Erbium-doped optical fibres are commonly used to realize amplifiers. To control and modify erbium spectroscopic properties in these silica-based optical fibres, we study an original way that consists in encapsulating ions into oxide nanoparticles obtained in-situ, directly during MCVD process. The modification of the erbium local environment allows to modify spectroscopic properties. These nanoparticles appear during the fabrication with the incorporation of a nucleation agent. Thermal cycles necessary to the preform fabrication ensure therefore to activate a spontaneous phase separation.This thesis aims to study the effect of different fabrication parameters, such as nucleating agent concentration in the doping solution or consolidation and collapsing phases, on the nanoparticle characteristics and erbium spectroscopic properties. In this manus- cript, this study of the different parameters is organised in two axes : material composition and thermal cycles. Nanoparticles have mainly been characterised by Scanning Electron Microscopy (SEM). Erbium spectroscopy has been analysed by means of emission spectrum measurements as well as measurements of the 1,5μm fluorescence lifetime. Spectroscopic modifications, i.e. emission spectrum broadening of 40 until 60%, have only been obtained for fibres that exhibit particles with high mean diameters ( 50nm). Transparency criteria could only be satisfied while manipulating particle density.
