掺镱光纤放大器及其在ICF激光驱动器中的应用的研究
文献类型：学位论文
| 作者 | 乔启全 |
| 学位类别 | 硕士 |
| 答辩日期 | 2003 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 林尊琪 |
| 关键词 | ICF激光驱动器前端系统 掺Yb光纤 光纤放大器 |
| 其他题名 | Yb-doped fiber amplier and its application in ICF laser driver |
| 中文摘要 | 惯形约束核聚变（ICF）激光驱动器前端系统作为一个高质量的种子光源，将为后级系统提供一个具有一定能量、带宽、高信噪比和高光束质量的脉冲。前端系统主要包括主振荡器、脉冲整形器、预放大和再生放大器。其中主振荡器是前端一个很重要的子系统，最终辐射核靶的激光脉冲就起源于该子系统产生的低功率光信号。在主振荡器采用DFB掺Yb光纤激光器时，由于输出的波长为1053nm连续光经过声光调制器斩波得到的脉冲信号峰值功率很低，只有几个毫瓦。因此，在脉冲进入相位调制器之前，必须对其进行放大，使其脉冲峰值功率达到几百毫瓦甚至瓦量级。本论文对满足此要求的高增益的掺Yb光纤放大器（YDFA）进行了研究。第一章介绍了掺德光纤放大器的发展，包括：石英光纤中Yb3“的能级结构与光谱特性；YDFA基本结构；YDFA中用到常用器件；YD队在其它领域的应用与发展。第二章对连续掺德光纤放大器的理论模型进行了二能级简化研究。本章分为两部分：第一部分给出了YDFA的基本方程：粒子数速率方程组及其稳态解；泵浦光和信号光的传播方程；放大自发辐射（ASE）的传播方程。第二部分在简化模型的基础上推导了YDFA工作在1O53nm时的一些公式：放大器的输出功率；信号光的饱和功率：YDFA的小信号增益；YDFA的大信号增益。第三章对连续掺Yb光纤放大器的两种常用结构进行了实验研究，并做了比较。从掺Yb光纤放大器的放大倍数和输出信号功率这两方面对正向单通结构和反向双通结构分别进行了实验研究后发现：反向双通结构具有更高的放大倍数和更大的输出功率。这就为脉冲掺Yb光纤放大器采用反向双程结构提供了依据。不过两种结构输出信号光的信噪比和消光比都有所降低，这是山于放大自发辐射的产生导致的。第四章利用光纤反射圈和光纤光栅对反向双通结构光纤放大器的放大自发辐射（ASE）进行了研究。第五章在实验的恭础上研究了脉冲掺Yb光纤放大器的特性。由于脉冲YDFA认的工作机制与连续YDFA不同，首先给出了其基本方程并从土能级粒-子数的角度推导了其增益方程。然后通过实验研究了：影响放大倍数的四个因素（掺镱光纤的-长度、浓度，输入信号功率和输入泵浦功率）；输出端脉冲波形的变化；脉冲放大器中ASE噪声。 |
| 英文摘要 | The front-end system of the ICF (inertial confining fusion) laser driver will provide a time shaping laser pulse with proper energy, proper bandwidth, high SNR(signal to noise ratio) and high quality for the subsequent system of amplifiers. The front-end system consists of master oscillator, pulse shaping system, pre-amplifier and regenerative amplifier by the demand of the ICF laser driver. The master oscillator is very important because it is responsible for generating the single pulse that seeds the entire ICF laser system. Because the DFB fiber laser is used as the master oscillator and its output power is very low, it must be amplified by a high gain Yb-doped fiber amplier (YDFA) bofore being forwarded to the phase moduator. This thesis mainly focuses on how to make a high gain YDFA. In the first chapter, the development of YDFA is summarized: the energy configuration and emission spectrum of Yb~(3+) in silica; the principle configurations of YDFA; the devices used in YDFA; the applications of YDFA in other areas. In the second chapter, we theoretically investigated YDFA by reducing it to two-level sysytem. Firstly, some basic equations such as the rate equations of populations changes, propagation of signal, propagation of pump, propagation of ASE are given. And secondly, based on the equations above, the expressions of the output signal powers(al the wavelength of 1053nm of YDFA), the signal saturation power, small signal gain and big signal gain have been obtained. In the third chapter, the two CW YDFA configurations, one pass forward setup and two pass backward setup, have been investigated at the base of expeiments. The amplification multiple and the output signal power from the two setups have both been obtained and compared. Then we found that the latter has advantages over the former althoulh both will reduce the SNR slightly. In the fourth chapter, the fiber ring reflector and fiber Bragg gratings have been used to investigate the ASE of YDFA. In the fifth chapter, two pass backward YDFA setup has been used. The factors relating to the gain and signal output power have been investgated and a optimized configuration is presented. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16529]  |
| 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 | 乔启全. 掺镱光纤放大器及其在ICF激光驱动器中的应用的研究[D]. 中国科学院上海光学精密机械研究所. 2003. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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