Inter-Core Crosstalk Dependence on Design Parameters in Coherent Detection Weakly-Coupled Multicore Fiber Systems

Abstract

We assess, through numerical simulation, the dependence of the variance of the inter-core crosstalk (ICXT) and the maximum allowable ICXT level on the design parameters of coherent detection MCF systems. The analysed design parameters are the order of the quadrature amplitude modulation (QAM) signals, roll-off factor, time misalignment between the signal in different cores and skew between cores. The results show that, when the rolloff factor is 0, the maximum allowable ICXT level is independent of the skew and decreases for higher QAM orders. For a roll-off factor of 1, the maximum allowable ICXT level depends on the skew and time misalignment of core signals. In this case, the maximum allowable ICXT level increases by 3.6 dB relative to the case of rolloff factor of 0 with null skew, and by 2 dB, when the skew is much higher than the symbol period.

Analysis of Inter-Core Crosstalk in Weakly-Coupled Multi-Core Fiber Coherent Systems

“…7, the symbols correspond to the BER obtained from MC simulation averaged along 500 time fractions, each one with 2 11 transmitted symbols in each polarization direction and with stopping criterion of 4000 errored symbols. These figures allow to have a good accuracy in the estimation of the BER, for BERs of about 10 −3 in presence of ICXT [21]. Figure 7 shows good agreement between the simulation and theoretical results.…”

“…In all these works [3], [16]- [20], the influence of the inter-core skew on the ICXT-induced performance degradation was not assessed. Preliminary simulation results reported that the pulse shaping and the inter-core skew influence the variance of the detected ICXT [21]. Thus, a deeper understanding and a rigorous assessment of the impact of the inter-core skew on the performance degradation of WC-MCF coherent systems induced by ICXT is required.…”

“…We analyze the evolution of STAXT, induced by PDM-QAM signals, the detected ICXT along time, and their relation to the evolution of bit error rate (BER) along time. The main contributions of this work are: (i) a thorough physical insight on the relation between STAXT and detected ICXT, and their influence on the BER are provided for arbitrary inter-core skews; (ii) extension of the study reported in [21] by proposing analytical expressions for the detected ICXT variance and optical signal-to-noise ratio (OSNR) penalty induced by ICXT in WC-MCF coherent systems with arbitrary skew between cores, and comparing with Monte-Carlo (MC) simulation results; (iii) from the derived expressions, the dependence of BER and OSNR penalty on the inter-core skew, pulse shape roll-off factor and QAM modulation format is unveiled and shown to be in agreement with MC simulation results.…”