Fiber Optic Sensors Based on the Faraday Effect

Abstract

Some 175 years ago Michael Faraday discovered magnetic circular birefringence, now commonly known as the Faraday effect. Sensing the magnetic field through the influence that the field has on light within the fiber optic sensor offers several advantages, one of them fundamental. These advantages find application in the measurement of electric current at high voltages by measuring the induced magnetic field, thus warranting application for this kind of fiber optic sensor (FOS) in future smart grids. Difficulties in designing and manufacturing high-performance FOSs were greatly alleviated by developments in optical telecommunication technology, thus giving new impetus to magnetometry based on the Faraday effect. Some of the major problems in the processing of optical signals and temperature dependence have been resolved, yet much effort is still needed to implement all solutions into a single commercial device. Artificial structures with giant Faraday rotation, reported in the literature in the 21st century, will further improve the performance of FOSs based on the Faraday effect. This paper will consider obstacles and limits imposed by the available technology and review solutions proposed so far for fiber optic sensors based on the Faraday effect.

One Approach to Improving Smart Environment Communication via the Security Parameter

“…By definition, the Faraday's angle is positive for counterclockwise rotation when the magnetic flux density vector has the same direction as the wave vector and for clockwise rotation when these vectors are in the opposite direction. Therefore, the Faraday's effect is truly a nonreciprocal effect, and the Faraday's angle will double after the light is reflected and goes back along the same path (Mihailovic & Petricevic, 2021). As it has been previously shown, Faraday's effect depends on multiple constants and variables.…”

Research on the Dual Modulation of All-Fiber Optic Current Sensor

“…The polarization state of the polarized light is adjusted by the magnetic field generated by the current to be measured. The rotation angle of the polarization plane is proportional to the electric current based on the principle of the Faraday effect [15]. AOM is applied to generate a pulsed light source based on a reflective interferometer current sensor.…”

Abnormal handling mechanism and improvement measures of optical DC current transformer in smart grid environment

“…All-FOCT generally use two beams of polarized light that are always transmitted in two orthogonal modes on the same sensing fiber, and in the sensing fiber, the two beams of circularly polarized light are transmitted at different speeds due to the Faraday magneto-optical effect of the magnetic field generated by the current in the wire, resulting in the Faraday phase difference ( Karabulut et al, 2019 ; Wu et al, 2021 ; Mihailovic & Petricevic, 2021 ). Therefore, the two beams carrying the Faraday effect phase information will interfere at the starter and then be coupled by the 3 dB coupler into the photodetector, and the interferometric light intensity information arriving at the photodetector is equationed as…”