Fig. 4: Benchmarking of our WSe₂ single-photon source against previous QKD experiments.

Rate-loss diagram considering our experimental data from Table 1 and the parameters from previous QKD experiments using semiconductor quantum dots (QD)⁴⁴,⁴⁷, and nitrogen-vacancy (NV) centers in diamond⁵¹ (see Methods section “Parameter optimization” for details on the key rate calculation). The black curves show the expected performance of our WSe₂-based source without (dashed line) and with (full line) optimization via temporal filtering. Implementing moderate improvements to our source (gray dashed line), tolerable losses exceeding 25 dB become possible, bringing satellite links within reach²⁸.