Appl Opt. 2023 May 1;62(13):3284-3288. doi: 10.1364/AO.489154.
We explore the suitability of a virtually imaged phased array as a spectral-to-spatial mode-mapper (SSMM) for applications in quantum communication such as a quantum repeater. To this end, we demonstrate spectrally resolved Hong-Ou-Mandel (HOM) interference with weak coherent states (WCSs). Spectral sidebands are generated on a common optical carrier, and WCSs are prepared in each spectral mode and sent to a beam splitter followed by two SSMMs and two single-photon detectors, allowing us to measure spectrally resolved HOM interference. We show that the so-called HOM dip can be observed in the coincidence detection pattern of matching spectral modes with visibilities as high as 45% (maximum 50% for WCSs). For unmatched modes, the visibility drops significantly, as expected. Due to the similarity between HOM interference and a linear-optics Bell-state measurement (BSM), this simple optical arrangement figures as a candidate for the implementation of a spectrally resolved BSM. Finally, we simulate the secret key generation rate using current and state-of-the-art parameters in a measurement-device-independent quantum key distribution scenario and explore the trade-off between rate and complexity of a spectrally multiplexed quantum communication link.
我们探讨了虚拟成像相控阵作为光谱-空间模式映射器（SSMM）的适用性，用于量子通信应用，如量子中继器。为此，我们演示了具有弱相干态（WCS）的光谱分辨 Hong-Ou-Mandel（HOM）干涉。光谱边带在公共光载波上产生，WCS 在每个光谱模式中制备，并发送到分束器，然后通过两个 SSMM 和两个单光子探测器，使我们能够测量光谱分辨的 HOM 干涉。我们表明，在匹配光谱模式的符合检测模式中可以观察到所谓的 HOM 凹陷，可见度高达 45%（WCS 的最大可见度为 50%）。对于不匹配的模式，可见度会显著下降，这是预期的。由于 HOM 干涉与线性光学 Bell 态测量（BSM）之间的相似性，这种简单的光学装置可作为实现光谱分辨 BSM 的候选方案。最后，我们在一种测量设备无关的量子密钥分发场景中使用当前和最先进的参数模拟了密钥生成速率，并探讨了光谱复用量子通信链路的速率和复杂性之间的权衡。
