Design And Research Of All-optical Logic Gate Based On Two-dimensional Photonic Crystal

Research on optical communication technology is very hot now,the future advantages of all-optical communication networks are becoming increasingly apparent,photonic crystals have made great progress in research as an artificial material.Due to the special periodic structure of photonic crystals,the electrons moving inside the crystal are subjected to Bragg scattering,which results in photonic band gap characteristics and photon local characteristics.All-optical logic gates can perform fast information processing and all-optical calculations in all-optical communication networks,improving the efficiency and reliability of all-optical network communication transmission.Using photonic crystal bandgap characteristics and photonic local characteristics,designing photonic crystal all-optical logic gate devices with superior performance will improve the judgment efficiency of the logic gate structure,make the density of optical integration higher,more widely used,and promote the rapid development of optical communication networks.This thesis first introduced the development and research status of all-optical logic gates.Due to the large size and complicated structure of the existing all-optical logic gates,there are many shortcomings.The use of photonic crystal materials in this thesis can greatly reduce the complexity of the structure.Secondly,two theoretical methods for studying photonic crystals in this thesis,plane wave expansion method and finite time domain difference method,are analyzed and introduced respectively.Then,the influencing factors of the photonic band gap formation were studied.Through simulation,the lattice type,dielectric column shape,medium filling rate and relative refractive index were the main influencing factors of the photonic band gap.At the same time,through deep research,we discovered the formation mechanism of photonic band gap under different influencing factors.Finally,based on the characteristics of the photonic band gap,an all-optical non-gate and NOR gate logic structure based on a two-dimensional photonic crystal ring resonator is designed.By selecting a square lattice circular dielectric column photonic crystal structure,a reasonable lattice constant,the radius of the dielectric column and the size of the refractive index,the plane wave expansion method is used to obtain the band gap structure of the two-dimensional photonic crystal structure under TE polarization,and the finite time domain difference method is used to analyze the corresponding electric field stability of each logic gate device under different input logic conditions.State distribution diagram and transmittance diagram.The results show that the structure designed in this thesis can realize the corresponding logic function,the selected photonic band gap parameters are reasonable,and the contrast is high,with a high extinction ratio,the response period of each logic gate is short,the structure size is small,and it is easy to integrate optical devices.Through this design study,it can be shown that photonic crystals will be widely used in optical devices and have great research potential.In the future,photonic crystal-based devices will be fully applied.