Single-mode fibre-optic magnetometer with DC bias field stabilization

Abstract

A sensitive dc field magnetometer, based on magnetostrictive straining of optical fibers is demonstrated, which utilizes active bias field stabilization to ensure that the magnetostrictive sensing element is maintained in a state of zero magnetization. This technique eliminates any problems arising due to magnetic hysteresis effects of the magnetostrictive material which affect the magnetometer output when operated in a conventional 'open-loop' mode. Detection sensitivities of the order of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8 \times 10^{-5}</tex> A . m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\sim10^{-16}</tex> Oe), and a linear dynamic range of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> are demonstrated.