Table 1 Comparison of some notable high-rate QKD systems.

The protocol implemented by Lucamarini et al. (37) is a d = 2 time-bin BB84 protocol, where the two bases are chosen with asymmetric probability. Zhong et al. (21) and Lee et al. (23) implement high-dimensional QKD (HD-QKD) using time-bin encoding schemes.

ProtocolLoss (dB)Equivalent fiber length (km)Secret key rate (megabits/s)Security level
Lucamarini et al. (37)T127
10
13
16
35
50
65
80
2.20
1.09
0.40
0.12
Collective
Zhong et al. (21)HD-QKD0.02
4
0.1
20
7.0
2.7
Collective
Lee et al. (23)HD-QKD0.1
7.6
12.7
0
38
63
23.0
5.3
1.2
Collective
This workHD-QKD4
8
10
14
16.6
20
40
50
70
83
26.2
11.9
7.71
3.40
1.07
Coherent/general*

*For the definition of coherent attacks, we refer readers to the study of Sheridan and Scarani (12).