The Researches Of Graphene Based Optical Switches And Routing Devices

Due to the development and progress of information technology,surface plasmon polaritons(SPP)devices have become an important research direction and hotspot in academic field,and the optical switch function based on SPP devices has attracted great attentions.The optical switching function realized by metal/dielectric waveguides is generally used.However,poor dynamic adjustability limits their development and application in optical switch.Graphene has attracted great attention because of its flexible tunability and high light constraints.In this dissertation,optical switch devices and optical routing devices based on graphene materials have been investigated in detail.The main researching contents are as follows:(1)A novel terahertz optical switch with graphene waveguide structure is proposed.Based on graphene material,different waveguide structures were designed and optimized to realize the efficient transmission and manipulation of THz wave in graphene waveguide.THz wave is incident from the left end of the graphene waveguide,coupled with the graphene waveguide and generates SPP wave which can be transmitted on the waveguide.By setting appropriate bias voltage in the specific output channel of the graphene waveguide and adjusting the graphene chemical potential of the output channel,we can control the conduction and interruption of the THz wave in the output channel,and also realize the input energy transmitted from the input channel to the specific output channel.(2)An active controllable Fano resonant terahertz optical switch is proposed.Based on the double-split-ring structure of graphene,plane waves are incident normal to structures with different parameters.The resonant characteristics and corresponding resonance wavelengths are studied.The structure parameters are optimized and adjusted to realize Fano resonance.We analyze the magnetic field distribution and explore the origins of Fano resonance,then the influence of the structure parameters of graphene on Fano curves are investigated.By setting appropriate bias voltage,we analyzed the effect of controlling graphene chemical potential on Fano resonance,and we have also investigated the effects of the rotating angles between two circular rings on the Fano resonance curves.