Via the CANARIE mailing list, there is news that NTT, the Japanese phone company, has broken new ground with Wave Division Multiplexing, or WDM. In "old" fiber systems, a single channel of information travels over a fiber pair. With WDM, you can have multiple channels of information on a single fiber.
One interesting consequence of WDM technology is that you can deliver two way communications over a single fiber, rather than needing two fibers (one for each direction). Typically, current WDM systems offer 10-20 channels over a single fiber. NTT researchers have successfully transmitted data over 1000 WDM channels on a single fiber, or about a two order of magnitude increase in capacity--over the same fiber.
That's why fiber is such a good, stable, long term investment. As the demand for bandwidth increases, you can keep adding more capacity to existing fiber by simply swapping out the equipment at both ends. Fiber is future proof.