| Since the surface plasmon was discovered,it has become more and more active in optical communication.It has the advantage of high energy localization,easy integration,and the ability of breakthrough of diffraction limit.Surface plasmon polaritons(SPPs)have been widely used in biosensor,optical communication,optoelectronic devices and other aspects.It has unique value in modern optical communication system.The surface plasmon will be effective by using metal-insulator-metal(MIM)three-layer waveguide.This kind of waveguide is easy to fabricate.It can be easily compacted in structure,and has excellent transmission and reflection characteristics.It has become the basis of many optoelectronic devices.As a mature structure which has been widely used in communication,fiber Bragg grating can be well combined with MIM structure to develop surface plasmon.This paper completes the following works:Firstly,the development history and current situation of surface plasmon are briefly introduced.In this paper,several different excitation modes of SPPs are introduced,and the dispersion equation is obtained by combining Maxwell equations.The reason that SPPs can only be excited in TM mode is explained.In addition,several characteristic parameters of SPPs and several numerical research methods of SPPs are introduced.In the follow-up research process of this paper,FDTD solutions is used for simulation.Secondly,the structural characteristics of MIM and the basic modes of SPPs propagation in MIM structures are mentioned.Odd symmetry mode and even symmetry mode are studied.In addition,the transmission characteristics of surface plasmons in MIM structures and MIM resonators are introduced.Then,fiber Bragg gratings and fiber Bragg gratings with MIM are introduced.The characteristics of Bragg grating and its application value in propagation devices are analyzed.It is possible to make transmission filtering by using the coupling of Bragg grating and cavity.Finally,we carry out a simple simulation of metal-Bragg grating array-metal structure by using FDTD method,and we analysis the results.Finally,we propose a structure of Bragg grating array-metal transmission broadband bandstop filter.After using FDTD method to study the transmission characteristics of the structure,we adjust the parameters of the structure and find a method to change its working frequency efficiently.Then,we change the shape of the arrays.We find that circular units,symmetric semicircular units,inverted trapezoidal units and hexagonal units in arrays have similar transmittance performance.Finally,this paper studies the transmission change of the damaged structure in special cases.The results show that the structure has a certain resistance to fracture and dislocation,but it would be affected in the case of bending.In conclusion,the transmission band stop filter proposed in this paper has value to be used.It can be refered in the simulation and adjustment of micro nano optoelectronic devices. |
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