Transmission Characteristics Of Subwavelength Optical Waveguide With Anistropic Zero-index Metamaterial

Over the past decade, subwavelength optical waveguides have been extensivelystudied. The wavelength selection filter in different optical frequency has showed manyprominent potential applications. Llight waves in the lateral of the MDM structure arelocalized on the interface (corresponding to the pure imaginary wave vector).As theeffective wave vector in its propagation direction increases, the correspondingeffective wavelength will be smaller. Thus we can control SPP through themicrocavity. The design principles of MDM waveguide filter can be broadly dividedinto two types. The first one is based on the filtering phase coherence, such as differentprofile of the groove and the forked waveguide structure. The second is based on theresonance of the coupling cavity. Much narrower wavelength bandwidth can beachieved through this structure, and the energy loss is smaller. Its filtering functionalityin the communication band is better than the first one.Study in this thesis is based on surface plasmon polaritons (SPPs) and the coupledmode theory. Aimed at the above two aspects, we use the matlab program and finiteelement method (FEM) to proceed numerical simulation of micro-cavity side coupledMDM subwavelength waveguide and analyze its field distribution and transmissionspectrum. By changing the size of the coupling cavity, coupling distance, the dielectricconstant and other parameters, we analyze the transmission characteristics of lightwaves through the metal structure. Furthermore, to realize the effect of filter inrelatively large coupling distance, we introduce a slit structure between the MDMwaveguide and the resonant coupled cavity. It is shown that by varying the slit position,the wavelength selection feature can be tunned.In addition, zero refractive index metamaterials have exotic electromagneticproperties and can achieve precise control on the optical phase. This will bring us a newideas in manipulating the transmission characteristics of the MDM waveguide bychanging the embedded structure’s physical parameters and designing the MDMsubwavelength waveguide coupled cavity. Then, we analyze the phase delaycharacteristics and the possibility of guiding SPPs about a rounded metal corner byanisotropic zero-index metamaterial (AZIM). We explore its application in therealization of the side coupled cavity structure MDM waveguide filter.The results in this paper may provide certain theoretical basis and practicalguidance for plasmonic interconnects in integrated ultra-high speed photonic circuits.