Method and arrangement for measuring a magnetic field using the Faraday effect, with compensation for intensity changes

摘要

Two light signals pass, in opposite directions, through a series circuit comprising a first optical fiber, a first polarizer, a Faraday sensor device, a second polarizer and a second optical fiber. To set the working point, additionally, the planes of polarization of both light signals are reciprocally rotated by a predetermined angle of rotation by rotation means between the two polarizers. From light intensities of the two light signals, after passing through the series circuit, a measuring signal is determined which is independent of vibrations and bending influences in the optical fibers.