Orbital-angular-momentum (OAM) multiplexing technology offers a significant dimension to enlarge communication capacity in free-space optical links. The coherent beam combining (CBC) system can simultaneously realize OAM multiplexing and achieve high-power laser output, providing substantial advantages for long-distance communication. Herein, we present an integrated CBC system for free-space optical links based on OAM multiplexing and demultiplexing technologies for the first time, to the best of our knowledge. A method to achieve flexible OAM multiplexing and efficient demultiplexing based on the CBC system is proposed and demonstrated both theoretically and experimentally. The experimental results exhibit a low bit error rate of 0.47% and a high recognition precision of 98.58% throughout the entire data transmission process. By employing such an ingenious strategy, this work holds promising prospects for enriching ultra-long-distance structured light communication in the future.

为了实现可见光波段多路不同波长激光的周期性闭环校正，设计了一种具有光束指向和位置偏差独立监测与调节的激光合束系统。首先，根据系统的应用需求，提出了合束系统的设计指标与整体合束方案。然后，在合束方案的基础上，建立了合束系统的光束控制模型，并通过数值仿真得到了合束系统光束控制的解算方法。闭环合束系统通过光束指向和位置监测装置分别实现合束激光指向偏差与位置偏差的独立监测，并根据监测结果进行光束调节装置控制量的解算；进而通过两维摆镜和一维平移台分别实现光束指向和位置偏差的独立高效调节。最后，采用两路不同波长的激光束，配合光束监测与调节装置，搭建了闭环合束模拟实验平台，对周期性闭环合束系统的合束效果进行了验证。实验结果表明：在长时间的工作过程中，两路激光均实现了与基准光路的精密合束，合束指向精度优于±7 μrad，位置精度优于±0.84 mm。本研究所组建的激光合束系统不仅具有合束精度高、校正速度快、光路扩展性强的优势，而且可实现激光束的周期性闭环校正，能够有效保证合束激光的长期工作稳定性。

将一个808 nm宽发射区半导体激光器应用于纵模选择束腰劈裂偏振合束外腔中，实现了高光束质量、高亮度和窄线宽的激光输出。所获激光输出功率为5.08 W，快慢轴光束质量M²=1.85×18.2，慢轴光束质量较自由运转激光器提高48%，输出激光亮度B=22.74 MW·cm^-2·sr^-1，是原激光器自由运转的1.3倍。所获激光光谱线宽为0.47 nm，压缩至原激光器自由运转的光谱宽度的0.14。

报道了一种基于光谱合束的Nd:YAG固体激光器双波长光源。系统由两个固体Nd:YAG脉冲激光器通过光谱合束组合而成，两个固体Nd:YAG脉冲激光器可独立工作，有利于输出脉冲的波长调谐、功率调节和相对延迟调整。通过光栅的色散特性以及输出镜的共同外腔反馈将各个激光器锁定在不同波长， 从而实现合束，获得的激光源中心波长锁定在1061.5 nm和1064.6 nm，两谱线中心间距为3.1 nm，组合光束的输出能量为173 mJ，组合光束的光束质量因子M²为2.8 × 2.2；两个Nd:YAG激光器独立工作的输出能量分别为94 mJ和92 mJ，在合束方向上的光束质量因子M²分别为2.7和2.1，在非合束方向上的光束质量因子M²分别为2.2和1.9；组合光束的输出能量为两个Nd:YAG激光器能量总和的93%，组合光束的光束质量因子与单个Nd:YAG激光束的光束质量因子M²基本相同。该双波长激光源满足波长间隔小、输出功率大小相近、同光轴等要求，在太赫兹波产生、测速激光雷达以及医疗仪器等应用领域具有重要作用。

The high-power mode-programmable orbital angular momentum (OAM) beam has attracted significant attention in a wide range of applications, such as long-distance optical communication, nonlinear frequency conversion, and beam shaping. Coherent beam combining (CBC) of an optical phased array (OPA) can offer a promising solution for both generating the high-power OAM beam and rapidly switching the OAM modes. However, achieving real-time phase noise locking and formation of desired phase structures in a high-power CBC system faces significant challenges. Here, an internal phase-sensing technique was utilized to generate the high-power OAM beam, which effectively mitigated thermal effects and eliminated the need for large optical devices. An OPA with six elements was employed for experimental demonstration. The first effective generation of over 1.5 kW mode-programmable OAM beam in a continuous-wave domain was presented. Moreover, the results demonstrated that the generated OAM beam could be modulated with multiple dimensions. The topological charge can be switched in real time from -1 to -2. Notably, this OAM beam emitter could function as an OAM beam copier by easily transforming a single OAM beam into an OAM beam array. More importantly, a comprehensive analysis was conducted on power scaling, mode switching speed, and expansion of OAM modes. Additionally, the system’s compact design enabled it to function as a packageable OAM beam emitter. Owing to the advantages of having high power and programmable modes with multiple dimension modulation in phase structures and intensity distribution, this work can pave the way for producing high-power structured light beams and advancing their applications.

为了分析光子灯笼用于光合束时的模式控制能力波动，建立算法提取光场灰度矩阵，使用数值计算结果替代角功率分布方差来分析光子灯笼模式控制能力随合束功率的波动。根据功率流方程与临近模耦合理论推导了算法的理论基础。从算法结构和灰度值提取精度参数两方面详细介绍灰度提取算法。通过对比复原图与原光场图，证明算法将光强分布情况转化成灰度值矩阵的数值准确性；最后，以自制的3×1光子灯笼在弱主动模式控制下的表现为例，分析其模式控制能力随合束功率变化导致的输出光质量与合束损耗的变化。实验结果解释了合束功率从0增加到270 mW时3×1光子灯笼的光合束损耗曲线斜率变化以及合束光最大高斯拟合度波动。算法能简单、快速地分析光子灯笼用于基模合束光制备时模式控制能力的波动情况，且环境敏感度低，光场功率分布提取准确率大于99%。

通过光纤激光光谱合成技术，可以打破单个光纤激光器输出功率受非线性因素制约的限制，实现更高功率的激光输出。通过梳理光谱合成技术的发展历程并分析其现状，对其原理及优劣势进行分析，结合自身研究，设计了一款便携式3路合成系统，通过设计及优化光纤激光器的放大结构，严格把控参与合束的子束光源的质量，将1055、1070和1085 nm三路高功率窄线宽光纤激光进行合束，对合成系统中采用的双色镜进行研究，对其膜系指标进行严格的设计，对高陡度截止滤光膜的设计方法以及制备工艺进行分析，对其热损伤规律及控制技术进行研究，优化整个合成系统，最终实现合成功率9650 W的高功率激光输出，合成效率92%，光束质量M²为1.7，并对未来双色镜光谱合成进行了展望。