Quantum physical-layer secure communication is a communication method that directly realizes classical information transmission between legitimate communicators through quantum channels. It is an important research direction of quantum communication, along with quantum key distribution and secret sharing. Unlike quantum key distribution, in quantum physical-layer secure communication, the communication parties do not need to establish the aforehand key, but directly complete the secure transmission of secret information. Based on the single photon frequency coding technology, our laboratory cleverly uses the statistical characteristics of the modulated photon sequence in the frequency domain to encode information on the spectrum of the photon sequence, thus eliminating the influence of channel loss and noise, and realizing the secure communication of the quantum physical layer under the condition of high noise and high loss. Our research also includes two-field quantum key distribution based on sideband interference. This scheme uses both sides to generate a single sideband through electro-optical modulation, codes the sideband phase, and supplements the sideband phase through the phase difference estimation of the prominent peak to realize efficient sideband interference coding of both communication parties.
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Experimental quantum secure direct communication with single photons. Light: Science & Applications, 5 (9), e16144, 2016.
Security proof of the two-way quantum secure direct communication with channel loss and noise. Europhysics Letters, 129 (1), 10004, 2020.