A VARIETY OF SLOW-LIGHT TECHNOLOGIES IN NONLINEAR DISPERSIVE MEDIA

Abstract

Over the past few years, researchers have directed a significant amount of effort towards realizing tunable all-optical devices using nonlinear optical methods. It is now possible to exercise dynamic control of the group velocity of light traveling through a wide variety of material systems. The slow and fast light refer to situations in which the group velocity íg of an optical pulse through a dispersive material can be made to be smaller and larger, respectively, than the phase velocity vp = c/n. This ability could overcome the remaining challenge in current optical networks of storing and manipulating an optical signal directly in optical domain so as to avoid a bottleneck due to optical-to-electrical (O/E) and electrical-to-optical (E/O) conversions. The overall purpose of the dissertation is to study novel slow-light systems that provide controlled generation of large pulse delays relative to the pulse width with minimal pulse shape distortion by optimally design resonance profiles of such systems. The system design studies utilize several measures of performance such as the fractional delay, power throughput, and signal distortion under the limited system resource constraints. To this end, powerful data fidelity metrics are required to quantify the performance of tunable delay devices. Here, a new framework for measuring an information velocity and throughput is described and implemented using Shannon mutual information concepts. This new technique is used to investigate trends, trade-offs, and limits in slow light devices, which are physically sensible and in good agreement with analyses obtained using a conventional eye-opening(EO) metric. Using these information-theoretic and/or conventional metrics, we present the quantifying performance of gain-based stimulated Brillouin scattering (SBS) system in optical fibers as well as optical passive devices such as Fabry-Perot, fiber Bragg gratings, and ring resonators. It is shown that combining the SBS gain medium with these passive devices can compensate their respective disadvantages and thus increase delay performance without using additional resource of SBS pump power. The results show the possibility of achieving a fractional delay up to 10 at a signal bandwidth up to tens of GHz.