Control Technology Research In Continuous Variable Quantum Key Distribution System

With the ever-increasing development of communication technology, information security has aroused wide concern. Nowadays, information leakage often happen around the society, the current Internet and classic communication network rely on traditional cryptography to ensure the safety of information. With the development of computing level in supercomputer and quantum computer, this structure cannot satisfy people's information demand. In such background, people begin to put more emphasis on quantum private communication. As a new discipline, it aroused widespread concern since it appears. Quantum private communication is an interdisciplinary subject of classic cryptology and traditional information technology, the information security of which is guaranteed by basic physical law such as Heisenberg uncertainty principle and no-cloning theorem. This provides new method to communication and inspires people's enthusiasm in researching and exploring new techniques. Currently, the quantum private communication has made great progress in many aspects, which bring huge hope to information safety in military and business, it has wide potential. In the age of information, with the natural advantages in information security, the quantum communication is widely researched by the government and universities that put a lot of financial and human resources on it.Compared to discrete variable quantum key distribution, as the advantages in low cost, high key rate and good stability, especially the ability of mixing with modern optical network, continuous variable quantum key distribution is drawn much attention. It has much development potential than DV-QKD. The paper mainly focuses on continuous variable quantum key distribution. The main researches are listed as follows:(1) The research on continuous variable quantum key distribution experimental system. Several main modules are introduced respectively. Firstly, the system is divided into several layers, and then we describe the basic function and relationship of optical module, upper monitor and reconciliation module in CV-QKD system.(2) The research on FPGA controlling module in CV-QKD system. To a communication system, the bottom data transmitted passageway is very important, while FPGA controlling module undertake this mission.First of all, the paper introduces main logical resources and the role played by FPGA, and then data and clock controlling are introduced detailedly. Around CV-QKD system, combined with this module, the important status of FPGA controlling module is shown.(3) The research on quantum signal detection and the design on data reception method in CV-QKD system. Signal detection and data reception are two important issues of CV-QKD system, several factors affecting detection effectiveness are introduced. After finishing quantum signal detection, Bob begins to receive data from detector. During this stage, a synchronization technology is described.(4) The paper proposes a new synchronization scheme in continuous variable quantum key distribution system. Aimed at the drawbacks of high-speed continuous variable quantum key distribution system synchronization scheme presented above and combined the good characteristics of m sequence in information technology, we design a different synchronization scheme. After introducing the synchronization mechanism theoretically, the performance is simulated and analyzed. Finally, the drawbacks and advantages in two synchronization schemes are compared.