| Wavelength Division Multiplexing (WDM) emerges as one of the most promising ways to increase the channel capacity of an optical communication network. Tunable filtering components are essential parts of a WDM system, and their performance directly affects the overall performance of the network. Although one can employ various technologies to realize such devices, it is often very difficult to satisfy all the requirements of tunable filtering using a single technology. In this work hybrid integration of polymers and compound semiconductors will be used. By employing low loss fiber-mode matched polymer waveguides as the main communication bus, low overall loss, and low cost will be ensured. By employing semiconductors as filtering elements, low crosstalk and fast tunability will be utilized. Higher functionality and performance will also be achieved by adding components such as high-contrast semiconductor gratings or micro-disc resonators.; In this thesis, design, fabrication and characterization of low loss polymer waveguides using BCB type polymers, and their integration with substrate-removed GaAs epi-layers will be reported. It will be shown that such a hybrid system defines a highly asymmetric directional coupler, and can act as a band-stop filter. Derivation, and demonstration of a characteristic equation for the operating wavelength, and a filter transfer function using appropriate coupled-mode equations will be studied. Multi-wavelength operation, as well as electro-optic, and thermo-electric tunability of such a device will be shown. Realization of a tunable grating reflector device with the addition of etched gratings on the GaAs surface will be presented. It will be demonstrated that the reflectivity of the gratings at the Bragg wavelength can be modulated from 0 to 100% with the coupler transfer function. A report on the realization of hybrid micro-disc resonator filters, with ultra-wide free spectral ranges due to suppression of the off-coupling resonances will also be presented. |
