TY - JOUR

T1 - Fully on-chip photonic turnkey quantum source for entangled qubit/qudit state generation

AU - Mahmudlu, Hatam

AU - Johanning, Robert

AU - Kashi, Anahita Khodadad

AU - Rees, Albert van

AU - Epping, Jörn P.

AU - Haldar, Raktim

AU - Boller, Klaus-J

AU - Kues, Michael

N1 - Acknowledgements: This project was funded by the German Federal Ministry of Education and Research, Quantum Futur Program (PQuMAL), and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 947603 (QFreC project), and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). R.H. acknowledges financial support provided by the Alexander von Humboldt Stiftung to conduct the research. A.v.R., J.E. and K.-J.B. acknowledge funding from the EU within the project 3PEAT.

PY - 2023/6

Y1 - 2023/6

N2 - Integrated photonics has recently become a leading platform for the realization and processing of optical entangled quantum states in compact, robust and scalable chip formats, with applications in long-distance quantum-secured communication, quantum-accelerated information processing and nonclassical metrology. However, the quantum light sources developed so far have relied on external bulky excitation lasers, making them impractical prototype devices that are not reproducible, hindering their scalability and transfer out of the laboratory into real-world applications. Here we demonstrate a fully integrated quantum light source that overcomes these challenges through the integration of a laser cavity, a highly efficient tunable noise suppression filter (>55 dB) exploiting the Vernier effect, and a nonlinear microring for entangled photon-pair generation through spontaneous four-wave mixing. The hybrid quantum source employs an electrically pumped InP gain section and a Si 3N 4 low-loss microring filter system, and demonstrates high performance parameters, that is, pair emission over four resonant modes in the telecom band (bandwidth of ~1 THz) and a remarkable pair detection rate of ~620 Hz at a high coincidence-to-accidental ratio of ~80. The source directly creates high-dimensional frequency-bin entangled quantum states (qubits/qudits), as verified by quantum interference measurements with visibilities up to 96% (violating Bell’s inequality) and by density matrix reconstruction through state tomography, showing fidelities of up to 99%. Our approach, leveraging a hybrid photonic platform, enables scalable, commercially viable, low-cost, compact, lightweight and field-deployable entangled quantum sources, quintessential for practical, out-of-laboratory applications such as in quantum processors and quantum satellite communications systems.

AB - Integrated photonics has recently become a leading platform for the realization and processing of optical entangled quantum states in compact, robust and scalable chip formats, with applications in long-distance quantum-secured communication, quantum-accelerated information processing and nonclassical metrology. However, the quantum light sources developed so far have relied on external bulky excitation lasers, making them impractical prototype devices that are not reproducible, hindering their scalability and transfer out of the laboratory into real-world applications. Here we demonstrate a fully integrated quantum light source that overcomes these challenges through the integration of a laser cavity, a highly efficient tunable noise suppression filter (>55 dB) exploiting the Vernier effect, and a nonlinear microring for entangled photon-pair generation through spontaneous four-wave mixing. The hybrid quantum source employs an electrically pumped InP gain section and a Si 3N 4 low-loss microring filter system, and demonstrates high performance parameters, that is, pair emission over four resonant modes in the telecom band (bandwidth of ~1 THz) and a remarkable pair detection rate of ~620 Hz at a high coincidence-to-accidental ratio of ~80. The source directly creates high-dimensional frequency-bin entangled quantum states (qubits/qudits), as verified by quantum interference measurements with visibilities up to 96% (violating Bell’s inequality) and by density matrix reconstruction through state tomography, showing fidelities of up to 99%. Our approach, leveraging a hybrid photonic platform, enables scalable, commercially viable, low-cost, compact, lightweight and field-deployable entangled quantum sources, quintessential for practical, out-of-laboratory applications such as in quantum processors and quantum satellite communications systems.

KW - physics.optics

KW - physics.app-ph

KW - quant-ph

UR - http://www.scopus.com/inward/record.url?scp=85158153711&partnerID=8YFLogxK

U2 - 10.48550/arXiv.2206.08715

DO - 10.48550/arXiv.2206.08715

M3 - Article

VL - 17

SP - 518

EP - 524

JO - Nature Photonics

JF - Nature Photonics

SN - 1749-4885

IS - 6

ER -