Stray current sensor with cylindrical twisted fiber.

In this paper, a stray current sensor with cylindrical twisted fiber is proposed. The quantitative method of linear birefringence on the sensing fiber is demonstrated. And the temperature-induced linear birefringence is about 4.63 deg per meter at 60 deg centigrade. Then, the demand of circular birefringence is determined based on the polarization division multiplexing model, which is produced by the cylindrical twisted fiber. According to the simulation results, the produced circular birefringence is about 2116.9 deg, which is enough to suppress the linear birefringence. The temperature experiment results indicate the positive effect of the cylindrical twisted fiber, which controls the linear birefringence error within 0.945×10(-5) per degree centigrade. Finally, the performance test results prove the cylindrical twisted fiber improves the accuracy of the stray current sensor. And its repeatability and sensitivity are about 0.367% and 0.0261/A, respectively.