College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha, 410073, China.
Sci Rep. 2017 May 19;7(1):2199. doi: 10.1038/s41598-017-02118-z.
In this paper, we experimentally validate a tiled-aperture conformal projection system with the largest array filling factor and element beam truncation factor to the best of our knowledge. The conformal projection system, which is made up of a hexagonal adaptive fiber-optics collimator (AFOC) array with the proximate ideal intensity distributions, is fabricated and the performance of output beam is tested and evaluated properly and carefully. Both of the active phase-locking control and precise tip-tilt control are implemented successfully in the CBC of the hexagonal seven-beam-array. Experimental results show a large energy proportion (47%, which increases by over 10% comparing with the previously demonstrated largest value) in the central lobe is achieved and the residual phase error is lower than λ/27. When the AFOC array performs, the precise tilt control makes the combining beams overlap well and the average normalized metric value is improved from 0.336 without control to 0.947 with both of active piston and tip-tilt phase controls while the fringe contrast increases from 19% to more than 91% correspondingly. This work presents a promising structure for the achievement of large energy proportion in the central lobe in high power fiber laser CBC systems.
在本文中，我们实验验证了一个具有最大填充因子和单元光束截断因子的拼接孔径共形投影系统，据我们所知，这是迄今为止的最佳结果。该共形投影系统由具有近似理想强度分布的六边形自适应光纤准直器（AFOC）阵列组成，我们对其进行了制造，并对其输出光束性能进行了适当和仔细的测试和评估。在六边形七光束阵列的 CBC 中，我们成功实现了主动锁相控制和精确的俯仰倾斜控制。实验结果表明，在中央叶实现了较大的能量比例（47%，比之前展示的最大值增加了 10%以上），残余相位误差低于λ/27。当 AFOC 阵列工作时，精确的倾斜控制使组合光束很好地重叠，平均归一化度量值从无控制时的 0.336 提高到主动活塞和俯仰倾斜相位控制时的 0.947，同时条纹对比度从 19%提高到 91%以上。这项工作为实现高功率光纤激光 CBC 系统中中央叶的大能量比例提供了一种很有前途的结构。
