Fig. 5: Correlation measurements of entangled photons across installed network link.
From: A tuneable telecom wavelength entangled light emitting diode deployed in an installed fibre network
a Horizontal-horizontal (HH) and horizontal-vertical (HV) polarisation detection. b Diagonal-diagonal (DD) and diagonal-anti-diagonal (DA) polarisation detection. c Right-right- (RR) and right-left-hand circular (RL) polarisation detection. d Fidelity to Bell \(\phi ^ +\) state. Data is displayed on 48 ps resolution timing grid. e Evolution of maximum fidelity and corresponding quantum bit error rate (QBER) over 40 h of continuous operation. Each data point corresponds to 2 h of data. All displayed error bars indicate one standard deviation propagated from Poissonian counting statistics.
