OPTICAL WAVEGUIDE ARRANGEMENTS COMPRISING AN AUXILIARY WAVEGUIDE - LIKE STRUCTURE

摘要

An optical waveguide arrangement is provided which comprises an active ridge waveguide structure12 formed by etching of a semiconductor substrate 1, 2, 3. There is also provided an auxiliary waveguide-like structure 8 formed on the substrate adjacent the active ridge waveguide structure12 to control the etched profile of the active waveguide structure. The arrangement of the auxiliary structure 8 on the substrate controls the etched profile over the cross-section of the active waveguide structure12 and along the length of the active waveguide structure12. Advantageously, this arrangement reduces or eliminates the disadvantages associated with etch-process induced asymmetries in the shape of closely spaced waveguides.