Lorentz Force Based Magnetic Field Sensor by Using Heterogeneous Integrated Optical Fiber with Side Nickel Core

A heterogeneously integrated fiber-optic magnetic field sensor is proposed and demonstrated in this work. The sensing fiber is thermally drawn and consists of a nickel side-core, a silica center core and a silica cladding. When exposed to the external vertical magnetic field, the Lorentz force will be generated in the electric current applied nickel side-core, and drive the motion of the entire heterogeneous fiber. Thus, by employing an interferometer system, the magnetic field can be sensed by the measurement of resulted optical phase variation. The proposed design has shown consistency in fabrication and ease of preparation. As a result, the magnetic field sensitivity can reach 3.38 rad/mT, showing its attractive potential in measuring weak magnetic fields.