BS EN IEC 60793-1-47:2018 – TC:2020 Edition
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Tracked Changes. Optical fibres – Measurement methods and test procedures. Macrobending loss
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 79 |
IEC 60793-1-47:2017 is also available as /2 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60793-1-47:2017 establishes uniform requirements for measuring the macrobending loss of single-mode fibres (class B) at 1 550 nm or 1 625 nm, category A1 multimode fibres at 850 nm or 1 300 nm, and category A3 and A4 multimode fibres at 650 nm, 850 nm or 1 300 nm, thereby assisting in the inspection of fibres and cables for commercial purposes. This document gives two methods for measuring macrobending sensitivity: – Method A – Fibre winding, pertains to class B single-mode fibres and category A1 multimode fibres. – Method B – Quarter circle bends, pertains to category A3 and A4 multimode fibres. For both of these methods, the macrobending loss can be measured utilizing general fibre attenuation techniques, for example the power monitoring technique (see Annex A) or the cut?b ack technique (see Annex B). Methods A and B are expected to produce different results if they are applied to the same fibre. This is because the key difference between the two methods is the deployment, including the bend radius and length of fibre that is bent. The reason for the difference is that A3 and A4 multimode fibres are expected to be deployed in short lengths with a smaller number of bends per unit fiber length compared to single-mode and category A1 multimode fibres. In this document, the ‘curvature radius’ is defined as the radius of the suitable circular shaped support (e.g. mandrel or guiding groove on a flat surface) on which the fibre can be bent. In addition, informative Annex E has been added to approximate bend loss for class B single-mode fibres across a broad wavelength range at various effective bends. This fourth edition cancels and replaces the third edition published in 2009. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: – former Annex A has been renumbered to Annex D; – introduction of new Annex A on the transmitted power monitoring technique; – introduction of Annex B on the cut-back technique; – introduction of Annex C on the requirements for the optical source characteristics of A1 multimode measurement; – introduction of Annex E on parallel plate (2-point) macrobend loss approximation. Keywords: macrobending loss of single-mode fibers
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 41 | undefined |
| 45 | English CONTENTS |
| 48 | FOREWORD |
| 50 | INTRODUCTION |
| 51 | 1 Scope 2 Normative references |
| 52 | 3 Terms and definitions 4 Apparatus 4.1 Method A – Fibre winding 4.2 Method B – Quarter circle bends Figures Figure 1 – Quarter circle guide groove in plate |
| 53 | 4.3 Input system 4.3.1 Optical source 4.3.2 Optical launch arrangement Figure 2 – General launch arrangement |
| 54 | Figure 3 – Lens system Figure 4 – Launch fibre |
| 55 | 4.4 Output system and detection 4.4.1 Optical divider 4.4.2 Optical detector Figure 5 – Mode scrambler (for A4 fibre) Tables Table 1 – Launch conditions for A2 to A4 fibres |
| 56 | 4.4.3 Optical detection assembly 4.4.4 Signal processing 5 Specimen 5.1 Specimen length 5.1.1 Method A – Fibre winding 5.1.2 Method B – Quarter circle bends 5.2 Specimen end face 6 Procedure 6.1 Method A – Fibre winding 6.1.1 General consideration |
| 57 | 6.1.2 Single-mode fibres |
| 58 | 6.1.3 Multimode (A1) fibres 6.2 Method B – Quarter circle bends |
| 59 | Figure 6 – Multiple bends using stacked plates |
| 60 | 7 Calculations 8 Results 8.1 Information available with each measurement 8.2 Information available upon request 9 Specification information |
| 62 | Annexes Annex A (normative) Change in transmittance by transmitted power technique A.1 Apparatus A.1.1 General Figure A.1 – Measurement of change in optical transmittance using reference specimen |
| 63 | A.2 Procedure A.3 Calculations Figure A.2 – Measurement of change in optical transmittance using stabilized source |
| 65 | Annex B (normative) Cut-back technique B.1 General B.2 Apparatus B.2.1 General apparatus for all fibres B.3 Procedure Figure B.1 – Arrangement of equipment to perform loss measurement at one specified wavelength Figure B.2 – Arrangement of equipment used to obtain a loss spectrum |
| 66 | B.4 Calculations |
| 67 | Annex C (normative) Requirements for the optical source characteristics for A1 multimode measurement C.1 Encircled flux (EF) C.2 Limits on encircled flux |
| 68 | Figure C.1 – Encircled flux template example Table C.1 – Threshold tolerance |
| 69 | Table C.2 – EF requirements for 50 μm core fibre cabling at 850 nm Table C.3 – EF requirements for 50 μm core fibre cabling at 1 300 nm Table C.4 – EF requirements for 62,5 μm core fibre cabling at 850 nm Table C.5 – EF requirements for 62,5 μm core fibre cabling at 1 300 nm |
| 70 | Annex D (informative) Small bend radius phenomena D.1 General D.2 Interference between propagating and radiating modes |
| 71 | Figure D.1 – Loss curves versus curve fits |
| 72 | D.3 Polarization effects D.4 High power damage |
| 73 | Annex E (informative) Parallel plate (2-point) macrobend loss approximation E.1 General E.2 Specimen E.3 Apparatus E.3.1 General |
| 74 | E.3.2 Stepper motor control E.3.3 Movable plate E.3.4 Fixed plate Figure E.1 – Schematic of possible (two-point bend) apparatus |
| 75 | E.4 Procedure E.5 Calculation E.6 Results |
| 76 | E.7 Comparison of results with normative test Figure E.2 – Example of applying an exponential fit to the spectral data of a B6_a2 fibre Figure E.3 – Example of 2-point bend test datafor a B6_a2 fibre |
| 77 | Table E.1 – Comparison of parallel plate (2-point) versus method Amacrobend loss measurement for a B6_b3 fibreat 10 mm diameter (ratio of mandrel / 2-point) |
| 78 | Bibliography |
