We report on the absolute calibration of photodetector quantum efficiency by using correlated photon sources, performed independently at two laboratories, the National Institute of Standards and Technology and the Istituto Elettrotecnico Nazionale (IEN). The goal is to use an interlaboratory comparison to demonstrate the inherent absoluteness of the photon correlation technique by showing its independence from the particular experimental setup. We find that detector nonuniformity limited this comparison rather than uncertainty inherent in the method itself. The ultimate goal of these investigations is development of a robust measurement protocol that allows the uncertainties of individual measurements to be determined experimentally and verified operationally. Furthermore, to demonstrate the generality of the procedure, the IEN measurement setup was also used to calibrate a fiber-coupled avalanche photodiode module. Uncertainties are evaluated for the detector both with and without fiber coupling and differences are discussed. The current IEN setup using a thinner and higher transmittance nonlinear crystal for the generation of correlated photons shows a significant improvement in overall accuracy with respect to previously reported results from IEN [Metrologia <b>32</b>, 501–503 (1996)].
© 2002 Optical Society of America
(030.5630) Coherence and statistical optics : Radiometry
(040.5570) Detectors : Quantum detectors
(120.3940) Instrumentation, measurement, and metrology : Metrology
(120.4800) Instrumentation, measurement, and metrology : Optical standards and testing
(120.5630) Instrumentation, measurement, and metrology : Radiometry
Alan Migdall, Stefania Castelletto, Ivo Pietro Degiovanni, and Maria Luisa Rastello, "Intercomparison of a Correlated-Photon-Based Method to Measure Detector Quantum Efficiency," Appl. Opt. 41, 2914-2922 (2002)