We proposed and demonstrated an innovative magnetic field optical fiber sensor utilizing magnetic ferrofluid and a thin-core fiber (TCF)-based modal interferometer. The modal interferometer was fabricated by splicing a TCF between two single mode fibers.
Two TCF interferometers with different dipwavelength were connected in a fiber to demonstrate the sensors multiplexing capability. The transmission dip wavelength of interferometer is shifting with a maximum sensitivity of 11.8 pm/Oe.