CHANNEL OPTICAL WAVE-GUIDES FORMED BY DEUTERIUM PASSIVATION IN GAAS AND INP

Channel optical waveguides have been formed on both GaAs and InP subst rates utilizing deuterium passivation of the surface to provide planar confinement and etching to provide lateral confinement. Design criter ia were established for obtaining single mode channel waveguides for t he present case of small index changes and thick surface layers associ ated with deuterium passivation. Planar and channel waveguide operatio ns were demonstrated and channel waveguide propagation losses have bee n measured, For GaAs channel waveguides, optical loss was measured as a function of channel waveguide width, ranging from 3 to 9 mu m, with a minimum loss found for a width of 6.0 mu m. Channel waveguide losses as low as 12.7 dB/cm for GaAs and 6.0 dB/cm for InP have been measure d at lambda = 1.3 mu m. For InP this loss value is close to the limiti ng value imposed by free carrier absorption in the semiconductor regio n below the passivated region. Since the waveguide loss due to free ca rriers can be reduced by increasing waveguide confinement, we anticipa te that lower loss optical channel waveguides could be formed by this technique. (C) 1997 American Institute of Physics.