Abstract
The main purpose of this thesis is to present a new geometric structure for the surface plasmon polariton (SPP) waveguide. In order to have low loss sub-wavelength field confinement, basic ideas for the proposed structure are based on the concepts of hybrid SPP modes that combine typical SPP modes with dielectric waveguide modes. Typical long-range SPP waveguides usually have more than 1 μm mode widths when propagation distances reach about 100 μm. The hybrid SPP waveguide structure have long-range propagation distance with relatively small mode confinement area. Different from some numerical methods in prior works, this thesis makes use of a methodology operated in HFSS to calculate the hybrid plasmonic guided-wave structures. With eigenmode solver in HFSS, eigenmodes or resonant frequencies of the optical waveguide structures are calculated and key parameters are extracted. This methodology is practiced and confirmed reliable since the simulated results are corresponding to data presented in prior works. With these industrial tool and simulation methodology, time for developing and analyzing new SPP waveguide structures is shortened. Based on typical hybrid SPP guided-wave structure, the proposed hybrid plasmonic waveguide structure contains an etched channel in silver under the GaAs cylinder. The calculated propagation distance of the proposed waveguide structure reaches about 30 μm with sub-wavelength field confinement. Comparing with typical cylinder based SPP guided-wave structure, the mode area shrinks more than 50% while the propagation distance only decreases only 10%. That is, the proposed hybrid plasmonic waveguide provides comparable propagation distance to typical design while enhancing the field confinement. As advancement of the lithographic micro-processing technology, the proposed optical waveguide structure will have chance to be used in newly optical integrated circuits.