A Highly-stacked Quantum-dot Mode-locked Laser Comb with 106-GHz Mode Spacing Enabling 4.48-Tb/s IM-DD Transmission Capacity

We design and fabricate a 15-layer highly-stacked quantum-dot mode-locked laser comb operating in C-band with 106GHz mode spacing. A $4.48-\mathrm{Tb} / \mathrm{s}(56 \lambda \times 80 \mathrm{~Gb} / \mathrm{s})$ aggregated IM-DD transmission capacity is experimentally demonstrated, meeting the BER threshold of standard 7% hard-decision FEC. To the best of our knowledge, this device enables the highest aggregated capacity among QD MLL-based IM-DD systems.