空间相干激光通信系统多普勒补偿技术

发布时间：2018-05-18 12:32

本文选题：相干探测 + 零差二进制相移键控　；参考：《长春理工大学》2014年硕士论文

【摘要】：相干探测在灵敏度等诸多方面优于其他探测形式,成为近些年来国内外研发的重点。同时,空间相干光通信涉及到大气链路,受到大气信道的影响,其不同于光纤中的相干光通信系统。通信终端间的快速相对移动所带来的多普勒效应将使系统载波同步受到影响。只需卫星和接收平台间的相对位置等信息从而可预先估计出卫星间的多普勒频移。相干光通信对信号光和本振光的频率和位相关系要求十分严格,光学锁相环(OPLL)可以解决二者相位同步的难题。本文对锁相环组成部分的功能进行了详细的介绍,目的是建立光锁相环数学模型的建立与仿真。最后论文对各种阶跃进行了模拟,指出随机噪声对锁相环的危害。本论文还涉及对本振激光器进行温度和外部输入电压的辅助调节,从而改变激光器的输出频率。最后为频率扫描方式的实现提供了一种自动化运行的方案。最终演示了带有多普勒频移补偿器的通信速率2.5Gbps的相干零差BPSK接收机实验。当发射信号存在频率±7.5GHz变化并得到补偿,采用二进制相移键控调制模式下,当误码率为1E-6情况下,最终接收机的灵敏度为26个光子／比特。
[Abstract]:Coherent detection, which is superior to other detection forms in sensitivity, has become the focus of domestic and international research and development in recent years. At the same time, the spatial coherent optical communication is different from the coherent optical communication system in optical fiber because of the influence of the atmospheric channel. The Doppler effect caused by the rapid relative movement between communication terminals will affect the carrier synchronization of the system. The Doppler shift between satellites can be estimated in advance only by the relative position between the satellite and the receiving platform. Coherent optical communication requires strictly the relationship between frequency and phase of signal and local oscillator, and optical PLL can solve the problem of phase synchronization. In this paper, the function of PLL components is introduced in detail, with the aim of establishing mathematical model and simulation of PLL. Finally, various steps are simulated, and the harm of random noise to PLL is pointed out. This thesis also involves the auxiliary adjustment of temperature and external input voltage of the local oscillator laser to change the output frequency of the laser. Finally, a scheme of automatic operation is provided for the realization of frequency scanning mode. Finally, the coherent homodyne BPSK receiver with Doppler shift compensator is demonstrated. The sensitivity of the final receiver is 26 photons / bits under the binary phase-shift keying modulation mode and when the BER is 1E-6.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1

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