一种基于确定性量子密钥分发误码判据的相位调制器半波电压的精确测定方法

基于相位编码的量子密钥分发系统需要对信息加载的相位调制器的半波电压进行精确的测定以减小量子密钥的误码率,相位调制器半波电压的测量精度直接影响到了量子密钥分发系统的最终误码.本文提出了一种基于确定性量子密钥分发误码率判据的相位调制器半波电压的精确测定方法,所采用相位调制器的半波电压的测量精度达到了2 mV,实验结果表明这种方法可以用于量子密钥分发实际应用系统中实时获得不同条件下的行波相位调制器的半波电压以最大程度地减小由于相位信息不准确加载而带来的系统误码. 关键词： 量子保密通信 相位编码 半波电压 误码率

A new differential phase shift quantum key distribution system with Faraday-Michelson interferometer

A new differential phase shift quantum key distribution system based on the intensity modulator with Faraday-Michelson interferometer is demonstrated experimentally. Some technologies are employed to improve the performance of the quantum key distribution system. These technologies include the clock generation technology of arbitrary frequency by a small scale frequency-split and phase locked loop scheme, the new method to acquire the half-wave voltage of the phase modulator with a high accuracy in the condition of the single photon count, and the auto-compensated polarization technology by the Faraday-Michelson interferometer. Finally, the quantum key distribution is achieved with a quantum bit error rate of 3.9% when the transmission distance reaches 50 km.