1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationOptical fibresPart 1-41: Measurement methods and test procedures BandwidthBS EN 60793-1-41:2010National forewordThis British Standard is the UK implementation of EN 60793-1-41:20
2、10. It isidentical to IEC 60793-1-41:2010. It supersedes BS EN 60793-1-41:2003which is withdrawn.The UK participation in its preparation was entrusted by Technical CommitteeGEL/86, Fibre optics, to Subcommittee GEL/86/1, Optical fibres and cables. A list of organizations represented on this committe
3、e can be obtained 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 2010 ISBN 978 0 580 64450 4 ICS 33.180.10Compliance with a British Standard cannot confer immunity from legal ob
4、ligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2010.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN 60793-1-41:2010EUROPEAN STANDARD EN 60793-1-41 NORME EUROPENNE EUROPISCHE NORM Oc
5、tober 2010 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2010 CENELEC - All rights of exploitation in any form and by any means re
6、served worldwide for CENELEC members. Ref. No. EN 60793-1-41:2010 E ICS 33.180.10 Supersedes EN 60793-1-41:2003English version Optical fibres - Part 1-41: Measurement methods and test procedures - Bandwidth (IEC 60793-1-41:2010) Fibres optiques - Partie 1-41: Mthodes de mesure et procdures dessai -
7、Largeur de bande (CEI 60793-1-41:2010) Lichtwellenleiter - Teil 1-41: Messmethoden und Prfverfahren - Bandbreite (IEC 60793-1-41:2010) This European Standard was approved by CENELEC on 2010-10-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the condi
8、tions 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 obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in th
9、ree 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 Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechni
10、cal committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech 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, Switze
11、rland and the United Kingdom. EN 60793-1-41:2010 - 2 - Foreword The text of document 86A/1294/CDV, future edition 3 of IEC 60793-1-41, prepared by SC 86A, Fibres and cables, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60793-1-41 on 201
12、0-10-01. This European Standard supersedes EN 60793-1-41:2003. The main change with respect to EN 60793-1-41:2003 is the addition of a third method for determining modal bandwidth based on DMD data and to improve measurement procedures for A4 fibres. This standard should be read in conjunction with
13、EN 60793-1-1 and IEC 60793-1-2, which cover generic specifications. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights. The following dates w
14、ere 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) 2011-07-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2013-10-01 Annex ZA has been added by CENE
15、LEC. _ Endorsement notice The text of the International Standard IEC 60793-1-41:2010 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: 1 IEC 60793-2-10 NOTE Harmonized
16、as EN 60793-2-10. 2 IEC 60793-2-30 NOTE Harmonized as EN 60793-2-30. 3 IEC 60793-2-40 NOTE Harmonized as EN 60793-2-40. _ BS EN 60793-1-41:2010- 3 - EN 60793-1-41:2010 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following
17、 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. NOTE When an international publication has been modified by co
18、mmon modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60793-1-20 - Optical fibres - Part 1-20: Measurement methods and test procedures - Fibre geometry EN 60793-1-20 - IEC 60793-1-42 - Optical fibres - Part 1-42: Measurement methods and test proced
19、ures - Chromatic dispersion EN 60793-1-42- IEC 60793-1-43 - Optical fibres - Part 1-43: Measurement methods and test procedures - Numerical aperture EN 60793-1-43 - IEC 60793-1-49 2006 Optical fibres - Part 1-49: Measurement methods and test procedures - Differential mode delay EN 60793-1-49 2006 BS
20、 EN 60793-1-41:2010 4 60793-1-41 IEC:2010 CONTENTS 1 Scope.6 2 Normative references .6 3 Terms and definitions .7 4 Apparatus.7 4.1 Radiation source .7 4.1.1 Method A Time domain (pulse distortion) measurement 7 4.1.2 Method B Frequency domain measurement 8 4.1.3 Method C Overfilled launch modal ban
