US Government As Represented by the Secretary of the Army

Brian T Kirby

Michael Brodsky

Daniel E Jones

Vladimir S Malinovsky

Siddhartha Santra

A novel methodology for characterizing and calibrating an entangled photon distribution system is disclosed. The entangled photon distribution system includes at least a source of entangled photon pairs, two photon detectors which detect photons among two channels and a controller. The methodology includes: for at least two different operational setting levels of the source of entangled photon pairs, measuring count rates for photons detected by the two photon detectors, individually and coincidently; fitting the measured individual and coincidence count rate data for the at least two different operational setting levels with theoretical models of detection probability; and determining operational parameters of the system from the fitting. The determined operational parameters of the system include the rate of generated entangled photon pairs by the source, the rates of Raman-scattered photons generated in the first and second channels, respectively, and the efficiency of the two photon detectors, respectively.

Methodology for in situ characterizing and calibrating an entangled photon distribution system

Methods and apparatuses are provided that compensate for the polarization dependent loss (PDL) of fiber-optic quantum channels. Compensation is accomplished by inserting a compensating PDL into another quantum channel carrying entangled photons that are entangled with photons in the first channel having losses that are to be compensated for. By selecting the optimum magnitude and orientation for the compensating PDL, compensation for the PDL in the first channel is maximized.

Compensating for entanglement loss in communication lines

Methods and systems for measuring interferometric visibility of telescopic signals using resources having imperfect quantum entanglement are disclosed. The novel methodology employed by embodiments of the present invention takes into account the difficulty in creating entanglement between distance telescopes, and describes how to incorporate problems associated with distributing quantum entanglement into the measurement procedure. This allows the distance that two telescopes in an optical array are spaced apart to be increased while still interacting.

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Baltimore, MD, United States of America

Brian T Kirby