An FPGA-based module for multiphoton coincidence counting
David Branning, M. Beck · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2012
We present a multi-channel coincidence-counting module for use in quantum optics experiments. The circuit takes up to four TTL pulse inputs and counts either 2-, 3-, or 4-fold coincidences, within a user-selected coincidence time window as short as 12 ns. The module can accurately count eight sets of multi-channel coincidences, for input rates of up to 84 MHz. Due to their low cost and small size, multiple modules can easily be combined to count arbitrary M-order coincidences among N inputs.