A high-power CW Yb:YAG slab laser amplifier with no adaptive optics correction has been experimentally established. At room temperature, the amplifier emits a power of 22 kW with an average beam quality (β) of less than 3 in 0.5 min. To our knowledge, this is the brightest slab laser without closed-loop adaptive optics demonstrated to date. In addition, an extracted power of 17 kW with an optical extraction efficiency of 33%, corresponding to a residual optical path difference of less than 0.5 µm, is achieved with the single Yb:YAG slab gain module. The slab gain module has the potential to be scalable to higher powers while maintaining good beam quality. This makes a high-power solid-state laser system simpler and more robust.

设计并制作了一种高灵敏度且制作简单的聚甲基丙烯酸甲酯（Polymethyl Methacrylate，PMMA）微球与单模光纤复合的湿度传感器。该光纤湿度传感器由PMMA微球与单模光纤构成。由于在微球中形成了法布里-珀罗腔，当外界环境湿度升高时，PMMA微球吸收水分子体积膨胀，导致法布里-珀罗腔的腔长增长，使得传感器干涉光谱的波峰（谷）发生红移，从而实现湿度传感。对所制作传感器的湿度响应、稳定性和重复性等进行了实验研究，实验结果表明：在30%~80%湿度范围内，该湿度传感器的灵敏度达173.36 pm/%RH，波长漂移随相对湿度变化呈良好的线性关系，其线性度达0.992 26，且具有良好的稳定性和重复性。该PMMA微球与单模光纤复合的湿度传感器具有灵敏度高、结构简单、无需镀膜且易于制作的优点。

在空间下行相干激光通信系统中，激光器的线宽大小会影响通信系统的性能，而窄线宽激光器能有效降低激光器线宽引起的激光器相位噪声，目前已经成为相干激光通信系统的首选。光信号在大气信道传输时，大气湍流会引起光信号强度和相位的波动，从而进一步影响系统的通信性能。针对上述问题，基于四相移键控(Quadri Phase Shift Keying, QPSK)通信系统的工作原理，进一步考虑窄线宽激光器线宽和大气湍流引起的光信号强度和相位的波动，给出了空间下行QPSK通信系统误码率模型。并基于该模型，数值仿真分析了窄线宽激光器对空间下行相干激光通信系统性能的影响。结果表明：大气湍流不仅严重影响系统性能，也会弱化激光器线宽对系统性能的影响。而对于大气湍流影响而言，其引起的相位波动要大于光强波动的影响。此外，随着通信速率增大，激光器线宽对于系统性能影响也会随之降低。文中对于空间下行相干激光通信系统的优化设计和调试具有一定的实际参考意义。

设计了一种高倍率的固体皮秒脉冲激光放大器，采用Nd:YAG板条作为激光增益介质。借助板条结构的角度选通结构，搭建了板条五通放大系统，实现了对注入皮秒脉冲激光的高倍率放大。种子源工作在脉冲模式，放大器泵浦源在连续模式工作。皮秒光纤激光器可以在不同的重复频率下工作，脉冲宽度为13.4 ps。种子光经过隔离和耦合系统之后，注入板条的单脉冲能量为25 nJ。当种子源工作重复频率为24.46 MHz时，板条放大器输出平均功率377 W，单脉冲能量15.5 μJ；当种子源工作重复频率为49.8 kHz时，板条放大器输出平均功率89 W，单脉冲能量1.8 mJ，峰值功率为134 MW，放大倍率达到7.2×10⁴。

报道了高效紧凑室温Yb:YAG板条全固态激光研究进展。建立了室温Yb板条激光动力学模型，分析了泵浦激光通量和注入激光亮度与光光效率的关系，以及板条边缘效应抑制方法。实验获得了输出功率22.3 kW、光光效率36%和光束质量优于2.4倍衍射极限的激光输出，为更高功率的Yb板条激光关键技术研究及开发小型化、轻量化、实用化的高功率激光器奠定了基础。

With the increasing demand for space optical communication security, space chaotic optical communication has attracted a great amount of attention. Compared with traditional space optical communication, a chaotic optical communication system has a higher bit error rate (BER) for its complex system design. In order to decrease the BER of space chaotic optical communication systems, we introduce two diffractive optical elements (DOEs) at a transmitting terminal (Tx). That is because the commonly used reflective optical antenna at Tx blocks the central part of the transmission beam, which leads to a great amount of power consumption. Introducing the DOEs into the optical subsystem at Tx can reshape the transmission beam from a Gaussian distribution to a hollow Gaussian distribution so that the block of the secondary mirror in the reflective optical antenna can be avoided. In terms of the DOE influence on communication quality, we give a BER model based on a minimum-shift-key (MSK) space uplink chaotic optical communication system to describe the DOE function. Based on the model, we further investigate the effect of the DOEs through analyzing the BER relationship versus basic system parameters based on the BER model. Both different mismatch conditions of chaotic systems and different atmospheric turbulence conditions are considered. These results will be helpful for the scheme design of space uplink chaotic optical communication systems.