NEW!IEC 60793-1-45:2017 is available as IEC 60793-1-45:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60793-1-45:2017 establishes uniform requirements for measuring the mode field diameter (MFD) of single-mode optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. This second edition cancels and replaces the first edition published in 2001. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - improvement of the description of measurement details for B6 fibre; - correction of Equations (1), (2), (5) and (6); - correction of Table E.1, Table E.2 and Table E.3. Keywords: mode field diameter (MFD)