基于双平行马赫增德调制器产生Nyquist脉冲及平坦光频梳的研究

发布时间：2018-04-10 20:13

本文选题：光Nyquist脉冲 + 光学频率梳　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着手机、个人电脑的普及以及各种宽带视频、多媒体业务的出现,通信系统的容量受到越来越大的挑战,超太比特的单信道传输速率的光通信网络成为研究的重点。基于光Nyquist脉冲的波分复用及正交时分复用技术是实现超级信道及提高频谱效率的最具前景的技术,产生理想的光Nyquist脉冲具有重要的现实意义。同时,光学频率梳实现了人类对光学频率的精密测量,也被广泛应用于微波光子学信号处理、光纤通信复用系统中,通过平坦光频梳直接合成光Nyquist脉冲的方法成为相关领域的研究热点。本文的研究内容主要针对平坦光学频率梳和光Nyquist脉冲两部分展开,完成的主要工作如下:1.对通过频域平坦光频梳来产生时域的光Nyquist脉冲进行了详细的理论证明,并且对基于射频单频驱动双驱动马赫增德尔调制器(DD-MZM)、射频倍频驱动DD-MZM和射频单频驱动双平行马赫增德尔调制器(DPMZM)、射频倍频驱动DPMZM产生光频梳进行了理论推导,仿真产生了具有多种梳线数目的平坦光频梳。2.提出了基于射频倍频信号驱动单个DPMZM产生光Nyquist脉冲的新结构,在理论分析的基础上仿真产生了相位锁定的具有5条梳线的光频梳,其平坦度高达0 dB,边模抑制比为41 dB,在时域对应理想的sinc型Nyquist脉冲。通过调整射频信号的频率,在0.01 V的驱动电压下产生了滚降系数均为0的周期为100 ps、50 ps及25 ps的光Nyquist脉冲序列,并且在较低的射频驱动电压下产生了具有9,5,4,3,2条梳线的光频梳,其中具有5,3,2条梳线的光频梳的平坦度均高达0dB,边模抑制比均高于34.5 dB。与前人的工作相比,本文基于射频倍频驱动DPMZM产生的光频梳具有更高的质量。3.通过探究基于单个EAM级联PM级联PM和单个EAM级联PM级联MZM中EAM对光频梳平坦度的影响,提出了两种产生平坦光频梳的新方法,即基于两个EAM级联PM级联PM和两个EAM级联PM级联MZM产生平坦光频梳,并且基于两个EAM级联PM级联PM产生了平坦度在2 dB范围内的具有37条梳线的光频梳,且中部平坦度在0.4 dB范围内的梳线有31条,与单个EAM级联PM级联PM相比,光频梳的平坦度提高了 6.6dB,中部平坦光频梳的梳线条数增加了 2条;基于两个EAM级联PM级联MZM产生了平坦度在0.7 dB范围内的具有41条梳线的光频梳,与单个EAM级联PM级联MZM相比,光频梳的平坦度提高了 0.7 dB,梳线条数增加了2条。
[Abstract]:With the popularity of mobile phones, personal computers and the emergence of broadband video and multimedia services, the capacity of communication systems is increasingly challenged.Wavelength division multiplexing (WDM) and orthogonal time division multiplexing (OTDM) based on optical Nyquist pulses are the most promising techniques to realize superchannel and improve spectral efficiency. It is of great practical significance to produce ideal optical Nyquist pulses.At the same time, optical frequency comb has realized the precise measurement of optical frequency, and has been widely used in microwave signal processing and optical fiber communication multiplexing system.The method of directly synthesizing optical Nyquist pulse by flat optical frequency comb has become a research hotspot in related fields.In this paper, we mainly focus on the flat optical frequency comb and the optical Nyquist pulse. The main work accomplished is as follows: 1.The generation of optical Nyquist pulse in time domain by flattened optical frequency comb in frequency domain is proved in detail.The theoretical derivation of optical comb is also given based on the single-frequency driving DD-MZM, the dual-parallel DD-MZM driven by the single-frequency RF and the DPMZM driven by the radio frequency doubling, respectively, and the optical comb generated by the DPMZM driven by the RF frequency doubling, which is based on the single-frequency driving and the dual-drive Machzendal modulator, and the dual-parallel DPMZM driven by the RF single frequency is used to generate the optical comb.A flattened optical frequency comb. 2 with a variety of combs is generated by simulation.A new structure of optical Nyquist pulse generated by a single DPMZM driven by RF frequency doubling signal is proposed. Based on the theoretical analysis, a phase locked optical frequency comb with five comb lines is simulated.The flatness is as high as 0 dB and the edge-mode rejection ratio is 41 dB, which corresponds to the ideal sinc type Nyquist pulse in time domain.The flattening degree of the optical comb with 5 ~ 3 ~ 3 carding lines is as high as 0 dB, and the edge-mode rejection ratio is higher than 34.5 dB.Compared with the previous work, the optical comb based on RF frequency doubling driven DPMZM has higher quality. 3.By exploring the influence of EAM on the flatness of optical comb in PM cascade PM cascade based on single EAM cascade and PM cascade MZM in single EAM cascade, two new methods to produce flat optical comb are proposed.That is, based on two EAM cascaded PM cascaded PM cascades and two EAM cascaded PM cascaded MZM to produce flat optical comb, and based on two EAM cascaded PM cascaded PM cascaded PM to produce optical comb with 37 comb lines in the range of 2 dB flatness.There are 31 comb lines with middle flatness in the range of 0.4 dB. Compared with single EAM cascaded PM cascaded PM, the flatness of optical comb is increased by 6.6 dB, and the number of comb lines of middle flat optical comb is increased by 2.Based on two EAM cascaded PM cascaded MZM, 41 comb lines with 41 comb lines are generated in the flatness range of 0.7 dB. Compared with single EAM cascaded PM cascade MZM, the optical frequency comb flatness is increased by 0.7 dB and the number of comb lines is increased by 2.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN761;TN929.1

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