Erbium-activated SiO2-HfO2 planar waveguides: a binary system for operation in the C-telecom band

70SiO2 - 30HfO2 planar waveguides, doped with Er3+ concentrations ranging from 0.3 to 1 mol%, were prepared by sol-gel route, using dip-coating deposition on silica glass substrates. The waveguides show high densification degree, effective intermingling of the two components of the film, and uniform surface morphology. Propagation losses of about 1 dB/cm were measured at 632.8 nm. When pumped with 987 nm or 514.5 nm continuous-wave laser light, the waveguides show the 4I13/2?4I15/2 emission band with a bandwidth of 48 nm. The spectral features are found independent both on erbium content and excitation wavelength. The 4I13/2 level decay curves presented a single-exponential profile, with a lifetime between 2.9 - 5.0 ms, depending on the erbium concentration