Brillouin optical time-domain analyzer with frequency shift keying probe

A Brillouin optical time-domain analysis (BOTDA) technique for enhancing the probe power to +5 dBm is proposed and demonstrated, which is based on a conventional dual sideband probe setup, but the probe waves are modulated by a frequency shift keying signal. The pump distortion is compensated in the time domain with this technique. By employing a 105-km sensing fiber, this technique is experimentally validated with 2-m spatial resolution. Furthermore, another experiment is designed to show the good tolerance for the sensing fibers combined with large Brillouin frequency shift (BFS) difference, as is demonstrated in a 50-km-long sensing fiber consisting of two segments with large BFS difference (200 MHz). (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)