With the arrival of wavelength division multiplexed (WDM) systems carrying
large numbers of wavelength channels, it appears that new cross-connect arc
hitectures that allow large numbers of wavelength channels to cross-connect
at the wavelength granularity level are required. We propose a number of s
uch architectures. The different architectures are compared in terms of com
plexity, cost, loss, crosstalk and filter narrowing. An analysis of the var
ious nonblocking properties of such crossconnects is also described.