Fabrication by rf-sputtering and diagnostics of Er3+/Yb3+ - activated silicahafnia waveguides

SiO₂-HfO₂: Er³⁺-Yb³⁺ waveguide was prepared by multi-target rf-sputtering technique on silica substrate. The optical parameters were measured by an m-line apparatus operating at 543.5, 632.8, 1319 and 1542 nm. The structural properties were investigated with energy dispersive spectroscopy and Raman spectroscopy. The planar waveguide had a single-mode at 1.3 and 1.5 mum and an attenuation coefficient of 0.2 dB/cm at 1.5 mum was obtained. The ⁴I_13/2 rarr ⁴I_15/2 emission of Er³⁺ ion transition with a 42 nm bandwidth and a lifetime of 4.6 ms was observed upon excitation in the TE0 mode at 980 and 514.5 nm. Photoluminescence (PL) excitation spectroscopy was used to obtain information about the effective excitation efficiency of Er³⁺ ions by co-doping with Yb³⁺ ions and the spectrum reported indicates that an effectual energy transfer from ytterbium to erbium ions is present. Additional work is currently under way to investigate the effect of the Er³⁺/Yb³⁺ concentration and excitation power on the Er3+ fluorescence intensity at 1.53 mum. Rib waveguide was also produced by photolithography and wet etching process. PL measurements were performed using the TE₀ mode excitation on the planar system, and injecting the laser light by a 20X microscope objective in the channel on the etched system. The spectral shape of the erbium emission at 1.5 mum obtained on the channel system is equal to that obtained on the planar system. The measurements of signal enhancement when pumping Erbium ions at 980 nm are in progress.