【作者】 赵晓萌；

【导师】 陈金宝；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2008， 硕士

【摘要】 激光相干合成技术是实现高功率高亮度激光系统的重要技术途径,主动控制的MOPA方案相干合成由于其并联放大器数量及功率理论上没有上限而有着其技术上固有的优势。相位检测与控制技术是MOPA方案相干合成的核心,本文较为系统地对MOPA相干合成相位控制系统进行了理论分析与仿真实验,基于反馈控制系统模型得出了优化的控制系统传递函数。分析了光纤放大器相位噪声的特性及产生机理,模拟产生了与真实放大器相位噪声频谱类似的噪声,对比了常用的光学外差探测及解调技术,对适用于MOPA相位控制系统的多光路混频技术进行了理论推导与数值模拟,并提出了非解调信号处理方案。基于反馈控制理论建立了MOPA相位检测与控制系统模型,推导出优化的控制函数形式；对系统闭环状态相位噪声残差随系统参数的变化进行了数值模拟,得出优化系统参数,分析了该控制函数作用下系统的开环及闭环幅频特性和控制带宽,以及系统控制性能。对优化的控制系统进行相位检测与控制仿真实验,分别使用单频信号和模拟放大器噪声作为相位扰动,检验相位控制系统性能,并对非解调信号处理方案的控制系统稳态、暂态性能进行仿真。本文为MOPA相干合成相位控制系统的性能提供了理论分析方法,并为其优化设计提供了理论指导,对实现大功率激光放大器相干合成具有重要的参考价值。更多还原

【Abstract】 Coherent combing of fiber lasers is effective to achieve both high power and high brightness. Compared with other programs of coherent combing, Master Oscillator Power Amplifier (MOPA) is predominance in technology for its unlimit in increasing the amount of fiber amplifiers theoretically. Phase detection and control is the key of coherent beam combining based on the program of MOPA. This paper investigates the control system through theoretical analysis and emulator experiments. And optimum transfer function of the control system is obtained based on the negative-feedback model.The characteristic and mechanism of the phase noise of fiber amplifiers are analyzed, and the emulational phase noise spectrum of a fiber amplifier is concluded. Several programs of heterodyne detection and demodulation in common use are compared. The technology of multipass frequency mixing applicable for the phase control system based on the program of MOPA is deduced theoretically and simulated numerically, and the signal processing program of non-demodulation is presented.A model of the phase detection and control system is constructed based on the theory of feedback control, and the optimum control function is deduced. The relationship between the closed loop output phase residual and the system parameters is simulated numerically, and the optimum system parameters are obtained. The open loop and closed loop amplitude frequency response characteristics, control band width and control performance under the optimum system parameters are analyzed.The phase detection and control emulator experiments are put into effect. Single-frequency signal and the emulational noise are used as phase disturbance respectively to examine the performance of the phase control system. The steady-state and transient-state behavior of the control system based on the non-demodulation signal process program is emulated.The research of this paper supplies theoretical methods to analyze the performance of the phase control system based on the program of MOPA and provides theoretical instruction for system optimum design.更多还原