Miniature optical fiber sensor for alternating magnetic fields based on In-BiCa vanadium iron garnet crystal

This paper introduces a high-sensitivity miniature optical fiber sensor for alternating magnetic fields based on the Faraday effect in bulk indium bismuth calcium vanadium iron garnet (In-BiCaVIG). It discusses the effects of the crystal's magnetic hysteresis on the sensor in detail. Because of its construction, and the methods that reduce the effects of the hysteresis, the sensor has a noise-equivalent magnetic field of 10/sup -8/ T//spl radic/(Hz) at 50 Hz and reaches an accuracy of 1% while the alternating magnetic field is changed from 0 to 45/spl times/10/sup -4/ T over the temperature range from -20/spl deg/C to 50/spl deg/C. The sensing head is only 0.003 m/spl times/0.15 m in size.