The influence of temperature on the absorption, fluorescence and small-signal gain characteristics of a silica-based erbium-doped fibre is investigated. The observed changes in the fluorescence and absorption spectra are found to be consistent with a Boltzmann-type redistribution of ion populations within the manifolds of the4I13/2:4I15/2transition. The influence of this behaviour on the gain characteristics of a cooled fibre amplifier is studied at two particular wavelengths: 1536 and 1553 nm. Significant improvements in amplifier performance are measured at both wavelengths when pumping into the4I9/2absorption band at liquid-nitrogen temperatures. The gain results are related to the absorption and fluorescence changes observed on cooling the fibre, and predictions of the importance of these results to device performance are made. The effect of cooling on the pump threshold performance of an erbium-doped fibre laser is also measured.