Degree-Expandable Colorless, Directionless, and Contentionless ROADM Without Drop-Side EDFAs

By using an N×M multicast switch, where N is expandable from 4 to ≥16, and M is 16, we experimentally demonstrate that in a metro optical network with OSNR ≥17dB, the sensitivity of an intradyne coherent receiver can reach < −34dBm for 28Gbaud DP-QPSK signals, thereby enabling a CDC ROADM with no drop-side EDFAs.