自由空间量子密钥分发中信号发生与处理方案

A scheme for random signal production and processing in free-space quantum key distribution

针对自由空间量子密钥分发系统中的随机信号发生及数据采集这一难题,提出了一种利用在LabVIEW环境下开发的虚拟仪器程序来控制数字I/O板卡的解决方案.发送端利用程序控制高速数字输入/输出板卡,产生随机信号用于实现光子路径的随机选择.接收端采用缓冲周期测量的计数方式,采用两个计数器记录两路随机信号的信息,通过程序来完成对计数器板卡的控制,将采集到的数据保存在两个本地文件中,以用于后续的数据处理分析.本方案具有易于开发和调试、维护方便、应用灵活、成本低等优点,已经成功用于基于B92协议的自由空间量子密钥分发系统中.

A solution is proposed to the random signal production and data acquisition in free-space quantum key distribution system. We advance a method to control the digital I/O board by utilizing virtual device programs developed under the LabVIEW environment. The transmitter, using such software to control high-speed digital I/O board, generates random signals to realize the random choices of optical paths. The receiver adopts a counting method called buffer-period-measurement, which needs to record the information of two random signals by two counters, to control the counter board by programs, then to save the acquired data on respective two local files for the future processing and analysis. This scheme, with very low expenditures, is easy to develop and debug, convenient to maintain and flexible in use. It has been successfully applied in the B92 free space quantum QKD system.