Optical fibre current transducer using Sagnac interferometer - has two polarised partial beams fed through current sensor coil in opposing directions

摘要

The current transducer uses 2 partial beams (A,B) obtained from a common light source (8) via a polarisation beam splitter which are fed through a sensor coil (2) wound around the current carrying conductor (1) in opposite directions. The 2 partial beams (A,B) received from the sensor coil (2) are sepd. out via second beam splitter (6) and fed to an evaluation device (7) providing the measured current from their detected phase shift. Pref. the quarter wavelength plates (3a,3b) lie at the opposite ends of the sensor coil (2) for converting the incoming linearly polarised light into circularly polarised light fed through the coil and vice versa. ADVANTAGE - Simplified measurement and evaluation.