Measurement of AC current using a superstructure fiber grating

In the power industry, current must be measured for metering and protection purposes. For such measurements, this article demonstrates an optical fiber sensor using a superstructure fiber grating (SFG) to measure AC current. The sensor head is based on superstructure fiber grating encapsulated in a polymer‐half‐field metal cylinder embedded a magnetic material. The sensor detects force when it is attracted by the induced magnetic force created by the solenoid along one radial direction only and responds to an axial force on the magnetic rod attached to the round plate, creating an axial attraction on the SFG. The SFG is composed of a fiber Bragg grating (FBG) and a long period grating (LPG). Therefore, variations in attractive force and temperature cause variations in SFG center‐wavelength. Thus, the sensor can be used to measure attracting forces and temperature effects simultaneously. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1168–1171, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23317