Figure 6

QBER and SKR. The Quantum Bit Error Rate and the Secure Key Rate obtained with our modular QKD source. An average \(\mathrm{Q}_{\mathcal{Z}} = 0.62 \pm 0.05\) and \(\mathrm{Q}_{\mathcal{X}} = 1.15 \pm 0.01\) were observed whereas a finite-key \(\mathrm{SKR} = 2603 \pm 21\) (\(\mathrm{SKR}_{\infty }= 2819 \pm 23\)) bits per second was obtained