scope:

The object of this document is to establish uniform requirements for measuring the cut-off wavelength of single-mode optical fibre, thereby assisting in the inspection of fibres and cables for commercial purposes. This document gives the methods for measuring the cut-off wavelength of fibre and cable. There are two methods for measuring cable cut-off wavelength, ë cc: . Method A: using uncabled fibre; . Method B: using cabled fibre. There is only one method (Method C) for measuring fibre cut-off wavelength, ë c. This test method describes procedures for determining the cut-off wavelength of a sample fibre in either an uncabled condition (ë c) or in a cable (ë cc). Three default configurations are given here: any different configuration will be given in a detail specification. This method applies to all category B and C fibre types (see Normative references). All methods require a reference measurement. There are two reference-scan techniques, either or both of which may be used with all methods: . bend-reference technique; . multimode-reference technique using category A1 multimode fibre