Quantum key distribution coexists with classical communication over the nanopore-assisted weakly coupled few-mode fiber

In this paper, the theoretical model of spontaneous Raman scattering (SpRS) in a few-mode fiber (FMF) is discussed. It evaluates the impact of SpRS on FMF-based quantum key distribution (QKD) by integrating wavelength division multiplexing (WDM) and space division multiplexing (SDM) techniques. To effectively suppress the interference of classical signal-induced noise on quantum signals, we propose a nanopore-assisted FMF, which significantly reduces the complexity of mode coupling and notably enhances the signal transmission distance of the system. Through numerical analysis, the transmission performance of quantum signals under different numbers of wavelengths and channel mode configurations is assessed, with the transmission distance increased by nearly 50% at maximum.