Post-Measurement Adjustment of the Coincidence Window in Quantum Optics Experiments

We report on an electronic coincidence detection circuit for quantum photonic applications implemented a field-programmable gate array (FPGA), which records each the time separation between events coming from single-photon detectors. achieve window as narrow 500 ps with series of optimizations readily-available and affordable FPGA development board. Our implementation allows real-time visualization measurements multiple widths simultaneously. To demonstrate advantage our high-resolution visualization, we certified generation polarized entangled photons by collecting data windows minimal accidental counts, obtaining violation Clauser-Horne-Shimony-Holt (CHSH) Bell inequality more than 338 standard deviations. results have shown applicability design in field information.