Demonstration of soliton transmission at 2.4 Gbit/s over 12000 km

The transmission of 60 ps solitons at 2.4 Gbit/s over paths as great as 12000 km in a recirculating loop of dispersion shifted fibre and erbium fibre amplifiers is reported. With a mode-locked diode laser as signal source, at each distance, a measurement is made of the effective pulse width that is very close to that predicted from jitter in pulse arrival times from the Gordon-Haus effect. With a gain-switched and optically filtered laser as source, however, gross excess pulse broadening is observed for distances greater than a few thousand kilometres.