Experimental wavelength-multiplexed entanglement-based quantum cryptography

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.

Automated summary

The study introduces a strategy utilizing wavelength multiplexing to generate quantum secure keys with the potential to significantly increase the key generation rate. This approach can be applied to various implementations and offers substantial scalability.