不同反射率光纤光栅再生过程及温度特性研究

Study on Regeneration Process and Temperature Characteristics of Fiber Grating with Different Reflectivity

针对再生光栅在高温退火后存在较低反射率导致高温测量受限的问题,采用244nm氩离子激光制作两支栅区长度分别为10mm和25mm的种子光栅,使用超高温箱式炉对种子光栅进行900℃的快速高温退火处理。在擦除初始种子光栅后制备出高温再生光栅,并在200℃-900℃温度范围内对高温退火后的两支再生光栅的高温传感特性进行实验测试。结果表明:在900℃温度稳定环境中测试100min,10mm再生光栅中心波长的稳定度为4pm,反射率为19.03%;25mm再生光栅中心波长的稳定度为8pm,反射率高达84.13%;在200-900℃温度范围内,两支再生光栅温度线性度较好,相关系数均在0.998以上;温度灵敏度系数分别为15.23pm/℃和15.24pm/℃;栅区长度为25mm的再生光栅更适合用于制作高温传感器。

In this paper,the regenerated grating has the lower reflectivity after high temperature annealing,which limits the application of high temperature measurement. Two regenerated seed gratings are fabricated by using 244 nm Ar＋laser,with the grating length of 10 mm and 25 mm respectively. The seed gratings are annealed at 900℃ in the ultrahigh temperature box-type furnace,and the high temperature regenerative gratings occurr after the initial seed gratings are vanished.The high temperature sensing characteristics of two regenerated gratings after high temperature annealing are tested under the condition of 200℃-900℃. The results show that the center wavelength shift of the 10 mm regenerative grating is 4 pm with the reflectivity of 19. 03%; the center wavelength shift of the 25 mm regenerative grating is 8 pm with the reflectivity of84. 13%,both of them are in a stable temperature environment with 100 min at 900℃. The linearity of the two non-encapsulated regenerative grating sensors is better,when correlation coefficients are both above 0. 998 at 200℃-900℃,and the temperature sensitivity coefficients are 15. 23 pm/℃ and 15. 24 pm/℃ or so. The regenerative grating with a grating length of 25 mm is more suitable for packaging high temperature sensors.