Simultaneous demodulation and slow light of differential phase-shift keying signals using stimulated-Brillouin-scattering-based optical filtering in fiber.

For the first time to our knowledge, we demonstrate simultaneous demodulation and slow-light delay of differential phase-shift keying (DPSK) signals at flexible bit rates using the stimulated-Brillouin-scattering-based optical filtering effect in optical fiber. Both $10$ and $2.5\mathrm{Gbit}∕\mathrm{s}$ DPSK signals have been demodulated and delayed with excellent performances. In the case of the$10\mathrm{Gbit}∕\mathrm{s}$ DPSK signal, after demodulation the tunable delay range with error-free operation is about $50\mathrm{ps}$, which we believe is the best result obtained for $10\mathrm{Gbit}∕\mathrm{s}$ slow-light demonstrations. For the $2.5\mathrm{Gbit}∕\mathrm{s}$ DPSK signal, the optimal sensitivity after demodulation is $-36.5\mathrm{dBm}$, which is comparable with the back-to-back sensitivity of a $2.5\mathrm{Gbit}∕\mathrm{s}$ nonreturn-to-zero signal.