A fiber strain and vibration sensor with high birefringence polarization maintaining fiber based on Sagnac interferometer

The paper describes a fiber sensor for the evaluation of static axis strain and dynamic vibration. A section of high birefringence polarization maintaining fiber (Hi-Bi PMF) is incorporated in a Sagnac fiber loop as the sensing element. The static axis strain measurement is realized by analyzing the attenuation peak wavelength shifts and the strain sensitivity of 1.09 pm/mu s is achieved. Using the power intensity demodulation method, the experimental results of dynamic acoustic vibration measurement show that it can detect the acoustic vibrations over the frequency range of 50 Hz to 22 kHz.