Integrated sources of multiphoton entanglement

Yunxia Dong, Xiangdong Zhang

A rigorous quantum theory for the generation of multiphoton entangled states based on two consecutive three-frequency interactions of waves in a one-dimensional nonlinear photonic crystal is developed using the field expansion and differentiation methods. The three-photon correlation coefficient and the average photon numbers generated in the structure are calculated. All order expansion terms are included in the calculation. The generation conditions for multiphoton entangled states in such a structure are also analyzed. It is shown that the created photons in the present structures obey the super-Poisson statistics at the interacting frequencies and are in a multiparticle entangled state. This means the nonlinear photonic crystal can be applied as a highly efficient source of an entangled multiphoton for highly integrated all-optical circuits.

Climério Paulo da Silva Neto

Sascha Gaertner, Mohamed Bourennane, Manfred Eibl +2 more

Ming Zhang, Lan‐Tian Feng, Zhiyuan Zhou +7 more

Multiphoton entanglement plays a critical role in quantum information processing, and greatly improves our fundamental understanding of the quantum world. Despite tremendous efforts in either bulk media or fiber-based devices, nonlinear interactions in integrated circuits show great promise as an excellent platform for photon pair generation with its high brightness, stability and scalability \cite{Caspani2017}. Here, we demonstrate the generation of bi- and multiphoton polarization entangled qubits in a single silicon nanowire waveguide, and these qubits directly compatible with the dense wavelength division multiplexing in telecommunication system. Multiphoton interference and quantum state tomography were used to characterize the quality of the entangled states. Four-photon entanglement states among two frequency channels were ascertained with a fidelity of $0.78\pm0.02$. Our work realizes the integrated multiphoton source in a relatively simple pattern and paves a way for the revolution of multiphoton quantum science.

Xiaoyuan Liu, Mu Ku Chen, Yongfeng Wu +5 more

We demonstrate a 100-path entangled photon-pair source by integrating a meta-lens array with a nonlinear crystal, which shows promise for quantum-optical technologies with high-dimensional entanglement and multiphoton-state generation.

Nicolas Gisin, John Rarity, Gregor Weihs