http://nanophotonics.ece.cornell.edu/Research/rese arch.htm

This group at Cornell moves light on the *inside* of a 50-nm silicon trench. Unlike fibers, the low index of refraction is the part the light moves through.

And they can couple it to a much larger optical fiber with very high efficiency–by thinning the structure down still further, making a 20-nm-long needle pointing at the fiber!

Chris