1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationOptical fibresPart 1-44: Measurement methods and test procedures Cut-off wavelengthBS EN 60793-1-44:2011National forewordThis British Standard is the UK implementation of EN 6079
2、3-1-44:2011. It isidentical to IEC 60793-1-44:2011. It supersedes BS EN 60793-1-44:2002which is withdrawn.The UK participation in its preparation was entrusted by Technical CommitteeGEL/86, Fibre optics, to Subcommittee GEL/86/1, Optical fibres and cables.A list of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
3、committee 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 2011ISBN 978 0 580 65854 9ICS 33.180.10Compliance with a British Standard cannot confer immunity fromleg
4、al obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 July 2011.Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 60793-1-44:2011EUROPEAN STANDARD EN 60793-1-44 NORME EUROPENNE EUROPISCHE NORM June
5、 2011 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2011 CENELEC - All rights of exploitation in any form and by any means reserve
6、d worldwide for CENELEC members. Ref. No. EN 60793-1-44:2011 E ICS 33.180.10 Supersedes EN 60793-1-44:2002English version Optical fibres - Part 1-44: Measurement methods and test procedures - Cut-off wavelength (IEC 60793-1-44:2011) Fibres optiques - Partie 1-44: Mthodes de mesure et procdures dessa
7、i - Longueur donde de coupure (CEI 60793-1-44:2011) Lichtwellenleiter -Messmethoden und Prfverfahren - Teil 1-44: Grenzwellenlnge (IEC 60793-1-44:2011) This European Standard was approved by CENELEC on 2011-05-25. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which st
8、ipulate 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 application to the Central Secretariat or to any CENELEC member. This European Stan
9、dard 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 has the same status as the official versions. CENELEC members are the natio
10、nal 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, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spai
11、n, Sweden, Switzerland and the United Kingdom. BS EN 60793-1-44:2011EN 60793-1-44:2011 - 2 - Foreword The text of document 86A/1369/FDIS, future edition 2 of IEC 60793-1-44, prepared by SC 86A, Fibres and cables, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was appr
12、oved by CENELEC as EN 60793-1-44 on 2011-05-25. This European Standard supersedes EN 60793-1-44:2002. The main change with respect to EN 60793-1-44:2002 is the withdrawal of Annex D. Annexes A, B and C form an integral part of EN 60793-1-44:2011. This standard should be read in conjunction with EN 6
13、0793-1-1. 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: latest date by which the EN has to be implement
14、ed at national level by publication of an identical national standard or by endorsement (dop) 2012-02-25 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2014-05-25 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International St
15、andard IEC 60793-1-44:2011 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: IEC 60793-2-10 NOTE Harmonized as EN 60793-2-10. IEC 60793-2-50 NOTE Harmonized as EN 60793
16、-2-50. IEC 60793-2-60 NOTE Harmonized as EN 60793-2-60. _ BS EN 60793-1-44:2011- 3 - EN 60793-1-44:2011 Annex ZA (normative) Normative references to international publications with their corresponding European publications The following referenced documents are indispensable for the application of t
17、his 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 common modifications, indicated by (mod), the relevant EN/HD appli
18、es. Publication Year Title EN/HD Year IEC 60793-1-1 - Optical fibres - Part 1-1: Measurement methods and test procedures - General and guidance EN 60793-1-1 - IEC 60793-1-40 (mod) - Optical fibres - Part 1-40: Measurement methods and test procedures - Attenuation EN 60793-1-40 - BS EN 60793-1-44:201
19、1 2 60793-1-44 IEC:2011(E) CONTENTS 1 Scope . 6 2 Normative references . 6 3 Background 6 4 Overview of methods 7 5 Mapping functions 7 6 Reference test method . 8 7 Apparatus . 8 7.1 Light source 8 7.2 Modulation 8 7.3 Launch optics 8 7.4 Support and positioning apparatus 8 7.5 Cladding mode stripp
20、er . 8 7.6 Deployment mandrel . 9 7.6.1 General . 9 7.6.2 Cable cut-off wavelength, Method A 9 7.6.3 Cable cut-off wavelength, Method B 9 7.6.4 Fibre cut-off wavelength, Method C . 9 7.7 Detection optics 11 7.8 Detector assembly and signal detection electronics . 11 8 Sampling and specimens 11 8.1 S
