Densification and crystallization processes of aluminosilicate planar waveguides doped with rare-earth ions

Aluminosilicate planar waveguides have been prepared using a sol-gel proces s and the dip-coating technique. The structure of Er3+- and Ce3+-doped as w ell as undoped films has been investigated as a function of the annealing t emperature. Low-wavenumber Raman scattering and opto-geometrical properties of these thin films have demonstrated the role of Er3+ and Ce3+ ions in th e densification and nucleation processes. Indeed, doping with rare-earth io ns first hinders the densification process in the amorphous phase, while cr ystallization begins at a lower annealing temperature for the doped wavegui des. It was found that the two behaviors are intimately linked to the dopin g effect. (C) 2001 Elsevier Science B.V. All rights reserved.