Wavelength assignment method for inhibition of WDM-QKD system four-wave mixing and Raman scattering noise

Abstract

The present invention discloses a wavelength assignment method for inhibition of WDM-QKD (Wavelength Division Multiplexing-Quantum Key Distribution) system four-wave mixing and Raman scattering noise.Aiming at interference problems in a WDM-QKD system, the spectrum assignment features of the four-wave mixing and Raman scattering noise in the system is fully considered, and a channel interleavingscheme for inhibition of four-wave mixing noise and an optimal channel interval scheme for inhibition of Raman scattering noise are provided so as to achieve combined inhibition of the four-wave mixing noise and the Raman scattering noise, effectively improve the system capacity and save the fiber resource. The method provided by the invention is low in interface and easy to enforce and provides theoretical basis for carrying of quantum signals in the classic light network.

Description

Technical field [0001] This patent relates to the field of quantum communication, in particular to quantum key distribution technology fused with classical optical networks. This scheme mainly provides a feasible wavelength allocation scheme for the co-fiber transmission system of quantum signals and classical signals based on wavelength division multiplexing, which can effectively reduce the interference of four-wave mixing noise and Raman scattering noise on quantum signals. Background technique [0002] Since the quantum key distribution protocol was first proposed in 1984, quantum key distribution technology (Quantum KeyDistribution, QKD) has made major breakthroughs in theory and practice. The longest transmission distance of the QKD system has reached 404km (independent of measurement equipment). QKD system transmission experiment in ultra-low loss optical fiber), the security key generation rate can also reach the Mbps level. As the QKD technology initially possesses prac...

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Problems solved by technology

The Raman scattering noise has a wider spectrum (about 200nm). For the C-band classical and quantum signal multiplexing system, the Raman scattering noise will cover the wavelength of the quantum channel and cause interference to the quantum channel.

Four-wave mixing is a fiber nonlinear effect caused by the disturbance of the refractive index of the fiber during the transmission of the pump signal. This effect will generate noise at a variety of new frequencies. If it is assumed that the frequencies of the three optical channels are f i , f j and f k (k≠i,j), the generated noise frequency satisfies f ijk = f i +f j -f k , if the frequency is equal to the frequency of the quantum channel, the four-wave mixing noise will fall on the quantum channel, thus affecting the performance of the quantum key distribution system

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