1、Optical amplifiers Testmethods Part 3: Noise figure parametersBS EN 61290-3:2008raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI British StandardsNational forewordThis British Standard is the UK implementation of EN 61290-3:2008. It isidentical to
2、IEC 61290-3:2008. It supersedes BS EN 61290-3:2000 which iswithdrawn.The UK participation in its preparation was entrusted by Technical CommitteeGEL/86, Fibre optics, to Subcommittee GEL/86/3, Fibre optic systems andactive devices.A list of organizations represented on this committee can be obtained
3、 onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2009ISBN 978 0 580 58630 9ICS 33.180.30BRITISH STANDARDBS EN 61290-3:2008Compliance with a British Standard cannot confer immunit
4、y fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on Amendments issued since publicationAmd. No. Date Text affectedMarch 200931EUROPEAN STANDARD EN 61290-3 NORME EUROPENNE EUROPISCHE NORM October 2008 CENELEC European Commit
5、tee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC m
6、embers. Ref. No. EN 61290-3:2008 E ICS 33.180.30 Supersedes EN 61290-3:2000English version Optical amplifiers - Test methods - Part 3: Noise figure parameters (IEC 61290-3:2008) Amplificateurs optiques - Mthodes dessais - Partie 3: Paramtres du facteur de bruit (CEI 61290-3:2008) Lichtwellenleiter-V
7、erstrker - Prfverfahren - Teil 3: Rauschzahlparameter (IEC 61290-3:2008) This European Standard was approved by CENELEC on 2008-10-01. 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 nation
8、al standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained 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
9、any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czec
10、h Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 61290-3:2008EN 61290-3:2008 2 Forew
11、ord The text of document 86C/842/FDIS, future edition 2 of IEC 61290-3, prepared by SC 86C, Fibre optic systems and active devices, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61290-3 on 2008-10-01. This European Standard supersedes EN
12、 61290-3:2000. EN 61290-3:2008 includes updates to specifically address additional types of optical amplifiers and to highlight that the EN 61290-3 series pertains to single-channel amplifiers. References have been added to the documents pertaining to multichannel amplifiers. The following dates wer
13、e 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) 2009-07-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2011-10-01 Annex ZA has been added by CENELE
14、C. _ Endorsement notice The text of the International Standard IEC 61290-3:2008 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated: IEC 61290-10 NOTE Harmonized in EN 61290-
15、10 series (not modified). _ BS EN 61290-3:2008 3 EN 61290-3:2008 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, onl
16、y the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year I
17、EC 61290-3-1 - 1)Optical amplifiers - Test methods - Part 3-1: Noise figure parameters - Optical spectrum analyzer method EN 61290-3-1 2003 2)IEC 61290-3-2 - 1)Optical amplifiers - Test methods - Part 3-2: Noise figure parameters - Electrical spectrum analyzer method EN 61290-3-2 2008 2)IEC 61291-1
18、- 1)Optical amplifiers - Part 1: Generic specification EN 61291-1 2006 2)1) Undated reference. 2)Valid edition at date of issue. BS EN 61290-3:2008 2 61290-3 IEC:2008 CONTENTS INTRODUCTION.5 1 Scope and object6 2 Normative references .6 3 Acronyms and abbreviations.6 4 Noise figure generalities.7 5
19、Noise figure contributions.8 6 Noise figure test methods.9 Bibliography11 Table 1 Parameters measurable with each of the two methods of Clause 510 BS EN 61290-3:200861290-3 IEC:2008 5 INTRODUCTION This International Standard is devoted to the subject of optical amplifiers. The technology of optical
20、amplifiers is still evolving, hence amendments to and new editions of this standard can be expected. Each abbreviation introduced in this standard is explained in the text at least the first time it appears. However, for an easier understanding of the whole text, a list of all abbreviations used in
21、this standard is given in Clause 3. BS EN 61290-3:2008 6 61290-3 IEC:2008 OPTICAL AMPLIFIERS TEST METHODS Part 3: Noise figure parameters 1 Scope and object This International Standard applies to all commercially available optical amplifiers (OAs), including OAs using optically pumped fibres (OFAs b
