【作者】 牛林全；

【导师】 孙传东；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 光学工程， 2013， 博士

【摘要】 激光器是激光雷达的核心，其性能指标直接决定了激光雷达的主要技术参数。基于脉冲测距体制的激光三维成像雷达是激光雷达的重要成员之一，要求激光器需具有高重复频率、窄脉冲宽度、高光束质量、高效率和体积小、重量轻等特点。本论文针对激光三维成像雷达的应用，对半导体激光器（LD）泵浦的被动调Q微腔激光器和基于主振荡功率放大（MOPA）掺Yb³⁺脉冲全光纤激光器进行了研究，并研制出MOPA脉冲光纤激光器工程样机，在激光三维成像雷达上进行了应用。本论文的主要工作和创新结果包括以下几个方面：1．基于Cr⁴⁺:YAG被动调Q速率方程，推导得出了激光脉冲输出特性相对于两个无量纲常变量z和α的函数；利用相应函数，对脉冲能量、峰值功率、脉冲宽度、激光效率等激光脉冲参数特性进行数值模拟和理论分析，为被动调Q微腔激光器的设计提供了理论指导。2．搭建了LD泵浦Nd:YAG/Cr⁴⁺:YAG被动调Q微腔激光器系统，实现稳定调Q激光脉冲输出。并针对在实验研究过程中观察到的双脉冲时间波形现象进行了理论分析和实验研究，发现双脉冲时间波形与激光空间模式分布存在着对应关系，经分析得到了激光器双纵模的振荡是导致这种现象的直接原因。提出了实际应用中避免此现象的解决方案并进行了实验验证。3．建立了基于MOPA结构的高峰值功率纳秒掺Yb³⁺全光纤激光器系统，实现1064nm脉冲宽度<1ns¹0ns可调、重复频率10kHz¹MHz可调、峰值功率为123kW的稳定单横模激光脉冲输出。这种峰值功率高、可控性强、稳定性好、可靠性高的全光纤激光器系统，对激光三维成像雷达整机性能的提升有极大的促进作用。4．研制出高峰值功率脉冲全光纤激光器工程样机应用于激光三维成像雷达系统，进行三维成像实验，激光三维成像雷达在40o×40o的视场范围内，获得了距离分辨率1.86cm，距离精度±7.5cm，角分辨率0.009°的激光三维扫描图像，成像实验结果表明研制的激光器可满足三维成像雷达的高分辨率成像需求。同时通过激光雷达系统的长期室内和户外工作验证了激光器的可靠性和稳定性。更多还原

【Abstract】 Laser is the core of LIDAR, which has a great impact on the key parameters ofLIDAR system. And3D imaging LIDAR based on the pulse ranging mechanismplays an important role in the system of LIDAR, which is an active device in that itcarries its own transmitter and does not depend on ambient radiation. As thetransmitter of3D imaging LIDAR, Laser must be required to some specialcharacteristics, such as high repetition rate, narrow temporal duration, excellentbeam quality, high efficiency, robust, and so on. This dissertation focuses on twokind laser technologies for the applications of3D imaging LIDAR: a passivelyQ-switched microchip laser and Yb³⁺-doped pulse all-fiber amplifier based onMOPA structure. Meanwhile, the practical sample of pulsed all-fiber laser has beensuccessful developed and applied to the3D imaging LIDAR system.The main research works and innovations of this dissertation are summarizedas follows:1. Basing on the rate equations of Cr⁴⁺:YAG passively Q-switched laser,the output characteristics of pulsed laser as a function of twodimensionless variables are derived. According to the relationships, thelaser parameters including pulse energy, peak power, pulse width, andlaser efficiency are acquired by means of theoretical analysis andnumerical simulation. It is useful to define the laser parameters whenthe anticipant pulse energy.2. Single-and dual-pulse oscillation delivered from a LD pumpedpassively Q-switched Nd:YAG/Cr⁴⁺:YAG microchip laser has beeninvestigated under the different pump levels. And the dual-pulse waveform consists of a main pulse and a satellite pulse with respectiveintensities and optical spectra. Experimental results indicate that thedual-pulse emission results from double longitudinal mode oscillation.The preponderant oscillating mode gives birth to the main pulse, andthe other oscillating mode corresponds to the satellite pulse.3. A compact high power nanosecond all-fiber MOPA system based onYb³⁺-doped fiber amplifier system is established. Laser pulse withstable wavelength, controllable repetition rate and adjustable pulseduration is obtained. And the peak power is up to123kW. As thetransmitter of3D imaging LIDAR, it is benefit to improve thecapabilities of the entire system. Temporal duration and repetition rateof the laser pulse can choose flexible according to the different practicalapplication.4. The proposed fiber amplifier is used as the laser source ofthree-dimension （3D） imaging LIDAR system, which achieves thefunction of3D imaging and gives the scanning imaging results. Theperformance of the laser is verified. The imaging results show that theproposed fiber amplifiers with high peak power have the excellentreliability and stability and are very suitable for3D imaging LIDARsystem. The3D scanning image has the ranging resolution of1.86cm,the ranging accuracy of±7.5cm, and the angular resolution of0.009°.更多还原