128 channel, 480 km FSK-DD transmission experiment using 0.98 µm pumped erbium-doped fibre amplifiers and a tunable gain equaliser

128 channel, 622 Mbit/s FSK-DD transmission is demonstrated using dispersion-shifted fibres, total fibre length of 480 km, with 13 inline 0.98 µm pumped erbium-doped fibre amplifiers (EDFAs) and a tunable gain equaliser. The gain imbalance and noise figure of the 0.98 µm pumped EDFAs are small compared to those of 1.48 µm pumped EDFAs, and the residual gain imbalance can be compensated for by just one waveguide-type tunable gain equaliser. As a result, all channels were successfully transmitted with power penalties of less than 1 dB.