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题名	全光纤纳秒脉冲激光放大器特性研究
作者	周翠芸
学位类别	博士
答辩日期	2013
授予单位	中国科学院上海光学精密机械研究所
导师	陈卫标
关键词	雷达光源 全光纤 主振荡-功率放大 高能量 非线性效应
其他题名	Study on all fiber nanosecond pulse fiber amplifier
中文摘要	高能量脉冲光纤激光器由于其在光束质量、体积、转换效率、散热性能及稳定性等方面的优势，在材料加工、激光雷达、军事及医学领域具有广泛的应用。本论文主要针对激光雷达所需要的激光雷达光源，对高能量纳秒量级掺镱全光纤放大器进行了理论与实验研究。 第一章综述了国内外测距、测绘雷达激光光源的发展现状及未来发展趋势。然后综述了不同脉冲宽度掺镱光纤激光器的发展现状。 第二章介绍了掺镱光纤的吸收发射特性，对光纤放大器中的增益特性进行理论模拟，并且对光纤放大中常见非线性效应进行了分析。首先根据光纤速率方程，利用有限差分的方法对光纤放大中的稳态及动态特性进行理论模拟。分析了光纤放大器中反转粒子数，前向与后向ASE的分布，给出了在连续信号注入下信号功率沿光纤的分布特性。并对脉冲信号在光纤中的传输特性进行了仿真模拟。接下来，对光纤放大器中的非线性效应进行理论与实验研究，分析了受激拉曼散射、受激布里渊散射、自相位调制与超连续谱的产生机理与抑制方法。该工作为研究脉冲光纤放大器提供了理论指导与依据。 第三章对全光纤放大器中的关键器件特性进行了分析。主要包括：脉冲调制LD的调制特性及其啁啾特性对放大器的影响；波长锁定LD的不同光栅锁定原理，对其输出光谱稳定性进行了实验分析；光纤隔离器的基本原理，隔离光谱特性与温度特性；波导型WDM与镀膜型WDM的波分复用特性；泵浦耦合器的基本原理及其热效应。深入研究各类器件的性能与局限性有助于开展光纤放大器的实验。 第四章分别对1064 nm与1030nm高重复频率全光纤纳秒脉冲放大器进行了实验研究。首先对1064 nm高重复频率全光纤放大器进行了实验研究，实现了单脉冲能量大于90 μJ，脉冲宽度小于10 ns，重复频率50 kHz的1064 nm全光纤脉冲放大器，并进一步对激光器在随机振动前后与真空环境下的性能进行实验验证。接着对1030 nm的MOPA结构高重复频率全光纤纳秒脉冲放大器进行了实验研究。在重复频率为50 kHz时，输出激光平均功率为5.07 W，相应的斜率效率为67%，脉冲宽度6.53 ns，脉冲峰值功率为16.08 kW，激光中心波长1029.49 nm。最后，利用相同掺镱光纤三级放大结构，两级预放采用单模光纤，主放采用30/250光纤，对1030nm与1064nm两个波段的增益特性进行了对比。实验结果显示，1030nm由于处于掺镱光纤的发射峰，其增益特性具有明显的优势。 第五章对1064 nm的高能量主振荡-功率放大结构全光纤脉冲放大器进行了实验研究。在连续泵浦下，实现了脉冲能量1.22 mJ，脉冲宽度3.4 ns，重复频率为1 kHz的脉冲激光输出，激光峰值功率达到0.38MW。在脉冲泵浦下，泵浦脉冲宽度设为1 ms，实现了脉冲能量5.97 mJ，脉冲宽度16 ns，重复频率为50 Hz的脉冲激光输出，激光峰值功率大于0.408 MW。最后，对于连续1 kHz状态与1 ms脉冲泵浦状态下的脉冲信号光与连续ASE基底的信噪比进行了实验分析。
英文摘要	High energy pulse fiber lasers are highly desirable in applications of material processing, lidar, defense and medicine due to their distinguished superiority in beam quality, volume, efficiency and robustness. In this paper, theoretical and experimental study on high energy nanosecond pulse Yb-doped fiber amplifiers for lidar transmitter is presented. In the first chapter, development of the ranging finder and mapping lidar are reviewed. The development of pulse Yb fiber lasers and amplifiers with different pulse width are presented. In the second chapter, the absorbing and emitting characteristics of Yb-doped fiber are reviewed. The gain characteristics of fiber amplifiers are simulated and the nonlinear effects in fiber are analyzed. The steady and dynamic characteristics of Yb-doped fiber amplifier are analyzed by transmission equations. The upper-level population densities, the forward, backward amplified spontaneous emission (ASE) and the amplified signal are analyzed. At last, the stimulated Raman scatter (SRS), the stimulated Brillouin scattering (SBS), the self-phase modulation (SPM) and supercontinuum generation in fiber are analyzed. In the third chapter, the indispensable key components in fiber amplifiers are analyzed. The principle and characteristic of the modulated pulse LD, the wavelength locked pump LD with grating, the in-fiber isolator, the wavelength division multiplexing (WDM）and the pump/signal combiner are analyzed. In the fourth charter, High repetition rate pulsed all-fiber master-oscillator power-amplifier（MOPA） lasers with center wavelength of 1064 nm and 1030 nm are developed. The 1064 nm laser achieved an average power of 4.7 W at a repetition rate of 50 kHz with pulse width of less than 10 ns. The characteristics of output laser under random vibration and vacuum environment are studied. Next, characteristics of the 1030 nm all-fiber amplifier are studied experimentally. At the repetition rate of 50 kHz, a maximum output power of 5.97 W with pulse width of 6.53 ns at center wavelength of 1029.49 nm is obtained. The corresponding peak power is 16.08 kW and slope efficiency is 67%. By the same structures of three-stage amplifiers, both the amplification characteristics of 1030 nm and 1064 nm amplifiers are compared. The result shows that the 1030 nm amplifier had an advantage for it is the emitting peak of Yb-doped fiber. In the fifth charter, A high pulse energy all-fiber master-oscillator power-amplifier （MOPA） laser system with and low repetition rate is developed. By cw pump, maximum output pulse energy of 1.22 mJ with pulse width of 3.4 ns is obtained in 1 kHz repetition rate. The corresponding peak power is 0.38 MW. By 1 ms pulse pumping duration, maximum output pulse energy of 5.97 mJ with pulse duration of 16 ns is obtained in 50 Hz repetition rate. The corresponding peak power reaches 0.408 MW. Finally, the signal-to-noise ratios under cw and pulse pump are analyzed experimentally.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15761]
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	周翠芸. 全光纤纳秒脉冲激光放大器特性研究[D]. 中国科学院上海光学精密机械研究所. 2013.

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