Chen Tian, Li Ke, Zuo Yuan, Zhu Bing
Appl Opt. 2018 Feb 1;57(4):817-822. doi: 10.1364/AO.57.000817.
We present a quantum receiver for quadrature amplitude modulation (QAM) coherent-state discrimination with the homodyne-displacement hybrid structure. Our strategy is to carry out two successive measurements on parts of the quantum states. The homodyne result of the first measurement reveals partial information about the state and is forwarded to a displacement receiver, which finally identifies the input state by using feedback to adjust a reference field. Theoretical analysis and numerical simulation results show that for 16-QAM, the hybrid receiver could outperform the standard quantum limit using only on-off single-photon detectors with a reduced number of signal-state partitions, showing great potential toward implementing the receiver practically.
我们展示了一种用于正交幅度调制（QAM）相干态判别、具有零差 - 位移混合结构的量子接收器。我们的策略是对量子态的部分进行两次连续测量。第一次测量的零差结果揭示了关于该态的部分信息，并被转发到一个位移接收器，该接收器最终通过使用反馈来调整参考场来识别输入态。理论分析和数值模拟结果表明，对于16 - QAM，该混合接收器仅使用开 - 关单光子探测器，通过减少信号态分区数量，就能超越标准量子极限，在实际实现该接收器方面显示出巨大潜力。
