长周期光纤光栅:原理、制备与应用

较全面介绍了长周期光纤光栅。对比Bragg光纤光栅说明了长周期光纤光栅的特点。对其耦合机理进行了分析 ,阐明了波长选择损耗特性。介绍了长周期光纤光栅的制备方法 ,大致分之为基于非形变的制备方法和基于形变的制备方法。详细阐述其在通信、传感领域的应用 ,尤其是新型应用 :带通滤波、光上下路复用、光纤光源、偏振器件、新型传感等。并针对长周期光纤光栅对温度、应力、外部折射率敏感的特性 ,探讨了调谐性以及温度稳定性的方案     

Characteristics of Multiply π Phase shifted Long period Fiber Gratings

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同步辐射弧矢聚焦双晶单色器传输效率的研究

本文对理想弧矢聚焦双晶单色器的相对传输效率进行理论分析;对第一晶体受高热负载发生的形变及第二晶体的鞍型形变对单色器的传输效率影响的原因,抑制第一晶体热形变、第二晶体鞍型形变所采取的结构和方法进行了简单的叙述;并对采取直接水冷的第一晶体和背部加肋的第二晶体进行了SHADOW光学追踪分析;进而得出整个单色器的实际传输效率.     

一维光子晶体的电磁波理论及实现方法

对一维光子晶体的电磁波理论及周期介质中的Bloch波解做了详细的推导,给出了光子晶体中的禁带存在的理论依据,并以此分析了禁带的特征.同时,对一维光子晶体的光学理论做了阐释,并应用于一维光子晶体的设计实践.列举了两个多层周期介质膜的禁带特性.最后对光子晶体的应用和制造前景做了展望.     

弹簧振子实验方法的运用和改进

对弹簧振子振动周期经验公式的实验拟合中所用的实验方法进行了总结,对部分实验方法和实验装置进行了改进。     

Symmetric period solutions with prescribed minimal period for even autonomous semipositive Hamiltonian systems

We study some monotonicity and iteration inequality of the Maslov-type index i-1of linear Hamiltonian systems.As an application we prove the existence of symmetric periodic solutions with prescribed minimal period for first order nonlinear autonomous Hamiltonian systems which are semipositive,even,and superquadratic at zero and infinity.This result gives a positive answer to Rabinowitz’s minimal period conjecture in this case without strictly convex assumption.We also give a different proof of the existence of symmetric periodic solutions with prescribed minimal period for classical Hamiltonian systems which are semipositive,even,and superquadratic at zero and infinity which was proved by Fei,Kim and Wang in 2001.     

带有脉冲药物治疗策略的SIA模型的全局稳定性

根据艾滋病的传播特点,建立了带有脉冲药物治疗策略的感染年龄结构SIA模型,得到了控制疾病传播的基本再生数R_O(p,T),并讨论了无病平衡态的全局稳定性.     

Mock period functions in higher level cases

Generalizing the results of Bringmann, Diamantis and Raum [3] we investigate a generating series of non-critical values which can be interpreted as a mock period function and prove that non-critical values can be encoded into a sesquiharmonic Maass form in higher level cases. Moreover we prove Eichler–Shimura-type isomorphism for the space of period polynomials and for that of mock period functions in level p   with p∈{2,3}$p\in \{2,3\}$.     

Calculation of cladding modes using both two layer and three layer geometry in LPFG

In this paper we have calculated cladding modes of long period fiber grating. We have calculated cladding modes using both two layer (Graphical solution method) geometry and three layer geometry proposed by Erdogan. We have compared both these techniques, discussed the limitations of Graphical solution method and benefits of three layer geometry.     

傅里叶望远镜部分周期信号解调及对成像的影响

为了解决傅里叶望远镜高功率短脉宽激光只能包含部分周期信号的难题,本文提出多脉冲拼接技术并对其基本原理和应用范围进行深入研究.首先介绍高功率短脉宽激光与声光移频器移频带宽之间的矛盾,进而引出利用傅里叶望远镜传统时间解调公式进行部分周期信号解调存在的困难.然后给出多脉冲拼接技术的基本理论,推导出理想情况下移频频率、脉冲重复率和脉宽满足的拼接条件.进而详细分析移频频率稳定性和脉冲重复率稳定性对多脉冲拼接成像结果的影响,并通过计算机仿真研究一般情况下脉宽变化对多脉冲拼接成像结果的影响.最后得出移频频率和脉冲重复率对成像无影响,激光脉宽变化小于25%仍可识别目标轮廓的结论.