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 on drop-side EDFAs.