DETERMINATION OF VOLUME AND SURFACE CONTRIBUTIONS TO THE TOTAL ATTENUATION IN ZNS WAVE-GUIDES

We relate the modal waveguide attenuation of polycrystalline ZnS films to their mode field properties, namely the field amplitudes at the in terfaces and the power confinement factor, to show that the total wave guide attenuation is caused by a combination of volume and surface eff ects. Our results show that the surface losses for the TE0 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 th e lower-order modes are dominated by volume effects such as scattering from crystallite boundaries and absorption.