Research On All-optical Encoder Based On Two-dimensional Photonic Crystal Logic Gat

With the development of communication technology,optical communication technology has also caught the "fast train" of development,and all optical communication networks are gradually receiving attention from people.All optical communication requires the conversion between light and electricity at each node,and photonic crystals can achieve efficient photoelectric conversion.Therefore,the research on photonic crystals is an important part of all optical communication networks,and the related research on photonic crystals is becoming increasingly mature.Photonic crystal is an artificial material with periodic internal structure,and its electrons are subjected to Bragg scattering.In all optical communication networks,all optical logic gates are an important component that can enhance the reliability and efficiency of communication in all optical networks,making contributions to the development of all optical networks.This thsis first analyzes the development and research status of all-optical logic gates,then analyzes the plane wave expansion method and finite difference time domain method,analyzes and introduces the periodic characteristics and local characteristics of photonic crystals,and then studies the main factors affecting the photon belt gap..After a series of simulation,it was found that the band gap is mainly controlled by four aspects: lattice type,dielectric column shape,dielectric column radius,and relative refractive index.Then the square lattice circular dielectric column structure is adopted,and the reasonable dielectric column radius,lattice constant and refractive index are set at the same time.The all-optical AND gate,OR gate,NOT gate and XOR gate logic structures are designed.The plane wave expansion method and the finite time domain difference method are used to obtain the transmittance map,response time map and electric field steady-state distribution map of the designed structure.Finally,an all-optical encoder based on two-dimensional photonic crystal logic gates is designed.The plane wave expansion method and the finite difference time domain method are also used to simulate the corresponding parameters,such as the electric field distribution map and the transmittance map.The results show that the designed logic gates have corresponding logic functions,small structural dimensions,reasonable parameter selection,good extinction ratio and response time,and have great potential in the field of integrated optics.