The increasing need for reconfigurability is advancing the need for replacement of optical add-drop multiplexers (OADMs) with reconfigurable OADMs (ROADMs). With the use of ROADMs, insertion loss per node increases from 3-6 dB to up to 12 dB. With power budgets approaching 80 dB in these case, the use of optical amplifiers specifically designed for metro WDM networks becomes necessary.

In this article, Ahmad Atieh and Robin Andrew of BTI Photonic Systems discuss the neccesity of ROADMs in metro WDM networks and the requirements and design parameters for optical amplifiers that are integrated with ROADMs.