• Mode-multiplexing over multimode fibers has the potential to scale WDM networks by a factor of 10 or more • Multimode components like wavelength selective switches and optical amplifiers can scale to large number of modes • Wavelength selective switches, which are the basic building block for WDM network can be extended to support multimode fibers • Spatial-diversity multimode WSSs can provide performance comparable to single-mode devices • The WSS switching capacity can be dramatically increased by using “interleaved Joint switching” • Free space multimode WSSs offer a simple optical design with increased switching capacity