Distributed Optical Fiber Current Sensor Based on Magnetostriction in OFDR

We present a distributed optical fiber current sensor based on magnetostriction using Rayleigh backscattering spectra (RBS) spectral shift in optical frequency-domain reflectometry. In the proposed sensor, the magnetostrictive Fe-Co-V alloy thin films as sensing materials are attached to a 63-m standard single-mode fiber (SMF). We detect the strain variation coupled to the SMF caused by the magnetic field variation by measuring the RBS shift. As the magnetic field variation is proportional to the current variation in the electric line, the current can be measured. In our experiment, we measure the current range from 0 to 11.8 A and 0 to 12.14 A at two locations using proposed method and obtain distributed current trace. We achieve the linear relationship between the RBS shift and the current variation. The minimal measurable current variation is 0.3 A when the sensing spatial resolution is 14 cm.