22、ased on either rare-earth doped fibres or on the Raman effect), semiconductor optical amplifiers (SOAs) and planar waveguide optical amplifiers (PWOAs). The object of this standard is to provide the general background for OA noise figure parameters measurements and to indicate those IEC standard tes
23、t methods for accurate and reliable measurements of the following OA parameters, as defined in IEC 61291-1: a) noise figure (NF); b) noise factor (F); c) multiple path interference (MPI) figure of merit; d) signal-spontaneous noise figure; e) (equivalent) spontaneous-spontaneous optical bandwidth (B
24、sp-sp); f) forward amplified spontaneous emission (ASE) power level; g) reverse ASE power level; h) ASE bandwidth. This standard addresses measurement of OAs that are to be used for amplifying single channels, that is signals from a single transmitter. Testing of OAs for multichannel use involves ad
25、ditional considerations, such as: the number, wavelengths and relative power of the signals, the ability to measure signals simultaneously and to measure the ASE between channels. NOTE Methods for measurement of OAs for multichannel use are included in the IEC 61290-10 series. 2 Normative references
26、 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 any amendments) applies. IEC 61290-3-1, Optical amplifiers Test methods P
27、art 3-1: Noise figure parameters Optical spectrum analyzer method IEC 61290-3-2, Optical amplifiers Part 3-2: Test methods for noise figure parameters Electrical spectrum analyzer method IEC 61291-1, Optical amplifiers Part 1: Generic specification 3 Acronyms and abbreviations ASE amplified spontane
28、ous emission Bsp-sp(equivalent) spontaneous-spontaneous optical bandwidth BS EN 61290-3:200861290-3 IEC:2008 7 ESA electrical spectrum analyzer F noise factor FWHM full width half maximum MPI multiple path interference NF noise figure OA optical amplifiers OFA optical fibre amplifier OSA optical spe
29、ctrum analyzer PWOA planar waveguide optical amplifiers SOA semiconductor optical amplifiers SNR signal-to-noise ratio 4 Noise figure generalities The noise figure is one of the most important parameters of an OA. Following the definition in IEC 61291-1, the noise factor, i.e. the linear form of the
30、 noise figure, can be expressed by: in2noiseout2noise2out2signalout2noisein2noisein2signaloutputinput1=iiGFiiiiSNRSNRF(1) where SNR denotes signal-to-noise ratios; i denotes photocurrents in an ideal photodetector with a quantum efficiency of 1; G denotes the optical signal gain. The input noise cur
31、rent is, by definition, the shot noise current caused by the optical input signal. This excludes other noise sources on the input side. The output noise current is the sum of five contributions. Each of these contributions can be expressed by a partial noise factor: a) signal shot noise factor, Fsho
32、t,sig, from shot noise from amplified input signal; b) ASE shot noise factor, Fshot,ase, from shot noise from amplified spontaneous emission; c) signal-spontaneous noise factor, Fsig-sp, from signal beating with ASE; d) spontaneous-spontaneous noise factor, Fsp-sp, from ASE beating with itself; e) n
33、oise factor from multiple path interference (MPI), Fmpi. The total noise factor (in linear, not logarithmic units) is: mpispspspsigaseshot,sigshot,totalFFFFFF +=(2) BS EN 61290-3:2008 8 61290-3 IEC:2008 The noise figure can be calculated using: ()totallog10 FNF = (3) Equation (2) can be used for opt
34、ical noise figure measurements, as well as for estimating the influence of various parameters in electrical noise figure measurements. It represents a complete noise figure model of an OA. 5 Noise figure contributions The signal shot noise factor is: GF1sigshot,= , (4) where G is the gain at the sig
35、nal wavelength. The ASE shot noise factor is: in2aseaseshot,PGPF = (5) where Paseis the wavelength-integrated ASE power; Pinis the optical input signal power. The signal-spontaneous noise factor is: sigpase,spsigh2GF =(6) where ase,pis the optical power density of spontaneous emission, in the same p
