IEC 60793-1-4:1995/AMD2:1998

Establishes requirements for measuring the mode field diameter (MFD) of fibres. Four methods are described: (a) direct far-field scan: (b) variable aperture in the far field: (c) near-field scan: (d) bi-directional backscatter using an optical time domain reflectometer. All four methods apply to type B single-mode fibres, operating near 1310 nm or 1550 nm. The contents of the corrigendum of July 2002 have been included in this copy.

Establishes requirements for measuring the numerical aperture of category A1 graded-index multimode fibre, and its light-gathering ability. This is used to predict lauching efficiency, joint loss at splices, and micro/macrobending perfprmance.

Gives two methods for monitoring the changes in optical transmittance of optical fibres and cables that occur during mechanical and environmental testing. It provides a monitor in the change of optical transmission characteristics arising from optical discontinuity, physical defects and modifications of the attenuation slope. The methods are the change in transmittance by transmitted power, and by backscattering. They apply to both multimode and single-mode fibres.

Establishes uniform requirements for measuring the attenuation of optical fibres. Four methods are described: (a) cut-back, (b) insertion loss, (d) backscattering, (d) modelling spectral attenuation. Methods (a), (b) and (c) apply to all categories of class A multimode fibres and class B single-mode fibres. Method (c), backscattering, also covers the location, losses and characterization of point discontinuities. Method (d) has been demonstrated only on class B fibres.