400 Mbit/s, 372 km coherent transmission experiment using in-line optical amplifiers

We report on an optical transmission experiment using four in-line optical amplifiers. With a net gain of 58,000 (47.7 dB)from the amplifiers, we were able to increase the longest non-regenerated transmission distance to 372 km. The system penalty associated with the amplifiers was only l.5 dB.