Figure 6

Maximum value of CHSH parameter \(S_{\max}\) for (a) heralded and (b) unheralded single photons in path-entangled state. The inset shows the photon counts recorded across 4 detectors for both the cases. With increase in pump power, \(S_{\max}\) is seen to decrease due to increase in detection of multi-photons across the detectors in the set time window (detector dead time). Due to saturation imposed by the heralding detector, a lower rate of bit generation is observed when compared to the case of using unheralded single photons as the source. The S parameter ensures that the bit generation is limited to a rate that qualifies the entanglement certification