基于被动锁模光纤激光器的自相似脉冲产生与传输理论研究

发布时间：2018-05-19 19:45

本文选题：被动锁模光纤激光器 + 自相似脉冲　；参考：《吉林大学》2016年博士论文

【摘要】：目前,光纤通信系统中最常用的信息载体是光孤子。光孤子可以在反常色散光纤中实现保形传输,但是光孤子的单脉冲能量受到非线性效应的限制,光能量无法发挥很高的水平,虽然传输中受到的损耗很小,但是在实际传输过程中需要在一定的传输距离后对光孤子进行中继放大。要实现光纤通信系统的远距离无中继传输,需要从系统光源和传输信道两方面入手,对现有系统进行改进。本文针对以上两个问题,分别对自相似锁模光纤激光器和自相似脉冲在光纤中的传输过程进行了研究,主要完成了以下几个方面的研究工作:1、对被动锁模掺镱光纤激光器输出自相似脉冲的色散范围和特性进行了仿真研究。数值分析了激光器腔内净色散、饱和增益能量和有限增益带宽等对输出自相似脉冲的脉宽、峰值功率等参数的影响。对激光器输出自相似脉冲进行了定量研究。2、对被动锁模光纤激光器内自相似脉冲对的相互作用机理进行了探索性的研究。实验结果表明,这种脉冲相互作用的现象首先取决于脉冲对间的间隔距离,距离越近作用越明显;其次,这种作用的强度也与增益饱和能量、腔内整体色散有关,表现出脉冲的排斥远离或脉冲的吸引碰撞。通常情况下,当脉冲距离与脉冲宽度相比很大的时候,脉冲间的作用力就已经很小,可以忽略不计。相反,在本文中,自相似脉冲的作用力范围要远远大于这个范围。从实验结果中可以看出,在脉冲宽度为1ps,脉冲间距离为20ps的情况下仍然存在着相互作用力。自相似脉冲对间的相互作用还与增益带宽有关,较大的增益带宽条件下的作用力更大。3、对自相似脉冲和自相似脉冲对在单模光纤中的传输过程进行了详细研究。研究表明,单一色散光纤并不能支持自相似脉冲和自相似脉冲对的保形传输。通过使用色散管理技术,可以实现这一点。本文对色散管理光纤的色散分布和长度进行了适当调整,定量分析了以上两种参数对自相似脉冲传输过程中的波形、能量、脉宽和谱宽等因素的影响,找到了其中的规律。这部分结论对远距离无中继光通信系统有一定的学术意义。通过对上述问题的研究,本文取得了以下几个方面的成果:1、建立了被动锁模光纤激光器的数学模型,提出了一种产生自相似脉冲的光纤激光器结构。开创性地对光纤激光器中自相似脉冲对的相互作用情况进行了研究,分析了内在的作用机制,指出非线性相移在自相似脉冲间的作用中起主导作用,找到抑制非线性相移的方法就可以减小脉冲间的作用。研究结果将对实际自相似锁模激光器的实验研究和优化设计提供理论参考;2、利用非线性薛定谔方程,对自相似脉冲和自相似脉冲对在光纤中的传输理论进行了研究。在单一色散光纤无法支持自相似脉冲保形传输的情况下,提出了一种利用色散管理光纤实现自相似脉冲远距离保形传输的方法。仿真结果证明,使用色散管理光纤作为自相似脉冲的传输介质要远远优于单一色散光纤和常见的色散渐减光纤。这部分结论对实现远距离无中继光通信系统有一定的指导意义,并将促进自相似脉冲在光纤通信系统中的应用。
[Abstract]:At present, the most commonly used information carrier in optical fiber communication system is optical soliton. The optical soliton can achieve conformal transmission in the anomalous dispersion fiber, but the single pulse energy of the optical soliton is limited by the nonlinear effect, and the light energy can not play a very high level. Although the loss is very small in the transmission, it needs to be transmitted in the actual transmission process. In order to realize the long distance and non relay transmission of the optical fiber communication system, we need to improve the existing system from the two aspects of the system light source and transmission channel. In this paper, the self similar mode locked fiber laser and the self similar pulse transmission in the optical fiber are carried out for the above two problems. The main research work is completed. 1, the dispersion range and characteristics of the passive mode locked ytterbium doped fiber laser output self similar pulse are simulated. The pulse width and peak of the output self similar pulse are analyzed by the numerical analysis of the net dispersion, the saturation gain energy and the limited gain bandwidth. The influence of the value power and other parameters. A quantitative study of the laser output self similar pulse is carried out. The interaction mechanism of the self similar pulse pair in a passive mode locked fiber laser is explored. The experimental results show that the phenomenon of the pulse interaction depends first on the interval distance between the pulse pairs, the closer the distance is, the closer the effect is to the.2 pulse. The more obvious it is; secondly, the strength of the action is also related to the gain saturation energy, the overall dispersion of the cavity, showing the pulse's exclusion or pulse attraction collision. Generally, when the pulse distance is large compared to the pulse width, the force between the pulses is very small and can be ignored. On the contrary, in this paper, self similar pulse is taken. The interaction force of the impulse is far greater than that in this range. It can be seen from the experimental results that the interaction force still exists when the pulse width is 1ps and the distance between the pulses is 20ps. The interaction between the self similar pulses is also related to the gain bandwidth, and the force under the larger gain bandwidth is more.3, and the self similar pulse is used. The transmission process of the self similar pulse in the single mode fiber is studied in detail. The study shows that the single dispersion fiber does not support the conformal transmission of the self similar pulse and the self similar pulse pairs. The dispersion management technique can be used to achieve this point. The dispersion distribution and length of the dispersion managed fiber are properly adjusted in this paper. The influence of the above two parameters on the waveform, energy, pulse width and spectrum width of the self similar pulse transmission is quantitatively analyzed, and the rules are found. This conclusion has some academic significance for the long distance non medium relay communication system. Through the study of the above problems, the following achievements are obtained in this paper: 1 The mathematical model of a passive mode locked fiber laser is set up. A self similar pulse fiber laser structure is proposed. The interaction of self similar pulse pairs in the fiber laser is studied and the internal mechanism is analyzed. It is pointed out that the nonlinear phase shift plays a leading role in the function of self similar pulses. Finding a method to suppress the nonlinear phase shift can reduce the effect of the pulse. The results will provide a theoretical reference for the experimental research and optimization of the actual self similar mode locked laser. 2, the theory of the transmission theory of self similar pulse and self similar pulse in the optical fiber is studied by using nonlinear Schrodinger equation. When fiber can not support the self similar pulse conformal transmission, a method of realizing the self similar pulse long distance preserving transmission by using dispersion managed fiber is proposed. The simulation results show that the dispersion managed fiber as a self similar pulse transmission medium is far superior to the single dispersion fiber and the common dispersion decreasing fiber. The conclusion has some guiding significance for realizing long-distance non repeater optical communication system, and will promote the application of self similar pulse in optical fiber communication system.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN248

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