Fig. 4: Energy-time entanglement verification.
a Franson interference fringes obtained at 1 Gpairs/s emission rate (Pin = 12mW) for the resonance pair λs, λi = 1536 nm, 1558 nm. The experimental coincidence rates (blue markers and left axis) are fitted with a sinusoidal function with a visibility \({\mathscr{V}}=93.81\pm 0.57 \%\). The experimental coincidence rates are obtained by the FHWM integral of the central peak of the coincidence histogram shown in b. The red and green squares represent the singles count rate (right axis) that does not vary during the measurement, attesting the absence of first order interference. The poissonian error is not represented because the error bar is smaller than the marker size. b Snapshot of the coincidence histogram at four notable phase settings of the interferometer.
