US 11,747,567 B2
Qudit pair generator
Jake Smith, Palo Alto, CA (US); and Konrad Kieling, Potsdam (DE)
Assigned to Psiquantum, Corp., Palo Alto, CA (US)
Filed by Psiquantum, Corp., Palo Alto, CA (US)
Filed on Jun. 8, 2021, as Appl. No. 17/303,819.
Claims priority of provisional application 63/119,411, filed on Nov. 30, 2020.
Prior Publication US 2022/0171133 A1, Jun. 2, 2022
Int. Cl. G02B 6/293 (2006.01); G06N 10/00 (2022.01); G06F 17/14 (2006.01)
CPC G02B 6/29395 (2013.01) [G02B 6/2935 (2013.01); G06N 10/00 (2019.01); G06F 17/141 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A circuit comprising:
a first set of waveguides and a second set of waveguides, wherein each of the first set of waveguides and the second set of waveguides includes a number n=2d of waveguides;
a first set of mode couplers, wherein each mode coupler in the first set is coupled between one of the waveguides in the first set of waveguides and one of the waveguides in the second set of waveguides;
a mode information erasure (MIE) circuit coupled to the waveguides of the second set of waveguides downstream of the first set of mode couplers;
a set of n photon detectors coupled to outputs of the MIE circuit, each of the n photon detectors being configured to count a number of detected photons;
a set of reconfigurable phase shifters, each reconfigurable phase shifter coupled to a different one of the waveguides in the first set of waveguides;
a second set of mode couplers, wherein each mode coupler in the second set is coupled between a different pair of waveguides in the first set of waveguides downstream of the reconfigurable phase shifters; and
a classical control logic circuit coupled to outputs of set of n photon detectors and configured to determine, based on a total count of photons counted by the n photon detectors, whether generation of a qudit pair succeeded or failed and further configured to determine, based on a pattern of photons counted by each of the n photon detectors, a phase shift configuration for each of the reconfigurable phase shifters.