PICOSECOND DARK SOLITON OVER A 1-KM FIBER AT 850 NM

We report the observation of nonlinear propagation of picosecond odd-s ymmetry dark pulses over 1-km single-mode fiber in the near infrared. The pulses are shown to propagate without distortion at the power corr esponding to the fundamental dark soliton of the nonlinear Schrodinger equation. Our measurements are in quantitative agreement with numeric al solutions to a modified nonlinear Schrodinger equation-including fi ber loss-and constitute the first evidence to our knowledge of dark so liton propagation over fiber lengths compatible with optical telecommu nication systems.