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Title: Intermittent Dynamics of an External-Cavity Semiconductor Laser
Committee:
Dr. Citrin, Advisor
Dr. Locquet, Co-Advisor
Dr. Butera, Chair
Dr. Williams
Abstract:
The objective of the proposed research is to investigate experimentally dynamical behaviors of an external-cavity laser (ECL) with various conditions. Nonlinear dynamics and chaos have been of interest to various scientific fields after Lorenz introduced deterministic chaos with the evolution of a simple model of the atmosphere in 1963. Thanks to the development of technology, it has recently been feasible to implement experiments to confirm and support theoretical ideas on nonlinear dynamics. In particular, laser diodes are an ideal testbed for fundamental nonlinearity because various dynamics including chaos can be observed when they have a time-delayed feedback via an external cavity. A thorough understanding of a complex external-cavity laser system will help to understand nonlinear dynamics and enhance novel applications such as secure communication, light detection and ranging, optoelectronic oscillator, random-number generation, and reservoir computing. Thus, we will focus on analyzing intermittent dynamics of an ECL at different injection current. At low injection current, we study a sudden surge of exceptional amplitude, i.e., extreme events from low frequency fluctuations. At high injection current, we study multistate intermittency, which is coexistence of several dynamical states at moderate feedback strength and switching between them irregularly. We analyze statistically how those irregular behaviors change as a function of parameter and what mechanisms of dynamics are involved in such behaviors. Subsequently, based on the results of these studies, we will investigate how to reduce optical feedback effects, which is crucial to maintain stable ECLs by avoiding conditions that cause irregular dynamical behaviors.
