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Quantum communications system with integrated photonic devices

United States Patent

9,819,418
November 14, 2017
View the Complete Patent at the US Patent & Trademark Office
Los Alamos National Laboratory - Visit the Technology Transfer Division Website
Security is increased in quantum communication (QC) systems lacking a true single-photon laser source by encoding a transmitted optical signal with two or more decoy-states. A variable attenuator or amplitude modulator randomly imposes average photon values onto the optical signal based on data input and the predetermined decoy-states. By measuring and comparing photon distributions for a received QC signal, a single-photon transmittance is estimated. Fiber birefringence is compensated by applying polarization modulation. A transmitter can be configured to transmit in conjugate polarization bases whose states of polarization (SOPs) can be represented as equidistant points on a great circle on the Poincare sphere so that the received SOPs are mapped to equidistant points on a great circle and routed to corresponding detectors. Transmitters are implemented in quantum communication cards and can be assembled from micro-optical components, or transmitter components can be fabricated as part of a monolithic or hybrid chip-scale circuit.
Nordholt; Jane E. (Los Alamos, NM), Peterson; Charles Glen (Los Alamos, NM), Newell; Raymond Thorson (Santa Fe, NM), Hughes; Richard John (Los Alamos, NM)
Los Alamos National Security, LLC (Los Alamos, NM)
14/ 422,106
20150236791
August 16, 2013
ACKNOWLEDGMENT OF GOVERNMENT SUPPORT This invention was made with government support under Contract No. DE-AC52-06NA25396 awarded by the U.S. Department of Energy. The government has certain rights in the invention.