Transient Brillouin optical correlation domain analysis

High spatial resolution measurement of the Brillouin frequency shift (BFS) is accomplished using transient analysis. The step response of the output signal wave is recorded for an arbitrary, known frequency offset between pump and signal, and compared against a library of modeled, reference functions. No spectral scanning or prior knowledge of the BFS is necessary. The principle is employed in a Brillouin optical correlation domain analysis (B-OCDA) of a 4 cm-wide fiber segment. A dynamic range of 130 MHz and an accuracy of ±1.9 MHz are achieved. Transient analysis may improve the precision and acquisition rate of B-OCDA.