Multichannel parallel continuous variable quantum key distribution method based on optical frequency comb

Abstract

The invention discloses a multichannel parallel continuous variable quantum key distribution method based on an optical frequency comb. The method comprises the steps that a sending end generates theoptical frequency comb as a multi-wavelength source; enabling the optical frequency comb to form a plurality of sub-channels through a demultiplexer; independent amplitude modulation and phase modulation are carried out on each sub-channel, and then the sub-channels are combined through a multiplexer and sent to a receiving end; the receiving end generates a local optical frequency comb, and demultiplexes the local optical frequency comb and the received signal; and the sender and the receiver perform post-processing according to the demultiplexing signal and complete final key distribution. According to the invention, a pair of optical frequency combs is used for transmitting a key for parallel transmission and coherent reception, the channel density of a wavelength division multiplexingsystem is higher, and the carrier recovery process is simpler than that of an independent laser; the key rate of the CVQKD system can be greatly improved; the method is high in reliability, good in practicability, easy to implement and high in key rate.

Description

technical field [0001] The invention belongs to the field of quantum communication, and in particular relates to a multi-channel parallel continuous variable quantum key distribution method based on an optical frequency comb. Background technique [0002] One of the most famous applications of quantum cryptography is quantum key distribution (QKD), which allows two distant parties to establish a public key in an untrusted environment. Both discrete variable quantum key distribution (DV-QKD) based on single photon detection and continuous variable quantum key distribution (CV-QKD) based on coherent detection have achieved remarkable achievements. The former encode key information as properties of individual photon pulses, which can be limited by the detection speed and efficiency of individual photon detectors. Fortunately, CVQKD can get rid of this limitation by encoding information on continuous variables, such as the orthogonal number of electromagnetic field patterns. T...

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Problems solved by technology

OFDM has the advantages of strong resistance to multipath fading and high spectrum utilization, but most of OFDM currently requires Fast Fourier Transform (FFT) or equivalent functions to realize the multiplexing and demultiplexing process, which is affected by the digital signal Processor processing speed limitation

WDM systems are known for being able to transmit hundreds of carriers of different wavelengths in parallel in a single fiber, however, using these systems requires a large number of laser sources in the transmitter and complex digital signal processing (DSP) for frequency and Phase estimation is inconvenient to use, difficult to implement, and takes up more resources

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