掺杂型双芯光子晶体光纤高灵敏声压传感结构

为了解决石英材料高杨氏模量对光纤传感器均匀径向上灵敏度提升的限制，提出一种掺杂型双芯光子晶体光纤传感结构。该设计将圆形空气孔分列在光纤包层上，构成六边形晶格，在其单侧空气孔环绕的基材区域掺入聚甲基丙烯酸甲酯材料。利用COMSOL分析了均匀应力作用下光纤截面参量对声压灵敏度的影响，得到最优参量匹配结构。结果表明, kPa量级的声压作用下，自由光谱宽度约13nm; MPa量级的声压作用下，自由光谱宽度约2.5465nm, 在1550μm波段下，x偏振声压灵敏度达0.15942nm/kPa; 相比Saganc光子晶体光纤压力传感器，传感尺寸小，均匀径向灵敏度提高了46.6倍。该研究对下一代水下声压传感器的设计有帮助。

Design of doped double-core photonic crystal fiber sound pressure sensor with high sensitivity

In order to break the limitation of high Young's modulus of quartz material on the sensitivity improvement of fiber optic sensor in uniform radial direction, a doped double-core photonic crystal fiber sensing structure was proposed. The circular air holes were arranged on the fiber cladding to form hexagonal lattice. Polymethyl methacrylate was doped into the base-material area surrounded by the air holes on one side of the double-core photonic crystal fiber. The influence of cross-section parameters on sound pressure sensitivity under uniform stress was analyzed by COMSOL and the optimal structure was obtained. At the kPa level, the free spectral width is about 13nm. At the MPa level, the free spectral width is about 2.5465nm. The results show that the sensitivity of x polarized sound pressure is 0.15942nm/kPa at 1550μm. Compared with the Sagnac PCF pressure sensor, the size of this sensor is smaller, and the sensitivity at uniform radial direction is increased about 46.6 times. This work contributes to the design of the next generation underwater sound pressure sensor.