Faraday Rotation and Sensitivity of Bi-Substituted Iron Garnet Single Crystal for Optical Current/Magnetic Field Sensors

Abstract

This paper is concerned with the preparation and magneto-optic characterization of the Bi-substituted rare earth ferrite garnet bulk single crystal of (BiYbY) 3 (FeGa) 5 O 12 .Here we focus our studies on improving the sensitivity constant and its temperature dependence of iron garnet for optical current/magnetic sensors through compositional modification. Due to the Bi 3+ ions substitution, the specific Faraday rotation of Bi 0.75 Yb 1.02 Y 1.23 Fe 4.72 Ca 0.28 O 12 crystal under saturation magnetic field was enhanced greatly to be about -161.7 0 /mm and -144.1 0 /mm at λ=1310 nm and 1550 nm respectively. Magneto-optic figure of merit is 87.6 0 /dB at λ=1550 nm and room temperature. The smaller Faraday rotation temperature coefficient (FTC) of 3.99×10 -5 /K at λ=1550 nm have been obtained owing to the compensation effect. The sensitivity have been enhanced by a factor of 24 with respect to pure YIG, given the same sensor length and demagnetization factor, by substituting Bi ions into Y sites and substituting diamagnetic Ca ions into Fe sites in YIG. These results suggest that the new garnet composition is a highperformance material suitable for current/magnetic-field sensors.

Research on the influence of temperature on the sensing function of Faraday effect optical magnetic field sensor

“…The Faraday effect optical magnetic field sensor uses the rotation of polarized light to realize the measurement of magnetic field. Compared with traditional active sensors, Faraday effect optical magnetic field sensors have extremely high insulation strength and wide frequency response range, which makes them have huge advantages in power system diagnosis and measurement [1][2][3][4][5]. Temperature has a significant influence on the Faraday effect optical magnetic field sensor, and temperature stability of the sensor has been the focus of research for a long time [2,6,7].…”