OPTICAL MEASUREMENT METHOD AND OPTICAL MEASUREMENT DEVICE FOR MEASURING AN ALTERNATING MAGNETIC FIELD WITH INTENSITY NORMALIZATION

摘要

Two light signals (L1, L2) pass in opposing directions though an optical series arrangement (30) comprising a first multimode fibre (4), a first polariser (5), a Faraday sensor device (3), a second polariser (6) and a second multimode fibre (7). Equal signal components (D1, D2) are used to derive an intensity-normalised measurement signal (M, M') from the light intensities (I1, I2) of both light signals (L1, L2) following passage through the series arrangement (30).