German engineers, using a single laser beam and orthogonal frequency division multiplexing (OFDM), hit a data rate of 26 terabits per second over a distance of 50 km. One source commented that that's 700 DVDs per second. I haven't done the math, but regardless, that's fast. (Hmmm, let me go check my Comcast upload speed. I wonder how close it is.) Here's the article.