Abstract: An optical cross-connect for the switching of optical channels at variable bit-rate (up to 10 Gbit/s), wavelength division multiplexed on bi-directional optical fibers forming the transmission backbone of a transport network; in particular the cross-connect can be interfaced to fibers crossing the nodes of a ring having large territorial extension, provided with protection fibers. The cross-connect includes a spatial Split & Select input stage of WDM aggregates, followed by a set of channel filters tunable on the whole optical range occupied by the channels, which jointly form a structure strictly not blocking the access to the channels by a set of bridge units whose functionality is selectable on a per-channel basis, such as for instance: transit, drop/insert, regeneration, etc. An output optical spatial Split & Select stage connects in a strictly non-blocking way the single channels from bridge units to optical multiplexers that reconstruct the WDM aggregate on the output fibers.