Erbium-activate HfO 2 -based waveguides for photonics

Abstract

70SiO₂ - 30 HfO₂ planar waveguides, activated by Er³⁺ concentration ranging from 0.3 to 1 mol%, were prepared by sol-gel route, using dip-coating deposition on silica glass substrates. The waveguides showed 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 showed the ⁴I_13/2 → ⁴I_15/2 emission band with a bandwidth of 48 nm. The spectral features were found independent both on erbium content and excitation wavelength. The ⁴I_13/2 level decay curves presented a single exponential profile, with a lifetime between 2.9 - 5.0 ms, depending on the erbium concentration.