基于光纤光栅的超短脉冲整形技术研究
文献类型：学位论文
| 作者 | 刘琼 |
| 学位类别 | 博士 |
| 答辩日期 | 2012 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 瞿荣辉 |
| 关键词 | 光纤光栅 啁啾脉冲放大 重构 时域微分器 热应力 有限元分析 |
| 其他题名 | Study of ultrashort pulse shaping technology based on fiber grating |
| 中文摘要 | 超短脉冲整形技术是对超短脉冲的时域或者频域进行操控，是当前国际上超短脉冲研究领域中的一个重要前沿领域。近年来，得益于光纤通信技术的迅速发展，光纤器件得以迅速发展，因此一些基于新型光纤光子器件的脉冲整形技术被提出。与其它技术相比，基于光纤光子器件的脉冲整形技术具有和光纤激光器的天然相容性、器件稳定性高、避免采用体光学器件以及潜在成本低等优点。在新型光纤器件中，光纤光栅具有许多可以改变的结构参数(如折射率调制深度、折射率调制相位、光栅长度、变迹形状、光栅周期等)，得到了研究者的广泛重视。因此探索如何利用超结构光纤光栅实现脉冲整形具有广泛的理论基础和应用前景，本文的主要研究内容如下: 针对光纤光栅对超短脉冲的响应特性，以及光纤光栅重构的剥层算法和遗传算法进行了深入的研究，在此基础对基于光纤光栅的脉冲整形技术在微波/毫米波脉冲信号的产生、任意波形产生等应用方面进行了模拟验证研究。 提出了一种基于光纤光栅的钕玻璃啁啾脉冲放大系统中脉冲畸变的预补偿方法。利用啁啾脉冲放大过程的逆工程算法，计算了预补偿用光纤光栅的光谱响应特性，然后利用遗传算法，计算了预补偿用光纤光栅的结构参数。模拟了一个从2ns，15nm，20μJ二阶超高斯脉冲放大到2ns，8nm，400J二阶超高斯脉冲的钕玻璃啁啾脉冲放大系统，并且设计了一个线性啁啾的超结构光纤光栅对种子脉冲进行预整形。结果表明，当使用一个合理切趾函数和啁啾率的光纤光栅时，增益窄化效应和增益饱和效应得到了很好的补偿。我们利用相位掩模板法制备了预补偿用光纤光栅，其反射谱与所需的光纤光栅反射谱吻合的很好。 提出和设计了一种基于莫尔光纤光栅的全光光学时域微分器，结果表明，当莫尔光纤光栅的折射率调制幅度只存在一个过零点，并且这个过零点位于莫尔光纤光栅的中点时，莫尔光纤光栅可以作为一阶时域微分器。同样，当莫尔光纤光栅的折射率调制幅度存在两个对称的过零点时，莫尔光纤光栅可以作为二阶时域微分器，更高阶的时域微分器可以通过级联啁啾光纤光栅和一阶时域微分器实现。我们利用拉伸法和二次曝光法制备了莫尔光纤光栅，结合Optisystem虚拟实验系统证明了使用莫尔光纤光栅作为时域微分器的可行性。利用重构-等效啁啾理论，设计了具有等效π相移点的取样光纤光栅，这种取样光纤光栅具有一阶时域微分器所需要的频率以及相位响应，因此可以作为一阶时域微分器。 利用有限元分析的方法，模拟了均匀镀膜光纤光栅，轴向镀膜不均匀光纤光栅以及径向镀膜不均匀光纤光栅三种情况下的残余热应力分布以及对光纤光栅特性的影响。结果表明，均匀镀膜光纤光栅的残余热应力沿着轴向和径向均匀，利用化学镀镍方法，制备了金属化光纤光栅，分析了由残余热应力引起的波长漂移，并且与有限元模拟分析结果对比，结果表明，两者之间的差别很小。这为金属化光纤光栅波长的精确控制提供了理论指导以及为金属镀层质量提高了参考。 |
| 英文摘要 | The ultrashort pulse shaping is a technology that manipulates the ultrashort pulse in the frequency domain and time domain, and it is now a very important research direction in ultrashort pulse area. Benefit from the development of the optical fiber communication, the fiber devices have obtained a huge advancement, the pulse shaping technologies based on fiber photonic components are proposed. Compare to other shaping components, the fiber photonic components have many advantages, such as the inherent all-fiber approach, high stabilization and lower cost. The fiber grating has many changeable parameters (the refractive modulation amplitude and phase, length, apodization function, chirp) and makes it plays a key role in the research area. So, study of the ultrashort pulse shaping technology based on fiber grating has a theoretical basis and application prospect, the main contents of this thesis are as follows: Study of the ultrashort pulse response function and reconstruction algorithm of the fiber grating, especially the layer peeling algorithm and the genetic algorithm, Some simulation demonstration of the microwave/millimeterwave pulse generation and arbitrary wave generation using the fiber grating is given. A pulse distortion pre-compensation method based on fiber grating in Nd: glass chirped pulse amplification (CPA) system is proposed. An inverse engineering operation of chirped pulse amplification processing is used to calculate response function of the fiber grating and then the structure parameter of fiber grating can be obtained using the genetic algorithm. Some numerical simulations are given to realize a 2ns, 20μJ, 15 nm ultrashort seed pulse to the 2ns, 400J, 8 nm optimal second order super-Gaussian chirped pulses in a Nd:glass amplification system and an linear chirp fiber grating is used to shape the initial seed pulse. The results show that the gain narrowing and gain saturation effects will be reduced largely when a fiber grating, which has a proper refractive index modulation distribution, chirp coefficient and length, is used. Using phase mask method，a practical fiber grating used for pulse distortion pre-compensation is fabricated and the reflectivity and the target reflectivity had a good accordance in the form. An all-optical temporal differentiator based on a simple moiré fiber grating operated in reflection is designed and demonstrated. The results prove that the refractive modulation envelope of a single moiré fiber grating with only one zero point can be acted as a first-order temporal differentiator and the zero point must be located at the center of the grating area. And the refractive modulation envelope of the moiré fiber grating incorporated two symmetrical zero points can be acted as a second order temporal differentiator. The higher order temporal differentiator can be achieved by connecting a linear chirp fiber grating with a first-order temporal differentiator. Using the tensile method and dual exposure method, a practical moiré fiber grating is fabricated and it proves that such a grating can be acted as a first order temporal differentiator using the Optisystem virtual experiment system. Based on the reconstruction-equivalent-chirp (REC) technique, A sampling fiber grating with equivalent π phase point is designed, this fiber grating has a proper frequence response function and can be acted a first order temporal differentiator. Using the finite element method, the residual thermal stress of the uniform metallic coated, ununiform metallic coated along the z axis and ununiform metallic coated along the cross section fiber grating is derived. The frequency response of the fiber grating is also calculated using transfer matrix method. We uniformly coat a fiber Bragg grating with a nickel layer using the chemical metallization method and analysis the shift of center wavelength affected by the residual thermal strain, There is a good accordance between the experiment results and simulation work. These will be some reference to control the center wavelength of fiber grating during metallization and present the quality of the plating layer. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15709]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 刘琼. 基于光纤光栅的超短脉冲整形技术研究[D]. 中国科学院上海光学精密机械研究所. 2012. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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