Elliptical Measurement for Faraday Rotation in Multimode TeO2-ZnO-Na2CO3 Fiber for Magneto Optical Current Sensor Application

The design and measurement of Verdet constant of magneto optical fiber is reported. An optical beam was found that it linearly polarized at the fiber input changes to elliptically polarized after propagating down the fiber and an elliptical fitting method was studied and reported. Traditional method is based on circle polarized principle, rotation angle is obtained through manually adjust the polarizer which is rather inaccurate especially for small rotations. Through the development of elliptical fitting equations and the test of intensity on major and minor points, fiber Verdet constant can be measured more precisely. The measured data of TZN (TeO 2 - ZnO-Na 2 CO 3 ) fiber was verified and it provides improved accuracy compared with existing methods.