Quantum Key Distribution Over Active Telecom Fibres

          @misc{ pirsa_PIRSA:11070069,
            doi = {10.48660/11070069},
            url = {https://pirsa.org/11070069},
            author = {Holloway, Catherine},
            keywords = {},
            language = {en},
            title = {Quantum Key Distribution Over Active Telecom Fibres},
            publisher = {Perimeter Institute},
            year = {2011},
            month = {jul},
            note = {PIRSA:11070069 see, \url{https://pirsa.org}}
          }
          

Abstract

Quantum Key Distribution is a form of public-key cryptography where the security comes from the unique properties of quantum mechanical systems: entanglement and the no-cloning theorem, rather than computational complexity. With increased adoption of fibre optic networks, it may be possible to implement QKD in parallel with classical data traffic. Many research projects have demonstrated QKD over fibre optic networks at the same wavelengths as existing network traffic. These projects require sophisticated noise cancellation due to wave mixing between quantum and classical signals, as well as having to use complex non-silicon based photodiodes. Our research uses lower wavelengths for QKD over active telecom fibres to avoid these problems. Entangled lower-wavelength photons are combined with telecom wavelength laser signals carrying a large amount of traffic, and passed through single mode telecom fibres. We show that data bandwidth usage has a negligible effect on the quantum bit error rate (QBER) and visibility for distances up to 6km. We find key rates of 61 bits per second with QBER rates of 10% at 6km. This research demonstrates the simplicity and applicability of QKD to existing fibre optic infrastructure in corporate, government, and academic campuses.