Ti3C2TX MXene-Coated Tapered No-Core Fiber Sensor with Enhanced Sensitivity for Magnetic Field Sensing

Magnetic field detection technology, as one of the core supporting technologies in the modern information industry, plays a key role in various fields such as power systems, non-destructive testing, and biomedicine. With advancements in new materials and micro-nano fabrication techniques, magnetic field detection technology is advancing toward higher precision and miniaturization. By coating the optical fiber with Ti₃C₂Tₓ MXene, the proposed magnetic fluid (MF)-based magnetic field sensor achieves significant sensitivity enhancement compared with the uncoated sensor. The sensor consists of a Mach-Zehnder interferometer formed by cascading single-mode fiber (SMF), thin-core fiber (TCF), tapered no-core fiber (TNCF), TCF, and SMF. A Ti₃C₂Tₓ MXene film is coated on the TNCF surface and the sensor is immersed in MF. Ti₃C₂Tₓ MXene exhibits excellent hydrophilic functional groups, an ultra-large specific surface area, and enhanced evanescent field characteristics. Combined with the inherent strong evanescent field effect of TNCF, these properties collectively contribute to a significant improvement in sensor sensitivity. Experimental results show that within a magnetic field range of 0 - 16 mT, the sensor achieves a sensitivity of 0.412 nm/mT, representing an 83% enhancement compared to the uncoated TNCF, with a detection limit of 0.146 mT. Furthermore, the proposed magnetic field sensor offers advantages of simple fabrication, low cost, and high stability. It exhibits improved sensing performance, and a laboratory-simulated railway current monitoring experiment further demonstrates its practical potential.