I was wondering the same thing, and tracked down the original article: http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2011.74.html http://www.

I was wondering the same thing, and tracked down the original article: http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nphoton.2011.74.html http://www.nature.com/nphoton/journal/vaop/ncurrent/full/nph... There's a diagram available in the abstract that compares OFDM (the technique they use) with WDM. Apparently OFDM only uses a single light-source, versus (C|D)WDM, which multiplex multiple discrete wavelengths onto the same fiber.