【作者】 黄俨；

【导师】 黄翊东；

【作者基本信息】 清华大学 ， 电子科学与技术， 2009， 硕士

【摘要】 光子晶体光纤(PCF)中异常布里渊散射是近年来新型微结构材料中非线性光学效应的研究热点之一。本论文基于PCF的结构特点和光学、声学特性,对异常布里渊散射现象及其应用进行理论和实验研究。本论文研究了PCF中异常布里渊散射特性的产生机理。从石英圆柱简化模型出发,近似模拟计算了PCF中声波模式的色散关系、声波模场分布、声光相互作用强度和布里渊散射增益系数谱,研究了布里渊增益系数谱中双峰结构随泵浦光波长和温度的变化关系。理论上得到了PCF中异常布里渊散射源于混合声波模式间模式耦合的物理解释。从有限元算法的基本原理出发,通过对称性边界条件克服有限元算法的时间和空间复杂度,实现了PCF中声波全矢量波动方程的波导有限元数值模拟程序。基于该程序计算了石英圆柱和不同结构PCF中声波模式模场分布特点和声光相互作用规律,初步论证了程序的可行性。实验研究了双峰布里渊散射增益介质在布里渊激光陀螺中的应用。将PCF中异常布里渊双峰结构推广到传统光纤,分析了具有布里渊增益双峰的混合环形腔性质,实现基于混合环形腔的布里渊激光器。首先实现单向泵浦激光器激射,发现不同激射波长的激光竞争激射的现象。基于此,在双向泵浦下实现了该激光器的双向双波长激射,并讨论了实现双向双波长单模运转的条件。更多还原

【Abstract】 The novel Brillouin scattering property in photonic crystal fibers (PCF) is one of the frontiers in nonlinear optical effect of novel microstructure materials in recent years. Based on the structure features, photonic and phononic properties in PCF, the novel Brillouin scattering phenomenon is theoretically studied, whose application is also experimentally investigated.The mechanism of novel Brillouin scattering is studied. Based on the silica rod model, the dispersion relationships of acoustic modes, the field distribution, the acousto-optic interaction intensity and the Brillouin scattering gain coefficient spectrum in PCF are calculated. The couplings among different hybrid acoustic modes and their impacts on the Brillouin scattering gain coefficient spectrumare analyzed by investigating the Brillouin scattering changes under different pump wavelengths and temperatures. Based on the above results, the conclusion is drawn that the novel Brillouin scattering is originated from the couplings among hybrid acoustic modes in PCF.The numerical simulation of Brillouin scattering in PCF is theoretically studied. Based on the fundamental principles of Finite Element Method (FEM) and overcoming the time and space complexity by utilizing the symmetric boundary conditions, the waveguide FEM program analyzing the full-vector acoustic wave equation is coded. By this program, the features of acoustic modes’field distributions and acousto-optic interactions in PCFs with different structures are analyzed. The influencing of structure parameters on Brillouin scattering is discussed.The applications of dual peaks of Brillouin scattering gain medium are experimentally investigated. By simulating the novel Brillouin gain coefficient spectrum of PCF in conventional fibers, the fiber Brillouin laser based on the hybrid ring cavity is realized. Firstly, the Brillouin lasing in the single direction is realized, and the lasing competition is discovered and studied. Then bi-directional dual-wavelength Brillouin lasing is realized. The single mode operating conditions of the laser is discussed.更多还原