Observation of prolonged power transients in a reconfigurable multiwavelength network and their suppression by gain-clamping of optical amplifiers

We observe channel power transients lasting several seconds in a reconfigurable multiwavelength network, which includes cascaded automatic channel power equalizers and fiber amplifiers in 1018- and 1898-km fiber links. Such prolonged power transients occur upon reconfiguration of the network due to coupling between the feedback control loops of the channel power equalizers and their interaction with the delay through the fiber link. Experiments performed under numerous conditions support this hypothesis. In particular, we experimentally demonstrate that gain-clamping of the amplifiers in the network significantly suppresses the power transients.