Raman investigation of germanium- and phosphorus-doping effects on the structure of sol-gel silica-based optical fiber preforms

Hicham El Hamzaoui (1) , Mohamed Bouazaoui (1) , Bruno Capoen (1)

1 PhLAM - Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523

This works reports the structural investigation of homogeneously doped solegel-derived silica optical fiber preforms. Crack-free germanosilicate (2.7 wt% Ge) and phosphosilicate (2.5 wt% P) glasses, suitable for optical fiber fabrication, have been prepared using the polymeric solegel route combined with the sol-doping technique. Space homogeneity of the doping oxide (GeO2 or P2O5) in the cylindrical preforms has been checked by chemical analysis. The structure of these glasses have been studied using Raman spectroscopy and compared to pure silica glasses. It is shown that phosphorus has a much more sensitive effect on the glassy structure than germanium, both at small and medium scales. Indeed, in the low wavenumber region (7-100 cm-1), the phosphorus-doping was found to affect the intensity of the boson peak, suggesting an enhancement of heterogeneity at the nanometer scale. At a shorter scale, both germanium- and phosphorus-doping were found to reduce the number of three- and four-membered rings in the silica glass network.

Mots clés: Raman Glass structure Solegel silica Germanium oxide Phosphorus oxide

Domaines: Optique [physics.optics]

Hicham El Hamzaoui, Mohamed Bouazaoui, Bruno Capoen. Raman investigation of germanium- and phosphorus-doping effects on the structure of sol-gel silica-based optical fiber preforms. Journal of Molecular Structure, 2015, 1099, pp.77-82. ⟨10.1016/j.molstruc.2015.06.061⟩. ⟨hal-01169237⟩