Quantum cryptography communication system with adaptive transmission distance

Abstract

The invention discloses a quantum cryptography communication system with adaptive transmission distance, including a quantum key transmission system; a communication channel and a quantum key receiving system; An adjustable dispersion management module; when the system is running or the length of the communication optical fiber is replaced, the adjustable dispersion management module is used to dynamically adjust the dispersion compensation amount of the compensated pulse laser, so that the compensation dispersion amount of the pulse laser input into the communication channel and Communication channel fiber introduces a comparable amount of dispersion. The present invention controls the amount of pulse broadening caused by system dispersion through the light source management module, reduces the influence of dispersion on communication distance and communication speed, and at the same time pre-deploys an adjustable dispersion compensation module in the system, which can match the amount of dispersion under different communication distances; By tracking the system bit error rate feedback and dynamically implementing optimal dispersion compensation, it supports quantum secure communication at different distances in laboratories and field tests.

Description

technical field [0001] The invention relates to a quantum communication system, in particular to a quantum cryptography communication system with adaptive transmission distance. Background technique [0002] Quantum information technology has developed rapidly in recent years, and as the most industrially feasible quantum secure communication technology, it has gradually embarked on the road of practical application. With the Beijing-Shanghai trunk line put into use, quantum security communication networks are gradually being established in industries that are sensitive to communication security. For quantum secure communication networks, the most rigid requirements at this stage are higher speed and longer distance, and these two parameters are limited by the influence of fiber dispersion: dispersion causes pulse broadening, which makes it difficult for high-speed systems to restore pulse timing, limiting system speed ; The increase of dispersion with the increase of trans...

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Problems solved by technology

However, such compensation schemes have obvious disadvantages

One is that the amount of dispersion compensation in this scheme is positively correlated with the length of the dispersion compensation fiber, so when the long-distance communication channel introduces a large amount of dispersion, the required DCF length is longer, and the DCF transmission attenuation coefficient is large, which will cause the insertion loss of the entire module to vary with the module compensation. The amount of dispersion increases linearly

The second is that the dispersion coefficient of DCF is about 100-200 ps / km / nm, that is to say, if it is necessary to compensate the communication optical fiber with a transmission length of 100km, a DCF of more than 10km is required. This optical fiber disk is large in size and heavy in weight, which is not conducive to integration into communication equipment , need to be carried independently outside the system

Third, the dispersion compensation amount of each dispersion compensation module is a fixed value. If the practical communication distance changes, the dispersion compensation module of the corresponding length needs to be replaced. A single module does not have universal applicability of distance

However, this solution also faces a problem, that is, the compensation distance of each module is fixed, it does not have the applicability of any distance, and the compensation accuracy cannot be adjusted

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