Modeling Nonlinearity in Coherent Transmissions with Dominant Intrachannel-Four-Wave-Mixing

By extending a well-established time-domain perturbation approach [1­4] to dual-polarization propagation, we provide an analytical framework to predict the variance induced by nonlinearity on the sampled field and the nonlinear threshold (NLT) in coherent transmissions with dominant intrachannel-four-wave-mixing (IFWM). Such a framework applies to non dispersion managed (NDM) very long-haul coherent optical systems at nowadays typical baudrates of tens of Gigabaud, as well as to dispersion-managed (DM) systems at even higher baudrates, whenever IFWM is not removed by nonlinear equalization and is thus the dominant nonlinearity. New closed-form NLT analytical formulas for both DM and NDM systems are checked against recent NLT Monte-Carlo simulations [5]. © 2011 Optical Society of America OCIS codes: (060.1660) Coherent communications, (060.4370) Nonlinear optics, fibers