Impact of Transient Response of Erbium-Doped Fiber Amplifier for OPS/WDM and Its Mitigation

We investigated impairments of optical packets when these packets amplified by cascaded EDFAs in several distinctive cases in WDM environment. The origin of impairments were mainly gain excursion and additional noise come from inter-channel cross talk between WDM channels, and the degree of impairment changed according to link utilization. Moreover, the impairment is cumulative by increase of the number of EDFAs cascaded. It means that the tolerance for error of optical packet receiver substantially reduces according to the traffic intensity and the number of hops each packet experiences. We proposed the mitigation by adopting special class of EDF which have larger active erbium core. Our methodology can supplement conventional electrical controlling measures against transient responses which have insufficient response speed in the application for short optical packet of sub-micro seconds long.