1、BSI Standards PublicationCalibration of optical time-domain reflectometers (OTDR)Part 1: OTDR for single-mode fibresBS EN 61746-1:2011Incorporating corrigendum September 2014BS EN 61746-1:2011ForewordThis British Standard is the UK implementation of EN 61746-1:2011, incorporating corrigendum Septemb
2、er 2014. It is identical to IEC 61746-1:2009. It supersedes BS EN 61746:2005, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee GEL/86, Fibre optics.A list of organizations represented on this committee can be obtained on request to its secretary.This pu
3、blication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014ISBN 978 0 580 88108 4 ICS 33.180.01 Compliance with a British Standard cannot confer im
4、munity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2011.Amendments/corrigenda issued since publicationDate Text affected30 November 2014 Implementaion of CENELC corigendum September 2014: Supersession inform
5、ation updatedBRITISH STANDARDEUROPEAN STANDARD EN 61746-1 NORME EUROPENNE EUROPISCHE NORM March 2011 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B
6、 - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61746-1:2011 E ICS 33.180.01 English version Calibration of optical time-domain reflectometers (OTDR) - Part 1: OTDR for single-mode fibres (IEC 61746-1:2009) t
7、alonnage des rflectomtres optiques dans le domaine temporel (OTDR) - Partie 1: OTDR pour fibres unimodales (CEI 61746-1:2009) Kalibrierung optischer Rckstreumessgerte (OTDR) - Teil 1: OTDR fr Einmodenfasern (IEC 61746-1:2009) This European Standard was approved by CENELEC on 2011-01-02. CENELEC memb
8、ers 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 obtained on applicati
9、on 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 Central Secretariat h
10、as the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, th
11、e Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Incorporating corrigendum September 2014EN 61746-1:2011 - 2 - Foreword The text of document 86/347/FDIS, future edition 1 of IEC 61746-1, prepared by IEC TC 86, Fibre optics, was
12、submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61746-1 on 2011-01-02. This European Standard supersedes EN 61746:2005. The main technical changes to EN 61746:2005 are: the adaptation of Clause 4; the deletion of Clause 10; the adaptation of some definitions and calculat
13、ions; the change of graphical symbology to IEC/TR 61930. 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 were fixed:
14、latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2011-10-02 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2014-01-02 Annex ZA has been added by CENELEC. _ Endo
15、rsement notice The text of the International Standard IEC 61746-1:2009 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: 2 IEC 60793-1-1 NOTE Harmonized as EN 60793-1-1
16、. 3 IEC 60794-1-2:2003 NOTE Harmonized as EN 60794-1-2:2003 (not modified). 4 IEC 60825-1 NOTE Harmonized as EN 60825-1. 5 IEC 60825-2 NOTE Harmonized as EN 60825-2. 6 IEC 61280-1-3:1998 NOTE Harmonized as EN 61280-1-3:1999 (not modified). 7 IEC 61300-3-2 NOTE Harmonized as EN 61300-3-2. 8 IEC 61300
17、-3-6 NOTE Harmonized as EN 61300-3-6. _ BS EN 61746-1:2011- 3 - EN 61746-1:2011 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
18、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 common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Tit
19、le EN/HD Year IEC 60793-1-40 (mod) - Optical fibres - Part 1-40: Measurement methods and test procedures - Attenuation EN 60793-1-40 - IEC 60793-2-50 - Optical fibres - Part 2-50: Product specifications - Sectional specification for class B single-mode fibres EN 60793-2-50 - ISO/IEC 17025 - General
20、requirements for the competence of testing and calibration laboratories EN ISO/IEC 17025 - ITU-T Recommendation G.650.1 2004 Definitions and test methods for linear, deterministic attributes of single-mode fibre and cable - - ITU-T Recommendation G.650.2 2002 Definitions and test methods for statist
21、ical and non-linear related attributes of single-mode fibre and cable - - BS EN 61746-1:2011 2 61746-1 IEC:2009(E) CONTENTS INTRODUCTION. 8 1 Scope.9 2 Normative references.9 3 Terms, definitions and symbols 9 4 Preparation for calibration.16 4.1 Organization .16 4.2 Traceability. 16 4.3 Preparation
22、. 16 4.4 Test conditions . .16 4.5 Documentation .16 5 Distance calibration General .17 5.1 General .17 5.2 Location deviation model 17 5.3 Using the calibration results . 19 5.4 Measuring fibre length . .19 6 Distance calibration methods . 20 6.1 General .20 6.2 External source method 20 6.2.1 Shor
