2008 Volume 1 Issue 4 Pages 271-274
This paper propose a method to enlarge the measurement range for Brillouin optical correlation domain analysis (BOCDA) system simplified with time-division pump-probe generation scheme. In this system, the pump and the probe lightwaves, which are modulated in frequency with a sinusoidal waveform to localize the stimulated Brillouin scattering (SBS) periodically, are additionally gated temporally to select only one localized position. We successfully measured distribution of fiber Brillouin gain spectrum over 250 m measurement range with 8 cm spatial resolution. We also propose an optimization of the time-gating scheme by applying separate time gates for the pump and the probe waves and introducing unbalanced Mach-Zehnder delay line, by which the performance was enhanced to 7 cm spatial resolution and 1 km measurement range.