Investigation Of Transmission Characteristics And Fabrication Of GeSbSe Glass Photonic Crystal Waveguides

Photonic crystal waveguides(PCWs) based on Ge Sb Se glasses have the band gap property of photonic crystal waveguide, as well as merits of chalcogenide materials, such as high refractive index, low two-photon absorption, good third-order nonlinear, and high transmission in mid-infrared area, which make it excellent candidates widely used in nonlinear optics and infrared sensor.In this thesis, the transmission characteristics and fabrication of the chalcogenide PCWs were investigated. Beginning with the structure design of chalcogenide photonic crystal, the structures of chalcogenide PCWs in communication and infrared wavelengths were proposed. Then the transmission characteristics of the 60° bent chalcogenide PCWs both in communication and infrared wavelengths were optimized, followed by the optimization of two consecutive 60° bent chalcogenide PCWs. Finally, the fabrications of chalcogenide PCWs were introduced, by using electron beam lithography plus inductive coupled plasma(ICP) etching, as well as focused ion beam etching, and analysis to the fabrication results were also presented.In chapter one, the concept and application of photonic crystals were introduced. Then the characteristics and advantages of chalcogenide glass were put forward. Finally, the research background of chalcogenide PCWs was illustrated.In chapter two, the basic theoretical principle of photonic crystals was presented. The plane wave expansion method which was used to calculate the band gap of photonic crystal, and the method of finite-difference time-domain used to simulate transmission efficiency were explained with details.In chapter three, based on the operation of optical software RSoft, the structures of chalcogenide PCWs in communication and infrared wavelengths were designed respectively. In simulation, the relations between the structure type of photonic crystal, lattice type, lattice radius and photonic crystal band gap were analyzed, to obtain broadband gap chalcogenide photonic crystals. Besides, when line defects were introduced in photonic crystals structure, chalcogenide PCWs with high performances could be obtained.In chapter four, the transmission efficiency of chalcogenide PCWs with 60° bent structure in communication and infrared wavelengths were investigated. In communication wavelength, the transmission efficiency could be proved by placing some air holes in the bending area. Similarly, for the infrared wavelength, two air holes in the bending area were added to make improve the transmission efficiency, and some more air holes could be added in the line defect area. After which, both transmission bandwidth and transmission efficiency could be improved greatly.In chapter five, the fabrication technologies of chalcogenide PCWs were introduced, mainly by electron beam lithography plus ICP etching, and focused ion beam etching. The characteristic of fabrication using these two methods were analyzed and a comparison between them is made.In chapter six, the summary of the thesis was made and shortcomings of this project were put forward.