Influence of modulation instability on distributed optical fiber sensors based on spontaneous Brillouin scattering

The performance of distributed fiber sensors based on spontaneous Brillouin scattering is largely determined by the peak power governed by nonlinear thresholds that can be launched into the sensing fiber. Our investigations show that, in long-range (>20-km) sensors that use a standard single-mode fiber operating at 1.5 µm, modulation instability can limit the acceptable pulse power to below 100 mW. Using a nonzero dispersion-shifted fiber with negative dispersion we can avoid this problem and obtain a ninefold increase in launched power.