Field demonstration of coherent WDM with a fibre amplifier repeater, for transparent optical network applications

A series of field experiments performed with two-wavelength transmissions at 622 Mb/s over 200-km of installed single-mode fiber using a diode-pumped erbium-doped fiber amplifier repeater are described. Both differential phase-shift keying (DPSK) modulation and frequency-shift keying (FSK) modulation were employed, along with two implementations of automated endless polarization control. In a further field experiment, a power budget of 64 dB was demonstrated in the form of repeaterless DPSK transmission at 622 Mb/s over 264 km of installed fiber. The use of such a large power budget to accommodate the sharing of power between many wavelength channels and the accumulation of spontaneous emission noise through cascaded optical amplifier repeaters is discussed. >