The Research Of Applications Of Dielectric-loaded Graphene Plasmon Waveguides

Dielectric loaded graphene plasmon waveguide(DLGPW)is a new kind of waveguide.Since graphene surface plasmons modes could be dynamically modified by chemical doping or electrical gating.DLGPW is a proper selection to design electrically controlled devices.The main work of this thesis is to design an electrically controlled directional coupler and a switch based on the DLGPW.The major results of our research are as follow.i.We design and numerically demonstrate that electrically tunable directional coupling and switching can be realized based on multimode interference(MMI) effect in DLGPWs.The total field profile resulting from a superposition of all guided modes in the multimode dielectric-loaded graphene plasmon waveguide is electrically controllable because the propagation properties of the guided modes supported by the DLGPW can be effectively manipulated by electrostatic doping of graphene.The functional size of the device is only several micrometres,which is much smaller than the working wavelength.It can perform the functions of directional coupling,switching,and beam splitting.Such electrically controlled multifunctional devices may find potential applications in high-density integrated active plasmonic circuits.ii.We numerically demonstrate that electro-optic switching in the mid-infrared range can be realized using a waveguide-ring resonator made of DLGPWs.The coupling effect of the ring cavity can be controlled by the external voltage,realizing the switching function.