Prevention of False Peak Detection of Brillouin Gain Spectrum by Using Peak Tracking and Trend Analysis

Abstract

Distributed optical fiber sensor based on a peak-frequency change of a spectrum of Brillouin scattering light has been extensively studied since it can measure strain and/or temperature in various applications. The distributed optical fiber sensor observes the spectrum of backscattered light from the specified section according to a spatial resolution and determines strain and/or temperature based on the peak-frequency change of the spectrum. However, the observed spectrum may have two maximum peaks that corresponds to strain and/or temperature included in the specified section of the optical fiber. Overlapped noise by the interrogator system to two peaks on the Brillouin gain spectrum causes false detection of the maximum peak-frequency. Although this false detection may occur, no workarounds has been discussed yet. This paper proposes a workaround by method of ‘peak tracking and trend analysis' that considers the change of peak intensity to determine peak frequency of the spectrum and confirms its effect of preventing false peak detection of Brillouin gain spectrum.