Abstract

A hybrid quantum network using multicore fibers, that supports both classical and quantum communications is implemented. Commercially available Quantum Key Distribution (QKD) systems were tested for loss tolerance, vulnerability to direct injection attacks, and the ability to generate secret keys in the presence of co-propagating classical communications was investigated. The loss of visibility, increase in the quantum bit error rate, and failure to generate secret keys is observed when an externally injected optical power typically exceeds -26 dBm. The dependence of the QKD operational vulnerability on copropagating signal wavelengths and implications for hybrid communications are discussed.

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