两个光纤激光器的相干合成及其闭环控制

 采用了并联主振荡-功率放大的相干合成方案，实现了光纤激光器的相干叠加。主振荡的输出光通过保偏光纤分束器分为两路，其中一路加入保偏光纤相位调制器以实现闭环控制，两个保偏光纤放大器分别对两路输出光进行放大，放大后的输出光再由一个2×2的保偏光纤耦合器会聚相干。合成输出光的一部分通过光电转换后进入数据采集卡，采集卡将采集到的数据送入计算机进行实时处理并将得到的反馈信号作用于相位调制器，相位调制器实时控制两路信号的相位差，从而实现整个实验系统的相干合成输出。系统实现闭环控制后，两路光纤放大器的相位差为2π的整数倍，输出光强始终保持最强。该相干合成方案简单易行，性能稳定。

Coherent combining and closed loop controlling of two fiber lasers

The master oscillator, power amplifier arrangement was experimentally investigated. The master laser was divided into 2 paths by a fiber beam splitter, and the two amplified beams were combined by a fiber coupler. A sample of the combined beam was relayed to a PC based on phase detection system which comprised photodiodes, preamplifiers and an A/D card. Phase corrections were calculated using Labview and the feedback voltages were applied to the phase shifters directly from analogue output channels. Coherent combining of two fiber lasers array was realized. After the control loop was turned on, optical path difference of two fiber amplifiers was modulo 2π, the output intensity was kept at the status of stable high brightness.