采用优化改进的CO2激光器制备了两种不同刻槽深度的长周期光纤光栅（LPFG），实验研究了光纤光栅刻槽区结构对应变传感特性的影响。研究结果表明:单侧周期性刻槽会在光纤光栅表面形成应力集中区，在轴向应变作用下发生微弯形成波状型结构，从而极大地提高了其应变响应灵敏度，深刻槽光纤透射谱的谐振波长线性漂移达到-10.96 nm，应变灵敏度达到－19.37 pm/με，且测量误差小。利用有限元分析软件ANSYS对刻槽型光纤光栅进行网格建模和模态仿真分析，得到其刻槽结构区的应变分布图。结果表明，深刻槽型光纤光栅随着应变增加，轴向微弯形变量增大，从而激发高阶包层模的耦合，提高了应变灵敏度响应。

Two kinds of long period fiber gratings (LPFGs) with different grooved depths are fabricated by means of the improved CO2 laser beam. The influence of the grooved structure of the fiber grating on the strain sensing characteristics is studied experimentally. The research results show that the stain concentration is occurred in the surface of the fiber grating because of the one-side periodical groove, and the grooved fiber grating slightly is bent to form corrugated structure, so the strain sensitivity response is greatly enhanced. Resonance wavelength of the transmission spectrum of the deeply grooved fiber can linearly driftes to -10.96 nm, the sensitivity can get to -19.37 pm/με and the measurement error is very small. The mesh modeling and static simulation of the grooved fiber grating are realized based on the finite element analysis software ANSYS, and then the strain distribution of the grooved structure section is obtained. The principal research and experimental testing demonstrate that the axial micro-bend deformation of the grooved LPFG increase with the increase of strain, so that the grooved fiber can trigger high-order cladding mode coupling, and improve strain sensitivity response.