36、olarization state as the output signal, at the signal wavelength, in W/Hz; h is Plancks constant; sig= c/sigis the optical signal frequency, in Hz. The spontaneous-spontaneous noise factor is: in2sigspsp2asespsph2 PGBF= (7) where aseis the optical power density of total (unpolarized) spontaneous emi
37、ssion, at the signal wavelength, in W/Hz; Bsp-sp is the equivalent spontaneous-spontaneous optical bandwidth defined in IEC 61291-1; it depends on power and wavelength of input signal. NOTE When Bsp-spis known, there is no need for separate measurement of Fsp-spbecause it can be calculated from the
38、signal spontaneous noise factor and the input power. Since ASE in any polarization state contributes to BS EN 61290-3:200861290-3 IEC:2008 9 Fsp-sp, this calculation also needs additional information if the ASE is not unpolarized, as is typical for example for SOAs. Multiple path interference (MPI)
39、noise is generated by beating between the output signal and one or more doubly reflected replica of the output signal. Two or more reflection points inside the OA are necessary to generate MPI noise. When all reflection points are separated by more than the coherence length of the optical source, th
40、en the MPI noise factor is as follows: ()+=iGpfPFicav,i22inmpih2(8) where Gcav,iis the cavity gain (gain in the ithparasitic cavity in the OA) = gain in forward direction reflectivity in forward direction gain in backward direction reflectivity in backward direction; piis the polarization alignment
41、factor, and expresses the matching of polarization states between the direct and doubly reflected signal in the ithcavity (between 0 and 1, p = 1 for perfect alignment); piGcav,iis the effective cavity gain of the ithcavity; is meant to collect all possible cavity gains in the OA; is the FWHM of the
42、 source linewidth (Lorentzian model); f is the baseband frequency. When two or more light beams are coherent with each other, i.e. generated by closely spaced reflection points, MPI cannot be considered as noise, but rather as slow power fluctuations. In these cases, MPI does not contribute to the N
43、F. The MPI contribution to the noise factor depends on the linewidth of the source, , a parameter of the transmission system or measurement apparatus but not on the OA. To remove this parameter from the OA noise factor, it is suggested to integrate the MPI noise factor and denote the integration res
44、ult a figure of merit, Impi, for the MPI characteristics of the OA. Impirepresents the area under the Fmpicurve; it does not depend on the linewidth of the source or the baseband frequency: ()=ifGpPfFIicav,iin0mpimpihdHz (9) where the MPI noise factor can be calculated from the figure of merit using
45、: 22mpimpi2+=fIF (10) A special form of MPI known as double-Rayleigh scattering can be a significant factor in Raman fibre amplifiers, where long spans of fibre can provide gain for the small amount of signal that is backscattered by the Rayleigh effect in fibre, rather than due to reflections. 6 No
46、ise figure test methods Two qualitatively different and commonly practised procedures for quantifying the noise figure of an OA are considered in this standard. The aim of the first procedure (see IEC 61290-3-1) is to determine the signal-spontaneous noise figure. This method uses an optical spectru
47、m analyzer to determine gain and spectrally resolved ASE; the signal-spontaneous noise figure is calculated from these two quantities as outlined in Clause 5. Except for the noise contribution from multiple path interference (MPI), BS EN 61290-3:2008 10 61290-3 IEC:2008 all other noise contributions
48、 can be calculated as well according to Clause 5. The noise contribution from MPI can only be determined if the reflection points are accessible, which is usually not the case on a finished OA test device. The MPI contribution of a well designed OA may be negligible, though. The signal-spontaneous n
49、oise figure obtained by this first procedure is generally accepted as suitable for digital communication systems. The aim of the second procedure (see IEC 61290-3-2) is to determine the total noise figure. It is based on measuring the electrical noise caused by the OA “black box“ with an electrical spectrum analyzer. This can be seen as a direct realization of Equation (1), without separating the individual noise contribut
