主要介绍了近年来光纤激光相控阵相干合成技术的发展现状，总结了中国科学院光电技术研究所在这方面的最新研究成果，包括基于振幅调制的光纤激光相控阵相干合成能力优化、光纤激光相控阵实现收发一体相干合成、光纤激光相控阵的目标在回路相干合成、光纤激光相控阵在大气湍流下实现耦合接收光束的共相合束、基于多孔径波前探测的相干合成方法、基于自适应光纤准直器和微透镜阵列的光束大角度高精度连续寻址扫描等。以上研究工作将促进光纤激光相控阵技术朝向更多单元、更高功率、更远距离等方向演进，并推动其与激光大气传输、空间激光通信、自适应光学等理论和应用的结合与发展。

甚多孔径光纤激光阵列是构建大功率、高光束质量、等效光学大口径的新兴技术手段之一，而基于相位精密操控实现阵列激光束的共相，乃至快速、灵活的光束偏转是当前光纤激光相控阵技术面向应用的关键。本文将光学相控扫描技术与光纤激光相干合成系统相结合，研究了甚多孔径光纤激光相控阵的光束扫描特性，通过改变准直激光阵列相邻子孔径间的相位差实现了光束扫描。对比分析了19、133、703孔径光纤激光相控阵的远场扫描光束形态分布特征，据此定义并计算了扫描极限范围。该结果为后续开展光纤激光相控阵在长程传输下精确指向控制实验研究提供了理论依据。

A self-comparison method with closely interleaved switching states is analyzed and used to evaluate some type-B uncertainties of an Rb87 atomic fountain clock. Free from additional frequency reference, the method can be applied to a running fountain to reach a precision beyond its uncertainty. A verification experiment proves an uncertainty of 9.2×10 16 at an averaging time of 242500 s. Further, the method is applied to measure light shift, and no visible relative frequency shift is found in the fountain within the uncertainty of 2.1×10 15. When applied to the evaluation of a cold collisional shift, the result gives a 2.2×10 15 shift with a 9.5×10 16 uncertainty.

We report a locking mode in which the local oscillator (LO) is locked to an atomic fountain and calibration of the residual frequency drift (RFD). In this running mode, the locked LO outputs a standard frequency signal, and a short-term fractional frequency stability of 2.7×10 13τ 1/2 is achieved. Due to the frequency drift of the LO in free running mode, a systematic frequency bias, or RFD, exists after being locked by the atomic fountain. We analyze and measure the RFD with a value of 3(2)×10 16. A sectionalized post-process method is adopted to calibrate the RFD.