研究了氧化石墨烯(Graphene Oxide, GO)修饰的色散拐点长周期光纤光栅(Dispersion-Turning-Point Long Period Fiber Grating, DTP-LPFG)传感器, 分析了其光谱特性及对外部折射率的灵敏度特性。利用准连续KrF激光器在载氢单模石英光纤上制作周期约为136μm的DTP-LPFG, 采用氢键结合的方式将GO涂覆于光栅表面, 构成基于GO修饰的DTP-LPFG传感器。实验结果表明：随着GO在DTP-LPFG表面的沉积, 其双谐振峰的左峰发生蓝移, 右峰发生红移, 双峰间距增大；在1.33~1.38折射率范围内, 该传感器在涂覆GO后, 谐振双峰间距变化量的折射率灵敏度约为831.89nm/RIU, 较未修饰GO的DTP-LPFG提高了1.05倍。

The optical sensor based on dispersion-turning-point long period fiber grating (DTP-LPFG) modified by graphene oxide (GO) was investigated, and its spectral characteristics and sensitivity to external refractive index (RI) were analyzed. The DTP-LPFG with a period of about 136μm was fabricated by using a quasi-continuous KrF laser in a hydrogen loaded single-mode fiber. GO was fixed on the grating surface by hydrogen bonding to form a GO functionalized DTP-LPFG sensor. The experimental results show that there are a blue-shift and a red-shift of the resonant bands at the lower and higher wavelengths, respectively, and the wavelength separation between the dual peaks increases with the deposition of GO on the surface of the DTP-LPFG. The sensitivity of the resonance bimodal spacing variation of the GO coated DTP-LPFG sensor is about 831.89nm/RIU in the RI range of 1.33~1.38, which is 1.05 times higher than that of the uncoated one.