Variational model for synchronous phase modulation in long-haul transmission systems

Summary form only given. Summary form only given. The performance of long-haul lightwave transmission systems can be improved by re-modulating the transmitted data signal with synchronous sinusoidal phase modulation. The improvement results from an increased eye opening caused by a conversion of the phase modulation to amplitude modulation by the system. In this paper we propose an analytical model based on a variational formalism, which leads to a set of simple dynamic equations. We have studied the PM to AM conversion using this variational approach. Good agreement between numerical simulations and measurements is shown for our model on a 4200 km test bed.