The Cisco ONS 15216 Mux/Demux 40-Channel Patch Panel introduces athermal arrayed waveguide grating (AWG) technology, which allows passive dense wavelength-division multiplexing (DWDM) systems to have the same optical performance as systems using active-temperature-controlled AWG technology. This breakthrough lets enterprises and service providers deploy 80 channels of DWDM capacity, taking advantage of a reduced footprint while consuming no electricity.The Cisco ONS 15216 Mux/Demux 40-Channel Patch Panels (Figure 1) are standalone units that contain both a 40-channel optical multiplexer and a 40-channel optical de-multiplexer, which are precabled in the housing for easy and immediate operation. Two units are available, covering the even and odd numbered channels specified by the (International Telecommunication Union) ITU grid. The Cisco ONS 15216 Mux/Demux Patch Panel 50-GHz Interleaver De-Interleaver easily plugs into the Cisco ONS 15216 Mux/Demux 40-Channel Patch Panel for in-service capacity upgrade from 40 channels up to 80 channels in a 4 rack unit (RU) footprint, combining both the odd and even channel units. Figures 2 through 5 illustrate the different application configurations in which the Cisco ONS 15216 Mux/Demux 40-Channel Patch Panel can be deployed.