Picosecond dark soliton over a 1-km fiber at 850 nm

We report the observation of nonlinear propagation of picosecond odd-symmetry dark pulses over 1-km single-mode fiber in the near infrared. The pulses are shown to propagate without distortion at the power corresponding to the fundamental dark soliton of the nonlinear Schrödinger equation. Our measurements are in quantitative agreement with numerical solutions to a modified nonlinear Schrödinger equation—including fiber loss—and constitute the first evidence to our knowledge of dark soliton propagation over fiber lengths compatible with optical telecommunication systems.