中文摘要：

强光致光纤布拉格光栅（FBG）光谱的变化是由非线性效应和光热效应共同作用的结果。基于FBG传感模型，利用非线性薛定谔方程和一维稳态热传导方程分析了非线性效应和光热效应各自对于光谱变化的贡献比例。通过分析波长漂移量与相位改变的关系，建立了基于FBG的非线性折射率系数计算模型；通过理论仿真光纤内温度分布情况，分析了光热效应对光谱啁啾化和波长漂移量的影响。理论与实验研究结果表明，对于普通单模光纤，当注入抽运光功率较小时，FBG光谱的变化主要是由光热效应造成的，而非线性效应则贡献较小。

英文摘要：

The change of the fiber Bragg grating （FBG） spectrum induced by intense light is caused by the nonlinear effect together with the photo-thermal effect. Based on the sensing model of FBG, the contribution of nonlinear effect and the photo-thermal effect on the FBG spectrum change is analyzed by using the nonlinear refractive index coefficient and one-dimensional steady state heat equation. By analyzing the relationship between the wavelength shift and phase change, nonlinear refractive index coefficient calculation model is built. And the photo-thermal effect on the spectrum chirp and wavelength shift is confirmed by theoretical simulation of temperature distribution. As the theoretical and experimental results show, for conventional single mode fiber, FBG spectrum change is mainly caused by the photo-thermal effect rather than the nonlinear effect when a relatively lower power pump is injected to single mode optical fiber.