Date of Award
Master of Science (MS)
Timothy X. Brown
The telecommunications and computer technology industries have been requiring higher communications speeds at all levels for devices, components and interconnected systems. Optical devices and optical interconnections are a viable alternative over other traditional technologies such as copper-based interconnections. Latency reductions can be achieved through the use of optical interconnections. Currently, a particular architecture for optical interconnections is being studied at the University of Colorado at Boulder in the EMT/NANO project, called Broadcast Optical Interconnects for Global Communication in Many-Core Chip Multiprocessor.
As with most types of networks, including optical networks, one of the most important components are modulators. Therefore adequate design and fabrication techniques for modulators contribute to higher modulation rates which lead to improve the efficiency and reductions in the latency of the optical network. Electro-optical modulators are presented in this study as an alternative to achieve this end.
In recent years, nonlinear optical (NLO) materials have been used for the fabrication of high-speed electro-optical modulators. Polymers doped with chromophores are an alternative among NLO materials because they can develop large electro-optic coefficients and low dielectric constants. These two factors are critical for achieving high-speed modulation rates. These polymer-based electro-optical modulators can be fabricated using standard laboratory techniques, such as polymer spin-coating onto substrates, UV bleaching to achieve a refractive index variation and poling techniques to align the chromophores in cured polymers.
The design of the electro-optic modulators require the use of the optical parameters of the materials to be used. Therefore the characterization of these materials is a required previous step. This characterization is performed by the fabrication of chromophores-doped polymer samples and conducting transmission and reflection measurements to obtain the optical density. Then, using the Kramer-Kronig analysis, the refractive index change can be calculated. Another measured parameter is the electro-optic coefficient. After obtaining these optical and electric parameters, they are used as inputs in the Computer Aid Design (CAD) software COMSOL Multiphysics to carry out the simulation of the modes of the waveguide.
Finally, an analysis of nanotechnology and nanophotonics in telecommunications can show us how the design of optical devices using NLO materials fits in a much larger technological area. It is important to have an understanding of the industry that this technology is a part of. A roadmap for nanophotonics shows where this technology is going and what kind of technological constraints or needs it can solve.
Espinoza, David, "Design of an Electro-Optic Modulator for High Speed Communications" (2011). Interdisciplinary Telecommunications Graduate Theses & Dissertations. 22.