TY - JOUR
T1 - Heralded Multiplexed High-Efficiency Cascaded Source of Dual-Rail Entangled Photon Pairs Using Spontaneous Parametric Down-Conversion
AU - Dhara, Prajit
AU - Johnson, Spencer J.
AU - Gagatsos, Christos N.
AU - Kwiat, Paul G.
AU - Guha, Saikat
N1 - Funding Information:
P.D., C.N.G., and S.G. acknowledge support from the National Science Foundation (NSF) Engineering Research Center for Quantum Networks (CQN), under cooperative agreement number 1941583. S.G. additionally acknowledges support from ATA, under a NASA-funded research consulting contract. The contributions of S.J. and P.G.K. are supported in part by NASA Grant No. 80NSSC20K0629 and the U.S. Department of Energy Office of Science National Quantum Information Science Research Centers. The authors acknowledge useful discussions with Dr. Brian Vyhnalek, Dr. Yousef Chahine, Dr. Ian Nemitz, and Dr. John Lekki of GRC, NASA; Dr. Hari Krovi of Raytheon BBN, and Dr. Babak N. Saif of GSFC, NASA.
Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/3
Y1 - 2022/3
N2 - Deterministic sources of high-fidelity entangled qubit pairs encoded in the dual-rail photonic basis, i.e., presence of a single photon in one of two orthogonal modes, are a key enabling technology of many applications of quantum information processing, including high-rate, high-fidelity quantum communications over long distances. The most popular and mature sources of such photonic entanglement, e.g., those that leverage spontaneous parametric down-conversion (SPDC) or spontaneous four-wave mixing, generate an entangled (so-called continuous-variable) quantum state that contains contributions from high-order photon terms that lie outside the span of the dual-rail basis, which is detrimental to most applications. One often uses low pump power to mitigate the effects of those high-order terms. However, that reduces the pair generation rate, and the source becomes inherently probabilistic. We investigate a cascaded source that performs a linear-optical entanglement swap between two SPDC sources, to generate a heralded photonic entangled state that has a higher fidelity (to the ideal Bell state) compared to a free-running SPDC source. Furthermore, with the Bell swap providing a heralding trigger, we show how to build a multiplexed source, which despite reasonable switching losses and detector loss and noise, yields a fidelity versus success probability trade-off of a high-efficiency source of high-fidelity dual-rail photonic entanglement. We find, however, that there is a threshold of 1.5 dB of loss per switch, beyond which multiplexing hurts the fidelity versus success probability trade-off.
AB - Deterministic sources of high-fidelity entangled qubit pairs encoded in the dual-rail photonic basis, i.e., presence of a single photon in one of two orthogonal modes, are a key enabling technology of many applications of quantum information processing, including high-rate, high-fidelity quantum communications over long distances. The most popular and mature sources of such photonic entanglement, e.g., those that leverage spontaneous parametric down-conversion (SPDC) or spontaneous four-wave mixing, generate an entangled (so-called continuous-variable) quantum state that contains contributions from high-order photon terms that lie outside the span of the dual-rail basis, which is detrimental to most applications. One often uses low pump power to mitigate the effects of those high-order terms. However, that reduces the pair generation rate, and the source becomes inherently probabilistic. We investigate a cascaded source that performs a linear-optical entanglement swap between two SPDC sources, to generate a heralded photonic entangled state that has a higher fidelity (to the ideal Bell state) compared to a free-running SPDC source. Furthermore, with the Bell swap providing a heralding trigger, we show how to build a multiplexed source, which despite reasonable switching losses and detector loss and noise, yields a fidelity versus success probability trade-off of a high-efficiency source of high-fidelity dual-rail photonic entanglement. We find, however, that there is a threshold of 1.5 dB of loss per switch, beyond which multiplexing hurts the fidelity versus success probability trade-off.
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U2 - 10.1103/PhysRevApplied.17.034071
DO - 10.1103/PhysRevApplied.17.034071
M3 - Article
AN - SCOPUS:85127524619
SN - 2331-7019
VL - 17
JO - Physical Review Applied
JF - Physical Review Applied
IS - 3
M1 - 034071
ER -