Fig. 4: The secure key rates with different losses between each user in the four-user MDI-QN.
From: A measurement-device-independent quantum key distribution network using optical frequency comb

a The solid line shows theoretical simulations, and the triangular symbols show experimental results of different user pairs with a total transmission loss of about 30 dB. The top-right (b, c) and bottom-left (d, e) insets are the zoomed-in views of results for different user pairs with a linear scale.