Methods for Stabilizing the Gain of EDFAs in Burst Switching Optical Networks

Transmitting optical bursts through a chain of erbium-doped fiber amplifiers (EDFAs) results in dynamic gain changes, which in turn lead to possibly large variations in output power of the data channels. There are many proposals how to control these optical amplifiers in order to minimize or eliminate the power variations. In this paper, we investigate the gain dynamics in a burst switching environment experimentally and numerically. With a categorization of gain control schemes we review the state of the art and discuss advantages and disadvantages of the different approaches particularly with regard to burst switching networks. A comparison of the performance of these methods is given. In our opinion there are two preferences, one for the scheme using electronic feedback on the EDFA's pump power, because of good performance, and another for schemes controlling whole links of EDFA cascades by an extra control channel, because of lower costs.