DWDM-BASED QUANTUM AND CLASSICAL HYBRID TRANSMISSION SYSTEM AND NOISE PROCESSING METHOD

摘要

Provided in the present invention is a DWDM-based quantum and classical hybrid transmission system, comprising quantum signal sending ends, quantum signal receiving ends, DWDMs, classical signal transceivers, attenuators, opto-isolators, and narrow band filters. In the noise processing method, primarily considered is the fact that during hybrid transmission, the enormous difference in power between a strong classical signal and a weak quantum signal introduces background noise, primarily comprising Raman scattering, four-wave mixing, and crosstalk from non-ideal channel spacing. Provided is an unequally spaced wavelength division method, in principle eliminating the influence of four-wave mixing. Use of opto-isolators eliminates the backwards Raman scattering that greatly impacts QKD systems. The present method features a simple design, and compared to traditional noise processing methods, the present noise processing solution allows the total key rate of quantum channels to be improved; or, under a condition of a set key rate, allows the quantity of QKD users supported to be maximized.