Fiber-Optic Vector Magnetic Field Sensor Based on Mode Interference and Magnetic Fluid in a Two-Channel Tapered Structure

Abstract

An innovative approach to high-sensitivity simultaneous intensity and direction measurement in a two-channel tapered sensor is proposed and demonstrated. The sensor is comprised of magnetic fluid (MF)-filled micro-capillary and two accompanying microfiber, thus enabling evanescent interaction to take place between the optical mode in the capillary and MF. Given the magnetic nanoparticles (MNPs) of MF manifest anisotropic magnetic field. Experimental and numerical simulations were performed simultaneously, which provided a better understanding of the interaction between light and MF in addition to clarifying the dynamic process of MNPs within MF with the assistance of varying magnetic field. The experimental results are well consistent with the numerical simulation results and show that the sensitivity of this sensor reaches up to 244 pm/mT, with the direction error being merely ±1.4°. Therefore, the proposed sensor exhibits a unique sensitivity for the measurement of magnetic field intensity and direction in 3D space, which makes it best suitable for applications in transportation, medicine, and smart device.

Magnetic Field Sensing Characteristics Based on Optical Microfiber Coupler Interferometer and Magnetic Fluid

“…The results show that the sensitivity of 54.71 and 48.21 pm/Oe was obtained when the OMC's waist radius was set at 3.5 and 4 µm (under the same length of OMC's waist), respectively. Compared with the traditional magnetic field sensors of OMC-Sagnac [14], OM-MF [24], and PCF-MF [16] structures, the advantages of the proposed sensor lie in its increased interference arm region. It is possible to integrate temperature-sensitive, pressure-sensitive, salt-sensitive, or humidity-sensitive materials into the interference arm of OMCI, which is of great significance for the realization of multi-parameter sensing or compensation performance, and the proposed sensor shows good vector property and time response.…”

“…When the magnetic vector (0-90 • ) changes, the direction of the alignment chain of Fe 3 O 4 nanoparticles around the OMC uniform waist region changes accordingly, thus affecting the refractive index around the OMC uniform waist region. Therefore, the output spectrum of the magnetic field response changes accordingly, indicating that the magnetic field sensor based on the OMC-MI refractive index control type was vectorizing compared with the OM-MF type [24].…”

Vector Magnetic Field Sensing at Tiny Angles Through a Nanofluid Functionalized Ultrathin Taper Interferometer

“…But few of them only can provide vector magnetic field sensing about which have been reported in recent research published in nearby years. Examples of such vector magnetic field sensors including with their citation are as follows: tapered fiber [4][5][6], photonic crystal fiber [2], large-core-offset Mach-Zehnder interferometer (MZI) [7], fiber Bragg grating (FBG) [8][9][10], U-bent single-mode fiber (SMF) [11], side-polishedfiber (SPF)-integrated with singlemode-no core-singlemode (SNS) structure [12], and few mode fiber based plasmonic vector magnetometer [13]. But studies show that the magnetic properties are greatly affected by the magnetic anisotropy of MNPs and by interparticle interactions that are the result of the collective magnetic behaviour of MNPs [10][11][12][13].…”

Two-channel photonic crystal fiber based on surface plasmon resonance for magnetic field and temperature dual-parameter sensing

“…19 Tian et al combined a MF-filled micro-capillary with two microfibers, realizing a magnetic field sensitivity of 24.4 pm Oe À1 . 20 These sensors are easy to produce, compact and capable of testing the magnetic field, but their sensitivities are low. In addition, since the magnetic nanoparticles in MFs are affected by both the temperature and magnetic field, the cross-sensitivity problem caused by temperature is an issue to consider.…”