High-dimensional autocompensating discrete modulation CV-QKD protocol in optical fibers

Abstract

In this work we present a high-dimensional discrete modulated CV-QKD protocol, with dimension 2N , in optical fibers, where N is the number of optical modes. We use N-dimensional product states of weak coherent states that undergo perturbations along optical fibers and that are cancelled in a passive way (autocompensation) and then measured by a standard balanced homodyne detection. We analyze the security of this high-dimensional protocol when an intercept and resend attack is implemented with simultaneous homodyne measurement in both quadratures and the resulting secure key gains are calculated showing a significative increase with dimension.