Design And Study Of All Optical Devices Based On Photonic Crystals

Presently,the development of advanced technology needs large information capacity and rapid transmission speed,and the problems of integrated circuit are more and more serious,therefore,its development is reaching bottleneck period,which requires urgently for a new integrated system to achieve large capacity information processing and transmission.Considering the light wave has greater ability in information transmission and processing due to its shorter wavelength,therefore,the integrated optical circuits will be the trend of the high information speed development in the future.As the key component of the future integrate optical circuits,the design and study of the all optical devices is imperative.Presently,considering that the photonic crystals have the same order of the magnitude with the wavelength and have advantages of being highly integrated and fast response,the all optical devices based on the photonic crystals have gained widely attention in and abroad.Therefore,if applying them on optical integrated circuits in all optical network as next generation devices in optical communications,and this is also the trend to satisfy the requirements of the future optical communication development.The aim of the thesis is to study the electromagnetic characters of the photonic crystals,including dispersive properties and slow light effect of the the photonic crystal waveguide,and analyze the electromagnetic wave propagating properties in the photonic crystals,and this can provide theory basis for time delay effect in the integrated optical circuits based on the photonic crystals in the future optical communication system.Furthermore,all optical logic devices in the integrated optical circuits are designed,including reconfigurable logical gates,half adder and half subtracter,etc.Finally,one kind of polarization beam splitters is proposed with separating spatial angel of 180 °.All optical devices based on the photonic crystals have the advantages of being highly integrated for their compactness,so studying on them can provide important theory basis and guiding significance for novel optical device designing in the future.The main studies and innovations include as follows:1.A reconfigurable logic gate based on the photonic crystals is proposed which can realize five kinds of logic functions,including XOR,OR,XNOR,A+B and NOT logic gate if different input ports or reference ports are chosen,meanwhile,the frequency requirements for the incident wave of the configurable logic gates proposed here are discussed.The proposal of the reconfigurable designscheme can make one structure realize many logic functions.The design model structure is of compactness,and more easy to be integrated,which can be applied in optical circuit integration in all optical communication network.2.It is firstly proposed to realize the half subtracter and three-person voting function based on the self-collimation effect by the two dimensional photonic crystals,and the simulation results agree well with the theory.The results show that high light contrast ratio at the output port can be obtained by this design scheme,and compared with the traditional circuit of the half subtracter and three-person voting function,the two proposed structure models need no combination of several basic logic gates and can easily be integrated for their compactness,which has the guiding signifecance in all optical design in the optical circuit integration system.3.A polarization beam splitter structure model with the separating angel of 180°is proposed.By controlling different parameters in different photonic crystals,the normarlized frequency of the incident wave can fall into the self-collimation frequency range of TE wave or TM wave for different photonic crystals,therefore,the different propagating characters will be obtained for TE wave or TM wave in the photonic crystals with different structure parameters.the polarization beam splitter propsed in the thesis can realize the separating angel of 180°,which has been greatly improved to the general polarization beam splitters.