Erbium-activated sol gel - derived silica-hafnia planar waveguides

Sol gel - derived SiO2-HfO2 planar waveguides of different molar composition and activated by different content of Er3+ ions have been prepared by dip-coating technique with the aim of improving their spectroscopic features for successful Er-doped waveguide amplifier (EDWA) fabrication. First, in order to assess the system, spectroscopic, optical, and structural properties of these waveguides have been investigated as a function of both the HfO2/ SiO2 molar ratio and erbium content. Several techniques such as luminescence upon continuous and pulsed excitation, m-line, and Raman spectroscopy have been employed Particular attention has been devoted to the study of upconversion processes upon 980 nm excitation as well as to the evaluation of the luminescence quenching concentration: both these factors are critical for the design of efficient active waveguides for photonic applications. Finally, some results on etching process fabrication and characterization of channel waveguides on silica-on-silicon substrates are reported. In conclusion, our preliminary results confirm the feasibility of silica-hafnia-based EDWAs.