Measured losses in fibres

Abstract

The sources of loss in fluoride optical fibres have been discussed in some detail earlier in this book. Chapter 5 covered intrinsic loss and Chapters 6 and 7 extrinsic loss. To recap briefly the main points discussed there, the intrinsic loss is limited at short wavelengths by the ultraviolet edge, due to electronic absorptions, and Rayleigh-Brillouin scattering inherent to the glass structure, and at long wavelength by the multiphonon absorption edge. Impurities and defects introduced by the fabrication process give rise to additional, or extrinsic loss. For fluoride fibres, the effective transmission lies between 1 and 4 µm, although short lengths (a few metres) of low loss fibre may transmit beyond these limits.