ABSTRACT
This chapter first introduces the concept of magnetostriction, listing important magneto-strictive materials and their properties, and then moves on to discuss highlysensitive interferometric sensors utilizing magneto-strictive materials, e.g., for the tracking of vessels and submarines via their perturbations of the earth’s magnetic field. Subsequently, magneto-strictive current transducers are presented that utilize fiber Bragg gratings for interrogation. Magnetic field concentrators serve to reduce the mass of the expensive magneto-strictive material to sub-gram levels. Another class of sensors makes use of magnetic-field-induced changes in the optical properties of magnetic fluids. The refractive index changes are observed by means of multiple mode fiber interferometers, micro-ring resonators, fiber gratings, or transmission changes of fluid-infiltrated photonic crystal fibers.
