Please use this identifier to cite or link to this item:
|Title:||Physics, Modeling and Design of Nonlinear Electroabsorption Modulators|
|Department:||Electrical and Computer Engineering|
|Keywords:||Modeling and Physics;Nonlinear electroabsobtion modulators;Computer Engineering;Electrical and Computer Engineering;Computer Engineering|
|Abstract:||<p>Wavelength division multiplexing (WDM) is the key technology of the current generation fiber-optics network. To build agile and intelligent next generation optical networks, optical wavelength conversion and signal regeneration are crucial new functions under intense research and development. These new functions call for innovative, low cost and high performance optoelectronic devices. One of such enabling devices is quantum-well electroabsorption modulators (EAM) that are appealing in terms of structural simplicity and low noise and are potentially advantageous on high-speed operation and low power consumption. The goal of this thesis is to systematically study EAM for optical signal functions in optical networks from various perspectives, including fundamental device physics, comprehensive models, innovative design, and experimental prototyping.</p> <p>After the first chapter of introduction, Chapter 2 and 3 are devoted to device models. In Chapter 2, a self-consistent and physics-based model has been developed for two key nonlinear optical mechanisms in quantum-well EAM: exciton saturation and electric field screening. Presented in Chapter 3 is a simplified but efficient model for EAM with a feature of handling strong electric field.</p> <p>Next, the fundamental physics relevant to nonlinear EAM are studied in Chapter 4 and 5. Exciton state mixing effects on intersubband transitions in quantum well have been investigated in Chapter 4 and a drastic different picture from that of the previous studies has been revealed. Studies have also been done in Chapter 5 on valence band mixing effects in exciton capture and escape in quantum well structures. And it is found that much faster capture and escape processes can be resulted from the band mixing effects.</p> <p>Then, the two key design issues of nonlinear EAM have been addressed. In Chapter 6, different saturation dynamics of electrons and holes in quantum wells have been thoroughly analyzed and utilized to achieve the best compromise between high-speed and low power consumption of EAM in optical wavelength conversion and signal regeneration. In Chapter 7, the polarization issue of transverse electric (TE) mode and transverse magnetic (TM) mode is addressed from two different perspectives: design for the most effective optical saturation by using TM mode absorption and design for TE and TM polarization insensitive operation.</p> <p>Finally, Chapter 8 presents the results of experimental proto typing on the design concept to enhance exciton absorption saturation using light-hole excitation through TM optical mode.</p>|
|Appears in Collections:||Open Access Dissertations and Theses|
Items in MacSphere are protected by copyright, with all rights reserved, unless otherwise indicated.