Brillouin frequency shift error estimation formula for distributed optical fiber sensing technology based on Brillouin scattering

In this work, the problems in the existing Brillouin frequency shift (BFS) error estimation formulas for distributed optical fiber sensing technology based on Brillouin scattering are discussed. Based on the analysis, a new, to the best of our knowledge, BFS error estimation formula is proposed. To validate the proposed formula, a large number of Brillouin spectra with different frequency sweep spans, signal-to-noise ratios, linewidths, and frequency steps are numerically generated, and at the same time, Brillouin spectra with different values of incident light pulse widths and frequency sweep spans are measured with a Brillouin optical time domain reflectometer. Based on those Brillouin spectra, the errors of the proposed formula and existing formulas are systematically compared. The results reveal that the proposed formula generally has a higher accuracy than the existing typical formulas, especially when the frequency sweep span or incident light pulse width is large. Therefore, it has a much wider application range.