High-speed and long-reach WDM networks using low-bandwidth transmitter

Reflective semiconductor optical amplifier (RSOA) has been widely employed in wavelength division multiplexed passive optical networks (WDM-PONs). In this paper, we propose a novel signal processing technique based on partial response (PR) equalization to enable high-speed and long-reach RSOA-based upstream transmission overcoming the bandwidth limitation from the RSOA and fiber channel. The selection of the target PR signal for the equalizer and its corresponding working range for the RSOA-based uplink are extensively studied. Our investigation reveals that the same PR equalizer can be applied on a range of distances, making the proposed technique practical for access networks. Moreover, experiments are carried out to demonstrate 10 Gb/s transmission over 125 km and 20 Gb/s transmission over 30 km using a 1 GHz RSOA using the proposed equalizer design in WDM access networks.