21、pecimen length 11 8.2 Specimen end face 12 9 Procedure 12 9.1 Positioning of specimen in apparatus 12 9.1.1 General requirements for all methods 12 9.1.2 Deployment requirements for each method 12 9.2 Measurement of output power . 12 9.2.1 Overview . 12 9.2.2 Bend-reference technique 13 9.2.3 Multim
22、ode-reference technique 13 10 Calculations . 13 10.1 Bend-reference technique . 13 10.2 Multimode-reference technique . 14 10.3 Curve-fitting technique for improved precision (optional) . 14 10.3.1 General . 14 10.3.2 Step 1, define the upper-wavelength region . 15 10.3.3 Step 2, characterize the at
23、tenuation curve . 15 10.3.4 Step 3, determine the upper wavelength of the transition region 16 10.3.5 Step 4, determine the lower wavelength of the transition region . 16 10.3.6 Step 5, characterize the transition region with the theoretical model 16 10.3.7 Step 6, compute the cut-off wavelength, c.
24、 17 11 Results . 17 11.1 Report the following information with each measurement: . 17 11.2 The following information shall be available upon request: 17 BS EN 60793-1-44:201160793-1-44 IEC:2011(E) 3 12 Specification information 18 Annex A (normative) Requirements specific to method A Cable cut-off w
25、avelength, cc, using uncabled fibre . 19 Annex B (normative) Requirements specific to method B Cable cut-off wavelength, cc, using cabled fibre . 20 Annex C (normative) Requirements specific to method C Fibre cut-off wavelength, c. 21 Bibliography 22 Figure 1 Deployment configuration for cable cut-o
26、ff wavelength, method A 9 Figure 2 Deployment configuration for cable cut-off wavelength, method B 10 Figure 3 Default configuration to measure c. 10 Figure 4 Deployment configurations for fibre cut-off measurement . 11 Figure 5 Cut-off wavelength using the bend-reference technique . 12 Figure 6 Cut
27、-off wavelength using the multimode-reference technique . 13 BS EN 60793-1-44:2011 6 60793-1-44 IEC:2011(E) OPTICAL FIBRES Part 1-44: Measurement methods and test procedures Cut-off wavelength 1 Scope This part of IEC 60793 establishes uniform requirements for measuring the cut-off wavelength of sin
28、gle-mode optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. This standard gives the methods for measuring the cut-off wavelength of fibre and cable There are two methods for measuring cable cut-off wavelength, cc: Method A: using uncabled fibre; Method B
29、: using cabled fibre. There is only one method (Method C) for measuring fibre cut-off wavelength, c. The test method in this standard describes procedures for determining the cut-off wavelength of a sample fibre in either an uncabled condition (c) or in a cable (cc). Three default configurations are
30、 given here: any different configuration will be given in a detail specification. These procedures apply to all category B and C fibre types (see Normative references). All methods require a reference measurement. There are two reference-scan techniques, either or both of which may be used with all
31、methods: bend-reference technique; multimode-reference technique using category A1 multimode fibre. 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 late
32、st edition of the referenced document (including any amendments) applies. IEC 60793-1-1, Optical fibres Part 1-1: Measurement methods and test procedures General and guidance IEC 60793-1-40, Optical fibres Part 1-40: Measurement methods and test procedures Attenuation 3 Background Theoretical cut-of
33、f wavelength is the shortest wavelength at which only the fundamental mode can propagate in a single-mode fibre, as computed from the refractive index profile of the fibre. In optical fibres, the change from multimode to single-mode behaviour does not occur at an isolated wavelength, but rather smoo
34、thly over a range of wavelengths. For purposes of BS EN 60793-1-44:201160793-1-44 IEC:2011(E) 7 determining fibre performance in a telecommunications network, theoretical cut-off wavelength is less useful than the lower value actually measured when the fibre is deployed. Measured cut-off wavelength
35、is defined as the wavelength greater than which the ratio between the total power, including launched higher-order modes, and the fundamental mode power has decreased to less than 0,1 dB. According to this definition, the second-order (LP11) mode undergoes 19,3 dB more attenuation than the fundament
