4×112 Gb/s/λ MCF Transmission Using Field PDM-PAM4 and Coherent Detection for Datacenter Applications

The inter-data center links are meeting the challenge of increasing transmission capacity continuously. Here, the tradeoff between transmission capacity and cost and power consumption especially needs to be considered. The field modulation polarization-division-multiplexed (PDM) four-level pulse amplitude modulation (PAM4) with coherent detection is a potential candidate for 400 Gb/s and beyond inter-data center transmissions, which has several advantages including low-cost, low optical signal to noise ratio (OSNR) requirement and high receiver sensitivity. In this paper, the feasibility and effectiveness of the field PDM-PAM4 coherent system are investigated over multi core fiber (MCF). In order to adapt to the field PAM signals, the signal-phase aid least-mean square (SP-LMS) and training multi-modulus algorithm (TMMA) are modified and analyzed for equalization and polarization demultiplexing. Finally, it is demonstrated that 4×112 Gb/s field PDM-PAM4 is successful transmitted over 16 km MCF and 384 km SSMF in C-band with a BER below 3.8e-3.