Sol–gel-derived Er-activated SiO2–HfO2 planar waveguides for 1.5 μm application

(100 − x)SiO2–xHfO2 (x = 10, 20, 30, 40 mol) planar waveguides, doped with 0.3 mol% Er3+ ions were prepared by the sol–gel route, using dip-coating deposition on v-SiO2 substrates. The waveguides were characterized by m-line, Raman and photoluminescence spectroscopies. The results are discussed with the aim of assessing the role of hafnia on the structural, optical and spectroscopic properties of the erbium-doped silica-hafnia planar waveguides. The spectral bandwidth of the 4I13/2 → 4I15/2 transition does not change practically with the hafnium content. The 4I13/2 level decay curves present a single-exponential profile, with a lifetime between 5.5 and 7.1 ms, depending on the HfO2 concentration.