodes (requires pre-measurement) 17. In other words, this method is expected to be applied to the monitoring points where electrical terminatio
45、n is impossible. If we think of the future all-optical network, an optical switching node has performance monitoring without electrical regeneration. Average Q-factor, Qavg, measurement through asynchronous sampling is a cost-effective alternative to BER measurements. This is one of the promising pe
46、rformance-monitoring approaches for intensity modulated direct detection (IM-DD) optical transmission systems. This method can be utilized for monitoring both relative and absolute values of optical signal quality. EN 61280-2-11:2006 6 With the averaged Q-factor obtained from amplitude histogram par
47、ameters (the standard deviation and average level), the over-all effect of the optical signal quality degradations due to the integral of the causes (such as ASE and Chromatic dispersion) can be monitored. Due to asynchronous sampling scheme, the averaged Q-factor is insensitive to the optical signa
48、l quality variations created by timing jitter. The following sections define the averaged Q-factor and provide a procedure to measure the optical signal quality via the averaged Q-factor. With the amplitude histogram parameters, it is also possible to distinguish the origins of the BER degradation (
49、SNR degradation, waveform distortion). The information about the dependence of the amplitude histogram parameters on OSNR and chromatic dispersion is shown in Annex F (informative). 0.2 Averaged Q-factor formula Figure 1 uses a typical asynchronous eye-pattern and its amplitude histogram, obtained by asynchr
