DEVELOPMENT OF AN FPGA-BASED COINCIDENCE COUNTING SYSTEM FOR MULTIPLE SIGNALS

The detection of temporally coincident signals plays an important role in different technological applications for metrology and communication, and particularly, in the area of quantum optics. In this sense, the simultaneous detection of two or more photons allows one to take advantage of the non-classical features of light that manifest themselves in certain types of correlations that cannot be described classically. We present here the development of programmable modules, by using FPGA technology, which are part of the coincident pulse detection and counting system. Our implementation, in a development board from Xilinx, allows to determine when two or more pulses overlap within a temporal window, with a configurable width in the range of 1 and 255 ns to compensate for possible path differences. We obtained the photodetection statistics result of the single and coincident pulse measurements and compared them with that predicted by a theoretical analysis. In addition, we have emulated the signals corresponding to different photon sources through a beam splitter, and obtained the photodetection statistics from which we determine, for each case, the second order correlation function g(2)(τ).