Directional Magnetic Field Sensing Based on Few Mode Fiber Long-Period Grating with Spatial Refractive Index Modulation

Yuehui Ma; Chen Jiang; Siyu Chen; Chengbo Mou; Kaiming Zhou; Yunqi Liu

doi:10.1109/JSEN.2025.3566555

Directional Magnetic Field Sensing Based on Few Mode Fiber Long-Period Grating with Spatial Refractive Index Modulation

Yuehui Ma
, Chen Jiang
, Siyu Chen
, Chengbo Mou
, Kaiming Zhou
, Yunqi Liu^*

^*Corresponding author for this work

Aston Institute of Photonic Technologies (AiPT)

Nanjing University of Posts and Telecommunications

Research output: Contribution to journal › Article › peer-review

Abstract

We present a highly sensitive directional magnetic field sensor based on a long-period fiber grating (LPFG) inscribed in few-mode fiber (FMF) and combined with magnetic fluid (MF). The unique spatial refractive index modulation (RIM) profile of the FMF-LPFG allows for the simultaneous measurement of magnetic field intensity, direction, and temperature. The interaction between the anisotropic refractive index of the MF and the LPFG is exploited to achieve directional magnetic field sensitivity, with a maximum intensity sensitivity of 717.5 pm/mT at 0° and directional sensitivity of 163.3 pm/° at 10.7 mT. Temperature crosstalk is mitigated by monitoring independent interference dips, enabling reliable dual-parameter sensing. The proposed FMF-LPFG sensor demonstrates excellent intensity sensitivity, precise directional detection, and effective temperature monitoring. This work offers a robust and versatile solution for high-precision magnetic field monitoring in applications ranging from industrial sensing to biomedical diagnostics.

Original language	English
Pages (from-to)	21683 - 21690
Number of pages	8
Journal	IEEE Sensors Journal
Volume	25
Issue number	12
Early online date	8 May 2025
DOIs	https://doi.org/10.1109/JSEN.2025.3566555
Publication status	Published - 15 Jun 2025

Bibliographical note

Copyright © 2025 IEEE. All rights reserved, including rights for text and data mining and training of artificial intelligence and similar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission. See https://www.ieee.org/publications/rights/index.html for more information.

Funding

This work was supported by National Natural Science Foundation of China (62075124), China Scholarship Council (202306890090).

Keywords

Sensors
Magnetic fields
Claddings
Optical fiber sensors
Refractive index
Magnetic sensors
Couplings
Sensitivity
Optical fibers
Gratings
Directional magnetic field sensor
Long-period fiber grating
Spatial refractive index modulation

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title = "Directional Magnetic Field Sensing Based on Few Mode Fiber Long-Period Grating with Spatial Refractive Index Modulation",

abstract = "We present a highly sensitive directional magnetic field sensor based on a long-period fiber grating (LPFG) inscribed in few-mode fiber (FMF) and combined with magnetic fluid (MF). The unique spatial refractive index modulation (RIM) profile of the FMF-LPFG allows for the simultaneous measurement of magnetic field intensity, direction, and temperature. The interaction between the anisotropic refractive index of the MF and the LPFG is exploited to achieve directional magnetic field sensitivity, with a maximum intensity sensitivity of 717.5 pm/mT at 0° and directional sensitivity of 163.3 pm/° at 10.7 mT. Temperature crosstalk is mitigated by monitoring independent interference dips, enabling reliable dual-parameter sensing. The proposed FMF-LPFG sensor demonstrates excellent intensity sensitivity, precise directional detection, and effective temperature monitoring. This work offers a robust and versatile solution for high-precision magnetic field monitoring in applications ranging from industrial sensing to biomedical diagnostics.",

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note = "Copyright {\textcopyright} 2025 IEEE. All rights reserved, including rights for text and data mining and training of artificial intelligence and similar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission. See https://www.ieee.org/publications/rights/index.html for more information.",

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AU - Ma, Yuehui

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AU - Chen, Siyu

AU - Mou, Chengbo

AU - Zhou, Kaiming

AU - Liu, Yunqi

N1 - Copyright © 2025 IEEE. All rights reserved, including rights for text and data mining and training of artificial intelligence and similar technologies. Personal use is permitted, but republication/redistribution requires IEEE permission. See https://www.ieee.org/publications/rights/index.html for more information.

PY - 2025/6/15

Y1 - 2025/6/15

N2 - We present a highly sensitive directional magnetic field sensor based on a long-period fiber grating (LPFG) inscribed in few-mode fiber (FMF) and combined with magnetic fluid (MF). The unique spatial refractive index modulation (RIM) profile of the FMF-LPFG allows for the simultaneous measurement of magnetic field intensity, direction, and temperature. The interaction between the anisotropic refractive index of the MF and the LPFG is exploited to achieve directional magnetic field sensitivity, with a maximum intensity sensitivity of 717.5 pm/mT at 0° and directional sensitivity of 163.3 pm/° at 10.7 mT. Temperature crosstalk is mitigated by monitoring independent interference dips, enabling reliable dual-parameter sensing. The proposed FMF-LPFG sensor demonstrates excellent intensity sensitivity, precise directional detection, and effective temperature monitoring. This work offers a robust and versatile solution for high-precision magnetic field monitoring in applications ranging from industrial sensing to biomedical diagnostics.

AB - We present a highly sensitive directional magnetic field sensor based on a long-period fiber grating (LPFG) inscribed in few-mode fiber (FMF) and combined with magnetic fluid (MF). The unique spatial refractive index modulation (RIM) profile of the FMF-LPFG allows for the simultaneous measurement of magnetic field intensity, direction, and temperature. The interaction between the anisotropic refractive index of the MF and the LPFG is exploited to achieve directional magnetic field sensitivity, with a maximum intensity sensitivity of 717.5 pm/mT at 0° and directional sensitivity of 163.3 pm/° at 10.7 mT. Temperature crosstalk is mitigated by monitoring independent interference dips, enabling reliable dual-parameter sensing. The proposed FMF-LPFG sensor demonstrates excellent intensity sensitivity, precise directional detection, and effective temperature monitoring. This work offers a robust and versatile solution for high-precision magnetic field monitoring in applications ranging from industrial sensing to biomedical diagnostics.

KW - Sensors

KW - Magnetic fields

KW - Claddings

KW - Optical fiber sensors

KW - Refractive index

KW - Magnetic sensors

KW - Couplings

KW - Sensitivity

KW - Optical fibers

KW - Gratings

KW - Directional magnetic field sensor

KW - Long-period fiber grating

KW - Spatial refractive index modulation

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JF - IEEE Sensors Journal

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ER -

Directional Magnetic Field Sensing Based on Few Mode Fiber Long-Period Grating with Spatial Refractive Index Modulation

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