BS EN 60793-1-60:2017
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Optical fibres – Measurement methods and test procedures. Beat length
| Published By | Publication Date | Number of Pages |
| BSI | 2017 | 26 |
This part of IEC 60793 defines test methods for both the phase beat length, and the group beat length. These two parameters are defined differently, and will give different results depending on the type of polarization-maintaining (PM) fibre.
The phase beat length is the relevant parameter for the fibres ability to maintain a high extinction ratio. This is described in more details in Annexes A and B.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | National foreword |
| 5 | Annex ZA(normative)Normative references to international publicationswith their corresponding European publications |
| 7 | CONTENTS |
| 8 | FOREWORD |
| 10 | 1 Scope 2 Normative references 3 Terms and definitions |
| 11 | 4 Testing conditions 5 Reference test method 6 Specimen 7 Test methods 7.1 Phase beat length measurement methods 7.1.1 General 7.1.2 Monitoring of output power using an electromagnet Figures Figure 1 – Apparatus of phase beat length measurement using an electromagnet |
| 13 | 7.1.3 Monitoring of SOP using a lateral force Figure 2 – Example of measurement profile by electromagnet |
| 14 | Figure 3 – Set-up for measuring LB(phase) when monitoring SOP together with a moving lateral force |
| 15 | 7.2 Group beat length measurement method 7.2.1 General 7.2.2 Apparatus and procedure Figure 4 – SOP measured at different levels of lateral force Figure 5 – Example of SOP evolution and normalized Stokes vector components |
| 16 | 7.2.3 Calculation 8 Results 8.1 Information available with each measurement |
| 17 | 8.2 Information available upon request |
| 18 | Annex A (informative)Difference of beat lengths by measurement method (phase beat length and group beat length) A.1 Phase modal birefringence and phase beat length A.2 Group modal birefringence and group beat length |
| 21 | Annex B (informative)Correlation between results obtained by the two methods (phase beat length and group beat length) B.1 General B.2 Example of correlation between phase and group beat lengths in the case of PANDA fibres Figure B.1 – Wavelength dependence of Bgroup/Bphase [3] |
| 22 | B.3 Example of correlation between phase and group beat lengths in the case of elliptical core fibres Table B.1 – Bgroup/Bphase of elliptical core fibres |
| 23 | Annex C (informative)Electromagnet for Faraday rotation Figure C.1 – Schematic of the electromagnet |
| 24 | Bibliography |
