Peak search algorithm in Brillouin-based strain sensor

In this paper, we introduce an optimal peak search strategy of Brillouin gain spectrum (BGS) and denoising method of central wavelength of BGS based on Brillouin optical time domain analysis (BOTDA) system. The system utilizes both up shifted and down shifted continuous-wave light to generate Brillouin scattering light, while using the amplified pulsed light to boost the signal by stimulated Brillouin scatting effect. In order to obtain an accurate strain change of fiber under test (FUT), the peak of each Brillouin scattering spectrum must be accurate and precise. In addition, the intensity of shifted light should be stable as well. Therefore, we propose a novel peak search algorithm of BGS of a BOTDA system, which keeps the right central wavelength even if the scan step of the frequency is in large condition. Besides that, we also proposed a time domain denoising method to enhance the signal to noise ratio. We also implement static experiments to verify our proposed scheme. Strain/temperature tests were taken out evaluate the performance of the BOTDA. Results showed that the resolution of BOTDA system could reach 13μe/0.65°C at 1 km fiber cable.