10 000-hop cascaded in-line all-optical 3R regeneration to achieve 1 250 000-km 10-Gb/s transmission

We demonstrate 1 250 000-km 10-Gb/s return-to-zero transmission over 10 000 stages of in-line all-optical reamplification, reshaping, and retiming (3R) regeneration spaced every 125 km. The all-optical 3R regenerator incorporates a 10-GHz all-optical clock recovery module including a Fabry-Pe/spl acute/rot filter and a semiconductor optical amplifier in a cascaded configuration for fast and stable response. Bit-error-rate (BER) performance measurements show less than 0.7-dB power penalty at the BER of 10/sup -9/ between 1 250 000- (Lap 10 000) and 125-km (Lap 1) transmission using pseudorandom bit sequence 2/sup 23/-1.