提出一种基于氧化石墨烯（GO）修饰的长周期光纤光栅（LPFG）传感器。利用氢氧化钠溶液对LPFG表面进行羟基化处理, 采用氢键结合的方式使GO固定在光栅表面, 形成基于GO修饰的LPFG传感器。实验研究了GO-LPFG对外部折射率及温度的响应特性, 结果表明: 该GO-LPFG的平均折射率灵敏度较未涂覆GO的LPFG提高1.09倍, 温度灵敏度略有降低。随着光栅直径的减小, GO-LPFG的平均折射率灵敏度进一步提高。当光栅直径为108 μm时, 在折射率1.333~1.448内的平均波长和耦合强度折射率灵敏度分别约为38.99 nm/RIU和57.33 dB/RIU, 与未采用GO修饰直径为108 μm的LPFG及直径为125 μm的GO-LPFG相比, 其平均波长和耦合强度折射率灵敏度分别提高1.45, 2.17, 3.80和3.42倍。该GO-LPFG传感器在各种大分子量的病毒抗原蛋白、生物病菌等生物检测领域具有潜在的应用价值。

A graphene oxide-functionalized long period fiber grating (GO-LPFG)-based fiber optic sensor is proposed. The surface of the LPFG was hydroxylated by sodium hydroxide solution, and GO was fixed on the grating surface by hydrogen bonding to form a GO modification LPFG sensor. The responses of the GO-LPFG to external refractive index and temperature were studied experimentally. The experimental results show that the average refractive index sensitivity of the GO-LPFG is 1.09 times higher than that of uncoated LPFG, and the temperature sensitivity slightly declines. With the decrease of grating diameter, the average refractive index sensitivity of GO-LPFG was further improved. The average wavelength and coupling intensity refractive index sensitivities of the GO-LPFG with a diameter of 108 μm in the refractive index range of 1.333-1.448 are ~38.99 nm/RIU and ~57.33 dB/RIU, respectively. These increased by 1.45, 2.17 and 3.80, 3.42 times, respectively, compared with those of bare LPFG and GO-LPFG with diameter of 125 μm. The proposed GO-LPFG sensor has potential applications in detecting various viral antigen proteins with high molecular weight and biological pathogens in biofields.