Comparison of signal processing schemes used in optical current transformers

Abstract The fundamental functions of the signal processing circuits used in optical current sensing systems are: measuring the quantities of the Faraday rotation, compensating the fluctuations of optical intensity caused by the optical sources, band-pass filtering the signals to enhance the signal-to-noise ratio of the system outputs, and amplifying the signals to the assigned voltages. The properties of three conventional signal processing schemes utilized in optical current sensing systems are compared and the experimental results are given, which may provide a basis for the choice of signal processing circuit of the optical current sensing systems.