Er doped oxide nanoparticles in silica based optical fibres

Erbium doped materials are of great interest ill optical telecommunications due to the Er(3+) intra-4f emission at 1.54 mu m. Erbium doped fibre amplifiers (EDFA) were developed ill silica glass because of the low losses at this Wavelength and the reliability of this glass. Developments of new rare earth doped fibre amplifiers aim to control their spectroscopic properties including shape and width of the gain curve and optical quantum efficiency. Standard silica glass modifiers, such as aluminium, result ill VC 41 good properties ill current EM. However, fir more drastic spectroscopic changes, more important modifications of the rare earth ions local environment are required. To address this aim, we present a fibre fabrication route creating rare earth doped calcia-silica or calcia-phosphosilica nanoparticles embedded ill silica glass. By adding alkaline earth elements such as calcium, ill low concentration, one call obtain a glass with all immiscibility gap so that phase separation occurs with all appropriate heat treatment. We investigated the role of two elements: calcium and phosphorus (a standard silica modifier). Scanning electron microscopy shouts that nanoparticles are only observed when calcium is incorporated. The size of the particles is determined to be around 50 nm ill preform samples. The nature of these particles depends oil phosphorus content: without P, electron diffraction shouts that the particles are amorphous whilst they are partially crystalline when phosphorus is added. Ill addition through use of energy dispersive x-ray techniques, we have shown that erbium ions are located ill the nanoparticles