Erbium activated SiO2-ZrO2 and SiO2-HfO2 planar waveguides doped with Er3+ ranging from 0.5 to 5 mol% were prepared by sol-gel route using dip-coating deposition on silica glass substrates. All the planar waveguides were optimized in order to confine one propagating mode at 1550 nm. The aim of this work is to present an alternative method for planar optical waveguides processing based on CO2 laser irradiation (wavelength, &lgr;=10.6μm). The effects of pulsed and continuous CO2 laser irradiation on the optical and spectroscopic properties of the waveguides are evaluated and the thermal conventional annealing effect for this system is reported for comparison. X ray diffraction and optical spectroscopy showed that after an adapted pulsed CO2 laser annealing, the resulting materials showed a crystalline environment. An increase of the
refractive index of approximately 0.04 at 1.5 μm has been observed on 70SiO2-30HfO2 planar waveguide after continuous CO2 laser annealing. A similar refractive-index variation was detected in all SiO2-ZrO2 planar waveguides after CO2 laser irradiation. We have observed, moreover, that continuous CO2 laser annealing can lead to waveguides with a lower attenuation coefficient: an attenuation coefficient of 0.8 and 1.2 dB/cm @ 632 nm was measured for silica-hafnia and silica-zirconia waveguides respectively, in respect to the attenuation coefficient higher that 2 dB/cm, measured for thermal annealed waveguides. Upon excitation at 514.5 nm continuous-wave laser light, pulsed CO2 irradiated silica-zirconia
waveguides show the 4I13/2 -> 4I15/2 emission band with a bandwidth of 12 nm. Before and after conventional thermal
annealing, the 4I13/2 level decay curves present a single-exponential profile with a lifetime of 4.0 and 5.7 ms respectively, but the lifetime increases up to 7.0 ms, after pulsed laser annealing treatment.