光纤Bragg光栅应力增敏研究

Study on stress sensitivity enhancing of optical fiber Bragg gratings

应力增敏的研究是光纤Bragg光栅传感的重要课题之一.提出了光纤Bragg光栅应力增敏的模型,推导了该模型的等效弹性模量计算公式,得到了应力与中心波长相对偏移量的关系和应力灵敏度系数表达式,表明通过适当选择弹性体的弹性模量和尺寸,就可以提高应力灵敏度系数.用弹性聚合物封装的光纤光栅理论和实验应力灵敏度系数分别是6.64×10-10Pa-1和6.14×10-10Pa-1,各为裸光纤光栅轴向应力灵敏度的57.8和54.8倍.应力灵敏度系数的理论值和实验值吻合很好.

The study on the theory and the techniques of stress sensitivity enhancing is one of the important research subjects on optical fiber Bragg gratings transducer. A model for the stress sensitivity enhancing of optical fiber Bragg gratings is proposed. The equivalent elastic modulus of the model is also derived. The relationship between the stress and relative offset of center wavelength and the expression of stress sensitivity coefficient are obtained. It is shown that the stress sensitivity coefficient can be enhanced by properly selecting the elastic modulus and the size of the elastomer. The theoretical and the experimental stress sensitivity coefficients of the fiber Bragg grating coated by elastic polymer are 6.64×10^(-10) Pa^(-1) and 6.14×10^(-10) Pa^(-1) respectively, and they are 57.8 and 54.8 times of those of bare fiber Bragg gratings respectively. They fit very well.