Graphene-Based Optical Waveguides for Surface Plasmon Polariton Transmission

Abstract

In this chapter, various ideas and designs related to plasmonic waveguides are reviewed. As plasmonic structures can confine light in small sizes, they can be considered a suitable option in the design of optical devices. In recent years, graphene has been known as an attractive material in optical applications and can be used to guide surface plasmons. By photo-stimulating surface plasmons at the semiconductor-graphene interface, plasmon polaritons can be confined near graphene and guided to several micrometers. Using this feature, various optical waveguides can be designed. The real and imaginary parts of the effective refractive index of the waveguide, the figure of merit, coupling length, crosstalk, and loss in decibels per micrometer are the most important parameters in the design of plasmonic waveguides. In recent years, various ideas such as the use of ridges, graphene nano-ribbons or strips, and graphene sheets have been proposed, which provide waveguides with different characteristics. In this chapter, the theory and basic relationships in light confinement in plasmonic waveguides are investigated first. In the following, different structures designed in recent years are reviewed.