21、dwidth calculated from differential mode delay (OMBc) .8 4.1.4 For methods A and B.8 4.2 Launch system 8 4.2.1 Overfilled launch (OFL) .8 4.2.2 Restricted mode launch (RML) 9 4.2.3 Differential mode delay (DMD) launch . 10 4.3 Detection system.10 4.4 Recording system10 4.5 Computational equipment 11
22、 4.6 Overall system performance 11 5 Sampling and specimens 11 5.1 Test sample 11 5.2 Reference sample .11 5.3 End face preparation .11 5.4 Test sample packaging12 5.5 Test sample positioning.12 6 Procedure 12 6.1 Method A Time domain (pulse distortion) measurement 12 6.1.1 Output pulse measurement1
23、2 6.1.2 Input pulse measurement method A-1: reference sample from test sample 12 6.1.3 Input pulse measurement method A-2: periodic reference sample .12 6.2 Method B Frequency domain measurement 13 6.2.1 Output frequency response13 6.2.2 Method B-1: Reference length from test specimen. 13 6.2.3 Meth
24、od B-2: Reference length from similar fibre 13 6.3 Method C Overfilled launch modal bandwidth calculated from differential mode delay (OMBc).13 7 Calculations or interpretation of results 14 7.1 -3 dB frequency, f3 dB.14 7.2 Calculations for optional reporting methods .15 8 Length normalization 15 9
25、 Results .15 9.1 Information to be provided with each measurement .15 9.2 Information available upon request15 10 Specification information 16 Annex A (normative) Intramodal dispersion factor and the normalized intermodal dispersion limit17 BS EN 60793-1-41:201060793-1-41 IEC:2010 5 Annex B (normati
26、ve) Fibre transfer function, H(f), power spectrum, |H(f)|, and f3 dB20 Annex C (normative) Calculations for other reporting methods. 22 Annex D (normative) Mode scrambler requirements for overfilled launching conditions to multimode fibres .23 Bibliography28 Figure 1 Mandrel wrapped mode filter 10 F
27、igure D.1 Two examples of optical fibre scramblers .24 Table 1 DMD weights for calculating overfilled modal bandwidth (OMBc) from DMD data for 850 nm only .14 Table A.1 Highest expected dispersion for commercially available A1 fibres 17 BS EN 60793-1-41:2010 6 60793-1-41 IEC:2010 OPTICAL FIBRES Part
28、 1-41: Measurement methods and test procedures Bandwidth 1 Scope This part of IEC 60793 describes three methods for determining and measuring the modal bandwidth of multimode optical fibres (see IEC 60793-2-10, IEC 60793-30 series and IEC 60793-40 series). The baseband frequency response is directly
29、 measured in the frequency domain by determining the fibre response to a sinusoidaly modulated light source. The baseband response can also be measured by observing the broadening of a narrow pulse of light. The calculated response is determined using differential mode delay (DMD) data. The three me
30、thods are: Method A Time domain (pulse distortion) measurement Method B Frequency-domain measurement Method C Overfilled launch modal bandwidth calculated from differential mode delay (OMBc) Methods A and B can be performed using one of two launches: an overfilled launch (OFL) condition or a restric
31、ted mode launch (RML) condition. Method C is only defined for A1a.2 (and A1a.3 in preparation) multimode fibre and uses a weighted summation of DMD launch responses with the weights corresponding to an overfilled launch condition. The relevant test method and launch condition should be chosen accord
32、ing to the type of fibre. NOTE 1 These test methods are commonly used in production and research facilities and are not easily accomplished in the field. NOTE 2 OFL has been used for the modal bandwidth value for LED-based applications for many years. However, no single launch condition is represent
33、ative of the laser (e.g. VCSEL) sources that are used for gigabit and higher rate transmission. This fact drove the development of IEC 60793-1-49 for determining the effective modal bandwidth of laser optimized 50 m fibres. See IEC 60793-2-10:2004 or later and IEC 61280-4-1:2003 or later for more in
34、formation. 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 any amendments) applies. IEC 60793-1-20,
35、 Optical Fibres Part 1-20: Measurement methods and test procedures Fibre geometry IEC 60793-1-42, Optical fibres Part 1-42: Measurement methods and test procedures Chromatic dispersion IEC 60793-1-43, Optical fibres Part 1-43: Measurement methods and test procedures Numerical aperture IEC 60793-1-49
