【作者】 禹国俊；

【导师】 姚建铨；

【作者基本信息】 天津大学 ， 物理电子学， 2004， 硕士

【摘要】 本文对基于准相位匹配参量过程的1.55μm附近宽带光源进行了理论分析并对其泵浦源946nm全固态Nd:YAG准三能级激光器进行了全面深入的研究。宽带光源在光通信、光传感、生物医学和光谱分析等许多领域都有着非常广泛而重要的应用。准相位匹配技术是实现光通信波段宽带光源的新方法。此项目的基本原理是利用参量振荡调谐曲线的折回特性，当泵浦波长取一合适值时，QPM调谐曲线折点附近一定范围内的输出波长对极化周期的变化很敏感（近乎无穷大），则折点处的极化周期可以对应一定的输出波长范围，此范围内的所有波长都能够近似满足相位匹配条件，得到有效输出。论文首先就对宽带光源的发展进行综述，列举了现有常见的宽带光源，分析了其优缺点及适用范围。在此基础上对基于准相位匹配的新型宽带光源进行了介绍；第二章，对准相位匹配的理论进行了深入探讨：从麦克斯韦方程出发推导出准相位匹配下的三波互作用耦合方程，并介绍了准相位匹配的优点和实现准相位匹配的关键——周期极化晶体；第三章，详细探讨了准相位匹配参量过程实现宽带光源的原理，对QPM-OPG的泵浦波长的选择和极化周期的确定进行了精确的数值计算；第四章，则侧重于QPM-OPG泵浦源的理论研究。其中，对LD纵向泵浦946nm Nd:YAG准三能级激光系统进行了理论分析，并对其阈值，输出功率和效率进行了数值模拟，得出最佳晶体长度和最佳模式匹配等结论；第五章，对946nm激光器的实验研究进行了总结和概括，并展望了下一步的工作，其中包括实现高平均功率的被动调Q 946nm激光器及用它去泵浦PPLN晶体实现准相位匹配宽带光源。综上所述，存在以下创新之处:从匹配宽度这一概念出发进行分析，以此作为判定QPM-OPG宽带光源带宽的依据，进行理论研究。采用一阶共线QPM-OPG来实现1.55μm附近光通信波段的宽带光源，确定所需的最佳泵浦波长实验上进行了LD纵向泵浦的946nmNd:YAG激光器的研制，获得最大功率为1.4W，斜效率为18.4％连续输出，并以此为泵浦源的PPLN-OPG的实验。更多还原

【Abstract】 In this thesis, a new-style broadband light source was theoretically analyzed and the pump source of it, 946nm Nd:YAG quasi-three-level laser system was investigated roundly and thoroughly.Broadband light source has very extensive and important applications in many fields such as optical communication, optical sensing, biomedicine and spectral analysis. Quasi-phase-match(QPM) is one of the new methods that could ennable broadband source. The principle taken use in this project is the retracing behaviors of parametric oscillation tuning curve. When pumping with proper wavelength the output wavelength is very sensitive to the variation of poled period at the break point in the QPM tuning curve, which is close to infinity, that is, that poled period corresponds to a certain range of output wavelengths all of that can approximately meet the phase match condition.In this paper, the research work and findings are as follows:The developement of broadband source. Familiar examples were enumerated, as well as the advantages, disadvantages and application of them. The new broadband source based on QPM was introduced.Quasi-phase-match theory was discussed in depth. QPM coupled equations was educed from Maxwell equation. Introduction of the advantages of QPM and the key component, periodically poled crystal.The theory of QPM-OPG broadband source was explored in detail. The pumping wavelength and specific poled period was accurately chosen by numerical calculation.The pumping source of QPM-OPG, LD longitudinally pumped 946nm Nd:YAG laser system was theoretically studied and the threshold ,output power and slope efficient were numerically simulated. The conclusions of Optimal crystal length and optimal mode overlap were derived from the computer simulationDemonstration of 946nm laser was concluded. A maximum CW output power of 1.4W and slope efficient of 18.4% was got. Some prospective work was put forward, such as passively Q-switched operation of 946nm laser and pumping PPLN crystal with it to get QPM-OPG broadband source. <WP=5>There following innovation points:Firtly, we start our analysis from the concept of phase match width and calculated the bandwidth of the QPM-OPG broadband source according as it.Secondly, we use first-order collinear QPM-OPG to produce broadband source centered at 1.55μm. And the determination of optimal pump wavelengthThirdly, the development of 946nm Nd:YAG laser and pumping PPLN with it更多还原