Preparation and fluorescence properties of sol-gel derived Er-doped SiO/sub 2/-GeO/sub 2/-Al/sub 2/O/sub 3/ planar optical waveguides

We focus on the optical properties of sol-gel derived Er-doped SiO/sub 2/-GeO/sub 2/-Al/sub 2/O/sub 3/ planar waveguides on SOS (silica-on-silicon) substrates. The study shows that the sol-gel method is a suitable technique to incorporate erbium ions in germanosilicate optical waveguides with a relatively high doping concentration, and aluminum co-doping can enhance the fluorescence intensity. The strong fluorescence emission implies that optical amplification can perhaps be realized if the propagation loss of the planar waveguide can be reduced.