【作者】 王伟；

【导师】 李思敏； 王祥传；

【作者基本信息】 南京航空航天大学 ， 物理电子学， 2020， 硕士

【摘要】 光学频率梳作为一种特殊的多波长相干光源,因其具有超宽频谱范围、固定重复频率,在高精度测量、光通信、超宽带微波信号接收等领域均有着重要的应用。然而光频梳的不稳定性容易造成不必要的测量误差、通讯系统连接中断以及微波信号接收失真,因此如何产生高稳定度的光频梳成为各个学科领域的研究热点。本文就基于电光调制器的光频梳产生方法及其稳定性提高方法这一课题展开了一系列研究,具体工作如下:(1)阐述了光频梳的主要产生方法和国内外研究现状。分析了基于电光调制器的光频梳产生原理,并就几种主要的基于电光调制器产生光频梳方案的结构、原理和性能进行了总结比较,为后续光频梳的产生和提高其稳定性的研究提供理论基础。(2)提出了一种基于级联相位调制器的光频梳产生方案。通过公式推导、数值仿真及搭建实验系统验证方案的可行性。在仿真中,5、7、9、11根梳齿的光频梳平坦度分别为0.64 dB、0.93 dB、2.45 dB和3.19 dB。在实验中,产生的5、7、9根梳齿的光频梳平坦度分别为0.59 dB、2.35 dB、3.92 dB。然后提出了利用倍频调制的方法,增强级联调制器产生光频梳的稳定性,分别分析了基于一倍频、二倍频、三倍频和四倍频调制产生的光频梳对调制系数的要求,实验证明采用二倍频调制时,产生的光频梳调制系数最低,稳定性较好。(3)提出了一种提高光频梳稳定性的反馈控制系统。通过理论分析和数值模拟,分析了调制器偏置漂移对光频梳稳定性的影响。提出了以光频梳总功率与光载波功率之比作为反馈参量来提高光频梳幅度稳定性的方法。在概念验证实验中,首先将反馈系统应用到基于偏分复用双驱马赫增德尔调制器的光频梳产生方案中,利用反馈方法,7根光频梳稳定性从1.5小时内大于3 dB提高到4小时内小于2 dB。在此基础上,将反馈系统应用到基于双驱马赫增德尔调制器产生光频梳的方案中,利用反馈方法,将5根光频梳稳定性从1小时内大于3 dB提高到4小时内小于1.7 dB。更多还原

【Abstract】 As a special multi-wavelength coherent light source,optical frequency comb has important applications in high-precision measurement,optical communication,ultra-wideband microwave signal reception and other fields because of its ultra-wide spectrum and fixed repetition frequency.However,the instability of optical comb is likely to cause unnecessary measurement error,communication system connection interruption and microwave signal reception distortion.Therefore,how to produce optical comb with high stability has become a research hotspot in various fields.In this paper,a series of researches are carried out on the generation method of optical comb based on electro-optical modulator and the subject of improving the stability of optical comb.The specific work is as follows:1.The main generation methods of optical frequency comb and the research status at home and abroad are described.This port analyzes the generating principle of optical comb based on electro-optic modulator,summarizes and compares the structure,principle and performance of several main schemes of generating optical comb based on electro-optic modulator,and provides a theoretical basis for the subsequent generation of optical comb and the research on improving its stability.2.An optical comb generation scheme based on cascade phase modulator is proposed.The feasibility of the scheme was verified by formula derivation,numerical simulation and experiment system.In the simulation,the flatness of 5,7,9 and 11 optical frequency combs were 0.64 dB,0.93 dB,2.45 dB and 3.19 dB,respectively.In the experiment,the flatness of the 5,7 and 9 optical frequency combs was 0.59 dB,2.35 dB and 3.92 dB,respectively.Then a method of frequency doubling modulation is proposed to enhance the stability of the optical comb generated by the cascade modulator.The modulation factors of optical comb based on one,double,triple and quadruple modulation are analyzed.The experiment shows that the modulation factor of optical comb is the lowest and the stability is better when using double frequency modulation.3.A feedback control system to improve the stability of optical comb is proposed.The effect of the modulator bias drift on the stability of the OFC is analyzed by theoretical analyses and numerical simulations.When the ratio between the total power of the OFC and the optical carrier power is used as the feedback parameter can effectively improve the amplitude stability of OFC.Firstly,the feedback system is applied to the PM-DMZM based OFC generation scheme.In the proof-of-concept experiment,by using the feedback structure,the seven-line OFC stability is experimentally improved from being large than 3 dB within 1.5 h to being below 2 dB more than 4 h.Then,the feedback system is applied to the DMZM based OFC generation scheme.In the proof-of-concept experiment,by using the feedback structure,the five-line OFC stability is experimentally improved from being large than 3 dB within 1 h to being below 1.7 dB more than 4 h.更多还原