In state-of-the-art quantum key distribution systems, the main limiting factor in increasing the key generation rate is the timing resolution in detecting photons. Here, we present and experimentally demonstrate a strategy to overcome this limitation, also for high-loss and long-distance implementations. We exploit the intrinsic wavelength correlations of entangled photons using wavelength multiplexing to generate a quantum secure key from polarization entanglement. The presented approach can be integrated into both fiber- and satellite-based quantum-communication schemes, without any changes to most types of entanglement sources. This technique features a huge scaling potential allowing to increase the secure key rate by several orders of magnitude as compared to non-multiplexed schemes.

在最先进的量子密钥分发系统中，提高密钥生成率的主要限制因素是检测光子的时间分辨率。在这里，我们提出并通过实验证明了一种克服这一限制的策略，也适用于高损耗和长距离实现。我们利用波长多路复用来利用纠缠光子的固有波长相关性，从偏振纠缠中生成量子安全密钥。所提出的方法可以集成到基于光纤和卫星的量子通信方案中，而无需对大多数类型的纠缠源进行任何更改。与非多路复用方案相比，该技术具有巨大的扩展潜力，允许将安全密钥率提高几个数量级。