Internetworking between two WDM ring networks, each carrying 160Gbit/s traf
fic, has been achieved using a monolithic 2X2 multi-wavelength filter. OC-1
92 wavelengths originating in one ring terminating in the other ring, trave
rsing up to three add/drop nodes and 75km of fibre, suffered less than 0.5d
B penalty.