Effect of unbalanced and common losses in quantum photonic integrated circuits

Ming Li; Changling Zou; Guangcan Guo; Xifeng Ren

doi:doi:10.3788/COL201715.092701

Chinese Optics Letters, 2017, 15 (9): 092701, Published Online: Jul. 19, 2018

Effect of unbalanced and common losses in quantum photonic integrated circuits Download： 1083次

Ming Li ^1,2Changling Zou ^1,2Guangcan Guo ^1,2Xifeng Ren ^1,2,*

Author Affiliations

¹ Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China

² Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China

Figures & Tables

Fig. 1. Eigenmodes of coupled waveguides. (a) A schematic of a directional coupler. (b) The cross-section electric field distributions of the eigenmodes for different cases. From the left column to right, the pictures correspond to the (i) ideal case $γ_{1,} = γ_{2}$ , (ii) $γ_{1} \neq γ_{2}$ , and material 3 is lossless, (iii) $γ_{1} = γ_{2}$ and material 3 is absorptive. For the left and right case, the two eigenmodes are orthogonal and the overlap is zero. For the middle case, the overlap of the two modes is positive.

下载图片查看原文

Fig. 2. (Color online) Two coupled waveguides with an unbalanced linear loss. (a) By injecting a single photon in port 1 in Fig. 1(a), the hopping probability to the outputs are plotted. Blue line: port 1. Red line: port 2. The inset shows the relative intensity eliminating the global damping factor. We set $C = 0.01 k_{0}$ and $Δ γ = 0.01 k_{0}$ . (b) The mode overlap ${| 〈 + | - 〉 |}^{2}$ of the two eigenmodes. (c) The real (blue) and imaginary (red) part of the difference between $β_{+}$ and $β_{-}$ . The cross point is the exceptional point. (d) $L_{0}$ is the minimum coupling length to achieve 1:1 splitting. (e). Two-photon quantum interference visibility on an ideal BS with $C = 0.01 k_{0}$ . (f) Two-photon quantum interference visibility on a BS with unbalanced linear loss as a function of the coupling length. $C = 0.01 k_{0}$ and $Δ γ = 0.01 k_{0}$ . In all the figures, the units of C and $γ_{i}$ are the free-space wave vector $k_{0}$ . We set $C = 0.01 k_{0}$ for all the cases.

下载图片查看原文

Fig. 3. (Color online) Single-photon and two-photon interference on a BS with shared CL. (a) Relative probability in two waveguides with single-photon input. (b) The mode overlap ${| 〈 + | - 〉 |}^{2}$ of the two eigenmodes. (c) The real and imaginary part of $β_{+} - β_{-}$ . (d) The visibility of two-photon quantum interference. The visibility becomes negative and approaches $- 1$ as the coupling region becomes longer. Here we set the damping rate the waveguides $γ = 0.001 k_{0}$ , $C_{1} = 0.01 k_{0}$ , and $C_{2} = 0.0005 k_{0}$ .

下载图片查看原文

Fig. 4. (Color online) Fidelity of quantum gates formed by a BS with shared loss. All quantum gates are decomposed to BSs and phase shifters and we assume the phase shifters are ideal. The fidelity is the minimum value searched through all input quantum states. (a) The gate fidelity for a BS, single-qubit operation, and quantum C-NOT gate. (b) The minimum fidelity for any two-qubit gate and any two-qubit quantum state. In the calculations, $C_{1} = 0.01 k_{0}$ .

下载图片查看原文

Ming Li, Changling Zou, Guangcan Guo, Xifeng Ren. Effect of unbalanced and common losses in quantum photonic integrated circuits[J]. Chinese Optics Letters, 2017, 15(9): 092701.

Effect of unbalanced and common losses in quantum photonic integrated circuits Download： 1083次

关于本站 Cookie 的使用提示

全站搜索

Effect of unbalanced and common losses in quantum photonic integrated circuits Download： 1083次

相关论文

相关资讯

关于本站 Cookie 的使用提示

全站搜索