Deployment of 100G WDM ports tripled in 2013 and continues to grow rapidly through 2014. But by 2016 deployment of this technology in core networks saturates— and then the opportunity for coherent WDM technology at rates for 100G and beyond really lies in the shorter spans of the metro. We discovered that the killer app for metro 100G in the next 12 months is data center interconnect (DCI).