Patent ID: 6034523
Filing Date: 2000-03-07
Classification: G01R

Abstract:
A method for measuring a magnetic field with a sensor device exhibiting the Faraday effect, the method comprising the steps of:a) supplying a first light signal and a second light signal, in mutually opposite directions, through an optical series circuit comprising a first optical transmission path, a first polarizer, the sensor device, a second polarizer, and a second optical transmission path;b) rotating, between the first polarizer and the second polarizer, each one of a first plane of polarization of the first light signal and a second plane of polarization of the second light signal by a predetermined angle of rotation .alpha. which is independent of the magnetic field; andc) determining, after each one of the first light signal and the second light signal passes through the optical series circuit, a measuring signal for the magnetic field from a first light intensity of the first light signal and a second light intensity of the second light signal, the measuring signal being essentially independent of intensity changes in the first optical transmission path and the second optical transmission path;wherein a first axis of polarization of the first polarizer and a second axis of polarization of the second polarizer are each rotated by a polarizer angle .gamma. in relation to an intrinsic axis of a linear birefringence in the sensor device, the polarizer angle .alpha. fulfilling, within .+-.5.degree., the equationsin (4.gamma.)=+2/3when the angle of rotation .alpha. corresponds, within .+-.10.degree., to an angle-(1+4n).multidot.45.degree., andsin (4.gamma.)=-2/3when the angle of rotation .alpha. corresponds, within .+-.10.degree., to an angle+(1+4n).multidot.45.degree., wherein n is a whole number.