Single Mode Fiber Optic Sensor For High Currents

• Main Authors: Veeser, Lynn R, Caird, Robert S, Freeman, Bruce L, Kania, Don R, Kruse, Peter J, Trainor, Robert J, Zimmermann, Eugene L
• Format: Report
• Language: English
• Subjects: FARADAY EFFECT; FARADAY ROTATION; FIBER OPTICS; Optical Detection and Detectors; OPTICAL DETECTORS; Refractory Fibers

We are developing a pulsed current sensor that will be less intrusive than present sensors and that we hope will remain linear to much higher current levels. Polarized laser light is transmitted by a low-birefringence, single mode optical fiber that encircles the current carrier. We observe the Faraday rotation of the polarization plane in the current-induced magnetic field, We have measured a Verdet constant of about 260 /MA for 633 nm light in Lightwave Technologies, Inc., Model F1506C fiber, and we have detected currents of up to 12 MA in pulses 0.5 to 40 micro s long. Our major problems have involved signal noise from stray plasma light getting into the fiber and shock-induced birefringence that rotates the polarization slightly. Future plans are to try a Sagnac interferometer to reduce the sensitivity to shock waves. See also ADM002371. 2013 IEEE Pulsed Power Conference, Digest of Technical Papers 1976-2013, and Abstracts of the 2013 IEEE International Conference on Plasma Science. Held in San Francisco, CA on 16-21 June 2013. U.S. Government or Federal Purpose Rights License.