Book Description

"The continually increasing speed of microprocessors over the past forty years has been due in large part to miniaturization. The smaller a transistor is made, the faster it can run, and the more can be packed onto a chip. More recently, the performance of the electrical interconnects, which are responsible for transporting data within the microprocessor and between the microprocessor and memory, has been unable to keep pace. As the interconnect is scaled down along with the transistors, its bandwidth decreases and its latency and power consumption increase. This not only decreases the bandwidth of the interconnect, but also increases both its latency and power consumption. Optical interconnects can directly address these problems by replacing electrical interconnects at the system level. In this work we outline the requirements for a successful optical interconnect, and show that the photonic crystal platform is ideal for optical interconnects. Specifically, we show how photonic crystals can be used to build one of the most basic components of an optical interconnect: the electro-optic modulator, which converts an electrical signal into the optical domain. We will first discuss the potential of photonic crystal slow light for modulation, and then introduce a new multi-channel slow light platform for improved bandwidth. Next we describe the design of a photonic crystal resonator that is embedded entirely in silicon dioxide, which is a fundamental requirement for chip compatibility. This resonator uses a graded cavity design and has a quality factor as high as 300,000. It can be coupled to standard strip waveguides, facilitating the integration of photonic crystal devices with other photonic devices. We will also describe a simplified model of photonic crystal line-defect cavities that can aid in their design. Finally, we propose a design for a low-energy electro-optic modulator based on this graded cavity. Due to the extremely small mode volume possible with photonic crystal resonators, the active region can be on the order of a single cubic wavelength in size. By optimizing a number of parameters, a theoretical switching energy as low as 1 fJ/ bit is possible using this design."--Leaves viii-ix