基于PPLN波导和频与差频过程的可调谐全光波长转换

发布时间：2018-12-30 12:34

【摘要】：在光传输网中,全光波长转换是一项关键的技术。它能实现光域上的信号在两个不同波长之间的转换,不受常规的光/电/光型波长转换器产生的速度限制。全光波长转换技术在很多领域中都有着广阔的发展前途,例如波长路由、光开关和波长重用等领域。周期极化铌酸锂(Periodically Poled Lithium Niobate,PPLN)波导的级联二阶非线性效应在全光波长转换技术上的应用对比于其他几种常见的全光波长转换技术来说,具有很多优势。在此基础上,本文的主要研究内容有:本文分别计算了波矢失配量在和频与差频(SFG+DFG)过程和倍频与差频(SHG+DFG)过程的允许范围,并在泵浦光波长变化量相等的条件下,对两种过程的波矢失配量进行了比较。同时本文给出了SFG+DFG级联型全光波长转换的耦合波方程组在慢变振幅近似条件下的表达式,通过数值模拟,得到了此过程中输入信号光、泵浦光、控制光、和频光以及输出光的三维脉冲图。为了提高波长转换器的可调谐性和灵活性,本文提出了一种基于PPLN波导,利用SFG+DFG二阶非线性过程的全光波长转换方案。该方案可以实现在一定波长范围内将任意波长的信号光转换到任意波长的输出光,成功地完成信号光中信息到转换光的复制。同时为了使宽带波长转换特性更加平坦,本文首次利用阶梯分段光栅结构对基于SFG+DFG效应的波长转换过程进行研究,以此来改变其PPLN波导参数。在波形上对信号光可调谐和转换光可调谐两种情况的转换结果进行了对比分析。从本课题研究的结果可以看出,本文设计的基于SFG+DFG二阶非线性过程的全光波长转换可调谐变换,得到的信号质量比较好,利用阶梯分段光栅结构对基于SFG+DFG效应的波长转换过程研究,获得了比较高的转换效率和增益平坦性,因此本课题的研究在全光波长转换的研究中具有非常重要的意义。
[Abstract]:In optical transmission networks, all optical wavelength conversion is a key technology. It can realize the signal conversion between two different wavelengths in the optical domain, and is not limited by the speed of conventional optical / electrical / optical wavelength converters. All optical wavelength conversion technology has a broad prospect in many fields, such as wavelength routing, optical switching and wavelength reuse. The cascade second-order nonlinear effect of periodically polarized lithium niobate (Periodically Poled Lithium Niobate,PPLN) waveguides has many advantages compared with other conventional all-optical wavelength conversion techniques. On this basis, the main contents of this paper are as follows: in this paper, the allowable range of wave vector mismatch in sum frequency and differential frequency (SFG DFG) process and frequency doubling and differential frequency (SHG DFG) process are calculated respectively, and under the condition that the pump wavelength variation is equal, The wave vector mismatch between the two processes is compared. At the same time, the expression of coupled wave equations with SFG DFG cascade all-optical wavelength conversion under the condition of slow-varying amplitude approximation is given. Through numerical simulation, the input signal light, pump light and control light are obtained. Sum-frequency light and three-dimensional pulse diagram of output light. In order to improve the tunability and flexibility of wavelength converters, an all-optical wavelength conversion scheme based on PPLN waveguide and SFG DFG second-order nonlinear process is proposed. The scheme can convert the signal light of any wavelength to output light of any wavelength in a certain wavelength range, and successfully copy the information from the signal light to the converted light. At the same time, in order to make the characteristics of broadband wavelength conversion more flat, the wavelength conversion process based on SFG DFG effect is studied for the first time in this paper by using stepped segmented grating structure to change the parameters of PPLN waveguides. The conversion results of signal and optical tunable harmonic and converted light tunable are compared and analyzed in waveform. It can be seen from the results of this research that the all-optical wavelength conversion tunable transformation based on SFG DFG second-order nonlinear process has good signal quality. The study of wavelength conversion process based on SFG DFG effect by using the structure of step segment grating has achieved high conversion efficiency and gain flatness, so the research of this topic is of great significance in the study of all optical wavelength conversion.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.1

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