Optimized Deposition and Structuring of Reactively Co-Sputtered Al2O3:Er Waveguide Layers with Net Optical Gain

Growth of reactively co-sputtered Al2O3 layers and micro-structuring using reactive ion etching have been optimized, resulting in channel waveguides in the as-deposited layers with optical propagation losses as low as 0.21 dB/cm. For active functionality, Erdoped Al2O3 layers have also been deposited by co-sputtering from a metallic Er target. At relevant dopant levels (~10 cm) lifetimes of the I13/2 level up to 7 ms have been measured and net optical gain of 0.7 dB/cm has been obtained in a 700-nm thick Erdoped Al2O3 waveguide. Investigation of active devices, such as lasers and amplifiers, exploiting the developed technology is on-going.