40 Gbit/s from a carrier's perspective

I will review the state-of-the art in technology for 40 Gbit/s high-speed electronics and optics. I will also try to point out technological challenges and tradeoffs, where applicable. Clearly, 40 Gbit/s must have a service or cost advantage in order to be deployed, so I will also talk about the economics from a big carrier's point of view.