Ring-Shaped Silicon Photonic Crystal Structures for Bio-Sensing and Optical-Interconnects
Lo, Ming Gai Stanley
In the last decade, the field of silicon photonics has emerged as a promising optical platform for applications such as optical-interconnects, telecommunications and sensing. In order to advance these technologies, development and implementation of new photonic structures is required. In this dissertation, two classes of novel ring-shaped nano-photonic structures with attractive optical characteristics are presented: (1) photonic crystal microring resonators and (2) embedded one-dimensional photonic crystal cavities. The photonic crystal microring resonator (PhCR) is first demonstrated for label-free biosensing, showing superior sensitivity over traditional ring resonator sensors due to enhanced light-matter interaction in the active sensing regions. Based on their unique optical mode patterns, PhCRs are further demonstrated to have the capability to select specific Bloch modes in the photonic crystal cavity, opening up the design freedom to achieve advanced optical-interconnect components including multiplexers and add-drop filters. A new broad-band coupling approach to PhCRs is also demonstrated by employing chirped photonic crystal mode converters. The embedded one-dimensional photonic crystal cavity (EPhCC) is introduced and demonstrated as a promising photonic structure for wavelength-division multiplexing applications. By employing a shifted-hole design, some of the radiation losses due to coupling channels can be compensated. In experiments, a loaded quality factor of ~52,000 is measured, providing 2-fold enhancement over a traditional one-dimensional photonic crystal with similar dimensions.