Before the deposition on the Er:Al2O3 active materials, the coupling circuit, i.e., the strip waveguides, the method changeover tapers as well as manner converters were included that has a 800 nm thick layer of hydrogen silsesquioxane (HSQ, n ~1.45) to avoid their coating with the active substance, as revealed in https://raelw974ven3.wikipowell.com/user