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^-8 T/√(Hz) at 50 Hz and reaches an accuracy of 1% while the alternating magnetic field is changed from 0 to 45×10^-4 T over the temperature range from -20°C to 50°C. The sensing head is only 0.003 m×0.15 m in size