Crosstalk reduction in hybrid quantum-classical networks

Abstract. In this paper, we propose and investigate several crosstalk reduction techniques for hybrid quantum-classical dense-wavelength-division-multiplexing systems. The transmission of intense classical signals alongside weak quantum ones on the same ber introduces some crosstalk noise, mainly due to Raman scattering and non-ideal channel isolation, that may severely aect the performance of quantum key distribution systems. We examine the conventional methods of suppressing this crosstalk noise, and enhance them by proposing an appropriate channel allocation method that reduces the background crosstalk eectively. Another approach proposed in this paper is the usage of orthogonal frequency division multiplexing, which oers ecient spectral and temporal ltering features.