36、al (LP01) mode at the cut-off wavelength. Because measured cut-off wavelength depends on the length and bends of the fibre, the resulting value of cut-off wavelength depends on whether the measured fibre is configured in a deployed, cabled condition, or it is short and uncabled. Consequently, there
37、are two overall types of cut-off wavelength: Cable cut-off wavelength, measured in an uncabled fibre deployment condition (method A), or in a cabled condition (method B); Fibre cut-off wavelength, measured on a short length of uncabled, primary-coated fibre. Cable cut-off wavelength is the preferred
38、 attribute to be specified and measured. 4 Overview of methods All of the methods shall use the transmitted-power technique, which measures the variation with wavelength of the transmitted power of a fibre under test compared to a reference transmitted-power wavelength scan. The reference scan norma
39、lizes wavelength-dependent fluctuations in the measurement equipment so that the attenuation of the LP11mode in the specimen can be properly characterized and the cut-off wavelength precisely determined. The reference scan uses one of the following two techniques: the specimen with an additional, sm
40、aller-radius fibre bend; a (separate) category A1 multimode fibre. This procedure can determine the cut-off wavelength of a fibre specimen in either a cabled or uncabled condition. Each method has its own default configurations; the detail specification will give any different configuration required
41、. The fibre cut-off wavelength, (c), measured under the standard length and bend conditions described in this standard, will generally exhibit a value larger than cc. For normal installed cable spans, it is common for the measured cvalue to exceed the system transmission wavelength. Thus cable cut-o
42、ff wavelength is the more useful description of system performance and capability. For short cables, e.g. a pigtail with a length shorter (and possibly a bending radius larger) than described in this method, the cable may introduce modal noise near the cut-off wavelength when lossy splices are prese
43、nt (0.5 dB). 5 Mapping functions A mapping function is a formula by which the measured results of one type of cut-off wavelength are used to predict the results that one would obtain from another type. An empirical mapping function is specific to a particular fibre type and design. Generate mapping
44、functions by doing an experiment in which samples of fibre are chosen to represent the spectrum of cut-off wavelength values for the fibre type, then measure the values using BS EN 60793-1-44:2011 8 60793-1-44 IEC:2011(E) the two methods to be mapped. Linear regression of the respective values will
45、often produce a satisfactory mapping function. When establishing criteria for fibre selection, residual errors in the regression shall be taken into account. The customer and the supplier shall agree to the confidence level of each mapping function established. 6 Reference test method Method A of ca
46、ble cut-off wavelength, using uncabled fibre, is the reference test method (RTM), which shall be the one used to settle disputes. The apparatus for each method is described in Clause 7. 7 Apparatus 7.1 Light source Provide a filtered white light source, with line width not greater than 10 nm, stable
47、 in position and intensity. The light source should be capable of operating over the wavelength range 1 000 nm to 1 600 nm for most category B fibres. An operating range of 800 nm to 1 700 nm may be necessary for some B4 fibres, B5 fibres or some category C fibres. 7.2 Modulation Modulate the light
48、source to prevent ambient light affecting the results, and to aid signal recovery. A mechanical chopper with a reference output is a suitable arrangement. 7.3 Launch optics Provide launch optics, such as a lens system or a multimode fibre, to overfill the test fibre over the full range of measuremen
49、t wavelengths. This launch is relatively insensitive to the input end face position of the single-mode fibre, and is sufficient to excite the fundamental and any higher-order modes in the specimen. If using a butt splice, provide means of avoiding interference effects. When using a multimode fibre, overfilling the reference fibre can produce an undesired ripple effect in the power-transmission spectrum. Restrict the launch sufficiently to eliminate
