Desarrollo de un sistema de control y caracterización simultanea de contadores de fotones

Abstract

The success of Quantum Key Distribution systems and a broad variety of Quantum Optics experiments depends on the ability to detect single photons. In the optical communications third window the most adequate detectors are the Single Photon Avalanche Photodetectors (SPADs). The Optical and Quantum Communications Group at the Polytechnical University of Valencia has acquired three of such photon counters to develop a Quantum Key Distribution system using benchtop fiber optics technology at 1550nm. These SPADs need to be studied, characterized and calibrated in order to configure them with the correct parameters of operation. In this Master Thesis we have studied these detectors and developed a control system to characterize them simultaneously. We have developed a Labview interface for the automated experimental characterization of the SPADs. Finally, we have performed experimental measurements with the aid of the control system and the Labview interface to verify the operation principle and characterize the photon counters in terms of their working parameters such as detection gate duration, probability of detection. We have also obtained the Signal to Noise Ratio and we have calibrated them for a detection gate of 14 ns.