Regeneration capabilities of passive saturable absorber-based optical 2R in 20Gbit/s RZ DWDM long-haul transmissions

A semiconductor saturable absorber-based optical 2R regenerator is implemented in a 20 Gbit/s WDM-emulated dispersion-managed loop transmission with 'standard' 50% RZ signals. When reducing the channel spacing from 200 down to 50 GHz, the optical 2R regenerator is seen to ensure Q-factors at 9000 km distance of 14.5 and 11.2 dB, respectively.