Sol-gel Er-doped SiO2–HfO2 planar waveguides: A viable system for 1.5 μm application

Abstract

70SiO 2 – 30HfO 2 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 or 514.5 nm continuous-wave laser light, the waveguides show the I413/2→I415/2 emission band with a bandwidth of 48 nm. The spectral features are found independent both on erbium content and excitation wavelength. The I413/2 level decay curves presented a single-exponential profile, with a lifetime between 2.9 and 5.0 ms, depending on the erbium concentration.