C. Tosello et al., Erbium-activated silica-titania planar waveguides on silica-on-silicon substrates prepared by rf sputtering, J NON-CRYST, 284(1-3), 2001, pp. 230-236
Erbium-activated silica-titania planar waveguides were prepared by radio-fr
equency (rf) sputtering technique. Silica-on-silicon substrates obtained by
plasma-enhanced chemical vapor deposition (PECVD) and rf sputtering (RFS)
were employed. The refractive indices. the thickness and the propagation lo
sses of the waveguides were measured. The refractive index and the roughnes
s of the silica substrates produced by RFS appear to be dependent on the th
ickness. Thermal annealing, which is a necessary condition to obtain light
propagation, induces a decrease of the refractive index in the silica subst
rates, The waveguide deposited on PECVD substrate exhibits several propagat
ing modes with an attenuation coefficient 1.7 dB/cm compared with 12.2 dB/c
m measured for the waveguide deposited on silica substrate produced by RFS
technique. Emission of the I-4(13/2) --> I-4(15/2) transition with a 53 nm
bandwidth was observed. (C) 2001 Elsevier Science B.V. All rights reserved.