光纤布拉格光栅γ辐射损伤及其对光谱特性的影响

摘要

The ionizing radiation effects on fiber Bragg grating are theoretically analyzed based on the color center model.And the relationship between the radiation induced refractive index change and dose is deduced.Fiber Bragg grating sample are irradiated by 7 ray with a total dose of 1×10~6 rad.Underγradiation the reflected spectrum peak wavelength of FBG sample is red shifted,but the full width at half maximent and the reflectivity are not changed obviously.The experiment results accord well with our function.With the low level radiation experiment,this expression can screen the FBG samples and predict their performances under high level radiation.%基于色心产生模型理论分析了电离辐射对光纤布拉格光栅的影响,并推导出了光栅有效折射率变化与辐射剂量的函数关系式.使用~（60）Coγ辐射源对光纤布拉格光栅进行了总剂量为1×10~6 rad的电离辐射实验,实验结果与理论符合较好.在辐射环境下,光栅反射谱的峰值波长随着剂量增加向着长波方向移动,由其计算所得的辐射致折射率变化规律与所得到的函数关系式相符.该公式结合低剂量辐射实验可预测光栅在高剂量辐射下的性能变化,对评估光栅产品抗辐射特性,及筛选出性能较好产品有着实际应用价值.