宽带光锁相环技术研究

发布时间：2018-04-29 07:14

  本文选题：科斯塔斯光锁相环 + 环路滤波器　； 参考：《电子科技大学》2014年硕士论文

【摘要】：星际自由空间的信息传输要求通信系统能够实现更宽的带宽,更高的数据传输速率和更长的传输距离。与传统的微波通信相比,激光通信具有更大的优势。例如,相干光通信技术可以提高系统的接收灵敏度,增强信号传输的抗干扰能力,非常适合信号的长距离传输,常用于自由空间光通信领域。其中,光锁相环是相干光通信的关键技术,它能实现本振光与信号光的相位同步,具有很大的研究价值。本文针对1064nm BPSK零差相干光通信系统,以宽带光锁相环为研究课题,重点关注光锁相环的捕获性能,希望能够快速地捕获较大的激光差频,本文的主要内容分为以下四个部分:1.介绍了光锁相环技术的研究背景,概述了国内外光锁相环的研究动态;以科斯塔斯光锁相环为结构基础,分析了光锁相环的工作原理,并分别对光锁相环的核心部件及其涉及的关键技术,包括高性能窄线宽的可调激光器,90°光混频器,环路滤波器以及频率辅助捕捉技术,进行了具体的分析。2.对科斯塔斯光锁相环系统进行拉普拉斯域的线性模型分析,通过数学计算和理论推导,设计了一组适合本课题的光锁相环参数;应用Matlab/Simulink软件对科斯塔斯光锁相环系统进行仿真实验研究,仿真实验表明科斯塔斯光锁相环能在80 ms以内捕获1MHz的激光差频,而对100MHz的激光差频就需要很长的时间,验证了光锁相环需要增添辅助频率捕获模块的必要性。通过改变科斯塔斯光锁相环的结构,提出了一种扫描方案来加快频率捕获过程。改进后的仿真系统成功实现了50ms内对7MHz差频的捕获。3.通过比较NPRO激光器温度调谐与PZT调谐的特点,课题先对NPRO激光器温度调谐,使得信号光与本振光的差频处于PZT调谐范围内,再利用PZT调谐实现快速锁相。采用MAX1978芯片设计了NPRO激光器的自动温度控制电路,实验测试该温控系统的温控精度高达0.01℃,温控后信号光与本振光平衡探测后的差频电信号输出波形相对稳定,其频率虽在不断波动,但处于60MHz以内。4.介绍了宽带光锁相环的鉴频捕获原理,并以STC89C51RC单片机为控制核心,设计了宽带鉴频捕获电路。实验测得光锁相环本身的捕捉带为600kHz,锁定状态持续时间约为16 min;而在增添鉴频捕获模块后,环路能够在1 s内快速捕获±60MHz的差频信号,并且此后的锁相状态能持续152 s左右。
[Abstract]:The information transmission of the interstellar free space requires that the communication system can achieve wider bandwidth, higher data transmission rate and longer transmission distance. Compared with the traditional microwave communication, the laser communication has a greater advantage. For example, coherent optical communication technology can improve the receiving sensitivity of the system and enhance the anti-interference ability of the signal transmission. The long distance transmission is very suitable for the signal. It is often used in the field of free space optical communication. In which the optical phase locked loop is the key technology of coherent optical communication. It can synchronize the phase of the light and the signal light. This paper focuses on the 1064nm BPSK zero difference coherent optical communication system, and focuses on the wide-band optical phase locked loop. The main contents of this paper are divided into four parts: 1. the research background of optical phase locked loop is introduced, and the research trends of optical phase locked loop at home and abroad are summarized. The working principle of the optical phase locked loop is analyzed based on the kastas optical phase locked loop. The key components of the optical phase locked loop and the key technologies involved, including the adjustable laser with high performance narrow linewidth, 90 degree optical mixer, loop filter and frequency assisted capture technology, are analyzed by.2.. The linear model of the Laplasse domain is analyzed by the Kostas optical phase locked loop system, and the mathematical calculation and the mathematical calculation are carried out. A set of optical phase locked loop parameters suitable for this subject are designed, and the simulation experiment of the costar optical phase locked loop system is carried out with Matlab/Simulink software. The simulation experiment shows that the costar optical phase locked loop can capture 1MHz laser difference frequency within 80 ms, while the laser difference frequency of 100MHz needs a long time, and the light is verified. The phase-locked loop needs to add the necessity of the auxiliary frequency capture module. By changing the structure of the costar optical lock loop, a scanning scheme is proposed to speed up the frequency capture process. The improved simulation system successfully realizes the characteristics of the 7MHz difference frequency acquisition in 50ms by comparing the temperature tuning of the NPRO laser and the tuning of the PZT. The temperature tuning of the NPRO laser makes the difference frequency between the signal light and the local oscillator in the PZT tuning range, and then uses the PZT tuning to realize the rapid phase lock. The MAX1978 chip is used to design the automatic temperature control circuit of the NPRO laser. The temperature control precision of the temperature control system is up to 0.01 C. After the temperature control, the signal light and the local vibration light balance are detected. The frequency of the differential frequency signal is relatively stable, although its frequency is constantly fluctuating, but within 60MHz,.4. introduces the principle of frequency discrimination capture of broadband optical phase locked loop, and designs a broadband frequency discrimination capture circuit with STC89C51RC single chip as the control core. The experiment results that the capture band of the light locked loop is 600kHz, and the lock state duration is about time. For 16 min, and after adding the frequency acquisition module, the loop can quickly capture the difference frequency signal of + 60MHz in 1 s, and thereafter the phase-locked state can last around 152 s.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1

【参考文献】

中国期刊全文数据库 前1条

1 徐东明;相干光通信的实用化研究[J];西安邮电学院学报;1996年01期

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