高速脉冲位置调制对SNSPD 探测光子计数特性影响(特邀)

Photocount Characteristics of SNSPD for PPM Signals inDeep-Space Laser Communication (Invited)

激光通信是近年深空探测领域的研究热点之一。深空激光通信采用脉冲位置调制(PPM)提升通信能量效率,并使用单光子探测器以高效地接收信号。其中,超导纳米线单光子探测器(SNSPD)被广泛认可是最优选择之一。本文分析了SNSPD的死时间和抖动特性,以及高速脉冲信号的拖尾现象,对基于PPM-SNSPD调制探测方式的深空激光通信产生的影响,并计算了SNSPD在该体系下的光子计数特性。基于分析,提出一种偏移补偿保护时隙PPM符号同步算法。相较普通的保护时隙同步算法,所提算法能有效减少PPM-SNSPD体系下的同步误差,提升系统误码率。

Deep-space laser communication systems commonly use pulse-position modulation(PPM)to improve the energy efficiency of communication and use single-photon detectors for efficient signal reception.In particular,superconducting nanowire single-photon detectors(SNSPD)are one of the most suitable detector choices.In this study,we investigated the performance of high-speed PPM-SNSPD-based deep-space laser communications in terms of the dead time and jitter of SNSPD as well as the trailing phenomenon of high-speed pulsed signals.The photocount characteristics of SNSPD were analyzed.Based on this analysis,we proposed a bias-compensated guard-time PPM symbol synchronization algorithm.Compared with the conventional guard-time symbol synchronization algorithm,the proposed algorithm effectively reduces synchronization errors and improves system error performance.