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A stable dynamic detection scheme for magnetostrictive fiber-optic interferometric sensors is studied. The working principle is presented and the experimental verification is performed. The results show that the system employing the dynamic detection scheme has better stability and sensitivity in comparison with the system employing quadrature control technique.

Directivity in magnetostrictive fiber-optic interferometric transducers was analyzed. Comparison was carried out theoretically and experimentally on cylindrical and racetrack transducers, and expressions were presented. The results show that the racetrack transducer has better performance both in sensitivity and directivity for it has a length of magnetostrictive strip in parallel to the measured field.

A novel configuration for the transducer of magnetostrictive fiber-optic sensors was proposed and implemented. It is composed of a rectangle and two half-circles. The transducer with the novel configuration has not only higher sensitivity than that of traditional configurations, but good directivity. The magnetostriction was analyzed compared with that of cylindrical transducers. It is shown that the system sensitivity can be improved by increasing the long-side of rectangle and shortening the perimeters of the two half-circles.Two transducers with cylindrical and racetrack configurations were fabricated. Moreover, an experimental setup to measure the low-intensity magnetic field detection responses was built up. Experimental results verified the analysis.For its good directivity, three of them can be compounded as a vector magnetometer to measure three orthogonal components of magnetic field.