36、:2006, Optical fibres Part 1-49: Measurement methods and test procedures Differential mode delay BS EN 60793-1-41:201060793-1-41 IEC:2010 7 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 bandwidth (3 dB) value numerically equal to the lowest
37、 modulation frequency at which the magnitude of the baseband transfer function of an optical fibre decreases to a specified fraction, generally to one half, of the zero frequency value. The bandwidth is denoted in this document as f3 dB. NOTE It is known that there can be various calculations, somet
38、imes called markdowns, to avoid reporting extremely high values associated with “plateaus”. For example the 1,5 dB frequency, multiplied by 2is one treatment used in IEC 60793-1-49. If such a calculation is used it should clearly be reported. 3.2 transfer function discrete function of complex number
39、s, dependent on frequency, representing the frequency-domain response of the fibre under test NOTE Method A determines the frequency response by processing time domain data through Fourier transforms. Method B can only measure the transfer function if an instrument which measures phase as well as am
40、plitude is used. Method C is similar to Method A as it uses Fourier transforms in a similar manner. The transfer Function is denoted in this document as H(f). 3.3 power spectrum discrete function of real numbers, dependent on frequency, representing the amplitude of the frequency-domain response of
41、the fibre under test NOTE Methods A and C determine the power spectrum from the transfer function. Method B determines the transfer function by taking the ratio of the amplitude measured through the fibre under test and the reference. The power spectrum is denoted in this document as |H(f)|. 3.4 imp
42、ulse response discrete function of real numbers, dependent on time, representing the time-domain response of the fibre under test to a perfect impulse stimulus. The impulse response is derived, in all methods, through the inverse Fourier transform of the transfer function. The impulse response is de
43、noted in this document as h(t). 4 Apparatus 4.1 Radiation source 4.1.1 Method A Time domain (pulse distortion) measurement Use a radiation source such as an injection laser diode that produces short duration, narrow spectral width pulses for the purposes of the measurement. The pulse distortion meas
44、urement method requires the capability to switch the energy of the light sources electrically or optically. Some light sources shall be electrically triggered to produce a pulse; in this case a means shall be provided to produce triggering pulses. An electrical function generator or equivalent can b
45、e used for this purpose. Its output should be used to both induce pulsing in the light source and to trigger the recording system. Other light sources may self-trigger; in this case, means shall be provided to synchronize the recording system with the pulses coming from the light source. This may be
46、 accomplished in some cases electrically; in other cases optoelectronic means may be employed. BS EN 60793-1-41:2010 8 60793-1-41 IEC:2010 4.1.2 Method B Frequency domain measurement Use a radiation source such as a continuous wave (CW) injection laser diode for the purposes of the measurement. The
47、frequency domain measurement method requires the capability to modulate the energy of the light sources electrically or optically. Connect the modulation output of the tracking generator or network analyzer through any required driving amplifiers to the modulator. 4.1.3 Method C Overfilled launch mo
48、dal bandwidth calculated from differential mode delay (OMBc) Use a radiation source as described in IEC 60793-1-49. 4.1.4 For methods A and B a) Use a radiation source with a centre wavelength that is known and within 10 nm of the nominal specified wavelength. For injection laser diodes, laser emiss
49、ion coupled into the fibre shallexceed spontaneous emission by a minimum of 15 dB (optical). b) Use a source with sufficiently narrow linewidth to assure the measured bandwidth is at least 90 % of the intermodal bandwidth. This is accomplished by calculating the normalized intermodal dispersion limit, NIDL (refer to Annex A). For A4 fibre, the linewidth of any laser diode is narrow enough to neglect its contribution to bandwidth measurement. c) For
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