Study of reactive ion etched (RIE) facets of silicon- on-insulator (SOI) rip waveguides

In our study we compare the quality of dry etched rip waveguide facets to facets prepared by a conventional polishing technique. Linear SOI waveguide arrays were fabricated on BESOI (bonded and etched-back SOI) material with a silicon top-layer of H = 4 /spl mu/m. We used standard contact lithography for patterning and a commercial RIE system for waveguide and facet etching. We studied different process flows (facet-first and rip-first), different masking materials and loading effects on the wafer. The surface of the facets was characterized by high resolution scanning electron microscopy (SEM). The additional coupling loss introduced by the process flow and by the etching conditions as well as the impact of the two on uniformity of the waveguide transmission were quantified by means of fiber-to-fiber optical measurements (at 1.55 /spl mu/m).