A fiber strain and vibration sensor based on high birefringence polarization maintaining fibers

In this study, a high birefringence (Hi-Bi) polarization maintaining fiber (PMF) is used as the sensing element for static axis strain and dynamic vibration measurements. This multifunctional fiber sensor adopts the Sagnac loop structure, where the Hi-Bi PMF is incorporated in the fiber loop. The static axis strain measurement is realized by interrogating the broadband transmission spectra and the strain sensitivity of 1.09 pm/µs is achieved. Furthermore, the Sagnac fiber loop is applied in dynamic acoustic vibration measurements. The experimental results show that it can detect the acoustic vibrations over the frequency range of 30 Hz to 22 kHz, and shows signal to noise ratios (SNRs) over 40 dB from 800 Hz to 9000 Hz.