小型高重复频率全固态激光器关键技术研究
文献类型：学位论文
| 作者 | 冯宇彤 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 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 | 被动调Q，声光调Q，电光调Q，激光雷达，全固态，双包层光纤 |
| 其他题名 | Research on the Key Technology of Compact High Repetition Rate All-Solid-State Lasers |
| 中文摘要 | 高重复频率、窄脉冲宽度输出是下一代激光雷达发射光源的主要技术指标，本论文瞄准这一需求，开展高重复频率、窄脉冲宽度全固态激光器关键技术研究，讨论了不同技术路线的原理和实现方式，通过实验摸底，初步判断了不同技术路线的输出特性，得到了相关实验结果，总结了不同激光器的优缺点，指出了不同类型激光雷达发射光源的适用技术方案。论文第一章简要回顾了空间激光雷达的发展历史，重点讨论了空间激光雷达发射光源的应用需求。 第二章介绍了以Nd:YAG晶体为激光工作介质，Cr4+:YAG晶体为被动Q开关，采用 “三明治”结构的被动调Q技术方案，实现了重复频率最高可达20kHz、脉冲宽度小于2ns、脉冲能量最高100μJ的激光输出。在输出激光重复频率约7kHz，脉冲能量约70μJ时，测量了脉冲宽度值为1.12ns，光束质量因子为M2x=1.66，M2y=1.54。 第三章介绍了以Nd:YVO4晶体为激光工作介质，采用声光调Q技术，实现了重复频率~100kHz量级的输出。在泵浦功率5.7W、重复频率150 kHz时，得到了平均输出功率2.49W，脉冲宽度15.3ns的激光输出。在平均输出功率约2W时，测得光束质量因子M2x=1.29，M2y=1.23。为了提高输出激光的单脉冲能量，以上述激光器为信号光光源，采用掺Yb3+离子的双包层石英光纤放大器，实现了平均功率20W、重复频率150kHz、脉冲宽度15ns、光束质量因子M2=1.24的激光输出。为了进一步压缩信号光脉冲宽度，采用声光Cr¬4+:YAG主被动双调Q方式工作，在重复频率为125kHz时，获得了平均功率440mW，脉冲宽度7ns的输出脉冲。 第四章介绍了以Nd:YVO4晶体为激光工作介质，采用RTP电光Q开关，实现了重复频率30 kHz、脉冲宽度7.8 ns、最大平均输出功率6.7W，相应峰值功率28.6 kW的激光输出。在平均输出功率约2W时，测得光束质量因子为M2x=1.7，M2y=1.5。 第五章介绍了采用主振荡功率放大（Master Oscillator Power Amplifier，MOPA）结构，对电脉冲调制的激光二极管输出的信号光进行了三级放大，其中前两级采用掺Yb3+离子的单模双包层光纤放大，第三级采用掺Yb3+离子的双包层石英光纤放大。对不同重复频率下激光二极管驱动的性能进行了测试，并在重复频率~100kHz时对系统的放大性能进行了测试，在重复频率125kHz时，得到了脉冲宽度10ns，平均功率2.5W的输出激光。 本论文系统地开展小型高重复频率全固态激光器的技术研究，得到不同体制激光器的输出特性，为研制各类激光雷达的光源奠定了良好的技术基础。 |
| 英文摘要 | High repetition rate and narrow pulse width are the main characteristics of next generation space-based Lidar transmmiter.To meet these requirements, research on the key technology of compact all-solid-state lasers with high repetion rate and narrow pulse width output are carried on. Principles and experimental setup of different technical solutions are discussed. The laser beam specifications are experimentally stydied. Analysing the results, the merits and drawbacks of different lasers are summarized. The most suited laser transmiter for different lidar is suggested. In Chapter 1, the brief history of space-based lidar is reviewed, and the lidar transmitter requirements are mainly discussed. In Chapter 2, a passively Q-switched laser is demonstrated with highest pulse repetition rate of 20 kHz, pulse width of less than 2ns, and pulse energy of up to 100μJ. The lasing material is Nd:YAG crystal,and the passive Q-switch is Cr4+:YAG crystal. All crystals are diffusion bonded in sandwich structure. When the laser is operating with the pulse repetition rate around 7 kHz and pulse energy around 70μJ, the pulse width and beam quality (M2) factor are measured as 1.12ns and M2x=1.66, M2y=1.54. In Chapter 3, an Acousto-optic (AO) Q-switched laser is demonstrated with pulse repetition rate of ~100kHz class. The experiment is based on diode end-pumped Nd:YVO4. Output power of 2.49 W is achieved with pumping power of 5.7 W. The pulse repetition rate of 150kHz, and the pulse width of 15.3ns. The M2 factor is measured as M2x=1.29, M2y=1.23 under the condition of about 2W output power. In order to achieve a much higher pulse energy, signal light from the AO Q-switched laser is amplified in a a power amplifier of Yb-doped double-cladding fiber.Finally, the output power of 20W, pulse repetition rate of 150kHz, pulse width of 15ns,and the M2 factor of M2=1.24 are achieved. In order to compress the pulse width of signal light, AO and passive double Q-switch is adopted.The output power of 440mW,the pulse width of 7ns, and the pulse repetition rate of 125kHz are achieved. In Chapter 4, an Electro-optic (EO) Q-switched laser is demonstrated with pulse repetition rate of 30kHz, pulse width of 7.8ns,the highest output power of 6.7W, and the corresponding peak power of 28.6kW. The lasing material is Nd:YVO4 crystal. The EO Q-switch is RTP crystal. The M2 factor is measured as M2x=1.7, M2y=1.5 when the output power is about 2W. In Chapter 5, the signal light generated by a modulated laser diode is amplified by three amplification stages based on Master Oscillator Power Amplifier (MOPA) architecture. In the first two stages, the Yb-doped single mode double-cladding fiber is used. The Yb-doped double-cladding fiber is used in the third stage. The laser diode driver is tested under different pulse repetition rate. The amplifier is tested under pulse repetition rate of around 100kHz. At the pulse repetition rate of 125kHz, output power of 2.5W and pulse width of 10ns are achieved. The main researches in this dissertation are synthetically studying all compact high repetition rate all solid-state laser. The performances for the different configuration solid-state laser are obtained. It is greatly benefit for the design and developing laser sources for different lidars. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15266]  |
| 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 | 冯宇彤. 小型高重复频率全固态激光器关键技术研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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