Analytical Signal-to-Noise Ratio Model on Frequency-Scanned Brillouin Optical Time-Domain Reflectometry

An analytical signal-to-noise ratio (SNR) model of standard frequency-scanned Brillouin optical time-domain reflectometry (FS-BOTDR) is established, by comprehensively taking into account nearly all non-negligible signal and noise terms with substantial impact on the sensing performance. The accuracy and generality of the proposed model are experimentally validated, supported by the fact that under various experimental conditions all experimental results are in good quantitative agreement with theoretical calculations. Serving as a theoretical tool, the established model makes it possible to accurately anticipate and comprehensively interpret the SNR behavior of the FS-BOTDR under any given measurement condition, without the need to construct an experimental system or carry out experiments. It also enables theoretically quantifying the SNR difference between FS-BOTDR and other distributed optical fiber sensors that already have mature SNR models. Furthermore, the proposed model provides guidelines on optimizing system parameters towards the highest possible SNR with minimized energy consumption.