  Continuous-variable quantum key distribution (CV-QKD) could allow QKD and
classical optical signals physically sharing the same optical fibers in
existing networks. However, Raman scattering imposes a limit on the optical
power, which in turn impacts the network capacity for classical traffic in
presence of CV-QKD. Network-planning simulations indicate that maxing out the
CV-QKD capacity in an optical link can adversely impact its classical capacity.
Although preliminary, these results show that designing a mixed classical and
CV-QKD network will require dedicated planning heuristics and tools that
specifically seek a compromise between classical and CV-QKD traffics.
