全光纤化脉冲光纤放大器及脉冲整形技术研究
文献类型：学位论文
| 作者 | 张芳沛 |
| 学位类别 | 博士 |
| 答辩日期 | 2008 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王之江 ; 楼祺洪 |
| 关键词 | 全光纤化脉冲光纤放大器 窄线宽连续光纤放大器 瞬态增益 大模场面积双包层光纤 脉冲整形技术 |
| 其他题名 | Study on all-fiber pulsed fiber amplifier and pulse-shaping technique |
| 中文摘要 | 高功率光纤放大器的研究是目前激光领域比较活跃的研究方向之一。光纤放大器在体积、重量、效率、结构等方面比其他固体激光器具有明显的优势，在工业、医疗、科研、军事等领域已展现出极其诱人的应用前景。在世界范围内，全光纤化光纤激光器及放大器被公认为是实用化和产业化的最佳途径，也是目前唯一进入商业化和产业化的技术方案。本文将从理论和实验两方面对全光纤化脉冲光纤放大器进行研究。 第一章综述了采用种子源主振荡－放大（MOPA）、调Q和锁模三种技术获得高峰值功率、高能量光纤激光输出的国内外新进展，分析了高功率脉冲双包层光纤放大器的工作原理及关键技术。 第二章根据激光功率传输方程和掺Yb3+双包层光纤放大器的物理模型，采用有限差分法对掺Yb3+光纤放大器的高功率放大特性进行了计算模拟，研究了脉冲信号通过掺Yb3+光纤放大器后的放大与波形畸变，该工作对于掺Yb3+光纤放大器的设计和研制有着一定的参考价值。 第三章采用国产的大模场面积双包层光纤和(2+1) ×1多模泵浦光纤耦合器，设计和研制了全光纤化高重频脉冲光纤放大系统，研究了种子光输出功率对放大性能的影响。结果表明，在泵浦功率一定的情况下，为保证脉冲光纤放大器稳定可靠地运行，种子光功率存在一个特定的取值范围。采用性能参数符合要求的Nd:YVO4声光调Q固体激光器作为种子源，获得了平均功率20 W的近衍射极限脉冲激光输出，光－光转换效率高于50%，脉冲频率在50~175 kHz连续可调，脉冲宽度约为15 ns。 单频、高功率激光在激光雷达、光谱学、精密测量等领域有非常广泛的应用。第四章采用5.3 m国产大模场面积双包层光纤，实现了波长为1064 nm的单频激光放大，在入纤泵浦功率28 W时，获得了7.3 W的窄线宽放大激光输出，斜率效率为39%，放大后仍旧保留振荡器的谱线特征。在此基础上，重点对该窄线宽放大系统的一些基本特性进行了研究，如输出功率特性、发射光谱特性及ASE的抑制等。 脉冲整形技术在非线性光学及激光惯性约束核聚变等领域有非常广泛的应用。第五章利用激光诱导等离子体开关技术，首先对355 nm脉冲激光自削波进行了实验和理论研究。分别采用5种不同焦距的透镜，集中讨论了透镜焦距及激光器输出单脉冲能量对脉宽压缩的影响，发现采用焦距为200 mm的透镜能够获得最佳的脉冲压缩效果。在激光电离Cu小孔内壁表面及空气击穿共同作用下，获得了脉宽最短达2.11 ns的脉冲激光输出。此外，根据实验结果得到了355 nm激光空气击穿阈值，并与理论估算值进行比较，发现两者结果较为一致。其次，对532 nm激光脉宽控制进行了实验研究。通过在光路中引入光程差，最终获得了1.5 ns~12 ns脉宽可调的绿光输出。 |
| 英文摘要 | At present, high power fiber amplifier is one of the most attractive research directions in laser fields. Comparing with other solid lasers, fiber amplifier has demonstrated a most attractive foreground in industry, medicine, scientific research, military affairs and so on because of its small volume, light weight, high efficiency, as well as compact architecture. All-fiber fiber lasers and amplifiers are considered as the optimal way to industrialization, and the only technical scheme to commercialization. In the thesis, theoretical and experimental research on all-fiber pulsed fiber amplifier is presented. In the first chapter, the latest progresses and development trends of high power pulsed fiber amplifier adopting master-oscillator power amplifier (MOPA), Q-switched and mode-locked techniques are reviewed, and the principle and key techniques of pulsed double-clad fiber amplifier are analyzed. In the second chapter, the high-power amplification characteristics are analyzed by virtue of laser power transmission equations and the physical model of Yb-doped fiber amplifier, and the waveform distortion of amplified pulse signal is investigated, which is valuable to develop the Yb-doped fiber amplifier system. In the third chapter, an all-fiber, high-repetition-rate pulsed fiber power amplifier system with near diffraction-limited output by use of homemade large-mode-area fiber and a (2+1) ×1 multimode combiner is developed, and the effects of seed power on amplification performance are investigated systematically. For the seed power, there exists a range within which the pulsed fiber amplifier can operate safely and reliably at one certain pump power. Based on the above conclusion, 20 W average power amplified output is achieved with an acousto-optic Q-switched Nd:YVO4 solid laser as the master oscillator, and the repetition rate can be varied from 50 kHz to 175 kHz (typical pulse duration: 15 ns). In the fourth chapter, a narrow-linewidth master-oscillator fiber power amplifier system with homemade large-mode-area fiber is demonstrated. The system generates up to 7.3 W of single-frequency radiation at a wavelength of 1064 nm with 39% slope efficiency, and the amplified laser still keeps up the spectral characteristic of master oscillator. Based on this system, some fundamental characteristics including the output power characteristics, the emission spectrum characteristics, as well as the suppression of ASE are investigated in detail. In the fifth chapter, adopting the laser induced plasma shutter technique, an experimental and theoretical study on the wave clipping of 355 nm laser radiation is conducted in the first place. Five lenses with different focal length are chose to investigate the effects of the focal length of lens and the laser pulse energies on pulse compression, and it is found that the best result can be obtained with the focal length of 200 mm. Under the ionization of the Cu pinhole and the atmospheric breakdown, the pulse width can be further shortened to 2.11 ns. In addition, the measured atmospheric breakdown threshold induced by laser radiation at 355 nm is in agreement with theoretical data. Secondly, an experimental research on controlling the 532 nm pulse width is also conducted. By changing the optical difference between two paths, the 1.5~12 ns width-tunable 532 nm laser pulses have been obtained. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15231]  |
| 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 | 张芳沛. 全光纤化脉冲光纤放大器及脉冲整形技术研究[D]. 中国科学院上海光学精密机械研究所. 2008. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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