High-Precision Temperature-Compensated Magnetic Field Sensor Based on Optoelectronic Oscillator

We have proposed and experimentally demonstrated a high-precision and temperature-compensated magnetic field sensor based on two optoelectronic oscillators (OEOs) incorporating cascaded magnetostrictive alloy-fiber Bragg grating (MA-FBG) and FBG filters. The optical sources are provided by the reflection signals of two FBGs. The optical source wavelength is related to the overall time delay of the OEO loop which determines the oscillating frequency of OEO. The central wavelengths of MA-FBG and FBG change along with the magnetic field and temperature. Therefore, we can estimate the magnetic field and temperature by measuring the oscillating frequencies of OEOs, simultaneously. Besides, since two OEOs are grouped into a cross-referencing structure by wavelength division multiplexing under the same environment, the magnetic field sensor can reduce the influence of temperature. The proposed sensor for magnetic field and temperature with sensitivities of 250 Hz/Oe and 1.97 or 1.42 kHz/°C are achieved. The maximum measurement errors of magnetic field and temperature obtained are within 22 Oe and 0.2°C. The proposed scheme has merits of simplicity and compact configuration. It can realize high-speed and high-resolution measurement, which has potential applications in magnetic field sensing.