Miniature Fiber-Optic Magnetic Field Sensor Based on Ampere Force and Fiber Laser

Weiren Cheng,Linghao Cheng,Bai-Ou Guan,Hao Liang,Tianming Luo

doi:10.1007/s13320-020-0590-5

Abstract

A compact fiber-optic magnetic field sensor is proposed by packaging an orthogonal dual-frequency fiber grating laser and a copper wire with alternating electrical current together inside epoxy resin. The alternating current generates Ampere force in a magnetic field, which changes the birefringence of the fiber laser and hence tunes the frequency of the beat signal after photodetection. The magnetic field magnitude can then be detected by measuring the frequency change of the beat signal. The sensitivity of the sensor can be tuned with a maximum response of 35.21 kHz/kGs demonstrated. Moreover, the sensor shows good immunity to environment interference.

Highlights

Magnetic field is of great importance in various areas and its detection has always been a research hotspot in the world [1], attracting the attention of institutions in many countries
The fiber laser is attached to a copper wire and both of them are surrounded by polymer of epoxy resin to form a fiber-optic magnetic sensor
When the copper wire is carrying alternating current (AC) current, it is slightly vibrating in the magnetic field due to the Ampere force

Summary

Introduction

Magnetic field is of great importance in various areas and its detection has always been a research hotspot in the world [1], attracting the attention of institutions in many countries. Sensing techniques based on other mechanisms typically measure magnetic field indirectly through external transducers to increase sensitivity, such as through magnetostrictive transducer and Ampere force [10,11,12]. Such schemes generally convert magnetic field to an intermediate physical measurand which can be measured through fiber-optics with high sensitivity. Based on the orthogonal dual-frequency fiber grating laser, some fiber-optic magnetic field sensors have been proposed, such as those employing magnetostrictive materials [15], magnet force, and Ampere force [16, 17]

Methods

Results

Conclusion