Study On Electro-Optical Diffraction Properties Of Periodically Poled Lithium Niobate And Its Integrated Device

PPLN has occupied an important position in nonlinear optics domain. In recent years, novel optical devices based on PPLN electro-optic effect become a research hotspot. When an electric field is being applied in the direction of polarization of the PPLN, PPLN will become refractive index grating. For the question of its electro-optical diffraction, there has been a little system theoretical analysis and the research of electro-optic diffractive properties. In this paper, according to lithium niobate crystal electro-optical effect of periodically domain inversion structure and the analytical method which puts beam propagation in lithium niobate crystals, we had obtained the applicable conditions of RCWA method, which can be applied to theoretical calculation which can be solved PPLN electro-optical refractive index grating diffraction problems, and then, detailedly derived the RCWA method of PPLN. We had studied the electro-optical diffraction properties of PPLN by numerical methods of RCWA, when PPLN was put in to different background index of refraction. Based on those and ABCD theorem, we had designed a kind of integrated electro-optical devices which can achieve the function of dynamic focusing and the light beam conversion. The main contents can be listed as follows:(1) We had introduced the research status of domain inversion structure electro-optical devices at home and abroad and briefly described chapter arrangement of this paper.(2) We had analyzed the electro-optic effect of PPLN and the applicable conditions by applying lithium niobate crystal electro-optical effect of periodically domain inversion structure and crystal index ellipsoid method which can be applied to using RCWA method to numerical calculation for electro-optical diffraction characteristics of PPLN, when the electric field was applied to the direction of polarization, and then, detailedly derived the RCWA method of PPLN.(3) By applying RCWA method, we had not only studied both physical parameters and geometric parameters which include electro-optic coefficient, crystal length, polarization period, duty cycle, temperature, angle of incidence and temperature and so on influence electro-optical diffraction efficiency of PPLN, but also studied specific properties of the electro-optical diffraction of PPLN under different parameters, when PPLN in four different background index of refraction. Additionally, we had analyzed electro-optical diffraction characteristics of7mol%Mg-doped and pure PPLN by comparative analysis method, which are used in the air is very common. We had also proposed a method which can be achieved high diffraction efficiency. (4) By utilizing the electro-optical diffraction properties of PPLN and the electro-optic focusing properties of lens-shaped domain inversion structure, we had proposed a integrated electro-optical devices which could achieve the function of dynamic focusing and the light beam conversion and made a specifically design, finally, used the BPM to make a simulation about it.