Remodulation schemes with reflective SOA for colorless DWDM PON

Abstract

Feature Issue on Passive Optical Network Architectures and TechnologiesThis article presents remodulation schemes with reflective semiconductor optical amplifiers (RSOAs), which have recently been developed for application to the wavelength-division-multiplexed passive optical network (WDM-PON). The remodulation schemes have a common feature that the optical signal modulated with downstream data is reused to carry the upstream data through the RSOA in the subscriber-side equipment by a series of processes such as being flattened out, reflected at the rear facet of the RSOA, and then remodulated with upstream data. The major advantage of remodulation schemes is the possibility of realizing the simplest WDM-PON optical link structure, which is directly reflected in cost-effectiveness of the network both in equipment and maintenance. Three schemes are presented; the simplest one is to use the RSOA gain saturation, the second uses the effect of frequency detuning on the extinction ratio of optical signal, and the third uses RSOA gain control by dynamically varying the current injection. Feasibilities of those schemes are discussed in the view of commercial application to WDM-PON.