For the cavity length demodulation of fiber-optic Fabry-Perot (FP) sensors, a frequency-doubled self-correlation algorithm was proposed. Since the frequency doubling can make the self-correlation peak sharper, the peak positioning accuracy can be effectively improved for the cavity length extraction. The feasibility and performances of the proposed algorithm was investigated by both simulation and experiment. The simulated demodulation accuracy was better than 1.9 nm. The experimental demodulation resolution for a fiber-optic FP stress sensor with an initial cavity length of 79.859 μm reached 4.32 nm.

中文翻译：

---

通过双频自相关方法解调光纤Fabry-Perot传感器

针对光纤法布里-珀罗（FP）传感器的腔长解调，提出了一种倍频自相关算法。由于倍频可以使自相关峰更尖锐，因此可以有效地提高峰的定位精度以进行腔长提取。通过仿真和实验研究了该算法的可行性和性能。模拟的解调精度优于1.9 nm。初始腔长为79.859μm的光纤FP应力传感器的实验解调分辨率达到4.32 nm。