Investigation and optimisation of fusion splicing abilities between erbium-doped optical fibres and standard singlemode fibres

Fusion splice loss between erbium-doped fibres (EDFs) and standard singlemode fibre is discussed. Special attention is paid to the wavelength dependence of splice loss. It is suggested that, for a conventional EDF step index profile, it is difficult to meet both common EDF cutoff requirements and minimising wavelength dependence at the same time. Therefore, a new refractive index profile is suggested. With this design an actual fibre has been made to demonstrate how splice loss as well as wavelength dependence can be reduced.