Bit-Error-Rate Measurements of a Multi-Thousand-Kilometer Fiber-Amplifier Transmission System Using a Circulating Loop,

Recently, we reported the results of a 2.4 Gbs and 5 Gbs feasibility demonstration of long distance erbium-doped fiber amplifier EDFA transmission systems using a circulating loop.1 The significance of this experiment was threefold. First, it demonstrated that high bit rate all-optical EDFA transmission systems are capable of achieving transoceanic distances. Second, it demonstrated a new measurement technique in which bit-error-rate BER is measured in a circulating loop. And, third, it achieved a new record in bit rate distance products. In this paper, we expand on the previously reported results by giving details of the experiment along with new transmission results. At 2.4 Gbs and 9000 km, we have found that the transmitters wavelength could be tuned over a 2 nm region while maintaining low BER. In addition, at 2.4 Gbs we have measured a BER of 10-9 at 16,000 km, using a transmitter with direct laser modulation.