摘要
Loss is inevitable for the optical system due to the absorption of materials, scattering caused by the defects, and surface roughness. In quantum optical circuits, the loss can not only reduce the intensity of the signal, but also affect the performance of quantum operations. In this work, we divide losses into unbalanced linear losses and shared common losses, and provide a detailed analysis on how loss affects the integrated linear optical quantum gates. It is found that the orthogonality of eigenmodes and the unitary phase relation of the coupled waveguide modes are destroyed by the loss. As a result, the fidelity of single-and two-qubit operations decreases significantly as the shared loss becomes comparable to the coupling strength. Our results are important for the investigation of large-scale photonic integrated quantum information processes.
Loss is inevitable for the optical system due to the absorption of materials, scattering caused by the defects, and surface roughness. In quantum optical circuits, the loss can not only reduce the intensity of the signal, but also affect the performance of quantum operations. In this work, we divide losses into unbalanced linear losses and shared common losses, and provide a detailed analysis on how loss affects the integrated linear optical quantum gates. It is found that the orthogonality of eigenmodes and the unitary phase relation of the coupled waveguide modes are destroyed by the loss. As a result, the fidelity of single-and two-qubit operations decreases significantly as the shared loss becomes comparable to the coupling strength. Our results are important for the investigation of large-scale photonic integrated quantum information processes.
作者
Ming Li
Changling Zou
Guangcan Guo
Xifeng Ren
李明;邹长铃;郭光灿;任希锋(Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China Synergetic Innovation Center of Quantum Information ＆： Quantum Physics, University of Science and Technology of China, Hefei 230026, China)
基金
supported by the National Natural Science Foundation of China(Nos.11374289,61590932,and 61505195)
the National Key R&D Program(Nos.2016YFA0301700 and 2016YFA0301300)
the Innovation Funds from the Chinese Academy of Sciences(No.60921091)
the Fundamental Research Funds for the Central Universities
the Open Fund of the State Key Laboratory on Integrated Optoelectronics(IOSKL2015KF12)
