基于空芯光子晶体光纤(HCPCF)的在线法珀标准件(ILFE)应变传感器的应变灵敏度高，对温度敏感系数小，其腔长可制作得比传统ILFE长，适于在一路光路中进行频分复用从而扩大多点应变检测的准分布应变传感系统的容量。理论分析了制作中提高基于空芯光子晶体光纤的在线法珀应变传感器输出信号的方案，通过实例讨论了光源时间相干长度对该类法珀腔腔长的限制。结合波分频分复用，进行了基于该复用方法的应变测试实验研究，实验结果表明，其测量精度可达±5 με，可用于大型结构健康监测。

Hollow-core photonic crystal fiber (HCPCF) based in-line fiber-optic etalon (ILFE), due to its high sensitivity to strain and low thermal coefficient, can be made with longer cavity length compared with traditional ILFE, making it suitable in quasi-distributed multipoint stain detection systems. The ways of enhancing the output signal of HCPCF based multiplexing strain detecting systems are analyzed. The effect of temporal coherence length of light source is analyzed through examples. A spatial-frequency division multiplexing (SFDM)/coarse-wavelength division multiplexing (CWDM) of ILFE strain sensors with four HCPCF-based ILFE strain sensors is demonstrated. The experimental results show that a strain accuracy of ±5 με can be achieved. Such an HCPCF-based ILFE strain sensor multiplexing system could be used for large engineering structure health monitoring.