METHOD AND DEVICE FOR CURRENT MEASUREMENT BY MEANS OF FIBRE-OPTIC IN-LINE SAGNAC INTERFEROMETER AND PHASE MODULATOR SUITABLE FOR THE ABOVE

摘要

A device (20) for current measurement, based on a fibre-optic in-line Sagnac interferometer, comprising a double refraction phase modulator (24), for the non-reciprocal phase modulation of two orthogonal polarisation modes of a light beam passing through the interferometer. Said device is characterised in that the phase modulator is a digital phase modulator (24). The advantage of the above is that the phase modulator (24) may be directly digitally controlled, permitting a simplification of a corresponding signal processing or control electronic device (32).