Based on the Faraday effect for measuring ac current, we describe a fiber-optic sensor that uses laser-diode intensity modulation to perform heterodyne signal detection. The sensor output at the carrier frequency is used as a reference signal to normalize the results. The sensing element consists of a few coils low-birefringence fibers between polarizers. We built the current sensor described above and tested its performance—sensitivity and noise—as functions of the angle between polarizers.
© 1999 Optical Society of America
José A. Ferrari, Alfredo Dubra, Alfredo Arnaud, and Daniel Perciante, "Current Sensor Using Heterodyne Detection," Appl. Opt. 38, 2808-2811 (1999)