Wavelength assignment in quantum access networks with hybrid wireless-fiber links

Abstract

We propose a low-complexity near-optimal wavelength allocation technique for\nquantum key distribution access networks that rely on wavelength division\nmultiple access. Such networks would allow users to send quantum and classical\nsignals simultaneously on the same optical fiber infrastructure. Users can be\nconnected to the access network via optical wireless or wired links. We account\nfor the background noise present in the environment, as well as the Raman noise\ngenerated by classical channels, and calculate the secret key generation rate\nfor quantum channels in the finite-key setting. This allows us to examine the\nfeasibility of such systems in realistic scenarios when the secret key exchange\nneeds to be achieved in a limited time scale. Our numerical results show that,\nby proper choice of system parameters for this noisy system, it is possible to\nexchange a secret key in tens of seconds. Moreover, our proposed algorithm can\nenhance the key rate of quantum channels, especially in high noise and/or high\nloss regimes of operation.\n