BURIED INALGAAS-INP WAVE-GUIDES - ETCHING, OVERGROWTH, AND CHARACTERIZATION

We report on the fabrication and characterization of InP-buried InAlGa As rectangular core waveguides. LP-MOCVD is used for growth of the InA lGaAs-InP material system and the regrowth of InP. Reactive ion-etchin g is employed for achieving smooth and precise etch profiles. An effic ient procedure for preparing the surface is described that results in homogeneous epitaxial InP overgrowth by preventing re-oxidation of the air-exposed etched surface. The-loss characteristics of waveguides wi th a core layer thickness of 450 nm and widths ranging from 3.5 to 6 m u m are investigated at 1.3-mu m wavelength. The propagation loss is f ound to increase from 3 to 10 dB/cm with decreasing core width. Scatte ring loss caused by residual sidewall roughness is found to be the dom inant loss mechanism.