Study On The Quantum Characterization Of The High-speed Single-photon Detection

Near-infrared single-photon detectors play a significance role in a wide range of applications, such as quantum key distribution, laser ranging and biological fluorescence imaging. In particular, InGaAs/InP avalanche photodiodes (APDs) operating in gated Geiger-mode are widely used in the near-infrared single-photon detection due to the compact structure and the non-cryogenic cooling. Thanks to these advances, single-photon detectors based on InGaAs/InP APDs have already demonstrated a desirable performance for single-photon-level sensing at high speed. Due to the ever-growing need for the high-speed infrared single-photon detection in different applications, especially in quantum optics such as quantum key distribution, quantum state engineering based on conditional measurement and linear optical quantum computing, it is necessary to assess the complete features of quantum detectors.We demonstrate high-speed and low-noise near-infrared single-photon detection by using a capacitance balancing circuit to achieve a high spike noise suppression for an InGaAs/InP avalanche photodiode. The single-photon detector could operate at a tunable gate repetition rate from 10 to 60 MHz. A peak detection efficiency of 34% has been achieved with a dark count rate of 9×10-3 per gate when the detection window was set to 1 ns. Additionally, quantum detector tomography has also been performed at 60 MHz of repetition rate and for the detection window of 1 ns, enabling to witness the quantum features of the detector with the help of a negative Wigner function. By varying the bias voltage of the detector, we further demonstrated a transition from the full-quantum to semi-classical regime.