909.5 Tbit/s Dense SDM and WDM Transmission Based on a Single Source Optical Frequency Comb and Kramers-Kronig Detection

Space-division multiplexing (SDM) has become a promising technology for optical communications to seek a sustainable increment in data capacity to keep up with the ever-increasing bandwidth demand. SDM could provide massive parallelization in addition to existing WDM technology for a high capacity without compromising the signal-to-noise ratio requirement of the transmitter. However, the WDM-SDM combination requires arrays of laser sources with associated active wavelength controls. This is not favorable in terms of energy consumption and cost. Single source optical frequency comb (SS-OFC) is an appealing candidate to provide coherent WDM sources, replacing the laser arrays and surpassing the performance by providing the possibility of joint digital signal processing across multiple channels. In this paper, we have generated an SS-OFC based on highly nonlinear fibers (HNLF) for short-reach applications such as optical interconnects, taking advantage of the high pump-to-comb efficiency. The 50-GHz spaced SS-OFC across the whole C band provides 99 comb lines as WDM channel sources. Combining adaptive-rate modulation, a 7.9-km 37-core fiber, and a polarization diversity Kramers-Kronig receiver, we have successfully transmitted 3663 channels (37 SDM × 99 WDM) with reliably error-free performance, achieving 909.5 Tbit/s net rate with an aggregated spectral efficiency of 184.42 bit/s/Hz.