Figures of merit and modelling of metallo-dielectric waveguides.

摘要

The thesis is divided into two topics. The first is a figure of merit study on 2D surface plasmon waveguides, assessing the trade-off between attenuation and confinement. Three figures of merit are used since there are three separate, but equally effective, ways of measuring confinement. Different stripe geometries are considered in this analysis as well as a comparison between Au, Ag and Al (as the stripe metal) over the wavelength range from 200 to 2000 nm. The figures of merit are generally applicable and should be useful to help compare, assess and optimize designs in other 2D absorbing waveguides.The second topic introduces a new waveguide structure, the metallo-dielectric waveguide, capable of aggressive bends and long-range propagation at optical wavelengths. Its design was inspired by the non-radiative dielectric waveguide which is effective at microwave frequencies but has been shown to have high loss at optical wavelengths. Since both waveguides use parallel plates as confinement mechanisms, one dimensional analysis is first performed to gain insight into their operation followed by full-wave 2D simulations of the two waveguides in their straight and curved form. Analysis of the parallel plates revealed the relation between the modes supported by the real metal and perfect electric conductors (PECs). The non-radiative dielectric waveguide is found to effectively suppress radiation however, its propagation loss is high and the mode becomes deformed along radial bends, as r0 &rarr 0, due to excitation of surface plasmon-polaritons. The newly introduced metallo-dielectric waveguide performs significantly better in that it is capable of long-range propagation while also supporting its fundamental TE mode along aggressive radial bends. This waveguide also has potential use in optoelectronic/electro-optic components due to the presence of the metal plates which could be used to apply electric fields or inject currents.