Hybrid silicon-organic ring resonator photonic devices

Thesis (Ph. D.)--University of Washington, 2006.This dissertation focuses on the intersection of two powerful technologies: organic electro-optic materials and silicon-based photonics. By combining the ever-increasing speed of the organics with the ubiquitous silicon, a new generation of photonic devices has been realized. The primary devices are ring resonator photonic components fabricated in silicon and integrated with electro-optic material to form electro-optic modulators for the purpose of converting data from the electronic to the optical domain. These devices represent a vast improvement over the current modulators used in fiber optic telecommunications networks worldwide. Two main types of devices are the focus: traditional ring resonators with single, monolithic waveguides and split-waveguide devices with the optical field concentrated between two electrically insulated rails separated by ∼100 nm.In order to capitalize on the benefits of silicon as a photonic medium significant challenges were overcome, the most significant of which was a large discrepancy between the dielectric breakdown point of the silicon resonators and the field needed to electrostatically pole the electro-optic polymer integrated with the resonators. This was accomplished through the use of intricate 3D lithographic processing in the case of monolithic rings and by using the individual waveguide rails themselves as electrodes for split-waveguide devices. Additional problems overcome in pursuit of developing theses modulators include developing techniques for poling using doped silicon as an electrode instead of metal and the use of nanoimprint lithography for completely and repeatably filling the nano-scale features of these devices.Complete and successfully functioning modulators of both types have been achieved with low drive voltages (∼1 V), high speeds (MHz), and three orders of magnitude decrease in size when compared to current devices. An additional result was the creation of a nano-scale photodetector, capable of detecting optical signals six orders of magnitude smaller than previously reported results, by running the electro-optic modulator in reverse: inserting an optical signal into the resonator and generating an electrical signal. The end result is the development of two vital components for future photonic integrated circuits: a modulator and a detector. These are the first reported devices to perform these functions by combining organic electro-optic materials and silicon photonic resonators, two significant technologies which will likely shape the future of telecommunications for years to come