Over 285 km repeaterless, dispersion-free transmission at 2.488 Gb/s using Er-doped fiber amplifiers in coherent detection and direct detection

Repeaterless, dispersion-free, 2.488 Gb/s transmission has been achieved over 285 km through nondispersion shifted fiber using FSK coherent polarization diversity detection and an Er-doped fiber amplifier power booster. The total T-R loss budget was 52 dB with a power booster output power of +14.5 dBm and a polarization diversity receiver sensitivity of -37.5 dBm for 10/sup -9/ BER. In direct detection, similar results were obtained using a Ti-LiNbO/sub 3/ modulator, a fiber power amplifier, and optical preamplifiers. Competing approaches to dispersion-free, unrepeatered lightwave systems are reviewed.<
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