Erbium Doped Al2O3 films for integrated III–V photonics

We describe the fabrication optimization of Er-doped Al2O3 films for III-V integrated photonics. Smooth and thick films, with high refractive index and Erbium emission in the C-band spectrum (1530 nm to 1565 nm) are obtained using the co-sputtering technique. Thermal annealing at 850 °C is shown to provide the highest Photoluminescence intensity of the films. However, the onset of crystallization leads to large fluctuation in refractive index. We also show that the annealing at temperatures larger than 600 °C causes well intermixing in the laser structure. Therefore, local annealing and/or a reduction in annealing temperature may be required. Alumina waveguides are fabricated by the same technique, but the process have to be improved, as optical losses are very high.