Frequency-Scanning BOTDA With Ultimately Fast Acquisition Speed

A polarization-independent fast and distributed frequency-scanning Brillouin optical time-domain analysis (BOTDA) technique is presented, capable of acquiring the full Brillouin gain spectrum at a speed limited only by the fiber length and the employed frequency scanning granularity. For a 145-m long fiber and 71 interrogating frequencies, the ultimate measurement speed of 9700 [full-fiber-Brillouin-gain-spectra]/second is demonstrated, covering a strain dynamic range of 4200 με with an accuracy of ±10 με. Dynamic measurements with a spatial resolution of 10 cm are also demonstrated by combining the technique with the double pulse pair BOTDA method.