Impairment Evaluation toward QKD Integration in a Conventional 20-Channel Metro Network Slavisa Aleksic, Florian Hipp, Dominic Winkler, Andreas Poppe, Bernhard Schrenk and Gerald Franzl © 2015 The Optical Society of America (OSA). This is an authors’ copy of the work. It is posted here by permission of OSA for your personal use. Not for redistribution. The definitive version will be published in the proceedings of the Optical Fiber Communication Conference and Exposition (OFC 2015), Los Angeles, CA, March 2015.