Magnetic-field sensor based on core-offset tapered optical fiber and magnetic fluid

A magnetic field sensor based on an asymmetrical fiber modal Mach–Zehnder interferometer (MMZI) is achieved by cascading tapered fiber with the core-offset structure. The MMZI is sealed by the magnetic fluid and its spectral dependence on magnetic field has been investigated. The results show that the transmission variations of the two dips are about 8 dB and 10 dB for a magnetic intensity range from 0 Oe to 400 Oe, respectively. The highest magnetic sensitivity reaches 0.03407 dB Oe −1 . The proposed sensor based on the intensity demodulation is cost-effective and robust; therefore, the device is beneficial to the magnetic field sensing applications and other magneto-optical tunable photonics devices.