A new fiber optic accelerometer with push-pull structure using 3x3 coupler

In this paper, we propose a new type of push-pull structure fiber optic accelerometer based on 3x 3 coupler for the first time and carried out measurements of its responsivity and cross-axis sensitivity. With specific algorithm, the phase signal of the sensor can be extracted without complicated modulation and demodulation. Experiments show that the responsivity of the accelerometer is larger than 40dB (0dB ref lrad/g) within the frequency band from 10Hz to 800Hz, which agrees well with the theoretical analysis. In addition, the cross -axis sensitivity can be optimized as low as about -30dB due to the push-pull structure. The results reported here indicate that this type of fiber optic accelerometer can be applied in vibration sensing such as micro seismic monitoring.