发现高频CO2激光脉冲写入的长周期光纤光栅(LPFG)的谐振波长的横向负载灵敏度具有很强的方向相关性,且在两个特定的负载方向上谐振波长对横向负载不敏感,而谐振峰幅值与不同方向的横向负载都有很好的线性关系。这种LPFG的谐振波长随温度变化而线性漂移,使谐振峰幅值对温度变化不敏感,由此提出了用单个LPFG的谐振波长和谐振峰幅值两个参量分别实现对温度和横向负载进行同时独立绝对测量的传感器设计方案,可望从根本上解决LPFG在测量中存在的温度和横向负载之间的交叉敏感问题。

In this paper, a novel long-period fiber grating(LPFG) sensor written by high-frequency CO2 laser pulses is demonstrated for simultaneous measurement of transverse load and temperature. Such a sensor could solve the cross-sensitivity problem between transverse load and temperature due to the unique features of the LPFG, i. e. the load-sensitivity of the LPFG against the resonant wavelength shift strongly depends on loaded orientation. Within the circular position 0°～180°, there are one orientation which is the most load-sensitive, corresponding to the resonant wavelength“red”shift and another orientation which is the most load-sensitive, corresponding to the resonant wavelength“blue”shift, in particular, there are two special orientations, which are the most load-insensitive.