| The Local Oxidation of Silicon (LOCOS) technique is used for the first time to define optical rib waveguides in silicon-on-insulator (SOI) material. Optical mode simulation was used to determine rib geometries suitable for single-mode propagation in the 1550 nm optical telecommunications band. Test devices were then fabricated in SOI material with a Si film thickness near 3 mum. Cut-and-etchback optical testing of 3 mum drawn width ribs showed the loss to be less than 1 dB/cm at 1555 nm. Unbalanced Mach-Zehnder interferometers with Y-splitter junctions were also fabricated and tested with input wavelength swept from 1470 to 1580 nm and showed an extinction of 6-10 dB, demonstrating the ability of the LOCOS rib technique to produce more complex waveguide devices. |
