112 Gb/s 16-QAM OFDM for 80-km Data Center Interconnects Using Silicon Photonic Integrated Circuits and Kramers–Kronig Detection

In this paper, we report the first demonstration of using silicon photonic integrated circuits for 62 Gb/s 4-quadrature-amplitude-modulation (4-QAM) orthogonal frequency-division multiplexing (OFDM) and 112 Gb/s 16-QAM OFDM over an 80-km standard single-mode fiber (SSMF) transmission with the Kramers-Kronig (KK) direct detection. Single sideband optical signals are generated by two silicon micro-ring modulators, and directly detected by a single integrated germanium-on-silicon waveguide photodiode fabricated in a multi-project wafer run. The complex optical field can be fully re-constructed by KK detection after an 80-km SSMF transmission. The integrated transceivers with KK detection are suitable for future low-cost, low-power, and small-footprint data center interconnects in the short and medium reach.