An optical channel monitor assembly for simultaneously measuring the optical power levels of multiple series of dense wavelength division multiplexed channels or the like traveling on separate optical fibers in an optical communications system includes an arrayed waveguide grating router having a first side and a second side, the first side including a first plurality of ports and the second side including a second plurality of ports, the first plurality of ports in optical communication with the second plurality of ports, wherein the first side includes a first input port for collectively receiving a first series of optical channels, wherein the second side includes a first plurality of output ports for individually delivering the first series of optical channels, wherein the second side includes a second input port for collectively receiving a second series of optical channels, and wherein the first side includes a second plurality of output ports for individually delivering the second series of optical channels.