OPTICAL INTERFEROMETRIC CURRENT SENSOR AND A METHOD FOR MEASURING AN ELECTRICAL CURRENT

摘要

The interferometric current sensor is for measuring an electrical current. It comprises a light source for generating a light beam; a single-mode birefringent waveguide having a linear birefringence and a circular birefringence, the circular and linear birefringences having respectively given orders of magnitude, the order of magnitude of the circular birefringence being equal or higher than the order of magnitude of the linear birefringence, the waveguide having a first loop portion for encircling the electrical current; a beamsplitter having a first input port optically coupled to the light source, and second and third input/output ports optically coupled to ends of the waveguide for launching counter-propagating light beams into the respective ends of the waveguide and for receiving the counter-propagating light beams therefrom; and a pseudo-depolarizer optically coupled in series with the waveguide for converting each of the counter-propagating light beams into a predetermined ratio of useful counter-propagating light signals and useless counter-propagating light signals. It also comprises an optical detector optically coupled to the ends of the waveguide via the beamsplitter for detecting a light intensity, the light intensity is representative of the current.