IEC 60793-2-50: 2018 is applicable to optical fibre categories B-652, B-653, B-654, B-655, B 656 and B-657. A map illustrating the connection of IEC designations to ITU-T designations is shown in Table 1. These fibres are used or can be incorporated in information transmission equipment and optical fibre cables. Three types of requirements apply to these fibres:
• general requirements, as defined in IEC 60793-2;
• specific requirements common to the class B single-mode fibres covered in this document and which are given in Clause 5;
• particular requirements applicable to individual fibre categories or specific applications, which are defined in Annexes A to F.
For some fibre categories (shown in the relevant family specifications), there are sub-categories that are distinguished on the basis of difference in transmission attribute specifications. The designations for these sub-categories are documented in the individual family specifications.
The sixth edition cancels and replaces the fifth edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) Introduction of a revised naming convention which better matches with those found in ITU T Recommendations G.652, G.653, G.654, G.655, G.656, and G.657. These changes are outlined in the scope of this document along with a cross reference table for the new names. Annexes have been rearranged to improve clarity based on the new naming;
b) Further details on the requirements for 200 micron coated single-mode fibre;
c) Harmonization with the following ITU-T Recommendations published in November 2016: G.652, G.654, G.657 including revised chromatic dispersion specifications, new categories and new application spaces for these fibre categories;
d) Descriptions of fibre types have been added to the titles of Annexes A to F.