56 Gb/s/λ over 13 THz Frequency Range and 400G DWDM PAM-4 Transmission with a Single Quantum Dash Mode-Locked Laser Source

The continued evolution of high capacity data center interconnects (DCI) requires scalable transceiver design. The Gigabit Ethernet (GbE) family of standards targets cost-effective and increased capacity transmission through the use of coarse wavelength division multiplexing (CWDM) and direct detection. Moving beyond near-term GbE deployments, multi-wavelength optical sources will be required to enable spectrally efficient WDM transmission, as well as small form-factor transceiver design. This work highlights the capability of a single section 32.5 GHz quantum-dash mode locked laser to provide >Tb/s capacity by demonstrating successful 50 Gb/s/λ pulse amplitude modulation transmission on modes spanning a >1 THz frequency range. Additionally, true 400G DWDM (8×56 Gb/s) C-band transmission is successfully demonstrated with the Q-Dash MLL, resulting in a spectral efficiency of 1.54 b/s/Hz.