Effect of stress birefringence on characteristics of FBG pressure sensing

The sensing and the testing on the pressure in a state of the fiber Bragg grating (FBG's) bend strain were realized, and the effect of using overall affix and two-spot affix between the FBG and underlay on the characteristics of the pressure sensing was compared both experimentally and theoretically. Our analysis found that the bigger nonlinearity effect caused by overall affix on the characteristics of output to input of the sensor can be produced, and the nonlinearity effect caused by the spectral width is expanded due to the stress birefringence and the stress grads etc. The experimental results show that the spectral width caused by using overall affix is 0.28 nm, and the linearity of using two-spot affix increases by 1.89%.