	US 12,294,413 B2
	Ultrafast temporal filtering for quantum communications
Frédéric Bouchard, Gatineau (CA); Duncan England, Ottawa (CA); Philip J. Bustard, Ottawa (CA); Khabat Heshami, Ottawa (CA); and Benjamin Sussman, Ottawa (CA)
Assigned to NATIONAL RESEARCH COUNCIL OF CANA, Ottawa (CA)
Appl. No. 17/927,829
Filed by National Research Council of Canada, Ottawa (CA)
PCT Filed May 20, 2021, PCT No. PCT/CA2021/050686 § 371(c)(1), (2) Date Nov. 25, 2022, PCT Pub. No. WO2021/237340, PCT Pub. Date Dec. 2, 2021.
Claims priority of provisional application 63/029,987, filed on May 26, 2020.
Prior Publication US 2023/0208532 A1, Jun. 29, 2023
Int. Cl. H04B 10/70 (2013.01)

CPC H04B 10/70 (2013.01)

22 Claims

1. A quantum communication method comprising:

at a sender, preparing photons encoded in a single spatial, spectral, and temporal (SST) mode to form a quantum signal; and introducing the quantum signal into a quantum channel;

at a receiver, a detector and filtering system optically processing the quantum signal and rejecting background noise photons in the quantum channel, and performing active temporal filtering by switching the polarization of the quantum signal without substantially adding noise; and

wherein the active temporal filtering minimizes saturation of the detector.