Effects of external modulation transmission at 10 Gb/s without dispersion compensation through an all-optical node concatenation

Originally designed for direct modulation at 2.5 Gb/s/channel, in a metropolitan scale basis, the optical metro network for emerging gigabit applications (OMEGA) test bed performance is evaluated in a transmission experiment through spans of 20 km of standard (STD) fiber, each, and transparent nodes, where one channel is externally modulated at 10 Gb/s. Measurements have been carried out in two configurations not employing dispersion compensation: point-to-point light paths and a re-circulating loop. Results are compared to those obtained with direct modulation at 2.5 Gb/s/channel. A penalty increase of /spl sim/2 dB at a no-floor bit-error rate (BER) of 10/sup -12/ after 80 km (five nodes) indicates that, for metropolitan areas, the OMEGA test bed original design may tolerate a cost-effective network capacity expansion that involves an upgrade of transponders only.