Performance analysis of PAM4 signal transmission in inter-datacenter multicore fiber links impaired by inter-core crosstalk

Abstract

In this work, we propose to use four-level pulse amplitude modulation (PAM4) and multicore fibers (MCFs) to support very high capacity inter-datacenter connections. The limitations imposed by inter-core crosstalk (ICXT) on the performance of 112 Gb/s up to 80 km-long optically amplified PAM4 inter-datacenter links with intensity-modulation and direct-detection (IM-DD) and full chromatic dispersion compensation in the optical domain are analyzed through numerical simulation. We show that those PAM4 inter-datacenter links achieve an outage probability (OP) of 10e-4 with a maximum ICXT level of -13.9 dB for high skew-symbol rate products and require an ICXT level decrease of about 8.1 dB to achieve the same OP for low skew-symbol rate products. Due to using full dispersion compensation, the OP is not much affected by increasing the MCF length, from 10 km, where electrical noise significantly contributes to the performance degradation, to 80 km, where signal-amplified spontaneous emission beat noise is dominant. For an OP of 10e-4, the maximum acceptable ICXT level shows only a 1.4 dB variation with the MCF length increase.