基于相位掩模板法二阶光栅刻写及传感特性研究

Research on Second-Order Grating Inscribing and Sensing Characteristics Based on Phase Mask

摘要:

为了将光纤光栅传感系统的工作波段拓展到硅基探测器可用的近红外波段，本文采用1550nm波段的相位掩模板进行780nm波段的二阶光栅刻写研究。首先分析了二阶光栅的成栅机理，随后搭建了紫外激光-相位掩模的刻写系统制备了二阶光栅，分析对比一阶与二阶中心波长呈二倍关系，并且二阶波长的带宽更窄。用刻写的光栅分别封装了应变传感器和温度传感器，对温度和应变传感特性展开研究，结果表明二阶波长的温度灵敏度和应变灵敏度约为5.52 pm/℃和0.61 pm/με，约为一阶波长灵敏度的一半，本文的研究为拓展光纤传感的工作范围提供了技术支持。

Abstract:

In order to extend the operational range of fiber grating sensing system into the near-infrared band accessible to silicon-based detectors, this paper employs the phase mask of 1550nm waveband for the second-order Bragg gratings inscribing research in 780nm waveband. Firstly, the grating formation mechanism of the second-order grating is analyzed, and then a grating inscribing system integrate ultraviolet laser with phase mask grating is established to fabricate the second-order FBG. It is indicated that the ratio of first-order wavelength to the second-order wavelength is 1.98, and the bandwidth of the second-order is narrower. The results indicate that the temperature sensitivity and strain sensitivity of the second-order grating are 5.28 pm/℃ and 0.65 pm/με, about half of the first order grating. This research provided technical support for expanding the working range of optic fiber sensing system and the waveband of the silicon-based detector.