This part of IEC 60793 establishes uniform requirements for measuring the attenuation of 
optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes.  
Four methods are described for measuring attenuation, one being that for modelling spectral 
attenuation: 
– method A: cut-back;  
– method B: insertion loss;  
– method C: backscattering; 
– method D: modelling spectral attenuation.  
Methods A to C apply to the measurement of attenuation for all categories of the following 
fibres: 
– class A multimode fibres; 
– class B single-mode fibres. 
Method C, backscattering, also covers the location, losses and characterization of point 
discontinuities. 
Method D is applicable only to class B fibres. 
Information common to all four methods appears in Clauses 1 to 11, and information 
pertaining to each individual method appears in Annexes A, B, C, and D, respectively. dition 2.0 2019-03 INTERNATIONAL STANDARD NORME INTERNATIONALE colour inside Optical fibres – Part 1-40: Attenuation measurement methods Fibres optiques – Partie 1-40: Méthodes de mesurage de l'affaiblissement IEC 60793-1-40:2019-03(en-fr) THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright ？ 2019 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publicat