更安全和更实用的测量设备无关量子密钥分发

Although being unconditional secure in principle, the actual security of quantum key distribution (QKD) still depend on physical devices. And measurement device independent quantum key distribution (MDI-QKD) has closed all the security loopholes relevant to detectors. The photon source is not so lucky. The decoy state protocol only beat the photon number splitting attack relevant to weak coherent pulse source. There still many other defects of current photo source of QKD. For example, the modulator may also change the wave spectrum while modulate the intensity or phase. The security of photon source will become hot topic soon. And the experiment on this topic is still rare, despite some theoretical analysis. This project proposes a new method to characterize the time evolution of intensity and wave spectrum in a single pulse of QKD photon source, so that can estimate information leaking of photon source. With this new method, we could find out the photon source that more suitable for practical long distant MDI-QKD. The synchronization and PMD compensation based on free running single photon detector is also proposed by this project, with the vision to simplify the MDI-QKD receiver design, and to make the MDI-QKD more secure and more practical.

虽然原理上量子密钥分发（QKD）是无条件安全的，但在目前的技术水平下其安全性还和具体的实现装置相关。测量装置无关量子密钥分发（MDI-QKD）方案的提出，彻底关闭了探测器的安全漏洞。然而光子源却没有那么幸运，诱骗态协议只是解决了弱相干光源的分光攻击威胁，还存在很多其它隐患。比如调制器在改变强度或者相位时，可能也同时悄悄地改变了波长等其它维度上的信息，从而导致信息泄露。预计光源安全性很快会成为研究热点。虽然这方面已经有一些理论研究，但实验上的工作还较少。本项目提出一种能够逐比特分析光脉冲的强度和波长随时间变化的方法，测试各种弱相干光子源方案的信息泄露情况，找出最适合应用于实用化长距离MDI-QKD的候选者，同时研究基于自由运行单光子探测器时间同步和偏振补偿方案，简化MDI-QKD接收方的设计，期望使MDI-QKD更加安全和实用。

虽然原理上量子密钥分发（QKD）是无条件安全的，但在目前的技术水平下其安全性还和具体的实现装置相关。测量装置无关量子密钥分发（MDI-QKD）方案的提出，彻底关闭了探测器的安全漏洞。然而光子源却没有那么幸运，诱骗态协议只是解决了弱相干光源的分光攻击威胁，还存在很多其它隐患。比如调制器在改变强度或者相位时，可能也同时悄悄地改变了波长等其它维度上的信息，从而导致信息泄露。因而，相对于经典通信，量子通信对光源驱动电路有更高的要求。本项目设计了一种高速多幅度的强度调制器驱动电路，并研究量子通信应用下的注入锁定光源，目标是使MDI-QKD更加高速、安全和实用。