  The scalability of quantum networking will benefit from quantum and classical
communications coexisting in shared fibers, the main challenge being
spontaneous Raman scattering noise. We investigate the coexistence of
multi-channel O-band quantum and C-band classical communications. We
characterize multiple narrowband entangled photon pair channels across 1282
nm-1318 nm co-propagating over 48 km installed standard fiber with record
C-band power (>18 dBm) and demonstrate that some quantum-classical wavelength
combinations significantly outperform others. We analyze the Raman noise
spectrum, optimal wavelength engineering, multi-photon pair emission in
entangled photon-classical coexistence, and evaluate the implications for
future quantum applications.
