Just before the deposition on the Er:Al2O3 active product, the coupling circuit, i.e., the strip waveguides, the mode transition tapers as well as the mode converters were coated having a 800 nm thick layer of hydrogen silsesquioxane (HSQ, n ~one.forty five) to stop their coating Using the active content, as https://barryp418chp3.wikigop.com/user