Al2O3-Y2O3 nanolaminated slab optical waveguides by atomic layer deposition

Atomic layer deposition (ALD) is a conformal, homogeneous and uniform technique, ideal characteristics for optical waveguides. Recent investigations prove that the advantages of ALD tend to reduce optical losses in submicron waveguides. Al2O3 and Y2O3 are known as optical materials with transparency characteristics in the visible-NIR region, which allow application sensors and telecommunications. In this work, Al2O3-Y2O3 nanolaminates films grown at 250 degrees C by thermal ALD were used as core for slab waveguides. Different proportions of Y2O3 were used, setting the total nanolaminate thickness at 500 nm. Refractive index of materials was estimated by Spectroscopic Ellipsometry, effective refractive index of waveguides at 632.8 nm was determined by prism coupling, and propagation loss coefficient were measured for a fiber-to-waveguide coupling setup. Microanalysis of samples was made by means of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Propagation of all samples was demonstrated at 632.8 nm.