Energy-Efficient Optical Transport Capacity Scaling Through Spatial Multiplexing

We discuss the role of parallel transport options such as spatial multiplexing or multiband transmission in the capacity scaling of optical transport systems. Taking current experimental spectral efficiency records as a baseline, a system supporting 20 b/s/Hz over 1500 km can be about 100 times more energy efficient when it is built using spatial multiplexing than when it is built using a single waveguide at high capacity.