Previous to the deposition of the Er:Al2O3 active content, the coupling circuit, i.e., the strip waveguides, the method changeover tapers and also the method converters ended up included with a 800?nm thick layer of hydrogen silsesquioxane (HSQ, n?~1.45) to avoid their coating with the active material, as shown in Fig. 1. The HSQ cladding was depo