First Demonstration of 112 Gb/s PAM-4 Amplifier-free Transmission over a Record Reach of 40 km Using 1.3 μm Directly Modulated Laser

A 112 Gb/s single-wavelength single-polarization PAM-4 transmission of a record distance 40 km without any amplification is experimentally demonstrated, enabled by a high-speed and high power directly modulated laser and low complexity equalization.