Nonlinear Properoties Research Of Te Based Chalcogenide Glasses And Fibers

Chalcogenide fibers are more and more applied in communication system,they have many advantages compared to other materials in infrared regions.They have broad infrared transmission,high linearity and nonlinearity.The suspended-core chalcogenide fiber which was fabricated by novel extrusion method has higher nonlinear,dispersion controllable compared with the ordinary structure of chalcogenide glasses.These properties would make them have important application value in infrared spectral broadening and chemical biological sensor.This paper is based on the reported research for the nonlinear property and mechanism of different element ratio chalcogenide glass and fibers.We put forward that the introduction of Te element into Ge-Se glass to improve the nonlinearity.At the same time we prepared As₂S₃ chalcogenide fiber with the improved mechanical extrusion.We analyze the supercontinuum generation with different fiber length,pump wavelength and different power.Finally,we taper the suspended-core fiber to obtain low dispersion.Firstly,we introduce the superior optical performance and optical applications of the chalcogenide glass,as well as the optical properties and advantages of the fiber based on chalcogenide glass.We also analyze and compare the nonlinear research progress of three different chalcogenide glasses.At the end of the chapter we introduce two kinds of photonic crystal fibers and the principle of the light transmission in the fiber.In the second chapter we mainly introduce the nonlinear of chalcogenide glass and summarize the third order nonlinear theory,nonlinear research model and several nonlinear measurements respectively.The unpaired electron model,band gap model and the MCN model are introduced on emphasis.They provide the theoretical basis and the research direction for the next research.The third chapter introduces the preparation and performance tests of the Ge-Se-Te chalcogenide glass.We prepared the chalcogenide glass with high Te element using conventional melt quenching cold method.Then we tested and analyzed the physical and optical properties of the Ge-Se-Te chalcogenide glass.The optical band gap and linear refractive index of the Ge-Se-Te glass were changed by changing the Te element content.Finally the nonlinear refractive index of the Ge-Se-Te chalcogenide glass was tested through the Z scan method.And the internal mechanism of the glass was further tested by the Raman analysis.In the fourth chapter we introduce a new preparation method for the chalcogenide suspended-core fiber.We successfully draw out a three-core As₂S₃ suspended-core fiber with core diameter of 2.33?m by extrusion and casing method.A fiber with core diameter of 0.76?m was obtained after tapering.We test the loss,dispersion,and the transmission of light in the three-core As₂S₃ suspended-core fiber,and simulate of nonlinear coefficient of the fiber.The fifth chapter focuses on the supercontinuum generation of the three-core As₂S₃ suspended-core fiber on different fiber length,pump wavelength and pump power.Firstly,the generalized nonlinear schrodinger equation is introduced.And the simulation of supercontinuum on different fiber length,pump wavelength and pump power was run using the MATLAB software.Then we pump the supercontinuum of the three-core As₂S₃ suspended-core fiber through experiment and compare the similarities and differences between the measured experiment data and the simulation results.At last,we summarize the full text and point out the shortages of the paper and the comments.The research points out the direction for the further study of the three-core As₂S₃ suspended-core fiber.