2.24 Tbit/s PAM-4 transmission by an InAs/InP quantum dot mode-locked laser

We have developed an InAs/InP quantum dot (QD) mode-locked laser (MLL) with the channel spacing of 50 GHz. Its 3-dB bandwidth covering from 1546.89 nm to 1560.69 nm is 13.8 nm to provide 35 wavelength channels. We have investigated the relative intensity noises (RINs), phase noises, pulse duration and RF beating signals. By using this QD MLL we have successfully obtained the clear PAM-4 eye diagrams from any one of the filtered individual channels of the 50-GHz QD C-band MLL to demonstrate 2.24 Tbit/s (35x64 Gbit/s) PAM- 4 transmission bandwidth.