介绍了量子密钥分发(QKD)系统及该系统中的单光子探测器,说明了为降低单光子探测器的暗计数而开发的收发端的激光同步系统。该同步系统由同步激光发射与接收方的激光甄别器组成,详细讲述了其中的同步激光甄别器各部分的制作,包括光电转换器、前置放大器、电压甄别器、电平转换电路4个部分。给出了最终的测试情况,通过长时间的测试实验证实了其工作稳定可靠、甄别性能良好,未发现误触发和漏触发。目前,该同步信号甄别器已成功地应用于量子密钥分发系统中,很好地实现了收发双方的同步,保证了单光子探测器的低暗计数和成码率。

The quantum key distribution (QKD) system and single-photon detector are introduced. For the reduction of the dark counts of the single-photon detector,a synchronized laser system which consists of a synchronized laser of the transmitter and a laser discriminator of the receiver is developed. The method of developing the synchronized laser discriminator including photo electricity translator,preamplifier,voltage discriminator and level translator is shown detailedly. Test results show that the synchronized laser discriminator works stably by long time experiments. Error discrimination and fault discrimination can not be found. Now the synchronized laser discriminator has worked well on the QKD system. Transmitter and receiver are synchronized exactly. The dark counts of the single-photon detector are reduced effectively.