| Reconfigurable, narrowband optical filters and add-drop multiplexers (ADMs) are key components for versatile high-capacity fiber-optic wavelength division multiplexed (WDM) communication systems. Implementing the filters and ADMs in semiconductor waveguide technology opens possibilities for integration with other passive and active devices for high-functionality modules.; The dissertation describes design, fabrication and characterization of InP waveguide based filters and ADMs with optical bandwidths below 50 GHz.; The devices are based on distributed Bragg reflector (DBR) filters. Methods to achieve optical bandwidths sufficiently narrow for dense-WDM are discussed. By using quarter-wave shifted DBR gratings in low loss waveguides, optical filter bandwidths of 38 GHz at 1.55μm wavelength were demonstrated. The bandwidth of these first-order filters was limited by waveguide propagation loss; design approaches for implementation of higher-order filters with even smaller bandwidth and less sensitivity to losses will be discussed. Finally, the dissertation covers integration of the narrowband filters with directional couplers to obtain add-drop multiplexers. |
