Sensing Magnetic Fields

About this technology

Overview

Innovators at NASA's Armstrong Flight Research Center have developed an optical waveguide fiber Bragg grating (FBG) that is sensitive to an external magnetic field. The technology allows direct coupling of the external field to the electromagnetic (EM) wave propagating in the fiber, bypassing the need to first measure strain. The properties of the waveguide material are directly and incontrovertibly influenced when exposed to an external field. In contrast to other FBG-based methods that detect external fields via a mechanical change (e.g., magnetostriction-induced strain), this innovation uses ferromagnetic nanoparticles to achieve a direct coupling of the external field to the optical behavior of the fiber. Thus, the technology can be used as a sensor to detect and map magnetic fields. Alternately, a known magnetic field can be applied to create a particular optical transmission behavior in the waveguide, thus creating an optical switch or selective filter.