随着光信息技术的发展, 长周期光纤光栅(LPFG)凭借其插入损耗小、传感灵敏度高, 体积小等优点, 广泛应用于光纤传感和光纤通信等领域, 成为最具有发展前途的光子无源器件。作为加工光纤传感器等重要功能器件的飞秒激光, 其在透明介质内部的三维结构加工上具有高峰值功率、热效应小等得天独厚的优势。介绍了采用飞秒激光刻写不同扭转周数的扭转型长周期光纤光栅, 并分析了其扭转特性。通过对比扭转2、4、6和8周的长周期光纤光栅的扭转调控实验结果, 发现8周的扭转型长周期光纤光栅在单方向上主谐振峰波长对扭转率的响应灵敏度达到了117.4 pm/(rad/m), 线性度达到了0.999 5, 波长调控范围约12.33 nm, 非常适合波长和带宽调控。实验研究了8周扭转型长周期光纤光栅的曲率特性, 发现这种方式下刻写的扭转型LPFG在大曲率(13)各个方向下, 光谱0°和180°相似, 90°和270°相似, 但是这两对光谱差异很大, 即该光栅依然有各向异性。

With the development of optical information technology, long period fiber grating (LPFG) is widely used in optical fiber sensing and optical fiber communications and other fields, due to its unique characteristics, such as low insertion loss, wide stop-band, low backward reflection, high sensitivity, resistant to corrosion and small size. It has become one of the most representative and promising fiber optic passive components.As an important machining tool, the femtosecond laser has the advantage of high peak value power, small thermal effect and so on. In this article we fabricated the different twisted long period fiber grating, using point by point method. By comparing its characteristics, found that the twisted long period fiber grating with 8 weeks torsion sensitivity is 117.4 pm/(rad/m) with a linearity of 0.999 5, and the wavelength adjustment range is about 12.33 nm, this is very suit for wavelength and bandwidth control. And experimental study for eight weeks type torsional curvature properties of long period fiber grating, result indicated that under large curvature the spectrum of 0° is similar to 180 °, 90 ° is similar to 270 °, but the difference is very big, the spectrum is still has anisotropic under big curvature.