Miniature Faraday current sensor based on multiple critical angle reflections in a bulk-optic ring

A novel optical element for a bulk glass current sensor that utilizes the Faraday effect is presented with a demonstrated sensitivity of 1 amp-turn and a flat frequency response in the range of 10-10(4) Hz. The new sensing element overcomes the problems associated with birefringence in optical fiber current sensors and the requirement to make bulk-optic current sensors in complex three-dimensional topologies.