Single Mode Fiber Optic DC Magnetometer Capable Of Multiple-Point Measurement

A multiple-point fiber optic sensor for the detection of weak and quasi-steady magnetic fields is described. The optical processing involves a single optical fiber sensing element configured as a two beam interferometer employing magnetostrictive sensing elements. Each sensing element is addressed by a different modulation frequency distinct in the frequency spectrum. The principle of operation is based on narrow band phase sensitive detection technique such that the multiplexing of a number of sensing elements is accomplished in the frequency domain. The fiber sensing elements can be remotely deployed, linked to the processing unit by an arbitrary length of down lead fiber. The investigated optical configuration facilitates the realization of a practical multiplexed magnetic field sensor.