Elimination of Disturbing Birefringence Effects on Faraday Rotation

The resolution of a practical Faraday effect device is limited by birefringence. The case where both Faraday effect and birefringence are small is treated. Aleans for obtaining a high degree of linearity between Faraday rotation and applied magnetic field are investigated. With a method requiring two nearly identical sensors, a very significant over-all improvement is achieved. A second method of compensation, which acts on the polarization of the incoming light, gives an improvement for low fields only. A slight mismatch between the two sensors may be almost completely offset by superimposing the first and second compensation methods.