Picosecond steps and dark pulses through nonlinear single mode fibers

Abstract

We experimentally observed transmission of “negative pulses” through a single mode optical fiber in conditions where self-phase modulation, due to self induced variations of silica refractive index, may be balanced by the positive group velocity dispersion (d V g/dδ#62;0). Soliton propagation could be expected at power levels where exact compensation of these two distorsions arises. The duration of the output dark pulses, determined by SHG correlation techniques, decreases when the launched power is increased, as predicted by computer simulation. For an input peak power of 0.2 W, corresponding to the theoretical soliton peak power, the emerging dark pulse looks like the input one.