基于光纤激光系统的波长转换研究

发布时间：2018-06-13 14:00

  本文选题：非线性光学 + 相位匹配　； 参考：《天津理工大学》2017年硕士论文

【摘要】：非线性波长转换在光信号处理、光信息存储、生物医学检测、遥感探测、工业加工及环境监测分析等方面起者重要的作用。随着超短脉冲激光技术的不断发展,宽带激光的波长转换受到广泛关注。光子晶体光纤激光器以其高光束质量、高电光效率、可靠性高、占空小及高重频等优异的特性,成为目前国内外研究热点。本论文基于光通信波段、高功率飞秒光纤激光系统,利用周期极化非线性晶体实现高效频率转换,提出了相位匹配和群速度匹配的温度调谐方案,分析讨论了谐波时域和频域特性及转换效率的影响因素,为实现结构紧凑、性能稳定的多波长输出系统提供了参考;结合涡旋光束在光通信领域的新应用,研究了波长转换过程的模式分布特性。具体内容如下:1、归纳总结了准相位匹配技术及其特点,在小信号近似下对二阶非线性参量过程的耦合波方程进行了理论推导,分析了走离效应和群速度失配对宽带波长转换过程的影响。2、针对光子晶体光纤激光频率转换过程进行了理论模拟和实验研究。分析了全光波长转换过程的温度依赖性,以及转换效率和输出波长的调谐特性。实验分别在100℃和75℃获得了最大转化效率为27.5%的二次谐波和4.3%的三次谐波,讨论了输出光谱的二、三和四次谐波转换过程。3、提出了一种同时满足相位匹配和群速度匹配的高效飞秒激光倍频方案。在特殊的偏振配置e+e-?o下,基频光波和倍频光波的群速度可以在特定温度匹配。将耦合波方程应用于1550nm波段掺镁周期性极化晶体波长转换过程,数值分析了基频和倍频光波的时域和频域特性,获得了最佳转换效率的条件。4、研究了轨道角动量光束在准相位匹配晶体中波长转换过程,得到了频率变换后光束的模式分布特性。
[Abstract]:Nonlinear wavelength conversion plays an important role in optical signal processing, optical information storage, biomedical detection, remote sensing detection, industrial processing and environmental monitoring and analysis. With the development of ultrashort pulse laser technology, the wavelength conversion of broadband laser has been paid more and more attention. Photonic crystal fiber laser (PCF) has become a research hotspot at home and abroad for its excellent characteristics such as high beam quality, high electro-optic efficiency, high reliability, small duty cycle and high repetition frequency. Based on optical communication band and high power femtosecond fiber laser system, a temperature tuning scheme based on phase matching and group velocity matching is proposed. The influence factors of harmonic time domain and frequency domain characteristics and conversion efficiency are analyzed and discussed, which provides a reference for the realization of compact and stable multi-wavelength output system, and combines the new application of vortex beam in optical communication field. The mode distribution of wavelength conversion process is studied. The specific contents are as follows: 1. The quasi-phase matching technique and its characteristics are summarized. The coupled wave equation of the second order nonlinear parametric process is derived theoretically under the small signal approximation. The influence of walk-off effect and group velocity mismatch on the broadband wavelength conversion process is analyzed. The theoretical simulation and experimental study on the laser frequency conversion process of photonic crystal fiber are carried out. The temperature dependence of all optical wavelength conversion process and the tuning characteristics of conversion efficiency and output wavelength are analyzed. The second harmonic and the third harmonic with the maximum conversion efficiency of 27.5% and 4.3% were obtained at 100 鈩，

本文编号：2014256