Magnetostrictive fiber sensors combine the phase sensitivity of interferometry with the magnetically induced strain of ferromagnetic materials. Configurations include fiber wrapped around mandrel halves separated by a magnetostrictive rod, fiber bonded to a magnetostrictive ribbon and fiber jacketed with a magnetostrictive film. Processing advances in the deposition of dense, uniform films on the cylindrical surface of the fiber offer the advantage of reduced demagnetization of the magnetostrictive material. In this paper, we investigate the design of a sensor based on a magnetostrictive film jacketing the fiber. We analyze the system resolution and minimum film thickness of the fiber sensor using nickel, Metglas and Terfenol-D films. For each of these magnetostrictive films, we present simulation results on the resolution as a function of the film-fiber interaction length. In our analysis, we assume a phase generated carrier demodulation scheme. We next analyze the magnetostrictive strain of the compound film-fiber system as a function of film thickness. This analysis sets the minimum film thickness for effective strain on the system. Finally, we propose a geometry which allows a compact sensor package with a reasonable film-fiber interaction length.

Date Published: 14 May 2019
PDF: 7 pages
Proc. SPIE 11000, Fiber Optic Sensors and Applications XVI, 110000Q (14 May 2019); doi: 10.1117/12.2519585

Published in SPIE Proceedings Vol. 11000:
Fiber Optic Sensors and Applications XVI
Robert A. Lieberman; Glen A. Sanders; Ingrid U. Scheel, Editor(s)