REDUCED MINIMUM CONFIGURATION FIBER OPIC CURRENT SENSOR

摘要

A reduced minimum configuration (RMC) fiber optic current sensor (FOCS) is proposed which includes a sensing coil or sensing region, a light source and an optical path arranged between the front output of the light source and th e fiber optic sensing coil/region. At least one quarter wave plate is disposed between the optical path and the sensing coil/region for converting linearly polarized light beams into circularly polarized light beams propagating through the sensing coil/region. The circularly polarized light beams propagating through the sensing region experience a differential phase shift caused by a magnetic field or current flowing in a conductor proximate to th e sensing coil. A light detector is located at the back output of the light source and produces an output signal in response to return light intensity transmitted through the light source. The return light intensity is a measur e of the magnetic field in the sensor coil/region. The magnetic field may be produced by an electric current flowing through a wire, wherein the sensor coil can be wound around the wire. Electronics is described which minimizes effects caused by changes in the environmental conditions.