Comprehensive Theoretical Studies of Guided Modes in Multilayer Hybrid Plasmonic Waveguides
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Date
2018-05-02
Authors
Aldawsari, Sarah
Journal Title
Journal ISSN
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Publisher
University of Waterloo
Abstract
Plasmonic waveguides (PWs) have integrated the strength of the miniscule size of electrical-wire interconnects and the large operational bandwidth of photonic waveguides. Beyond the diffraction limit, PWs have the ability to manipulate light at nanoscale structures through surface plasmon polaritons (SPPs) at metal-dielectric interface. Much interest has been paid to PWs because they are promising candidates for developing the next generation highly-dense integrated photonic circuits. However, the tradeoff between mode confinement and propagation loss is an issue encountering PWs. Fortunately, hybrid plasmonic waveguides (HPWs) are recent novel type of PWs, which have shown a favorable balance between mode confinement and propagation loss. Despite the excessive schemes of HPWs that have been proposed and studied theoretically for further enhancement such as symmetrical hybrid plasmonic waveguides, most of these studies are based on using simulation softwares. There is a lack of theoretical study for HPWs based on analytical derived equations, which are important to understand the hybrid guided mode deeply, and study all the key factors that might enhance the optical performance, and help the waveguide designers for the fabrication of plasmonic waveguides.
In this dissertation, comprehensive theoretical studies are presented based on analytical derived expressions for different types of multilayer hybrid plasmonic waveguides. They are hybrid-dielectic-metal-dielectric (DMD) and hybrid-metal-dielectric-metal (MDM) plasmonic waveguides. The guided modes equations have been derived, and their modal properties have been investigated numerically based on the derived analytical equations for different materials, including the modal index and the propagation length. The profile of the fields of the guided modes such as the electric field and energy flux density have been visualized. The hybrid guided modes characteristics has been analyzed thoroughly by proposing two effective criteria. The optical performance of the multilayer hybrid plasmonic waveguides has been also examined by measuring the normalized mode size, figures of merit, and confinement factor of the hybrid guided modes. Moreover, different factors have been taken into accounts in the study, such as the geometrical parameters and the optical properties of the materials. Consequently, these multilayer hybrid plasmonic waveguides have shown a better compromise between mode and propagation loss compared to the PWs. Such waveguides structures can be utilized for ultra-compact active/passive nanophotonic devices.
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Keywords
Plasmonic Waveguides, Hybrid Plasmonic Waveguides, Integrated Optics