Lorentz Force Magnetic Field Sensor Using Cladding-Etched Heterogeneous Integrated Optical Fiber with Triple Side Nickel Cores

A Lorentz force magnetic field sensor is demonstrated using a cladding etched heterogeneous integrated optical fiber with triple-side nickel cores (TSNCF). The sensing fiber heterogeneously integrates three nickel side cores in a single-mode fiber. When electric current is injected into the nickel side cores in the presence of orthogonal magnetic fields, the generated Lorentz force causes the vibration of the fiber. By employing a Mach-Zehnder interferometer to detect the resulting phase shift in the optical fiber, the sensor effectively perceives the magnetic field. The results show that TSNCFs with smaller diameters demonstrate higher sensing performance due to lower fiber stiffness. The sensitivity of the 90 μm-TSNCF is 3 times that of a single side nickel core fiber with a 125 μm cladding diameter. The maximum sensitivity of magnetic field intensity achieved in our experiment is 9.91 rad/mT by using the 90μm-TSNCF. This compact, highly sensitive, and corrosion-resistant device holds potential for applications in magnetic field sensing.