US 12,355,869 B2
System and method for quantum key distribution with entangled photon pairs
Kadir Durak, Istanbul (TR); and Melis Pahali, Istanbul (TR)
Assigned to QUBITRIUM TEKNOLOJI SANAYI VE TICARET ANONIM SIRKETI, Istanbul (TR)
Appl. No. 17/928,619
Filed by OZYEGIN UNIVERSITESI, Istanbul (TR)
PCT Filed Jul. 8, 2020, PCT No. PCT/TR2020/050610
§ 371(c)(1), (2) Date Nov. 30, 2022,
PCT Pub. No. WO2022/010427, PCT Pub. Date Jan. 13, 2022.
Prior Publication US 2023/0198750 A1, Jun. 22, 2023
Int. Cl. H04L 9/08 (2006.01); H04B 10/70 (2013.01); H04L 9/06 (2006.01)
CPC H04L 9/0852 (2013.01) [H04B 10/70 (2013.01); H04L 9/0662 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A system for a quantum key distribution comprising a photon source configured to generate an entangled photon pair comprising a first photon and a second photon and two receiving units configured to receive separately the first photon and the second photon; wherein each of the two receiving units comprises:
an optoelectronic polarization rotator (OPR) configured to polarize a photon in a selected polarization orientation;
a polarizing beam splitter configured to reflect and transmit polarized particles;
at least two photon detectors configured to detect a photon output from the polarizing beam splitter and to determine coincidence particles in a predetermined time interval between the two receiving units; a coincidence analyzer configured to collect and record coincidences; and
a quantum random number generator configured to provide a quantum number and to choose OPR polarization angles;
wherein three types of the coincidences are measured by the coincidence analyzer, wherein the three types of the coincidences are a raw key coincidence, a security check coincidence, and an unused, discarded coincidence; and wherein the quantum random number generator is configured to regain the unused, discarded coincidence to the system by providing random bits denoted by the unused, discarded coincidence as the quantum number for choosing said OPR polarization angles.