Statistical characterization of the effect of random core loss on the intercore crosstalk in long-haul uncoupled multicore fiber links

We characterize the statistical properties of direct average intercore crosstalk (ICXT) in long-haul uncoupled multicore fiber (MCF) links consisting of concatenated MCF segments, where core dependent loss (CDL) in each segment varies randomly. Numerical simulation results show that the direct average ICXT power at the output of long-haul MCF links with random CDL is well described by a Gaussian distribution. A statistical distribution, which accounts for only two values of core loss (the highest and lowest core loss) with equal probability, is proposed as the worst-case distribution of core loss resulting in the maximum excess of direct average ICXT power. With this distribution, practical values of random CDL, 20 MCF segments per span and 2000 km-long links, analytical and simulation results show the maximum excess of direct average ICXT power does not exceed 0.25 dB, being further lower for a higher number of segments. An analytical approximation for the maximum excess of direct average ICXT power in long-haul uncoupled MCF links with similar spans is presented. Demonstrating high accuracy (with less than 0.02 dB discrepancy relative to simulation results in all cases evaluated), this approximation provides a simple and efficient means for estimating the worst-case impact of random CDL on ICXT power in long-haul MCF links.