Pilot comparison on the measurement of detection efficiency of InGaAs/InP single-photon detectors (Conference Presentation)

InGaAs/InP single-photon detectors are today the most frequently used detectors for fibre-based Quantum Key Distribution (QKD) [1,2]. The performance of the QKD-systems greatly depends on the optical properties of its detector, such as quantum efficiency, dead time, dark counts, gating rate, etc., which need to be metrologically characterized to fully grantee the QKD network security. Therefore, several European National Metrological Institutes (NMIs) are putting today great efforts in developing novel measurement methods and calibration facilities, which allow to perform the traceable characterisation of single-photon detectors by using reference standards [3, 4]. From the metrological, and specifically radiometric, point of view, the detection efficiency of the single-photon detector is the main parameter that needs to be traceable to the primary standard for optical power (i.e. the cryogenic radiometer), which is maintained by most of the NMIs. Recently, four European NMIs have carried out a pilot comparison on the detection efficiency of a free-running InGaAs/InP single-photon detector, which main purpose has been to provide a snapshot of the measurement capabilities of the four European NMIs in the field of photon counting detection. The comparison was carried out in the framework of the EMPIR project 14IND05 “Optical metrology for quantum-enhanced secure telecommunication (MIQC2)” at the telecom wavelength of 1550 nm by using different reference standards with independently traceability chains. The results of this comparison, including the different experimental setups, the measurement methods, the traceability chain and the uncertainty evaluation of each participant, will be presented in this conference. References: [1] Akihisa Tomita, et al., “High speed quantum key distribution system”, Optical Fiber Technology, 16, Issue 1, 55-62 (2010). [2] Damien Stucki, et al., “Photon counting for quantum key distribution with peltier cooled InGaAs/InP APDs”, Journal of Modern Optics, 48, Issue 13, 1967-1981 (2001). [3] M. Lopez, et al, “Detection efficiency calibration of single-photon silicon avalanche photodiodes traceable using double attenuator technique, Journal of Modern Optics 62, S21 – S27, 2015. [4] G. Porrovecchio, et al., “Comparison at the sub-100 fW optical power level of calibrating a single-photon detector using a high-sensitive, low-noise silicon photodiode and the double attenuator technique”, Metrologia 53, 1115-1122 (2016).