中文摘要：

利用熔融淬冷法制备了Ge20AszoSe，5Te惦硫系玻璃，测试结果表明该玻璃在中红外波段具有良好的红外透过特性和极高的非线性，采用z一扫描技术测试其中红外三阶非线性系数高达n2=6．72x10^18m：yw@4μm。以此材料为基质，设计了两种工作在中红外波段的硫系玻璃光纤光栅光开关。利用分布时域传递矩阵；（TD-TMM）和非线性耦合方程模拟计算了光栅光开关的反射谱和波长偏移特性。研究结果表明，通过调节输入光强可以灵活调节光纤光栅的中心波长向短波或长波方向移动，进而可以获得光开关。在调制深度为lxl0^8的均匀硫系光纤光栅，获得光开关的功率阈值约为1．6GW／cm2，当引入相移光栅后，调制深度可以降低为3x10^4，并且其光开关的功率阈值也降低到210MW／cm2。

英文摘要：

Geaua.s20Se20Te4s chalcogenide glass was prepared by a melt-quenching method. Testing resultsshow that this glass posses high nonlinear characteristics and wide infrared transmission windows in theinfrared region. The third-order nonlinear coefficient was tested to be n2=6.72x10-18m2/W @ 4 Ixm by aZ-scan technique. Two kinds of chalcogenide glasswith this glass. The reflection spectrum and gratinginfrared fiber grating optical switches were designedwavelength shift of optical switches were calculatedwith the distributed time-domain transfer matrix method （TD-TMM） and non-linear coupling equations.Results show that the Bragg wavelength can be flexibly tuned by modulating the input intensity andoptical switch can be achieved. It was found that the power threshold is about 1.6 GW/cm2 for an opticalswitch with a modulation depth of l x10-8 in a uniform chalcogenide Bragg fiber grating and the powerthreshold can be significantly reduced to about 210 MW/cm2 in a phase-shift chalcogenide fiber gratingwith a modulation depth of only 3x10-4.