InP-based high index waveguides on GaInAsP/InP for applications in active/passive ring resonators

Miniaturization of waveguide circuits is inherently connected with the implementation of highly confined waveguides as one prerequisite for the building of sharp bends and optical microring circuits. Integrated optical ring resonators are promising candidates for compact optical filters and wavelength (de)multiplexers. Their realization in active semiconductor material opens the potential to verify "lossless" filter devices as well as novel laser components with outstanding performance. Since ring resonators do not require facets or gratings for optical feedback they are particularly suited for monolithic integration. Design and technology for device fabrication are summarized. Recent results on transmission and emission mode characteristics of fabricated passive ring resonators as well as gain-included "all-active" resonators in the transmission and emission mode are presented.