Method for measuring linear birefringence inside bulk glass current-sensing elements

Linear birefringence is one of the most important parameters of optical (fibre-optic) current-sensing heads, which can obviously affect the performance of optical current sensors. Therefore, it is of great importance to measure the linear birefringence inside the optical current-sensing head to enhance the properties of sensors. A novel method to measure the linear birefringence inside bulk glass current-sensing heads is reported in this paper, which gives a theoretical analysis of the principle, the measurement uncertainty analysis-using the Jones matrix as a mathematical tool-and an applied example. This method overcomes the shortcomings of the two methods reported before which cannot uniquely determine the value of the linear birefringence or introduce large measurement uncertainty. The experimental result shows that this method can certainly enhance the measurement precision.