Spectroscopy, Cooperative Upconversion and Optical Gain in Amorphous Al2O3:Yb3+ Waveguides on Silicon

Ridge waveguides in amorphous Al 2 O 3 :Yb3+ are produced by reactive co-sputtering and reactive-ion etching. Their spectroscopic properties, optical gain, and cooperative upconversion are studied and explained based on a model of distinct ion classes.