Spatially disaggregated model for self-channel interference in mixed fiber optical network segments

Coherent transmission technology is widely diffused in backbone optical uncompensated transmission (UT) network segments. In metro and access network segments instead, intensity-modulated direct detected channels at 10 Gbps requiring inline dispersion compensation units (DCUs) are still largely used. While the transition to coherent technology is foreseen in the dispersion managed (DM) network segment, in the meantime, it would be handy to route coherent channels through DM network segments to fully exploit deployed hardware and available spectrum and improve network flexibility. In this scenario, self-channel interference (SCI) exhibits strongly coherent accumulation due to the presence of DCUs, which is not well modeled by traditional analytical models for non-linear interference estimation used for path feasibility assessment. In this paper, we propose a semi-analytical model able to fill this gap. We show that our proposed model is able to provide a quick, conservative estimation of the SCI noise on both UT and DM systems, including optical line system configurations with mixed fiber types.