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 bis muth 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, th e sensor has a noise-equivalent magnetic field of 10(-8) T/root Hz at 50 Hz and reaches an accuracy of 1% while the alternating magnetic field is chan ged from 0 to 45 x 10(-4) T over the temperature range from -20 degreesC to 50 degreesC. The sensing head is only 0.003 m x 0.15 m in size.