Figure 2

Full configuration of the switched QKD network with a focus on the QKD modules and reconfigurable optical add-drop multiplexers (ROADMs) interconnecting them. At least one lightpath can be created between any of the five senders and any of the five receivers, respectively. The arrow directions indicate the input and output ports of the switches, fixed (de)multiplexers, and QKD devices. The number of occupied DWDM channels and the presence of an O-band channel are indicated for each multiplexer (mux) and demultiplexer (demux) with the arrows at the client side. A double-line arrow stands for multiple fibres, the attached label indicates the number of occupied DWDM channels. “pass” refers to the pass-through lightpath of a (de)mux for all not-listed DWDM channels, e.g., all wavelengths but DWDM channel 34 in the link between Quijote and Quintín. Other classical and quantum communication infrastructure which does not intermingle with the switched QKD signals is omitted from the figure, e.g., the classical connection between Quintín and Quijote