We report on an electronic coincidence detection circuit for quantum photonic applications implemented on a field-programmable gate array (FPGA). which records each the time separation between detection events coming from single-photon detectors. We achieve a coincidence window as narrow as 500 ps with a series of optimizations on a readily-available and affordable FPGA development bo... https://www.jmannino.com/deal-time-bio365-BIOLITE-Soil-Grow-Bags-2-Gallons-great-save/