Fast Brillouin Optical Time Domain Analysis Measurement Based on Broadband Probe Light

This article focuses on distributed vibration measurement based on Brillouin optical time-domain analysis (BOTDA). We propose a new method to obtain the frequency spectrum of Brillouin scattering using broadband light as a probe light of BOTDA and coherent detection. By using the proposed method, the Brillouin gain spectrum (BGS) consisting of multiple frequency components can be obtained in a single measurement. This fast measurement characteristic enables dynamically and rapidly changing strains, or vibrations, to be measured. The method also enables a simpler configuration compared with conventional fast BGS measurement methods. To obtain a more accurate BGS, we also propose and successfully demonstrate compensating for the effect of intensity fluctuation on the spectrum of the broadband probe light by generating an additional pulse with the same spectrum.