  The light-matter quantum interface that can create quantum-correlations or
entanglement between a photon and one atomic collective excitation is a
fundamental building block for a quantum repeater. The intrinsic limit is that
the probability of preparing such non-classical atom-photon correlations has to
be kept low in order to suppress multi-excitation. To enhance this probability
without introducing multi-excitation errors, a promising scheme is to apply
multimode memories into the interface. Significant progresses have been made in
temporal, spectral, and spatial multiplexing memories, but the enhanced
probability for generating the entangled atom-photon pair has not been
experimentally realized. Here, by using 6 spin-wave-photon entanglement
sources, a switching network and feed-forward control, we build a multiplexed
light-matter interface and then demonstrate a ~6-fold (~4-fold) probability
increase in generating entangled atom-photon (photon-photon) pairs. The
measured compositive Bell parameter for the multiplexed interface is 2.49+-0.03
combined with a memory lifetime of up to ~60 microseconds.
