Fig. 4
From: 40-user fully connected entanglement-based quantum key distribution network without trusted node
Performances of symmetric DO-QKD in the network. (a) Measured secure key rates between any two users in subnet A; 28 links are labeled by numbers on x-axis. Link 1 has transmission fibers of 1 and 2 km at two sides, separately. Links 2–7 only have transmission fibers of 1 km at one side, and links 8–13 only have transmission fibers of 2 km at one side. Links 14–28 do not have these transmission fibers. (b) Measured secure key rates between users in different subnets. There are ten links among the five users in five different subnets. The letters on the top of each result indicate two subnets of the two users in the link. All the links with the user from subnet A (1–4) have transmission fibers of 1 km at one side. Other links (5–10) do not have transmission fibers. (c) Corresponding QBERs between the users in the subnet A. (d) Corresponding QBERs between two users in each two of five subnets