There is no knocking Nokia’s achievement in getting closer to the theoretical maximum performance possible over a single optical fiber, increasing capacity by 25% over the most recently deployed systems and up to 65% over older networks. Yet this aspect of Nokia’s new Photonic Service Engine (PSE) chipset is less useful for operators than some of the other features that increase flexibility. It also highlights the value of the Shannon limit for defining what is possible over optical networks and therefore identifying what other measures need to be taken to meet the exploding demand for data capacity over fiber infrastructures ranging from metro networks to trunk undersea cables. The answer is Spatial Division Multiplexing (SDM), which Nokia itself is working…