Method for magnetooptic current measurement and magnetooptic current- measuring device

摘要

Simple methods for magnetooptic current measurement and magnetooptic current-measuring devices are specified, which are independent of temperature influences on the measurement result and require no compensation device for the light intensity of light sources (LD1, LD2) employed. Light beams (1, 2) from the two laser light sources (LD1, LD2) are alternately polarized orthogonally relative to one another by means of a beam splitter (3), and are transmitted to light detectors (D.sub.A, D.sub.B) via collimators (4, 6), which are connected via a polarization- maintaining high-index birefringent HI fiber (5), through a magnetooptic current sensor (7), an analyzer (10), 2 collimators (11, 12) and multimode fibers (13) and (14). 1st and 2nd light output signals S. sub.A1 and S.sub.B1 as well as 3rd and 4th light output signals S.sub.A2 and S. sub.B2 are derived sequentially in time from the light detectors (D.sub.A, D.sub.B). A signal characterizer (232) of a control and evaluation device (15) is used to calculate a current intensity I detected by means of the magnetooptic current sensor (7), in accordance with I=[S.sub.A1 . multidot.S.sub.B2 /(S.sub.A2 . multidot.S.sub.B1)-1] /(8·V), V being the magnetooptic Verdet's constant. It is also possible to work using frequency multiplexing instead of time multiplexing. It is possible to use a low-index birefringent LI fiber instead of a solid optical current sensor (7), light being sent through in both directions and evaluated separately.