Fiber Optic Current Sensor Based on Special Spun Highly Birefringent Fiber

A fiber optic current sensor based on a polarization-rotated reflected interferometer has been constructed. A special spun highly birefringent fiber is designed and achieved for the sensor by heating and spinning commercial linearly birefringent fiber. In contrast with conventional fibers, the fiber integrates a function of a quarter wave plate. Particularly, fabricating and working principle of the current sensor head using the fiber are expounded. The sensor achieves an accuracy with 0.5% and good linearity shown in temperature dependence (a temperature drift of 0.008%/degrees C) over a temperature range 40 degrees C-70 degrees C. Further, under simple temperature compensation, the sensor accuracy is within +/- 0.1% over in a wide range of current and temperature ranges.