中文摘要：

理论和实验上研究了利用飞秒激光微纳加工技术制备的广义高斯切趾光纤布拉格光栅（FBG）的带宽特性。模拟结果表明，FBG带宽随着折射率调制度的增大而增大，随着光栅长度的增大先减小后趋于饱和。利用飞秒激光相位掩模法制备FBG的实验结果表明，当飞秒激光功率较小时，随着激光功率的增加，FBG带宽基本不变；激光功率超过一定阈值，FBG带宽随着激光功率的增大而逐渐增大。曝光时间较短时，FBG带宽随曝光时间的增加而急剧增大；随着曝光时问的继续增加，FBG带宽逐渐趋近于饱和。FBG带宽随着飞秒激光功率和曝光时间的变化可以归因于飞秒激光诱导FBG折射率调制度和光栅长度的变化。这些规律为调控利用飞秒激光微纳加工技术制备FBG带宽提供了参考。

英文摘要：

The bandwidth characteristics of fiber Bragg grating （FBG） made with femtosecond laser radiation are studied theoretically and experimentally. The simulation results show that the FBG bandwidth increases with refractive index modulation increasing, while it decreases dramatically and then saturates with grating length increasing. FBGs are fabricated in silica fiber with femtosecond laser radiation and a phase mask and then characterized by spectral analyser. FBG bandwidth remains constant when the laser power is low. However, when the laser power is large enough, FBG bandwidth increases with laser power increasing. With the exposure time increasing, FBG bandwidth increases initially and then become saturated. These results can be attributed to the change of the refractive index modulation and the grating length with femtosecond radiation.