The effect analysis of impact on a fiber optic current sensor

Nowadays, the fiber optic current sensor (FOCS) has been massively used on the warships. However, the performance of the FOCS will be greatly affected by the impact on warships, since the stress field caused by the impact will introduce an elastic-optic effect-induced bias error to the FOCS. To improve the performance of FOCS applied in warships, the accurate model of elastic-optic effect-induced bias error is necessary for its practical applications. In this paper, we analyze the mechanical stress on an in-line Sagnac fiber optic current sensor during the impact and find that the bias error is mainly caused by the stress acting on the delay coil. Then we present a mathematical model of non-anisotropic phase error caused by impact on delay coil from the perspective of the three-dimensional model and theoretical results are obtained by simulation. Finally, experiments are carried out according to the test methods specified in national standards. The correctness of the error mathematical model is verified by experiments that the differences between simulation and experiment are within 10%.