基于单光子探测及脉冲位置调制的激光通信关键技术研究

为了实现高灵敏度的空间激光通信,并提高传输信道的抗干扰能力,将单光子探测技术和脉冲位置调制技术相结合,采用门控电路与反馈淬灭电路相结合的方式淬灭单光子探测器雪崩,设计了插入帧头法用于脉冲位置调制解调。用现场可编程门阵列进行了脉冲位置调制解调过程的仿真,验证了插入帧头法的有效性与可行性。在此基础上搭建了1 550 nm的脉冲位置调制激光通信实验,同时测试了单光子探测器在不同参数下的性能。结果表明,当探测效率为25%,触发延时为8.00 ns,门宽为5.0 ns,死时间为0.1μs时,单光子探测器性能最佳。最后测试了不同调制速率下单光子探测器的探测灵敏度,结果表明,当通信码速率为1 Mbps时,通信灵敏度为-51.8 dBm;当通信码速率为4 Mbps时,通信灵敏度为-41.0 dBm,实现了高灵敏度的空间激光通信。

Key Technologies of Laser Communication Based on Single Photon Detection and Pulse Position Modulation

In order to achieve high sensitivity space laser communication and improve the anti-interference ability of the transmission channel,this article combines single photon detection technology and pulse position modulation technology,the single photon detector avalanche is quenched by the combination of the gated circuit and the feedback quenching circuit. The insert frame header method was designed to modulate and demodulate the pulse position. The pulse position modulation and demodulation process was simulated by field programmable gate array,which verified the effectiveness and feasibility of the insert frame header method. On this basis,a 1 550 nm pulse position modulation laser communication experiment was built,and the performance of the single photon detector under different parameter was tested at the same time.The results show that the single photon detector has the best performance when the detection efficiency is25%,the trigger delay is 8.00 ns,the gate width is 5.0 ns and the death time is 0.1 μs. Finally,the detection sensitivity of single photon detectors with different modulation rates was tested. The results show that the communication sensitivity is-51.8 dBm when the communication code rate is 1 Mbps;the communication sensitivity is-41.0 dBm when the communication code rate is 4 Mbps,which realizes high sensitivity space laser communication.