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Center for Nonlinear Studies |
We investigate the dynamics of optical pulse parameters in broadband fiber optics communication systems employing a large number of pulse sequences (corresponding to different frequency channels). One nonlinear effect that is particularly important in these systems is called delayed Raman response. We show that in transmission lines where the information is encoded in the amplitude the interplay between bit-pattern randomness and Raman-induced energy exchange in pulse collisions leads to exponential growth of the nth normalized moments of pulse parameters. This behavior, which can be interpreted as intermittent dynamics, has important practical consequences by leading to relatively large values of the probability for an error. One method to overcome the Raman-induced effects is by encoding information in the phase. We find that in this case amplitude dynamics in an N-channel system is described by an N-dimensional predator-prey model. By finding the equilibrium states of the model and obtaining the Lyapunov function we show that stable transmission can be achieved by a proper choice of the frequency profile of the net gain/loss coefficients.
Host: Misha Chertkov