RF-sputtering fabricated silica-hafnia planar waveguides activated with Er3+/Yb3+ for integrated optics

Recently we have shown that SiO2-HfO2 is a viable system for fabrication of sol gel-derived Er-activated planar waveguides for 1.5 ?m applications1. Also, we have shown that rf-sputtering (RFS) is a suitable technique for fabrication of silica-titania planar waveguides activated by rare-earth ions2. In this work, we present results on the fabrication by rf-sputtering technique and spectroscopic characterization of Er3+/Yb3+-activated SiO2-HfO2 planar waveguide. Moreover, we present a preliminary result concerning the patterning of channel waveguides in these films. Er3+/Yb3+-codoped 95.8 SiO2 - 4.2 HfO2 planar waveguide was fabricated by the rf-sputtering technique. The sample was activated with 0.2 mol% Er and 0.2 mol% Yb. The optical parameters of the waveguide were measured by an m-line apparatus operating at 543.5, 632.8, 1319 and 1542 nm. The losses, for the TE0 mode, were evaluated at 632.8, 1319 and 1542 nm. The structural properties were investigated with Energy Dispersive Spectroscopy and Raman spectroscopy. The waveguide exhibits a single-mode at 1.3 and 1.5 ?m and an attenuation coefficient of 0.2 dB/cm at 1.5 ?m. The emission of 4I13/2 ? 4I15/2 of Er3+ ion transition, with a 42 nm bandwidth was observed upon excitation in the TE0 mode at 980 and 514.5 nm. The 4I13/2 level decay curve presented a single-exponential profile, with a lifetime of 4.6 ms. Photoluminescence excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er3+ ions by co-doping with Yb3+ ions. Channel waveguide in rib configuration were obtained by etching the active film by a wet etching process. Scanning Electron Microscopy was used to analyze the morphology of the waveguides.