Single-Photon Avalanche Detector Calibration at PTB

In this paper we present the traceable calibration of the detection efficiency of Si and InGaAs/InP single-photon avalanche detectors (SPADs). We describe the calibration facilities and the reference standard detectors used, as well as the traceability chain of the measurements to the primary standard for optical power (Cryogenic Radiometer) of PTB. As an example, the detection efficiency of a Si and InGaAs/InP SPAD detector measured at wavelengths of 850 nm and 1550 nm, respectively, for different photon flux rates is presented. The standard uncertainty of the measurements is ≤ 1 %.