Title

High-Speed All-Optical Signal Processing Using Ultrafast Devices and Nonlinear Fibers

Date of Completion

January 2012

Keywords

Physics, Optics

Degree

Ph.D.

Abstract

The next generation of fiber-optic communication systems is looking to convert from the current electro-optical network to the potentially faster and more efficient all-optical network. This conversion requires simple and effective functional devices to perform all-optical data processing, switching, pulse regeneration and compression. In this dessertation, I will show the designs of several key functional units based on the ultra-fast nonlinear effects in highly nonlinear optical fibers and semiconductor waveguides such as quantum dot (QD) semiconductor optical amplifiers (SOA). This dissertation includes the small-signal study of the four-wave mixing (FWM) process in quantum dot SOA, the design and performance analysis of all-optical XOR, AND, NOT, NAND Boolean logic gates operating at 250 Gb/s or higher based on two different schemes: (1) the cross gain and phase modulation (XGM and XPM) in quantum dot semiconductor optical amplifiers and (2) the two-photon absorption (TPA) effect in bulk semiconductor optical amplifiers. Designs of optical pseudo random binary sequence (PRBS) generators based on both schemes are included and simulations of 250 Gb/s PRBS generations are shown. An effective optical pulse compressor is designed and experimentally demonstrated. The compressor utilizes a highly nonlinear photonic crystal fiber (PCF)-based nonlinear optical loop minor (NOLM) in a ring structure to realize multi-step compression. Results show that rational harmonic mode-lock fiber laser pulse trains at 40 Gb/s can be compressed to ~570 fs using this compressor. ^