Regenerative wavelength conversion of PAM-4 signals using XGM with blue-shift filtering in a QD-SOA

We have experimentally demonstrated all-optical wavelength conversion of PAM-4 signals based on cross gain modulation in a quantum-dot semiconductor optical amplifier. As a result, we have successfully achieved 5-nm regenerative wavelength conversion of 20-Gbit/s PAM-4 signals at the total required input power 4.8 dBm. Moreover, the improvement of BER with signal regeneration effect by uniforming the power intervals of the PAM-4 signal was successfully achieved.