Optical switch

A wavelength selective optical switching arrangement comprising:

• a set of input ports;
• a set of output ports;
• a switching matrix;
• and
• a plurality of de-multiplexers each comprising an aggregate port and a plurality of tributary ports, each aggregate port being connected to an input port and each tributary port being connected to the switching matrix, the switching matrix being coupled between the tributary ports and the output ports,
• wherein the wavelength selective optical switching arrangement is configured to:
• receive at an input port a group of optical signals, each optical signal being transmitted on a different wavelength and being assigned to one of a plurality of destination nodes;
• de-multiplex the group of optical signals in said de-multiplexer;
• re-group different subsets of the optical signals into different destination groups according to their destination nodes, wherein each subset of the optical signals with a common destination are re-grouped together, wherein re-grouping different subsets of the optical signals into different destination groups according to their destination nodes comprises:
• re-grouping a first subset of the optical signals into a first destination group to be routed to a first destination node;
• and
• re-grouping a second subset of optical signals into a second destination group to be routed to a second destination node;
• and
• route each destination group to a respective output port assigned to the destination group.