Simple structure of tapered FBG filled with magnetic fluid to realize magnetic field sensor

A magnetic field sensor based on tapered FBG wrapped in magnetic fluid is proposed and experimented. The center of FBG is tapered to form a nanofiber, thereby enhancing the interaction between structure and magnetic fluid. The magnetic fluid's perception of the external magnetic field will affect the optical path of the nanofiber in the center of the tapered FBG, which is reflected in the transmission spectrum of the sensor. The manufacturing method is simpler and more sensitive to external changes. The experimental results show that the intensity change of the sensor has good linearity corresponding to magnetic flux density, and the sensitivity is 0.035 dB/mT. The sensor can also measure the magnetic field below the critical magnetic field. After packaging with a glass tube, the magnetic fluid has difference responses to different directions of the magnetic field.