23、t description and advantage 20 6.2.2 Equipment .20 6.2.3 Calibration of the equipment . .21 6.2.4 Measurement procedure . 22 6.2.5 Calculations and results . .23 6.2.6 Uncertainties . .24 6.3 Concatenated fibre method . .25 6.3.1 Short description and advantages . 25 6.3.2 Equipment .25 6.3.3 Measur
24、ement procedures. .27 6.3.4 Calculations and results . .27 6.3.5 Uncertainties . .28 6.4 Recirculating delay line method. 29 6.4.1 Short description and advantage 29 6.4.2 Equipment .29 6.4.3 Measurement procedure . 31 6.4.4 Calculations and results . .31 6.4.5 Uncertainties . .32 7 Loss calibration
25、 General . 33 7.1 General .33 7.2 Determination of the displayed power level F 33 7.3 Selection of an appropriate reference loss Aref . .34 7.4 Development of a test plan . .35 7.5 Polarization dependence.37 7.6 Calculation of the calibration results38 7.7 Using the calibration results . 38 8 Loss c
26、alibration methods 38 BS EN 61746-1:201161746-1 IEC:2009(E) 3 8.1 General .38 8.2 Fibre standard method. .39 8.2.1 Short description and advantage 39 8.2.2 Equipment .39 8.2.3 Measurement procedure . 40 8.2.4 Calculations and results . .41 8.2.5 Uncertainties . .41 8.3 External source method (see Fi
27、gure 16).42 8.3.1 Short description and advantage 42 8.3.2 Equipment .42 8.3.3 Calibration of the reference loss.43 8.3.4 Measurement procedure . 44 8.3.5 Calculations and results . .45 8.3.6 Uncertainties . .45 8.4 Splice simulator method46 8.4.1 Short description and advantage 46 8.4.2 Equipment .
28、46 8.4.3 Procedure. .47 8.4.4 Calculations and results . .49 8.4.5 Uncertainties . .49 8.5 Power reduction method .50 8.5.1 Short description and advantage 50 8.5.2 Equipment .51 8.5.3 Measurement procedure . 52 8.5.4 Calculations and results . .53 8.5.5 Uncertainties . .53 9 Reflectance calibration
29、. .54 9.1 Objective .54 9.2 Reflectance measurements (see Figure 23) 54 9.3 Use of the backscatter parameter, K . .54 9.4 Range of reflectance measurement.55 9.5 Development of a test plan . .56 9.6 Equipment . .57 9.7 Measurement procedure .58 9.7.1 Preparation58 9.7.2 Taking reflectance measuremen
30、ts. 58 9.7.3 Calculation and results.58 9.7.4 Uncertainties . .58 Annex A (normative) Recirculating delay line for distance calibration . .60 Annex B (normative) Optical fibre standard for loss calibration. 64 Annex C (normative) Standard splice simulator for loss calibration.68 Annex D (normative)
31、Mathematical basis . 72 Annex E (normative) Reflectance standard . 75 Annex F (normative) Simple version of reflectance standard 81 Annex G (informative) OTDR basis: Backscatter theory Reflectance measurements using an OTDR Determination of fibre backscatter parameter . 85 Bibliography . 90 BS EN 61
32、746-1:2011 4 61746-1 IEC:2009(E) Figure 1 Definition of attenuation dead zone 10 Figure 2 Representation of the location deviation L(L)18 Figure 3 Equipment for calibration of the distance scale External source method . .21 Figure 4 Set-up for calibrating the system insertion delay. .22 Figure 5 Con
33、catenated fibres used for calibration of the distance scale. . 26 Figure 6 Distance calibration with a recirculating delay line .30 Figure 7 OTDR trace produced by recirculating delay line . 30 Figure 8 Determining the reference level and the displayed power level . 34 Figure 9 Measurement of the OT
34、DR loss samples . 35 Figure 10 Region A, the recommended region for loss measurement samples . .36 Figure 11 Possible placement of sample points within region A . .36 Figure 12 External source method for testing the polarization dependence of the OTDR . 37 Figure 13 Reflection method for testing the
35、 polarization dependence of the OTDR . 37 Figure 14 Loss calibration with a fibre standard 39 Figure 15 Placing the beginning of section D1outside the attenuation dead zone. 40 Figure 16 Loss calibration with the external source method.43 Figure 17 Location and measurements for external source metho
36、d . 44 Figure 18 Set-up for loss calibration with splice simulator . 46 Figure 19 OTDR display with splice simulator . 47 Figure 20 Measurement of the splice loss . .48 Figure 21 Loss calibration with “fibre-end“ variant of the power reduction method . . 51 Figure 22 Loss calibration with “long-fibr
37、e“ variant of the power reduction method. .52 Figure 23 Parameters involved in reflectance measurements . 54 Figure 24 The same reflectance at the end of three fibres with different values of the backscatter parameter shows different pulse amplitudes 55 Figure 25 Maximum and minimum values for the p
38、ulse amplitude, F .56 Figure 26 Range of reflectance measurement. 56 Figure 27 Determining the default displayed power level and the default location . 57 Figure 28 Set-up for reflectance calibration58 Figure A.1 Recirculating delay line. .60 Figure A.2 Measurement set-up for loop transit time Tb .
