Research On Chalcogenide Glass Ultrafast Photonic Crystal Optical Switching

The dramatic growth of information will inevitably promote the optical network to the direction of speed higher,capacity greater in modern society.All-optical switching proves to be the development orientation of the current optical network,and the realization of all-optical switching is mainly dependent on optical switches and related devices.The switching speed of the traditional optical switch cannot meet the requirement of modern optical switching.Fortunately,the switching speed of the light control type optical switch can reach the order of picosecond.Therefore,the research of the light control type optical switch has practical theory significance and practical value.However,the volume of all-optical switching prepared by traditional means is relatively large,which is harmful to the future integration of all-optical devices,and some methods of experimental conditions are extremely stringent requirements.All-optical switching based on photonic crystals has many unparalleled advantages.At present,the researchers study the silicon-based photonic crystal optical switching the most.However,in order to achieve better switching effect,the role of light and device must make a long enough distance or greatly improve the laser power.Looking for a higher nonlinearity,faster response matrix material is the direction of future research.Chalcogenide glass is such an optical material with a very high nonlinear coefficient and extremely fast response,the design and performance of a new type of photonic crystal switch is simulated.This paper mainly includes the following six chapters:The first chapter mainly introduces the background and current situation of the research.At first,we introduce the application,current situation and existing problems of optical switch,and elucidate the research significance of this dissertation,then,introduce the concept,application and fabrication process of photonic crystal.We then introduce the development status of photonic crystal optical switch that designed with chalcogenide glass material.At last,the research purpose and corresponding research contents are expatiated.The second chapter,we introduced some basic theoretical analysis methods of photonic crystal optical switch briefly.The realization method of photonic crystal optical switch is described and the plane wave expansion method and finite difference time domain method are introduced emphatically.The third chapter,we introduced the preparation technology of chalcogenide glass,and the related parameters of chalcogenide glass are tested.We measured the third-order nonlinear coefficient of Ge-Sb-Se chalcogenide glass and the refractive index,phase-change time and other parameters of Ge-Sb-Te glass.In the fourth chapter,we study the characteristics of the ultra-fast photonic crystal optical switch of chalcogenide glass.The plane wave expansion method is used for analyzing the bandgap.Based on this,we simulated the characteristics of the designed photonic crystal optical switch by using the finite-difference time-domain method.The structure of the photonic crystal optical switch near the communication wavelength of 1.55?m obtained and the photonic crystal optical switch with ultra-fast response speed,high transmittance and quality factor.The fifth chapter is the key part of the paper.In the fifth chapter,the structure design and performance of the photonic crystal switch divider based on Ge₂Sb₂Te₅ chalcogenide glass are studied.The photonic bandgap distribution of square lattice photonic crystals studied by plane wave expansion method.The photonic crystal switch divider with three channels designed and the transmittance of the structure analyzed by finite difference time domain method.Through further optimization of parameters of the microcavity,the switch divider which can work in 2.0?m and 5.0?m wavelength and can respectively realize "on","off" and "division".In chapter sixth,the structure design and performance of the photonic crystal optical switching based on Ge₂Sb₂Te₅ chalcogenide glass are studied.The structure of the optical switching optimized to make the control light enter to the waveguide and the control light and signal light in the same plane.The method of controlling light and signal light in the same plane is simple and practical.The last chapter summarizes the achievement of this article.