Photoluminescence of Erbium-doped Silica-based Waveguide Film via Flame Hydrolysis Deposition and Aerosol Doping

Silica based waveguides on Si fabricated by flame hydrolysis deposition were doped with erbium ions using an aerosol doping technique, and co-doped with GeO2, P2O5 and B2O3. Erbium doping levels in the films were dependent on the nebulized solution concentration and delivery rate of the aerosol to the torch. The erbium solution concentration was varied from 4 to 8 wt%. The refractive index was measured by a prism coupler at 633 nm. FTIR absorption spectra and XRD profiles were made to check the OH concentration and the morphology of the films. A photoluminescence peak was observed at 1542 nm with a FWHM of 65 nm, which corresponds to the I13/2 → I15/2 transition. As a function of Er concentration, the photoluminescence (PL) intensity first increases, but decreases above a 6 wt% Er solution concentration. The decrease in PL intensity with concentration is attributed to concentration quenching caused by Er-Er interaction. The dependence of PL intensity on pump intensity further verifies the co-operative upconversion occurs.