Magnetic field sensors, in particular optical fiber magnetometers

摘要

In a fiber optic interferometric magnetic sensor or magnetic gradient detector a magnetic bias field is applied to a magnetically sensitized portion of an optical fiber by means which are driven by optical power whereby a completely passive sensor head arrangement may be achieved. In a magnetic gradient detector optical power from a high power laser (34) may be supplied via an optical fiber (35) to illuminate a solar cell 27 to whose electrical output terminals solenoids (25,26) are connected. A portion of a respective optical fiber (21, 22) which is magnetically sensitized, by for example bonding to a strip of magnetostrictive material (23, 24), is disposed inside each solenoid (25, 26).