Wavelength contention-free via optical bypass within a colorless and directionless ROADM [invited]

A conventional colorless and directionless reconfigurable optical add/drop multiplexer (ROADM) architecture is modified to add intra-node optical bypass and achieve either statistical or absolute contention-free performance. The contention-free performance is accomplished without relying on external transponders and optical transport network (OTN) switches. Furthermore, the overall ROADM has a smaller size, lower power consumption, and lower cost than those of conventional colorless, directionless, and contentionless ROADMs.