Fig. 9: Proposed experimental implementation of a multiplexed repeater chain.

a Proposed implementation of a multiplexed repeater chain using a high-dimensional biphoton frequency comb (BFC). b Measured frequency correlation matrix of the BFC for the multiplexed elementary link that we implemented. c Polarization entanglement measurements of the implemented BFC. d Schmidt number and Hilbert-space dimensionality scaling for different dimensions in the implemented BFC.