Theoretical Study And Structural Design Of Silicon Material Electro-optic Modulator

This paper mainly studies electric field-induced linear electro-optic effect on the basis of silica-based electro-optic effect.It explains the physical mechanism of field-induced linear electro-optic effect according to polarization theory,defines the point group symmetry of silicon materials and deduces various forms of field-induced electro-optic tensor.In the end,it discusses field-induced linear electro-optic effect in detail according to the theory on refraction index ellipsoid.When studying the characteristics of silica-based electro-optic modulation,especially that of MIS capacitance structure under exhaust state,reversed schottky barrier structure,reversed PIN structure and reversed PN structure,the paper applies different doping density of current carrier to generate built-in electric field in various electricity structures.Besides,it also applies device simulator ATLAS of Silvaco as well as limited numerical method to establish simulated model of several classic MOS electricity structure.By analyzing electricity structure under balanced state,the paper finds that generation of built-in electric field can damage the symmetry of silicon materials and therefore change refraction index,which is the precondition for generating field-induced electro-optic effect.Maximum field-induced linear electro-optic effect of 4 electricity structures is simulated when the breakdown electric field intensity of silicon is 3×105 V/cm.Major work and innovation that have been realized are as follows:(1)After imposing direct-current electric field on several classic MOS electricity structures,it is deduced that the grid breakdown voltage of MIS capacitance structure under exhausted state is 17 V,grid breakdown voltage of schottky barrier structure is-150 V,anodic breakdown voltage of reversed PIN structure is-172 V and the anodic breakdown voltage of reversed PN structure is-15.9V when the break down electric field strength of silicon material is 3×105 V/cm.(2)According to the exponential relationship between direct-current electric field strength and the changing refraction index,the greater the direct-current electric field strength is,the more obvious the field-induced linear electro-optic effect will be.Therefore,reversed PIN structures are the optimum structure and voltage data of these direct-current electric fields can be helpful in designing electricity structure of silica-based electro-optic modulator based on field-induced linear electro-optic effect.