Fig. 3: Remote heralding with 280 time-bin modes.

a The heralding protocol of remote atom-photon quantum correlation over an L = 12 km fiber enhanced by 280 time-bin modes. The first four modes are generated at t = 0 when the addressed write beam excites the first memory cell. The time-bin modes of a signal photon are traveling in the long fiber as a long pulse train, with an interval at 400 ns (between modes from the same cell) or 500 ns (between the 4th mode from the previous cell and the 1st mode from the current cell). b The histogram of the arrival time for the heralding TTL received by the memory, at an average success probability of \(\bar{p}=0.18\%\). The inset is a zoom-in in the long time-bin pulse train, the shaded four modes are from the same memory cell. The temporal width of each signal mode is ~100 ns. The bin size of the histogram is 10 ns.