Birefringence and polarization properties of a spun fiber around conductor with electrical currents

The linear birefringence is not easy to remove, since the spun fiber is used in optical fiber current sensor. We discuss the birefringence properties of a spun fiber around conductor with electrical currents, including the nonlinearity of linear birefringence and linearity of circular birefringence of the spun fiber. Theoretical results show that with the increase of load current, the linear birefringence of spun fiber will increase rapidly. By analyzing the impact of different polarization incident angle on the Poincare sphere it is possible to obtain the influence of Faraday effect on spun fiber around conductor with electical currents in a high current generating system environment. We believe that the properties presented in this paper will be beneficial for reducing the influence of linear birefringence, as well as high accuracy fiber optic current sensors.