Nonlinear Picosecond-Pulse Propagation through Optical Fibers with Positive Group Velocity Dispersion

The predictions of the nonlinear Schr\"odinger equation have been tested by passing 5.5-psec optical pulses through a 70-m single-mode optical fiber. With use of a precise cross correlation technique based on pulse compression, dramatic reshaping of the input pulses into flat-topped, frequency-broadened, and positively chirped 20-psec output pulses with self-steepened fall times of less than 2 psec was observed. The observations are in good agreement with theory.