基于扭曲长周期光纤光栅的高灵敏度压力传感器

A High Sensitivity Pressure Sensor Based on Twisted Long-Period Fiber Grating

研究了高频CO2激光脉冲写入的长周期光纤光栅在扭曲状态下的横向负载特性.发现扭曲降低了光纤光栅谐振波长横向负载灵敏度的方向相关性,使得这种光栅在各圆周方向上谐振波长对横向负载都不敏感,而谐振峰幅度随横向负载的增加线性减小,且谐振峰幅度的负载灵敏度随扭曲率的增加而提高.在扭曲率为1 .8°mm-1时负载灵敏度可达0 .47 dB/(g.mm-1) ,是自由状态长周期光纤光栅横向负载灵敏度的7倍,最后给出了利用这种扭曲长周期光纤光栅通过强度解调实现压力传感的实验研究结果.

The transverse load characteristics of twisted long-period fiber grating （LPFG） written by highfrequency CO2 laser pulses was demonstrated. Theoretical analyses and experimental results show that its transverse load sensitivity is up to 0.47 dB/（g·mm^-1） ,which is 7 times higher than that of a free LPFG induced by the same method. It is found that the strong orientation-dependence of the transverse load sensitivity of the free LPFG reported previously has been weakened considerably. An intensity demodulating method when the twisted LPFG was used to be a pressure sensor was presented.