New design of optical current sensor for sensitivity improvement

A new structure of Faraday effect based optical current sensor is proposed and developed. The sensor, being of a ring core type, is a simple prism-shaped topology that employs a number of critical angle reflections inside the bulk glass. The optical beam is made to retrace its path by coating the far end with high reflection coating. As a result, the sensitivity of the sensor can be improved and the total optical power losses minimized. The number of reflections inside the sensor, which is related to the sensitivity, can be changed easily by adjusting the incident point of light. The design also has the advantage of reducing the package size of the sensor probe. The performance of an experimental sensor is reported and computer simulations of the sensor response with non-critical angle reflections are discussed