| Microring resonators are promising devices for all-optical signal processing. Small rings are required to increase the free-spectral range of the devices, however radiation loss during bending places a lower limit on the minimum ring radius. This thesis investigates improved tight-bending structures for microring resonators. Two-dimensional finite-difference time-domain simulations were used to compare the performance of tight bends with double mirror, resonant cavity and circular geometries. Although for some cases tight bends of non-circular shape provided higher transmission at 1.55 mum, microrings incorporating circular bends generally had the most uniform transmission across the spectrum. In collaboration with the University of Glasgow, tight bends and microring resonators were fabricated in AlGaAs. These microrings are the smallest demonstrated to date in a III-V semiconductor. |
