Optical fibre magnetic field sensors

A class of high sensitivity fibre-optic magnetic sensors has been developed and successfully tested in the laboratory for the first time. The magnetic sensors employ magnetostrictive jacketing materials in conjunction with conventional single-mode optical fibres. An all-fibre Mach-Zender interferometer was used to detect the magnetically induced changes in optical path length which arise because of strains transferred to the fibre from the magnetostrictive jacket.