Optically-amplified WDM ring network incorporating channel-dropping filters

We analyze the critical parameters in an optically-amplified WDM ring network. We find that a ring can accommodate 27 nodes when incorporating an EDFA and a channel-dropping filter in each node, a significant advance over nonamplified rings. We compare several node configurations, and find that the sequence of an EDFA followed by an optical tap and a channel dropping filter provides the highest performance for a wide range in system variables including input signal power, inter-node link loss and its variability, power-tapping ratio, and small-signal gain. Limited network modularity can he achieved.>