Fig. 5: Overpass and memory buffer effects with \({\eta }_{{{{{{{{\rm{loss}}}}}}}}}^{{{{{{{{\rm{sys}}}}}}}}}=40\) dB and fs = 500 MHz.
From: Finite key performance of satellite quantum key distribution under practical constraints
a Secret key length (SKL) (left axis) and minimum memory buffer (right axis) as a function of ground track distance. We consider QBERI = 0.5%, and pec = 1 × 10−7 (System D). A larger memory buffer permits a longer transmission time, which extends the operational footprint of the SatQKD system. Further, a larger minimum memory buffer requirement is observed at larger ground track distances to generate non-zero finite keys. This provides an indication of SatQKD system specifications. b Annual expected SKL for an OGS at a latitude of 55. 9∘ N as a function of Memory Buffer. We illustrate four distinct system configurations {QBERI, pec}: A = {0.1%, 1 × 10−8}, B = {0.5%, 1 × 10−8}, C = {0.1%, 1 × 10−7}, and D = {0.5%, 1 × 10−7}. Dashed lines indicate the annual SKL expected without memory constraints.
