Theoretical Research Of Silicon-based Micro Ring Resonator Modulator

The electro-optic modulator is the key component in optical fiber communication system,and it is the research emphasis of electro-optic modulator with high speed,wide bandwidth,small size and easy integration.The traditional electro-optic modulator is mainly used to achieve high speed electro-optic modulation by using the refractive index effect of LiNbO3 or III-V materials.However,it faces the universal problems of large size,low integration and high production cost.Silicon-based light modulator with optoelectronic and microelectronic integrated potential using cheap silicon materials and mature silicon-based technology,is particularly vital for the realization of electro-optic modulation with high-speed,wide bandwidth,small size,enable-integrated.In this thesis,silicon-based electro-optic modulator based on micro ring resonant structure has been researched.The electro-optical modulation principle,structure design and device simulation of embedded graphene silicon-based micro ring has been intensively researched.The main contents are as follows:Firstly,the coupled mode equations of silicon-based optical waveguide was researched,the theoretical model of silicon-based micro ring resonant structure has been obtained,and the effects of some micro ring parameters on micro ring resonator,including the micro ring radius,waveguide spacing and micro ring loss was analyzed.Besides,the working principle of electro-optic modulation of graphene-silicon-based micro ring has been also discussed,which provides a reference for the graphene silicon-based micro ring modulator design;Secondly,the embedded type double-layer graphene silicon waveguide structure has been designed,the correlating relationship of voltage and effective index of graphene silicon waveguide via finite element analysis method is established,and the characteristics of electro-optical modulation of TE and TM modes of double-layer graphene silicon-based electro-optic modulator is also acquired.A double-layer graphene silicon-based micro ring modulator has been designed employing this waveguide,the graphene silicon-based micro ring electro-optic modulator with high speed,wide bandwidth and small size has been achieved through optimizing the location of embedded graphene in waveguide,isolation layer thickness and materials,and waveguide dimensions;Thirdly,in order to further enhance the interaction between graphene and lightwave,the multilayer graphene embedded in silicon waveguides has been proposed.It is found that the optimal layers of graphene silicon-based waveguide is four using comparing the diameters of different layers.The results indicate that the TE modulation mode extinction embedded four layers of grapheme silicon-based micro ring modulator ratio is 32.1dB,the driving voltage is 6.22 V,the energy loss is 6.8f J/bit;the TM mode modulation extinction ratio can reach to 37.4d B,the driving voltage is 2.2V,the energy consumption is 0.92fJ/bit,the modulation bandwidth is 140 GHz.In order to eliminate the difference between the TE mode and the TM mode,a four layer graphene silicon-based micro ring polarization-insensitive electro-optic modulator is proposed by introducing both the horizontal and vertical graphene layers.Finally,the work of this paper is summarized,and the prospects of the graphene silicon-based micro ring electro-optic modulator is prospected.