Er3+/Yb3+-activated silica-hafnia planar waveguides for photonics fabricated by rf-sputtering

95.8SiO ₂–4.2HfO ₂ planar waveguide activated by 0.2 mol% Er and 0.2 mol% Yb was fabricated by multi-target rf-sputtering technique. The optical parameters were measured by an m-line apparatus operating at 543.5, 632.8, 1319 and 1542 nm. The waveguide compositions were investigated by energy dispersive spectroscopy. The waveguide exhibits a single propagation mode at 1.3 and 1.5 μm with an attenuation coefficient of 0.2 dB/cm at 1.5 μm. The emission of ⁴I _13/2 → ⁴I _15/2 transition of Er ³⁺ ion, with a 42 nm bandwidth was observed upon TE ₀ mode excitation at 980 and 514.5 nm. Photoluminescence excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er ³⁺ ions by co-doping with Yb ³⁺ ions. Channel waveguide in rib configuration were fabricated by wet etching process in the active film.