1000 cascaded stages of optical 3R regeneration with SOA-MZI-based clock enhancement to achieve 10-gb/s 125 000-km dispersion uncompensated transmission

We propose an optical 3R regenerator that incorporates a clock enhancement stage based on a semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer and a 10-GHz all-optical clock recovery module employing a Fabry-Perot filter and an SOA. The experiments assess the optical 3R regeneration technique using a fiber recirculation loop containing 125-km dispersion uncompensated large effective area fiber with a total chromatic dispersion of 531.25 ps/nm. The optical 3R regeneration achieves error-free 125 000-km dispersion uncompensated return-to-zero transmission at 10 Gb/s over 1000 optical 3R stages. The bit-error-rate (BER) measurements show that there is only 1.2-dB power penalty at 10/sup -9/ BER between 125 000-km (Lap 1000) uncompensated transmission and back-to-back using pseudorandom bit sequence 2/sup 23/-1.