Determination of volume and surface contributionsto the total attenuation in ZnS waveguides.

We relate the modal waveguide attenuation of polycrystalline ZnS films to their mode field properties, namely the field amplitudes at the interfaces and the power confinement factor, to show that the totalwaveguide attenuation is caused by a combination of volume and surface effects. Our results show that the surface losses for the TE(0) mode, which are approximately 1.5 dB/cm, are independent of the total attenuation, which varies from 6 to 40 dB/cm. This suggests that the losses of the lower-order modes are dominated by volume effects such as scattering from crystallite boundaries and absorption.

Optical waveguide characterization of dielectric films deposited by reactive low-voltage ion plating.

We determine the quality of single films of various oxides, which are deposited on thermally oxidized silicon wafers by reactive low-voltage ion plating (RLVIP), by measuring their optical waveguide losses. We use a prism coupler for inserting the radiation of a wavelength-selectable He-Ne laser into the waveguide and a CCD camera for imaging the light scattered from the surface of the films. The waveguide losses of the RLVIP films are typically of the order of 1 to 10 dB/cm. Some data obtained for TiO(2) layers on thermally grown SiO(2) and RLVIP SiO(2) seem to confirm the presence of an absorbing boundary layer between RLVIP SiO(2) and TiO(2) that has been found in SiO(2)-TiO(2) multilayers. The waveguide measurements also reveal unusual index gradients in thick (~ 10 µm) single layers of Al(2)O(3) derived from multimode effective index calculations.