Channel capacity and modeling of optical fiber communications

We use the method of multiple scales borrowed from perturbation theory to derive a new time-domain transfer function of the nonlinear fiber-optic wave-division multiplexing (WDM) communications channel. The obtained channel response, derived from the nonlinear Schrodinger equation is shown to be equivalent to the multi-path fading frequency selective channel encountered in wireless links. In the linear regime, the channel response is shown to be equivalent to a standard intersymbol interference (ISI) channel and is used to derive new bounds on the capacity of the dispersive optical fiber channel.