Device Design And Application Research Based On Photonic Crystal Ring Cavity

In the 1980s,the concept of photonic crystal was put forward,which opened the door to the world of optical communication network.Compared with traditional electronic communication,optical communication system has the advantages of low energy consumption,wide transmission frequency band,high data storage density,fast response and no electromagnetic interference.As an important material in the field of optical communication,photonic crystal has rapidly become the research focus of researchers,and caused a research upsurge in the development and preparation of photonic functional devices.Through the photonic band-gap and photonic localization characteristics,as well as the coupling principle between defects,various optical devices with excellent performance can be designed.Based on the structure of the ring cavity,a photonic device with the functions of filtering and beam splitting is designed through the resonant coupling between the waveguide and the ring cavity;By adding nonlinear materials,optical switches based on photonic crystal ring cavity are designed.The performance of these devices meets the basic requirements of optical communication.In this paper,the two-dimensional triangular lattice photonic crystal structure is adopted,and the photonic device is simulated and calculated by using Rsoft simulation software.The transmission spectrum,light field distribution and time-domain steady-state response diagram of photonic crystal functional devices are obtained.Firstly,this paper describes the research background and significance of photonic crystal devices,and briefly describes the concept,characteristics,preparation and research progress of devices based on photonic crystal ring cavity.The numerical analysis methods of photonic crystals are introduced in detail,including the Plane Wave Expansion method and the Finite Difference Time Domain method,and the Coupled Mode Theory of photonic crystal coupling region is briefly analyzed.Then the point defect,line defect and ring defect of photonic crystals are studied and analyzed.Secondly,using the coupling principle of waveguide and ring cavity,a photonic device based on the filtering and beam splitting function of photonic crystal ring cavity is designed.The influence of the number and density of the central column of the annular cavity on the transmittance is studied,and the optimal structural parameters of the device are obtained.The filtering of 1.346 μm and 1.455 μm and the beam sharing function of 1.414 μm are realized.The transmittance is 72.2%,79.7% and 41.2%respectively.The device is simple in structure and small in size,which can achieve dual-function effect,and provides a new idea for application design based on photonic crystal ring cavity structure.Finally,by adding photosensitive gallium arsenide(Ga As)material into the ring cavity and using the interaction principle between light and nonlinear materials,an optical switch based on photonic crystal ring cavity is designed.By studying the influence of the radius of the central column of the ring cavity on the defect mode and transmission spectrum,it is concluded that the central column radius of 0.17 a is the best structural parameter design to regulate the third communication wavelength of 1550 nm.According to the adjustment mechanism of pump light on the refractive index of Ga As,the on-off function of optical switch is realized by analyzing the change of defect mode of annular cavity under different refractive index.The extinction ratio of the structured light switch is 18.779 d B and the overall response time is 100.8 ps.