耦合飞秒光孤子的相互作用研究

发布时间：2018-04-10 03:01

本文选题：耦合光孤子　切入点：相互作用　出处：《聊城大学》2017年硕士论文

【摘要】：在光通信系统中,孤子通信具有着它独特的魅力。特别是在高速通信中,其利用色散与非线性效应相互平衡的方法,使得非线性效应对系统性能的不良影响大大降低。另外,光孤子通信还具有中继距离长,误码率低,节约中继成本等特点。现代光通信系统正在向着高速率、大容量、长距离的方向发展,光脉冲的宽度早已经提高到了飞秒量级,随着信号频率的逐渐增加,其中涉及的非线性和色散效应也越来越复杂,所以利用飞秒光孤子通信来克服这种问题具有迫切的现实意义。在高速光通信系统中,为了提高通信速率,脉冲之间距离也要随之压缩,这会引起通信系统中光脉冲间的相互作用问题。耦合飞秒光孤子通信是集多路复用和孤子传输为一体的现代通信技术。在同一根光纤中传输多路信号时也会引起相互干扰的问题,对通信造成严重影响。本文利用基于符号计算的双线性法,对不同高速通信系统中的光孤子进行解析求解,并对孤子间的相互作用进行分析。具体完成工作如下:1.在波分复用(WDM)系统中,利用多种不同波长的载波来传递信号,并最终耦合到同一根光纤中进行传输,实现了传输容量的倍增。但是在WDM系统中不同波长脉冲之间的相互干扰,一直是提高复用效率的难点。本文将利用孤子传输来克服不同波长信号间的相互干扰问题,同时对每一路信号中脉冲间的相互作用进行研究。在高速WDM系统中,孤子脉冲的传输模型为N路耦合高阶非线性薛定谔方程(N-CHNLSE)。我们将利用双线性方法对N-CHNLSE模型进行孤子求解,对每一路的传输状态进行观察,并通过改变其中一路孤子脉冲的传输状态,对产生的相互作用进行研究。2.在双折射光纤中,脉冲传播时会形成x和y两个方向的偏振态,科学家们利用这种特性可以实现偏振复用来提高通信容量。而光脉冲以孤子的形式传播时,可以可以克服普通光脉冲无法保持恒定的偏振态的困扰。在双折射光纤中,孤子脉冲不仅可以保持强度和波形不变,还能实现偏振态稳定传输的效果。本文将对双折射光纤中的高维飞秒耦合亮孤子和暗孤子进行探索,研究的模型为(3+1)维耦合高阶非线性薛定谔方程。我们将利用双线性方法对模型求亮、暗孤子解,在不同平面上观察孤子的传输演化情况,并改变孤子的状态,对孤子间的相互作用进行研究。并且,经过退化得到了(2+1)维耦合飞秒光孤子。3.在耦合飞秒光脉冲满足的传输模型的基础上,本文将对最近几年在光学领域发现的另一种特殊波形“光怪波”进行探索。通过对传输模型的拓展,本文利用双线性法得到了多维的耦合飞秒呼吸子和光怪波,并分析了它们在长度、宽度、峰值等方面的特性,发现了光学怪波在通信系统中同样拥有着极其重要的应用价值。
[Abstract]:In optical communication system, soliton communication has its unique charm.Especially in high speed communication, the negative effect of nonlinear effect on system performance is greatly reduced by using the method of mutual balance between dispersion and nonlinear effect.In addition, soliton communication has the advantages of long relay distance, low bit error rate and low relay cost.The modern optical communication system is developing towards the direction of high speed, large capacity and long distance. The width of optical pulse has been increased to the order of femtosecond, and with the increasing of signal frequency,The nonlinear and dispersion effects involved are becoming more and more complicated, so it is of urgent practical significance to use femtosecond optical soliton communication to overcome this problem.In high speed optical communication system, in order to improve the communication rate, the distance between pulses must be compressed, which will cause the interaction between optical pulses in the communication system.Coupled femtosecond optical soliton communication is a modern communication technology which integrates multiplexing and soliton transmission.The transmission of multichannel signals in the same optical fiber will also cause the problem of mutual interference, which will seriously affect the communication.In this paper, a bilinear method based on symbolic computation is used to solve the solitons in different high-speed communication systems, and the interaction between solitons is analyzed.The details of the work are as follows: 1.In wavelength division multiplexing (WDM) WDM) system, a variety of carriers with different wavelengths are used to transmit signals, which are finally coupled to the same optical fiber for transmission, so that the transmission capacity is doubled.However, the interference between different wavelength pulses in WDM system is always difficult to improve the efficiency of multiplexing.In this paper, soliton transmission is used to overcome the problem of interference between different wavelength signals, and the interaction between pulses in each signal is studied at the same time.In a high-speed WDM system, the transmission model of soliton pulses is N-channel coupled higher-order nonlinear Schrodinger equation (N-CHNLSEE).We will use the bilinear method to solve the soliton of N-CHNLSE model, observe the transmission state of each channel, and study the interaction by changing the transmission state of one of the soliton pulses.In birefringent fiber, the polarization states in x and y directions can be formed when the pulse propagates, which can be used by scientists to realize polarization multiplexing to improve the communication capacity.When the optical pulse propagates as a soliton, it can overcome the problem that ordinary optical pulse can not maintain a constant polarization state.In birefringent fiber, the soliton pulse can not only keep the intensity and waveform unchanged, but also realize the effect of stable transmission in the polarization state.In this paper, the high-dimensional femtosecond coupled bright solitons and dark solitons in birefringent optical fiber are investigated. The model is the high-order nonlinear Schrodinger equation.We will use the bilinear method to obtain the bright and dark soliton solutions of the model, observe the propagation evolution of the soliton on different planes, change the state of the soliton, and study the interaction between solitons.Furthermore, we have obtained the femtosecond soliton. 3.Based on the transmission model of coupled femtosecond optical pulses, this paper will explore another special wave "light strange wave" which has been discovered in the field of optics in recent years.By extending the transmission model, the multi-dimensional coupled femtosecond respitons and optical strange waves are obtained by bilinear method, and their characteristics in length, width and peak value are analyzed.It is found that optical strange waves also have very important application value in communication system.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.1

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