39、.61 Figure A.3 Calibration set-up for lead-in transit time Ta62 Figure B.1 Determination of a highly linear power range. .65 Figure B.2 Testing the longitudinal backscatter uniformity of the fibre standard .66 Figure C.1 Splice simulator and idealized OTDR signature68 Figure C.2 Determination of the
40、 reference loss Aref . 70 Figure E.1 Reflectance standard description and trace.75 Figure E.2 Calibration set up and reference points for calibration .78 Figure F.1 Reflectance standard description and trace.81 Figure F.2 Calibration set up and reference points for calibration .83 Figure G.1 OTDR si
41、gnals used for determining reflectance .86 Figure G.2 Set-up for measurement of the backscatter coefficient . .88 BS EN 61746-1:201161746-1 IEC:2009(E) 5 Table 1 Attenuation coefficients defining region A.35 BS EN 61746-1:2011 8 61746-1 IEC:2009(E) INTRODUCTION In order for an Optical time-domain re
42、flectometer (OTDR) to qualify as a candidate for complete calibration using this standard, it must be equipped with the following minimum feature set: a) a programmable index of refraction, or equivalent parameter; b) the ability to present a display of a trace representation, with a logarithmic pow
43、er scale and a linear distance scale; c) two markers/cursors, which display the loss and distance between any two points on a trace display; d) the ability to measure absolute distance (location) from the OTDRs zero-distance reference; e) the ability to measure the displayed power level relative to
44、a reference level (for example, the clipping level); f) the ability to evaluate the reflectance of a reflective event. BS EN 61746-1:201161746-1 IEC:2009(E) 9 CALIBRATION OF OPTICAL TIME-DOMAIN REFLECTOMETERS (OTDR) Part 1: OTDR for single mode fibres 1 Scope This part of IEC 61746 provides procedur
45、es for calibrating single-mode optical time domain reflectometers (OTDR). It only covers OTDR measurement errors and uncertainties. This standard does not cover correction of the OTDR response. 2 Normative references The following referenced documents are indispensable for the application of this do
46、cument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60793-1-40, Optical fibres Part 1-40: Measurement methods and test procedures Attenuation IEC 60793-2-50, Optical fibres Part 2-
47、50: Product specifications Sectional specification for class B single-mode fibres ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories ITU-T Recommendation G.650.1:2002, Definitions and test methods for linear, deterministic attributes of single-mode fibre a
48、nd cable ITU-T Recommendation G.650.2:2002, Definitions and test methods for statistical and non-linear attributes of single-mode fibre and cable 3 Terms, definitions and symbols For the purposes of this document, the following terms, definitions and symbols apply. NOTE For more precise definitions,
49、 the references to IEC 60050-731 should be consulted. 3.1 attenuation loss A optical power decrease in decibels (dB) NOTE If Pin (watts) is the power entering one end of a segment of fibre and Pout (watts) is the power leaving the other end, then the attenuation of the segment is =outin 10log 10 PPA dB (1) IEV 731-01-48, modified BS EN 61746-1:2011 10 61746-1 IEC:2009(E)
