449. J. M. Kahn and D. A. B. Miller, "Communications expands its space," Nature Photonics 11, 5 – 8 (2017) doi:10.1038/nphoton.2016.256
Optical communication systems have traditionally sent the most information possible through a few spatial channels to minimize cost and maximize density. Energy constraints now compel systems at the longest and shortest distances to employ a new strategy of using more spatial channels, each carrying less data.
Link to preprint