Simulation of the operation of a distributed fiber-optic current sensor using Brillouin scattering

Subject of study. This study investigates a distributed fiber-optic current sensor based on Brillouin scattering induced by fiber deformation. Aim of study. The study aims to simulate Brillouin scattering in an optical fiber under deformation caused by the Ampère force, facilitating the calculation of current sensor parameters. Method. The study involves calculating the transfer function of a three-wave interaction among a pump wave, a probe wave, and an acoustic wave, incorporating the characteristic amplification factors of stimulated Brillouin scattering. Main results. The operation of a current sensor was simulated based on Brillouin scattering. The transfer function was evaluated, and the effects of temperature exposure were analyzed for optical fibers containing germanium oxide. The sensor operation was simulated for a maximum measured current of 50 kA with a sensitivity of 72 A. The potential for reducing measurement time was explored by limiting the modulation-frequency range. A frequency range of 100 kHz to 300 MHz, with a spatial resolution of 0.5 m and frequency increment of 100 kHz, was chosen for a fiber length of 500 m. Practical significance. A simulation was performed to estimate the system parameters using a mathematical model of stimulated Brillouin scattering in optical fibers. A spatial resolution of 0.5 m was used for the sensor for determining the length and location of fiber sections when using optical-signal amplitude modulation in the range of 100 kHz to 700 MHz with a sensitive fiber length of 500 m. The optical resolution of the sensor was 72 A at a pump and probe radiation-frequency difference of Δ f =500kHz. The maximum current value measured was 50 kA at a frequency difference of Δ f =50MHz, which was twice the maximum value of the measured current of previously reported sensors of this type.