Fiber Optic Electric Field Sensor Technology

The present review is restricted to fiber optic sensors for AC electric fields. Sensors for DC electric fields which use optical fibers are described in the paper by A. R. Johnston and H. Kirkham in these proceedings. Several fiber optic electric field sensor configurations have been recently studied. Most of these configurations have used a piezoactive plastic coating, or ribbon, bonded to the glass fiber. The incident electric field generates strains in the piezoactive plastic, which are transmitted to the glass fiber, and the resultant optical phase shift is detected by making the sensor one arm of a Mach-Zehnder interferometer. In the sections which follow the properties of piezoactive plastics are first reviewed, followed by a review of the fiber optic electric field sensors which have been studied so far. Next, a particular configuration consisting of a concentric piezoactive jacket on the glass fiber, is discussed in detail and the frequency response of this sensor is projected over a wide range of frequencies. Finally, the conclusion section includes a discussion of the advantages of fiber optic electric field sensors.