Undersea lightwave communications systems using erbium-doped fiber amplifiers

The new lightwave technology based on the erbium-doped fiber-amplifier (EDFA) will allow the next generation of undersea cable systems to have eight times the capacity of existing cables. In this paper error-free transmission over 9000 km has been demonstrated using EDFAs both at 5 Gb/s and 10 Gb/s. The characteristic of optical amplifier systems - more noise on the marks rail than the spaces - is easily observed. The shapes of the waveforms before and after transmission are very similar. This shows that the deleterious effects of nonlinearities and dispersion that could distort the waveform have been properly managed