Superluminal propagation through 500 m optical fiber via stimulated Brillouin scattering

We have experimentally demonstrated superluminal propagation through a 500 m optical fiber using stimulated Brillouin scattering (SBS), which is the longest superluminal propagating distance reported so far, to the best of our knowledge. Brillouin-induced loss resonance for fast light generation of pump signals is achieved in a single frequency Brillouin lasing oscillator with a highly nonlinear fiber as the SBS medium. The single frequency operation is realized by embedding the saturable absorber fiber loop with an unpumped erbium-doped fiber. Consequently, signals with a pulse width of 710 ns experience a maximum advancement of 1330 ns. Furthermore, the effects of pulse width and the duty cycle of pump signals are also investigated.