采用相位掩模板法，实验研究了准分子激光器制作光纤布拉格光栅(FBG)过程中，紫外光热效应对光栅生长过程和光谱结构的影响。研究发现，相位掩模板法直接曝光法中，对同一段光敏光纤进行累加曝光，其反射率不会随着曝光量的增大而线性增长，而在多次曝光时会产生光栅反射率变小的“漂白”现象，并且多次曝光的时间间隔越短，“漂白”的过程也越长；相同的曝光量下，激光器重复频率越高，则曝光所用时间越短，所形成的光纤光栅的反射率越高；扫描曝光制作光纤光栅时，在相同的曝光参数下，扫描移动方向的不同会导致光栅旁瓣分布规律的不同，由此提出了光栅制作过程中存在“热致啁啾”现象。

Thermal effect of ultraviolet laser in fabricating and spectrum of fiber Bragg grating (FBG) was experimentally researched by phase mask method. Results indicated that, getting the same photosensitive fiber had accumulative exposures by the way of phase mask straight exposure, the grating reflectivity will not be linearly increased with the exposure level, but will be diminished, which is called “bleaching”. The process of bleaching had some connection with the interval of multiple-exposure. The shorter of interval was, the longer time of bleaching process will take. On the condition of having the same quantity of illumination, the higher exposure frequency rate of laser was, and the less time the exposures take, the grating reflectivity will be higher. During scanning exposal to make uniform FBG, on the condition of having the same exposure parameter, differ of scanning directions leads to different regularities of distribution of side lobes. Thermal-induced chirping in FBG fabrication was proposed for the first time.