Power Spectrum Estimation in Strain Border Area using Two Different Fiber Optic Strain Sensor Outputs

Abstract

It is necessary to estimate the Brillouin scattering power spectrum in a fiber optical strain sensor. This is because optical fiber strain depends on the Brillouin scattering frequency shift. However, this requirement is not met in the strain border area because the Brillouin scattering power spectrum cannot be approximated by one Lorentzian function and therefore the conventional least squares method with linearization cannot be employed. This paper proposes a new power spectrum estimation method that uses two different outputs from a fiber optical strain sensor in the strain border area. The effectiveness of the new method is confirmed by simulation.