Improved CAR and noise analysis for photon-pair generation in an ultra-compact silicon slow-light photonic crystal waveguide

We report the improvement and noise analysis of correlated photon-pair generation in an ultra-compact 96 μm long dispersion-engineered silicon slow-light photonic crystal waveguide pumped by picosecond pulses. The key metrics for a photon-pair source: coincidence to accidental ratio (CAR) and pair brightness were measured to be a maximum 27 at a pair generation rate of 0.002 pair per pulse. We performed the noise analysis by comparing the single and coincidence count rate at the output end of the waveguide. The noise analysis shows that detector dark counts, leaked pump light, linear and nonlinear losses, multiple pair generation and detector jitter are the limiting factors to the CAR performance of the sources.