EFFECT OF REACTIVE ION ETCHING-GENERATED SIDEWALL ROUGHNESS ON PROPAGATION LOSS OF BURIED-CHANNEL SILICA WAVE-GUIDES

Different mask materials (photoresist and amorphous silicon) and diffe rent sample temperatures can influence the roughness of sidewalls prod uced during reactive ion etching of silica. Buried-channel waveguides with different microroughness on the core sidewalls (corrugation perio ds less than 1 mu m) have been fabricated and characterized for their propagation loss at 1.3 mu m wavelength. An increase in the sidewall r oughness amplitude of around 0.05 mu m results in an increase in the p ropagation loss of 0.2 dB/cm. Sidewall roughness with a larger period appears to have smaller effect on loss. (C) 1996 American Institute of Physics.