Patent ID: 8285515

Claim:
An apparatus for characterizing a single-photon detector operating with a plurality of trigger rates, the apparatus comprising: means for, for each of the plurality of trigger rates: recording dark counts with the single-photon detector and computing a dark count probability; and for each of a plurality of optical powers generated by a source of photon pairs, recording counts with the single-photon detector and computing a count probability; and means for calculating a single-photon detector operational parameter based at least in part on the plurality of computed dark count probabilities and the plurality of computed count probabilities; wherein: the means for calculating a single-photon detector operational parameter comprises means for calculating at least one of: an efficiency η; an afterpulsing constant Q 0 ; and a detrap time τ; and the means for calculating at least one of an efficiency η, an afterpulsing constant Q 0 , and a detrap time τ comprises: means for fitting the plurality of computed dark count probabilities and the plurality of computed count probabilities to a user-defined relationship comprising: P c = P ⁢ ⁢ 1 ⁢ { • } + 1 2 ⁢ P ⁢ ⁢ 2 ⁢ { • } + P ⁢ ⁢ 3 ⁢ { • } , ⁢ wherein ⁢ : P ⁢ ⁢ 1 ⁢ { • } = 2 - ⅇ 1 / R ⁢ ⁢ τ - ( 1 - P dc ) ⁢ ( 1 - P ph ) ⁢ ( 1 - Q 0 ) 2 , ⁢ P ⁢ ⁢ 2 ⁢ { • } = [ 2 - ⅇ 1 / R ⁢ ⁢ τ - ( 1 - P dc ) ⁢ ( 1 - P ph ) ⁢ ( 1 - Q 0 ) ] 2 , ⁢ P ⁢ ⁢ 3 ⁢ { • } = 4 ⁢ ( ⅇ 1 / R ⁢ ⁢ τ - 1 ) ⁡ [ 1 - ( 1 - P dc ) ⁢ ( 1 - P ph ) ] , ⁢ P ph = 1 - exp ⁡ ( - μ ⁢ ⁢ η ⁡ ( 2 - η ) ) , P c is a count probability, P dc is a dark count probability, μ is an average number of photons per detector gate, and R is a trigger rate.