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Step-index optical waveguides have been obtained by means of silver ion implantation on fused silica substrates. Step index profiles have been reached using a sequential multiple ion implantation process with energies of implantation from 4.3 to 9 MeV and fluences of 1014–1015 ions/cm2. Optical absorption spectra, propagation losses, intensity distribution, and effective refractive indices of the propagation modes of the waveguides are presented. An approach of refractive index profile of ion-implanted waveguides was fitted as function of polarizability, compaction, and stress. [ABSTRACT FROM PUBLISHER]

We have measured the propagation losses of Cu-Na-ion-exchanged channel glass waveguides using both scattering and interferometric methods. In the first method, the waveguide was coated with a fluorescence film to enhance the scattered optical field along the channel waveguide which was then captured by a charge-coupled device camera. A straight line is adjusted to the intensity profile by the least-squares method, and the slope yields the attenuation coefficient. In the interferometric method, the temperature of the waveguides was changed and the intensity output was measured. From contrast changes of waveguide's intensity output, the attenuation coefficient is calculated. Also, an analysis of the optical absorption of copper waveguides in the 200-1900 nm range to detect the copper oxidation state is presented. [ABSTRACT FROM AUTHOR]

Nanolaminate multilayers made of Al 2 O 3 and Y 2 O 3 bilayer slabs were grown at 250 °C by means of thermal Atomic Layer Deposition (ALD). Several samples were prepared, where the number of ALD cycles for the Al 2 O 3 slab was kept constant at 17 ALD cycles, while the number for the Y 2 O 3 slabs was varied from 1 to 100. An optical model was built and adapted for each sample considering the Cauchy relationship, which was used to simulate the optical response for transparent materials. The thickness obtained from the optical model was in agreement with the thickness of cross-sectional SEM images. The optical band gap, obtained from single-effective-oscillator model, varied from 5.45 to 4.24 eV as a function of the Y 2 O 3 slab thickness. The refractive index as well as the optical band gap can be modulated systematically using the Al 2 O 3 :Y 2 O 3 ratio as control parameter. By means of simulated propagation modes it is shown that there is a multimode behavior for thickness around 200 nm at wavelengths between 300 and 1550 nm. This study reveals the possibility of using Al 2 O 3 -Y 2 O 3 nanolaminates as the core of optical waveguides. It also shows the potential of ALD technique for fabrication of submicron waveguides useful in miniature optical circuits. [ABSTRACT FROM AUTHOR]

Atomic Layer Deposition (ALD) is an advantageous technique to obtain alumina (Al 2 O 3) optical waveguides based on the trimethylaluminum-water (TMA-H 2 O) process. However, the influence of ozone (O 3) as oxygen source on pure Al 2 O 3 ALD waveguides has not been studied yet. In this work, the optical design, fabrication and characterization of slab optical waveguides based on Al 2 O 3 thin films using water (Al 2 O 3 –H 2 O) or ozone (Al 2 O 3 –O 3) as oxygen source is presented. Ellipsometry measurements show a refractive index of 1.64 for Al 2 O 3 –H 2 O and of 1.65 for Al 2 O 3 –O 3 waveguides. The intensity distribution at the waveguides output demonstrates propagation of visible light (λ = 632.8 nm) for both type of waveguides. Optical propagation losses are smaller for O 3 than for H 2 O waveguides, the lowest value for Al 2 O 3 –O 3 is 0.51 dB/cm and 3.03 dB/cm for Al 2 O 3 –H 2 O. Fourier transform infrared spectroscopy (FTIR) analysis shows a prominent band for bulk OH group in water oxidized samples, which may be associated with the increase of propagation losses. X-ray photoelectron spectroscopy (XPS) show no differences in chemical composition (supplementary material). • Al 2 O 3 ALD waveguides can be fabricated with either water or ozone as oxygen source. • Al 2 O 3 waveguides fabricated with ozone as oxidant source show lower propagation losses. • Bulk OH groups in water oxidized samples are higher, which may be associated with the increase of propagation losses. [ABSTRACT FROM AUTHOR]

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. Al 2 O 3 and Y 2 O 3 are known as optical materials with transparency characteristics in the visible-NIR region, which allow application sensors and telecommunications. In this work, Al 2 O 3 -Y 2 O 3 nanolaminates films grown at 250 °C by thermal ALD were used as core for slab waveguides. Different proportions of Y 2 O 3 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. • Submicron atomic layer deposited waveguides show propagation in the visible. • Al 2 O 3 -Y 2 O 3 nanolaminated optical losses are suitable for integrated optics applications. • Waveguide properties were tuned by changing the Y 2 O 3 thickness in the nanolaminated. [ABSTRACT FROM AUTHOR]