基于光纤光栅偏振特性的横向压力传感器

Transverse Pressure Sensor Based on the Polarization Properties of Fiber Grating

与通常的基于光谱分析的光纤布拉格光栅（FBG）传感器的原理不同,提出一种利用FBG的偏振相关损耗（PDL）特性来实现横向压力测量的新方法,从理论和实验两方面研究了FBG在横向压力作用下PDL参数的响应机制,建立了利用PDL实现横向压力传感的理论模型并进行了数值模拟。理论分析表明,FBG的PDL对横向压力的响应非常敏感,在小压力条件下比单纯的光谱分析更适合于测量横向应力。实验中在0-180 N的横向压力条件下,以PDL随波长变化曲线的质心高度和两峰值的波长间隔分别作为编码实现了解调,获得了在小压力（0-80 N）情况下0.06 dB/N和大压力（81-180 N）情况下2.5 pm/N的灵敏度,实验和理论模拟结果相符,证实了该方法的可行性。

Different from the basic sensing theory of the fiber Bragg grating（FBG） sensors based on spectral analysis,a new method utlizing the polarization dependent loss（PDL） of FBG for transversal pressure measurements is proposed.The evolution of the PDL with wavelength with respect to transversal pressure is studied theoretically and experimentally.A theoretical model for transversal pressure sensing by use of PDL is built and numerical simulation is also carried out.The theoretical analysis suggests that the PDL of FBG is more suitable for measuring transverse pressure than single spectral analysis in the low pressure region because of its greater sensitivity.Under the transverse pressure conditions of 0-180 N,the demodulation is realized by use of the centroid height and the wavelength spacing of the two peaks respectively.The resolutions of 0.06 dB/N for small pressure（0-80 N） and 2.5 pm/N for large pressure（81-180 N） are demonstrated.Good agreements between experimental results and numerical simulations verify the feasibility of the method.