Nortel, Brampton, ON, Canada, has built a 2.4-m dispersion compensating grating for fiber-optic networks and claims it is the longest in the world. Increasing the grating length to 2.4 m means more dense wavelength-division multiplexing channels can be transmitted on the same fiber. The grating offers an alternative to tens of kilometers of dispersion-compensating fiber, which is an expensive specialty fiber.