Real-time performance improvement of an interferometric fiber-optic vibration sensor based on phase shift integration

A fast demodulation method based on phase shift integration (PSI) is proposed for fiber-optic vibration sensors with heterodyne detection, which effectively accelerates the phase demodulation process of the sensing system. The PSI-based principle utilizes the phase relationship between adjacent sampling points within a heterodyne carrier period to recover the vibration signal to be measured through basic algebraic calculations. Simulation and experimental results show that the demodulating speed is at least seventy times higher than the traditional method. By adjusting the frequency of the carrier, the demodulating speed can be further improved. Meanwhile, the power of high-order harmonic terms in demodulation is suppressed by at least 18.5 dB. Therefore, this scheme has advantages in improving the real-time performance and the demodulated effect.