Erbium-activated silica-titania planar waveguides prepared by rf-sputtering

Abstract

Erbium-activated silica-titania planar waveguides were prepared by rf-sputtering technique. The films were deposited both on v-SiO<SUB>2</SUB> and silica-on-silica substrates obtained by plasma-enhanced chemical vapor deposition. The refractive index, the thickness and the total attenuation coefficient of the waveguides were measured by prism coupling technique. Scanning electron microscopy was used to analyze the morphology of both substrates and waveguiding film. Energy Dispersive Spectroscopy was performed in order to obtain a compositional analysis. Roughness measurements were carried out by means of a stylus profilometer. After thermal annealing at 600 degrees C for 6 hours the waveguides exhibited several well confined TE and TM propagating modes at 633 nm and one mode at 1550 nm. The attenuation coefficient at 1550 nm was 0.9 and 0.7 dB/cm for the films deposited on silica-on-silicon waveguide Raman spectroscopy. Waveguide luminescence spectroscopy was used to study the <SUP>4</SUP>I<SUB>13/2</SUB> yields <SUP>4</SUP>I<SUB>15/2</SUB> transition of Er<SUP>3+</SUP> ion. The emission at 1530 nm was observed at room temperature upon continuous wave excitation at 514.2 nm. A lifetime of 3.7 ms for the metastable <SUP>4</SUP>I<SUB>13/2</SUB> level was measured.