Optimum configuration and characteristic comparisons of multiwavelength erbium-doped fiber amplifier for hybrid digital/analog WDM systems

We theoretically investigate various configurations of erbium-doped fiber a mplifier (EDFA) for simultaneously amplifying AM-VSB analog CATV signal and multiple optical digital baseband signals in hybrid wavelength-division mu ltiplexing (H-WDM) systems. The design criterion of H-WDM EDFA is to keep t he differential channel output power among digital channels at less than or equal to 0.2 dB while providing a high saturated output power of less than or equal to 60 mW and a low noise figure of less than or equal to 4 dB for the analog channel. A total of nine EDFA configurations are examined and c ompared in this work, including the dual-forward, dual-backward, and differ ent bidirectional pumping schemes, each with and without the midway optical isolator. The investigation provides the optimum EDFA configuration to des ign both power and in-line amplifiers for hybrid analog/digital WDM lightwa ve systems. Such H-WDM technology allows direct transmission of AM-VSB/QAM video traffic from the fiber backbone supertrunking networks to the hybrid- fiber-coaxial (HFC), fiber-to-the-curb (FTTC), or fiber-to-the-home (FTTH) broadband access networks without the complicated and costly signal format conversion at the CATV head-end and hubs. (C) 2000 Published by Elsevier Sc ience B.V. All rights reserved.