  Extended quantum networks are based on quantum repeaters that often rely on
the distribution of entanglement in an efficient and heralded fashion over
multiple network nodes. Many repeater architectures require multiplexed sources
of entangled photon pairs, multiplexed quantum memories, and photon detection
that distinguishes between the multiplexed modes. Here we demonstrate the
concurrent employment of (1) spectrally multiplexed cavity-enhanced spontaneous
parametric down-conversion in a nonlinear crystal; (2) a virtually-imaged
phased array that enables mapping of spectral modes onto distinct spatial modes
for frequency-selective detection; and (3) a cryogenically cooled Tm3+:LiNbO3
crystal that allows spectral filtering in an approach that anticipates its use
as a spectrally-multiplexed quantum memory. Through coincidence measurements,
we demonstrate quantum correlations between energy-correlated photon pairs and
a strong reduction of the correlation strength between all other photons. This
constitutes an important step towards a frequency multiplexed quantum repeater.
