Single photon detection used in quantum communication

In order to improve the sensitivity of single-photon detection systems, InGaAs/InP avalanche photodiode (InGaAs/InP APD) is used in the design of single photon detector of quantum communication. Single photon detector bias generation circuit in gate pulse mode, single-photon signal amplification circuit, single photon signal detection circuit and temperature control module were realized. By selecting high-precision OP37 preamplifier and precision comparator AD8561, quantum efficiency was increased to 18.3%, dark count was controlled within 4.1 10-6/ns.