Characterization of single-photon detectors using a source of photon pairs
AssigneeAT&T Intellectual Property I, L.P.
InventorsMichael Brodsky, Cristian Antonelli, Jungmi Oh
Life of this patent
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Abstract
Operational parameters of a single-photon detector are determined with a source of photon pairs. At a fixed trigger, a dark count probability and a series of count probabilities at different optical powers are determined. A particular optical power is selected by adjusting the optical power of the source of photon pairs. The dark count probability and the count probabilities are determined for different trigger rates. The operational parameters include efficiency, afterpulsing constant, and detrap time. The operational parameters are computed by fitting the computed dark count probabilities and count probabilities to a user-defined relationship.
Claims2
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 Q0;
- and
- a detrap time τ;
- and
- the means for calculating at least one of an efficiency η, an afterpulsing constant Q0, 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
- )
- )
- ,
- Pc is a count probability,
- Pdc is a dark count probability,
- μ is an average number of photons per detector gate, and
- R is a trigger rate.
A computer readable medium storing computer program instructions for characterizing a single-photon detector operating with a plurality of trigger rates, wherein the computer program instructions, when executed on a processor, cause the processor to perform a method comprising:
- 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
- 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:
- calculating a single-photon detector operational parameter comprises calculating at least one of:
- an efficiency η;
- an afterpulsing constant Q0;
- and
- a detrap time τ;
- and
- calculating at least one of an efficiency η, an afterpulsing constant Q0, and a detrap time τ comprises:
- 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
- )
- )
- ,
- Pc is a count probability,
- Pdc is a dark count probability,
- μ is an average number of photons per detector gate, and
- R is a trigger rate.
Dependencies are inferred from the claim text.