Detection of low-frequency magnetic signals in a magnetostrictive fiber-optic sensor with suppressed residual signal

A correlation is presented between experimental data obtained under various operating conditions and a modified coherent rotation model which predicts the behavior of the residual signal and the sideband noise. The authors identify an operating regime that eliminates the residual signal and gives rise to a reduction in noise levels by a factor of five over previously reported results. Minimum detectable fields of 11+or-2pT/ square root Hz at 1 Hz and 38+or-8 pT/ square root Hz at 0.2 Hz are achieved.>